INTRODUCTION

Fractures of the shaft of the femur are a major cause of morbidity and mortality in patients with lower extremity injuries. With the exception of infractions through pathologic bone, violent forces are needed to create these fractures. Fractures of the shaft of the femur can be life-threatening from an open wound, fat embolism, adult respiratory distress syndrome, or resultant multiple organ failure.

    Even with survival of the initial trauma, many patients suffer major physical impairment as a result of these fractures. Functional loss does not arise from any inherent problem with fracture healing. This longest and strongest of the human bones possesses a well-vascularized, thick envelope of muscles that predictably promotes rapid fracture healing in most patients. Rather, disability usually results from fracture shortening, fracture malalignment, or prolonged immobilization of the extremity by traction or casting in an attempt to maintain fracture length and alignment during the early phases of healing. Even minor degrees of shortening and malalignment can eventuate in a limp and posttraumatic arthritis. Therefore, the art of femoral fracture care is a constant balancing of the often conflicting goals of anatomic alignment and early functional rehabilitation of the limb.

    The history of femoral fracture management reflects this underlying dilemma. Before the turn of the century, most treatments involved splinting or encasing the thigh with a variety of materials. The early use in ancient civilizations of wood splints wrapped with sinews of leather or fibrous plants110 and various fabrics encased with wax2 gave way to bandages stiffened with gum324 and, more recently, fabrics hardened with plaster of Paris.212 None of these materials alone, however, offered sufficient strength to maintain fracture alignment. The advent of skeletal radiography at the end of the 19th century clearly demonstrated the mechanical inadequacies of these traditional treatments.

    In 1907, Steinmann334 introduced his first traction pin apparatus, and in 1909, Kirschner213 proposed his alternative traction design featuring a small-diameter wire placed under tension (Fig. 27-1). The application of the Thomas splint, which provides countertraction on the leg through its ring, allowed for improved control of the traction forces. Modifications in the Thomas splint since its first clinical use during World War I for the transport of casualties with femoral fractures have enhanced the mobility of both the patient and the joints of the injured leg. The basic traction techniques, however, have remained unchanged for nearly a century.

    Early attempts at internal fixation of femoral fractures were fraught with serious complications, especially infection and implant failure. The concept of intramedullary fixation was applied early to fractures of the femoral shaft. Although isolated cases of intramedullary nailing were reported early in the century, the modern era of nailing was ushered in by Küntscher.182 His 1939 presentation to the Medical Society of Kiel of his first case of intramedullary fixation using a V-shaped cross-section-designed nail was followed 4 months later by his report of 12 additional cases to the German Surgical Society in Berlin. The initial response to his work was unfavorable. Many of his colleagues condemned the concept as 'nonphysiologic' and predicted a disastrously high nonunion rate. The excellent clinical results, however, resulted in the wide dissemination of the technique in Europe during World War II and in North America after the war.

    The Küntscher technique for femoral nailing has been refined and embellished over the last 50 years. Changes have included alterations in both the cross-sectional and longitudinal design of the nail, modifications in the technique of its insertion, the use of fluoroscopy for closed nailing, and innovations in instrumentation. Recent improvements in the mechanical properties and design of intramedullary nails have stimulated their use in increasingly more complex fractures.

SURGICAL ANATOMY

The femoral shaft is essentially a tubular structure. It flares posteriorly along the linea aspera, where its cortical thickness is the greatest. The linea aspera (Latin for rough line) serves as a site of attachment for the fascia. The proximal and distal metaphyseal widening of the tube in the subtrochanteric and supracondylar regions of the bone results in stress concentration at these levels. Pathologic fractures, especially in the elderly, commonly occur at these metaphyseal-diaphyseal junctions. The most prominent feature of the femoral shaft is its anterior bow or antecurvature. Wide individual variations exist in the magnitude of this bow. The normal physiologic bow often is increased in certain pathologic conditions, such as fibrous dysplasia and Paget disease. The clinical importance of the antecurvature of the shaft has long been appreciated. Most modern intramedullary nails are prebent, with an average 10- to 12-mm-high arch at their midpoints to accommodate the bow. Straight, stiff implants used in the early years of femoral nailing straightened the shaft, leaving a posterior gap at the fracture site. Straight nails also resulted in fracture comminution and occasionally even perforation of the anterior cortex.

    The femoral shaft is subjected to major musculature forces that deform the thigh after a fracture (Fig. 27-2). The action of the gluteal musculature that inserts on the greater trochanter abducts the proximal femur after subtrochanteric and high proximal shaft fractures. These proximal-third fractures of the shaft also are flexed and externally rotated by the action of the iliopsoas muscle's pull on the lesser trochanter. The adductor muscles span most shaft fractures and exert a strong axial and varus load to the bone. Distal shaft fractures, especially those extending into the supracondylar region, tend to angle into flexion through the pull of the gastrocnemius muscle. Adjustments in traction or bracing devices are needed to counteract these deformity muscular forces.

Fig.27-2 Fortele musculare deformatoare de pe femur: A.abductori; B.iliopsoas; C.adductori; D.originea gastrocnemian.Fortelor de angulare mediale li se opun fascia lata (E). Potentiale zone de leziune vasculare sunt hiatul adductorilor si perforantele din artera femurala profunda.

    The quadriceps musculature and hamstring musculature function within well-defined compartments (Fig. 27-3). The thigh contains three distinct fascial compartments. The anterior compartment encases the quadriceps femoris, sartorius, iliacus, psoas, and pectineus muscles, as well as the femoral artery and vein, femoral nerve, and lateral femoral cutaneous nerve. The medial compartment contains the gracilis, adductor longus, adductor brevis, adductor magnus, and obturator externus muscles, along with the profundus femoris artery, obturator artery and vein, and obturator nerve. The posterior compartment includes the biceps femoris, semitendinosus, semimembranosus, and a portion of the adductor magnus muscles, as well as branches of the profundus femoris artery, sciatic nerve, and posterior femoral cutaneous nerve. The thick lateral intermuscular septum divides the anterior and posterior compartments. The medial and posterior intermuscular septa are much thinner. Because of the high volume of these three compartments, compartmental syndrome of the thigh is much less common than that of the leg. Severe bleeding into one or more compartments is necessary to elevate the compartment pressure above the critical level.342 The distinction between the normal swelling after a shaft fracture and an early thigh compartmental syndrome often requires the measurement of intracompartmental pressures.

    The femur possesses a rich vascular supply. The arterial supply is derived mainly from the profundus femoris artery. Although some anatomic variations occur in humans, the nutrient vessel usually enters the bone proximally and posteriorly along the linea aspera. In his cadaver dissections of adult femora, Laing184 found that there was usually only a single nutrient vessel, and in none of his specimens did a major artery enter the lower third of the shaft. The maximum number of nutrient vessels that he noted in any femur was two. After penetrating the posterior cortex, the nutrient vessel arborizes proximally and distally to provide the endosteal circulation to the shaft.

Fig. 27-3 Sectiune transversala coapsa cu evidentierea celor trei compartimente

    Most of the periosteal vessels also enter the bone along the linea aspera. They align themselves perpendicularly to the cortical surface with few, if any, traversing along the periosteum longitudinally. Because of this perpendicular orientation of the periosteal vessels, they seldom are extensively stripped during fractures except during severe open injuries. Preservation of this periosteal circulation is a high priority during any open surgical procedure on the femur. Damage to the vessels is minimized by avoiding any soft-tissue stripping of the linea aspera. Although broad bands or tapes around the shaft should be shunned, simple cerclage wires alone will not devascularize the cortex because there is little or no longitudinal flow in the periosteal vasculature. Severe traumatic or operative damage to the periosteal vessels will result in delayed fracture healing.

    The microcirculation of the femur is similar to that of the diaphyses of other long bones. Although their contribution is controversial, endosteal vessels are thought to provide (under normal physiologic conditions) circulation to the inner two thirds to three quarters of the cortex.281,282,283 They anastomose with the scattered blood vessels of the periosteal circulation. The normal blood flow is centrifugal, although some blood returns to the large venous sinusoids of the medullary canal. The periosteal arteries normally provide flow limited to the outer one quarter of the cortex, especially posteriorly along the linea aspera at the site of their penetration into the bone.

    After diaphyseal fractures, the circulatory pattern is radically altered. In the rare nondisplaced fracture of the shaft, the endosteal supply can be relatively undisturbed and remain dominant. With most fractures, however, the major fragments displace, resulting in complete disruption of the medullary vessels. Proliferation of the periosteal vessels is the paramount vascular response to the fracture. The rapidly enhanced periosteal circulation is the primary source of cells and growth factors for healing. The medullary supply eventually is restored later in the healing process. Once reconstituted, the medullary circulation again gains dominance.

    The effect of intramedullary nails on the diaphyseal circulation has been studied extensively by Rhinelander and colleagues.283 Intramedullary nails have the theoretic disadvantage of preventing restoration of the normal endosteal flow during fracture healing. Cylindrical or tubular nails that completely fill the canal can have a deleterious effect on reconstitution of the medullary arterial and venous flow. The impedance of venous outflow may have as profound an effect on blood flow to the fracture as any damage to the arteries. Fortunately, no commercially available nails possess such a circular cross-sectional design. Cloverleaf, diamond-shaped, fluted, flanged, delta, and other nails provide potential space for neovascularization of the endosteum. Restoration of endosteal vessels occurs quickly after fracture when such nails are used. During the early stages of fracture healing, the periosteal circulation appears to be able to maintain vascularity to the outer half of the cortex, even with complete filling of the canal with an intramedullary nail.283 The rapid healing and remodeling of fractures after closed intramedullary nailing attest to the abundant collateral circulation to the femoral shaft.

    Nearly all open procedures on the femoral shaft should be performed through a longitudinal lateral incision. For rare specific indications, the distal metaphyseal-diaphyseal junction can be approached medially by elevation of the vastus medialis obliquus muscle. The anterolateral approach to the shaft through the substance of the vastus intermedius muscle should be avoided. Postoperative adhesions between the individual muscles of the quadriceps resulting in knee contractures are common with this latter approach.

    The lateral approach uses an incision of variable length over the lateral aspect of the thigh along a line from the greater trochanter to the lateral femoral condyle (Fig. 27-4). The fascia lata is incised longitudinally in line with the skin incision. The posterior part of the vastus lateralis muscle is exposed by anterior retraction of the muscle and dissection along the fascia posteriorly to the linea aspera. The muscle and fascia are split about 1 cm lateral to the linea aspera. The perforating branches of the profundus femoris artery are identified and ligated. These vessels course perpendicular to the long axis of the femur at intervals of about 3 cm. The periosteum is split and elevated anteriorly along the vastus lateralis muscle. Only a minimal amount of periosteal stripping and muscle elevation should be performed. The intermuscular septum should not be dissected off the linea aspera unless it is imperative for surgical exposure. This lateral approach to the shaft results in minimal scarring of the quadriceps and can be reused in future surgery on the shaft as may be indicated.

Fig. 27-4 Abord lateral si posterolateral 13 medie coapsa. A.Abordul posterolateral de-a lungul septului intermuscular este preferat deoarece este minima disectie prin vastul lateral. B. Abordul lateral cu incizia vastului lateral si intermediar de-a lungul fibrelor

MECHANISMS OF INJURY

A fracture of a normal femoral shaft requires major trauma. Most fractures are sustained by young adults during high-energy injuries such as motor vehicle accidents, auto-pedestrian accidents, motorcycle accidents, falls from heights, or gunshot wounds.

    Epidemiologic studies show a correlation between the mechanism of injury and the types of associated injuries.343 Auto-pedestrian accident victims have a high prevalence of head, chest, pelvis, arm, and leg injuries. Motorcyclists tend to sustain associated pelvis and ipsilateral leg injuries. Fall victims less frequently sustain major associated injuries.343 Lesser degrees of trauma can fracture a femur with pathologic bone. Such pathologic fractures often start at the weak metaphyseal bone at the ends of the femur and propagate into the shaft.

    Fatigue failure is a rare cause of fracture of the femoral shaft.273 Usually located in the proximal or midshaft areas, fatigue or stress fractures occur mainly in military recruits undergoing a marked and prolonged increase in physical activity.

    The incidence of stress fractures of the femoral shaft in civilian populations appears to be rising with the recent emphasis on physical fitness. Running accounts for most such fractures, but they also have been seen after triathlon events and aerobic dancing.90 Most runners report an increase in their training during or immediately before the onset of their pain. Plain radiographs often are normal, and radioisotope scans have proven to be the most sensitive tests for the early detection of these injuries. Displacement of these stress injuries can occur occasionally, but most heal with rest or substitution of low-impact exercises such as cycling and aquatic exercise for running.

    Like most bones, the femoral shaft fails under tensile strain.109 The most common mechanism of injury is bending load, resulting in a transverse fracture. Higher-magnitude injuries cause varying degrees of fracture comminution. It has been estimated that 250 Nm of bending movement are needed to fracture a normal adult femoral shaft.183 Additional force is dissipated on the soft tissues. Pathologic bones are prone to spiral fractures after minor torsional loads. Such fractures rarely are comminuted or associated with severe soft-tissue damage.

CLASSIFICATION

No universally accepted classification scheme exists for fractures of the femoral shaft. Most investigators categorize fractures according to specific variables that directly influence their preferred treatment. Such factors as soft-tissue injury, geographic location, fracture geometry, fracture comminution, and associated injuries are used most often in classifying these fractures.

    Open wounds occur less frequently with femoral shaft fractures than with tibial fractures. Open fractures can be subdivided into the standard grades I, II, IIIA, IIIB, and IIIC, according to the Gustilo-Anderson method.130,131 The abundant soft-tissue coverage of the femoral shaft makes grade III, especially IIIC, open fractures relatively uncommon.

    The interobserver agreement with the Gustilo-Anderson classification system for open tibia fractures is only moderate to poor.54 A similar problem with its reliability and reproducibility may exist for femoral fractures, although this issue has not been studied. The definitive grading of the soft-tissue wound should be delayed until thorough inspection and debridement of the soft tissues and bone are completed.

    Femoral shaft fractures can be categorized geographically as proximal third, midshaft, or distal third. Because the isthmus of the medullary canal usually is located in the midshaft, distal-third fractures also are called infraisthmal fractures. The variable anatomy of the medullary canal and the different mechanical stresses in these three regions of the shaft influence the techniques and results of intramedullary fixation.

    Fractures also can be classified according to the geometry of the major fracture line. The terms transverse, oblique, spiral, and segmental are self-explanatory. The AO/ASIF classification distinguishes simple (A), wedge (B), and complex (C) patterns in its scheme for femoral diaphyseal fractures240 (Fig. 27-5). The simple fractures are subdivided according to the obliquity of the single fracture line. The wedge fractures can be a spiral, bending or fragmented configuration. The complex fractures include segmental fractures and fractures with extensive comminution over a long segment of the diaphysis. It is unclear how this AO/ASIF scheme may influence the preferred treatment of any given fracture or be predictive of its outcome.

Fig. 27-5 Clasificarea ASIF

    The degree of fracture comminution has implications for the preferred form of medullary fixation and locking of the major fracture fragments. The Winquist classification of comminution is widely used369 (Fig. 27-6). Type I comminution is defined as minimal or no comminution at the fracture site. Any small fragment that is present should have no effect on fracture stability after intramedullary nailing. Type II comminution involves a fragment larger than that in type I but has at least 50% of the circumference of the cortices of the two major fracture fragments intact. Because the broad cortical contact after fracture reduction and nailing prevents shortening and malrotation, simple intramedullary nails suffice for most type II fractures. Nevertheless, static locking is used routinely for these type II injuries because of the risk of postoperative loss of fixation secondary to unrecognized comminution.59

Fig. 27-6 Clasificarea Winquist: A. Tip I; B. Tip II; C. Tip III; D. Tip IV.

    In type III injuries, between 50% and 100% of the circumference of the two major fracture fragments is comminuted. Such large butterfly fragments compromise fracture fixation because broad cortical abutment of the major fracture fragments is impossible. Simple intramedullary nails are insufficient for type III fractures and must be supplemented with interlocking screws, cerclage wires, or postoperative traction or bracing. All cortical contact is lost in type IV injuries. The cortex is comminuted circumferentially over a segment of bone. Even with intramedullary nailing, there is no contact between the proximal and distal fragments. All inherent stability of the fracture is lost. Longitudinal fractures with cortical fissures traversing the entire shaft occasionally can be sustained with gunshot injuries.

    Finally, a patient can be categorized as having either an isolated femoral fracture or multiple injuries. The presence of associated injuries often is the single variable that determines the preferred timing for fixation of fractures of the femoral shaft.254 The Injury Severity Score (ISS) is one of several scales used to grade the severity of the multiply injured patient.19 Injuries to six body regions (head and neck, face, chest, abdomen and pelvic viscera, extremities and bony pelvis, and integument) are graded to quantify the extent of trauma. Each area is assessed as mild (1), moderate (2), severe (3), critical-outcome usually favorable (4), or critical-outcome usually lethal (5). The sum of the squares of the three highest grades equals the ISS. The maximal score, therefore, is 75.19,94 Retrospective studies show that the median lethal ISS scores vary with the age group.126 The median lethal ISS score is 40 for patients 15 to 44 years of age but drops to 29 for patients 45 to 64 years of age and to 20 for patients 65 years of age and older.

SIGNS AND SYMPTOMS

The clinical diagnosis of fracture of the femoral shaft usually is obvious, with pain, deformity, swelling, and shortening of the thigh. A thorough physical examination is imperative, however, because most fractures are a result of high-speed trauma and associated injuries are common. Orthopaedic assessment of the entire limb should be systematic and complete. The pelvic ring and hip are inspected for tenderness. Swelling or ecchymosis may signal concomitant pelvic disruption or hip fracture. Because the hip cannot be moved voluntarily by the patient, palpation of the groin and buttock is important.81,278 Fullness of the buttock with flexion and adduction of the proximal femur can denote a posterior dislocation of the hip.

    A similarly thorough inspection and palpation of the knee should be performed. Ligamentous injuries and internal derangements of the knee are commonly associated with femoral fractures.234,267,323,352 Formal stress testing of the ligaments is not feasible in the presence of a shaft fracture. Careful palpation of the collateral ligaments and joint space, however, may raise the index of suspicion for ligamentous injury, and clinical or radiographic stress testing can be deferred until after femoral fixation.

    The precise prevalence of meniscal injuries associated with femoral shaft fractures is unknown. In an arthroscopic study of the knees of 47 patients with closed femoral shaft fractures, nearly half were found to have meniscal tears.352 Complex and radial tears outnumbered peripheral or bucket-handle tears. The clinical significance of such tears remains unclear, however, and routine arthroscopy of the knees of patients with femoral fractures probably is not justified. Diagnostic assessment of persistent knee complaints should be delayed until the completion of fracture rehabilitation of the limb unless severe symptoms of locking and giving way are present.

    Although neurovascular injuries rarely are associated with closed shaft fractures, a complete preoperative examination for vascular and neurologic damage is mandatory. Because of the severe pain and spasm accompanying femoral fractures, the motor strength of muscles below the knee may be diminished. Distal pulses should be palpable.

    Although few patients with isolated fractures of the femoral shaft are in hypovolemic shock, major blood loss into the thigh is present in most cases.361

    In a retrospective study of patients with isolated shaft fractures, Lieurance and colleagues195 reported that 21 of 53 required transfusions and estimated the average blood loss in all 53 patients to be more than 1200 mL. Therefore, careful preoperative assessment of the hemodynamic stability of the patient is necessary, regardless of the presence or absence of associated injuries.

RADIOGRAPHIC FINDINGS

Before diagnostic radiographic studies are performed, longitudinal traction or splinting of the extremity is applied to ensure minimal additional soft-tissue injury to the thigh. If a Thomas splint is used, the metallic ring and caliber should not obscure any part of the bone. Nondisplaced fractures of the femoral neck frequently are missed because of the overlying shadow of a splint or inadequate quality of the preoperative radiograph (Fig. 27-7). If the hip is externally rotated on the preoperative radiograph, there can be rotational artifact. In such cases, it is advisable to obtain an anteroposterior radiograph of the hip with the proximal femur internally rotated in the anesthetized patient before the operative procedure.

    Initial radiographs should include an anteroposterior view of the pelvis and anteroposterior and lateral views of the knee and the entire femur. Baseline chest radiographs also are helpful in the event of the development of a fat embolism syndrome. The quality of the femoral radiographs must be sufficiently good to detect longitudinal cracks and nondisplaced comminution of the proximal and distal fragments. Poor-quality radiographs also can disguise subtle scalloping or erosion of the cortex, which may be the only sign of a pathologic fracture. Such a fracture can be easily misdiagnosed as a traumatic injury to a normal femur. Suboptimal radiographs should not be accepted.

TREATMENT

Nonoperative Techniques

Traction

Traction has been the time-honored method of treating femoral shaft fractures and can be divided broadly into skin traction and skeletal traction techniques. Skin traction encompasses those traction modalities that apply longitudinal force to the limb through the skin. Skeletal traction includes all traction designs that apply force to the limb directly through the skeletal system, most often through a percutaneous pin in the tibia or femur.

    Centuries ago, De Chauliac and coworkers100 suggested the concept of skin traction on the leg with the knee in extension for fractures within the thigh. Their method was modified in the 1860s by Buck,64 whose name is still associated with this form of traction. The major disadvantage of skin traction is the inability to apply sufficient forces to the limb to obtain fracture reduction. The application of major force can cause slippage of the skin traction or skin necrosis. Furthermore, because of the deforming muscle forces on the proximal and distal fragments, displacement of the femoral shaft fracture commonly occurs when the knee is held in extension.78 Other methods of skin traction, including Bryant and split Russell303 traction, have been suggested to counteract these disadvantages. These traction techniques are indicated only in young children.

    Although it is recognized that skin traction cannot supply a constant force of sufficient magnitude to maintain length and alignment of femoral shaft fractures in the adult, it is still used in emergency immobilization and transport of the patient who has sustained a lower extremity injury. In this situation, the fractured femur is splinted with traction applied through a padded wrap around the foot and heel with countertraction in the groin (Fig. 27-8). Limb rotation is controlled through multiple elastic straps that circumferentially encase the thigh. This technique greatly decreases patient discomfort and facilitates patient transfers in the prehospital and emergency department settings. However, it should always be considered a temporary measure. Definitive techniques to restore the fractured femur to length and alignment should be planned and executed as soon as the patient's condition permits. Because extensive thigh swelling can cause the elastic straps surrounding the thigh to act as tourniquets, the tension of the traction and of the thigh straps should be checked and appropriately adjusted once patient transfer is complete.

    Skeletal traction, the most common method of definitive treatment of femoral shaft fractures for decades before the 1970s, remains the method of choice for early fracture care. Sufficient force can be applied to the limb to achieve fracture reduction. The skeletal traction pin most commonly is inserted through the tibial tubercle, a relatively subcutaneous area anatomically removed from the knee joint and not contiguous with the fractured bone. However, proximal tibial skeletal traction may be contraindicated when ligamentous injury to the ipsilateral knee accompanies the femoral shaft fracture.

    The distal femur has been used successfully for skeletal traction and offers more direct longitudinal pull on the fractured femur than does similar traction through the proximal tibia. Theoretically, infection of a distal femoral traction pin could involve the knee joint, but this complication has not been identified as a serious clinical problem. Skeletal traction through the distal femur has been associated with a higher rate of knee stiffness after fracture union, undoubtedly because of pin-tract scarring of the vastus medialis and vastus lateralis. The orthopaedist treating traumatic injuries should be facile at skeletal traction pin insertion at both sites.

    Debate has continued over which type of traction device, the Kirschner wire or the Steinmann pin, is superior for skeletal traction. Charnley and Guindy80 expressed a preference for the Steinmann pin, believing that its larger diameter provides better fixation, especially in osteopenic bone. They argued that the Kirschner wire has two definite disadvantages: (1) every movement of the traction bow with a Kirschner wire is transmitted to the bone, permitting rotation at the bone-pin interface, and (2) the wire can cut through the bone and subsequently loosen. Other authors recommend the Kirschner wire over the Steinmann pin because the former is a smaller device and, thus, creates less soft-tissue damage on insertion.231 They also believe that, with traction, the Böhler bow connections to the Steinmann pin fail to swivel, creating rotation of the pin within the bone. Although the best traction is a matter of surgeon's preference, it is agreed that threaded pins should not be used because they are weaker than smooth pins of the same diameter.231

    Appropriate sterile technique, including skin preparation and towel draping, and local anesthesia are mandatory for pin insertion. The proximal tibial skeletal traction pin is inserted at the level of the tibial tubercle. Pin insertion through the dense anterior cortex of the tibia should be avoided because bicortical pin placement is preferred. Thermal necrosis of the anterior cortex of the tibial crest also can result in pin-tract infections.

    Many variations of limb suspension for traction on the fractured femur have been devised; most are modifications of the Thomas splint with the Pearson attachment. This type of balanced skeletal traction has replaced the fixed splinting devices such as the Böhler-Braun frame78 (Fig. 27-9). The half-ring of the Thomas splint fits loosely around the upper thigh. Slings support the thigh, helping to prevent soft-tissue and bony sag through gravity. Traction is applied in the general line of the femur, and the foot is supported in the Pearson attachment.277 The Thomas splint and the Pearson attachment are suspended by traction ropes to support the lower limb, hence the term balanced skeletal traction. Adjustments in limb rotation and alignment are possible with the use of secondary slings. Charnley79 has provided a complete description of the technique of fracture reduction and alignment. This technique permits early function of the thigh musculature and some early knee motion. Emphasis on early knee motion by Delorme and associates,102 Hogden,145 and Perkins67 brought about further modifications of this classic design.

    Another variation, Neufeld traction,53,116,213 incorporates the limb and the Steinmann pin in plaster casts and applies traction through a roller system that permits greater early knee motion (Fig. 27-10). Traction is placed on the plaster cast, which transfers this force to the bone through the incorporated Steinmann pin. The increased knee motion permissible with Neufeld traction has not led to an increase in fracture nonunion. Alterations of this method can permit increased patient mobility, because the patient can have continuous traction while being positioned on either flank. In addition to permitting the maximum amount of knee motion and muscular activity of any traction technique, this method may allow improved pulmonary toilet in the multiply injured patient. Most skeletal traction methods require that the patient remain in the supine position.

Fig. 27-10 Exista doua linii - pt

tractiune si pt suspensie. De notat

folosirea tensiunilor variabile prin

modificarea pozitiei carligului

    Finally, 90-90 traction is so named because the hip and knee each are positioned in 90° of flexion225,247 (Fig. 27-11). This method is applicable to more proximal femoral shaft injuries, especially those extending into the subtrochanteric region, in which flexion of the proximal fragment occurs. The foot is incorporated in a plaster cast or supportive sling, and the traction pin routinely is inserted through the distal femoral condyles. Countertraction is provided by the patient's own body weight. This technique affords excellent access to wounds in the posterior thigh. Circulatory compromise in patients with peripheral vascular disease can occur with this method, so it is not recommended for elderly patients. Knee subluxation with proximal tibial 90-90 skeletal traction has complicated this technique.225

Fig. 27-11 Tractiunea 90-90 utila in fracturi subtrohanteriene, leziuni inghinale si ale fetei posterioare a coapsei. Tractiunea condililor femurali este mai eficienta. Suspensia gambei intr-un gips este de-obicei necesara.

    One early goal of skeletal traction is to restore the fractured femur to proper length within the first 24 hours after injury. After that time, the fracture hematoma begins to organize, and pulling the fracture out to normal length requires increasing amounts of traction. These increasing traction forces can cause the patient to be pulled toward the end of the bed, often resulting in abutment of the patient or the traction equipment on the foot of the bed. Inadequate traction and failure to restore the fracture to length can result. Multiple radiographs should be taken to determine the efficacy of the traction in the first 24 hours after its application, because slight fracture distraction is preferred over continued overriding of the fracture fragments. It is not unusual to place 30 to 40 lb of traction initially, only to need diminished amounts later.

    Before the 1970s, skeletal traction therapy was continued for a patient until significant radiographic and clinical evidence of fracture union was apparent, usually requiring a minimum of 6 weeks of in-hospital care. A unilateral weight-bearing spica cast then was applied, and the patient began to ambulate with progressive weight bearing. The spica cast was removed 3 to 6 months after injury, and range-of-motion exercises of the ipsilateral hip and knee were begun.

    The results of traction therapy for fractures of the femoral shaft have been acceptable.103,236 Most studies report the rate of union of closed fractures of the femoral shaft treated with skeletal traction to be between 97% and 100%.67 However, delayed union has occurred in up to 30% of cases, possibly from continual distraction of the fracture site.70,247 Control of limb length is difficult, especially in comminuted injuries, with frequent shortening of 1 to 3 cm reported.103,313 Rotational malalignment generally has been attributed to maintenance of the foot pointed toward the ceiling. Such positioning with the patient supine in bed results in internal rotatory malalignment of the distal fragment.

    Knee stiffness is the most common clinical problem after prolonged traction therapy.69,299 In a study by Winant,367 no patient regained full knee flexion and only 47% regained more than 90° of knee flexion. Loss of knee flexion has been noted by several other investigators as well,67,103,118 although some document return of the knee's full range of motion in many patients. Despite the mixed results with traction treatment, it is clear that rotational deformity, loss of range of knee motion, and limb-length discrepancy can be well tolerated by many patients.236 However, other areas of concern persist. The required lengthy hospitalization, prolonged recumbency, and major cost of traction treatment remain serious problems.69 In the last few decades, the detrimental effects of traction therapy as opposed to early operative fixation of femoral shaft fractures have been documented. Major patient benefits are derived from early fracture stabilization and patient mobilization. Therefore, the enthusiasm for skeletal traction treatment has waned over the years in favor of surgical techniques.

    There is no doubt that traction historically has been the treatment method of choice for femoral shaft fractures.268 It has been used successfully in both closed and open injuries for decades and remains the least invasive treatment method for these injuries. Knowledge in this area is still required for the application of traction as a temporary method of stabilization before and during more modern internal fixation procedures. Although the treatment of femoral shaft injuries has shifted to an operative approach in the last few decades, patients occasionally must still be treated definitively with traction.

Cast Brace

The development of cast brace systems was motivated both by a desire for ambulatory treatment and by a need to prevent the hip and knee contractures that were frequent sequelae of spica cast treatment. The cast brace is essentially an external support device that has several theoretic advantages. It permits progressive weight bearing, which leads to graduated functional improvement in the muscles and joints and to increasing skeletal stresses that stimulate fracture healing. It works by partial unloading of the fracture through circumferential support of the soft tissues by a smooth, total contact plaster or plastic thigh cuff (Fig. 27-12).

Fig. 27-12

    Although the precise effect of a cast brace on fracture loading depends on several variables, including fracture location and anatomy, soft-tissue coverage, and contouring of the thigh plaster, several of its mechanical properties are well defined.232 The fracture itself controls loading in a cast brace.219 Most cast braces carry loads of only 10% to 20% of body weight and function mainly as antibuckling hinged tubes. The major deformation counteracted by the cast brace is lateral angulation produced by the thigh musculature. Once telescoping of the thigh has ceased, the muscles provide little hydraulic support to the fracture. Electrogoniometer and cineroentgenography studies demonstrate that sizable translation of the fracture occurs with weight bearing.92 This motion progressively decreases as fracture healing proceeds.

    Open fractures, distal-third fractures, and comminuted midshaft fractures are relatively good indications for cast bracing.92,229 Proximal shaft fractures and simple transverse or oblique fractures are less amenable to cast bracing because of their high stress concentration and tendency toward angulation. Cast bracing also can be used to supplement limited internal fixation of shaft fractures, such as with small-diameter nonlocked intramedullary nails.321 Its function in such applications is primarily to neutralize torsional loads on the femur that might lead to rotational malalignment of the fracture. The technique of cast bracing is well described in many publications.188,219,231,232 Careful application is critical for success. It can be used as a substitute to hip spica casting after 6 to 8 weeks of traction or as a primary treatment after 1 to 2 weeks of traction. The timing of application should be dictated by the experience of the treating orthopaedist and the likelihood of loss of reduction of any given fracture. A prerequisite of cast bracing is that satisfactory reduction in traction be achieved before the cast is applied. The best results are obtained when the cast brace is applied after pain and swelling have subsided and early callus formation is evident on radiographs. Serial radiographs are imperative to check the alignment and judge the advisability of early weight bearing.

    The goals of early limb rehabilitation and rapid fracture healing can be realized in most patients. Most investigators report a consistently high rate of union, usually by 13 to 14 weeks after injury.137,215,231,232,321 However, major complications haunt most cast brace systems. Femoral shortening, averaging 1 to 1.5 cm in even the best of series, often requires corrective shoe lifts at the completion of treatment. Varus angulation of more than 5° to 10° results in excessive loading of the medial compartment of the knee and cosmetic deformity. Although knee motion with cast bracing often is described as good, well-documented series of patients treated by cast bracing reveal residual knee motion at follow-up of less than 100°.215,231 The prevalence of these complications is especially high in the hands of physicians who use cast bracing infrequently. Various modifications of the standard plaster cast brace, such as adjustable thigh sections, pelvic belts for suspension, and improved hinges, have been recommended to address these common problems.92,188

    The popularity of cast bracing peaked many years ago, and it has been largely supplanted by newer techniques of internal fixation. However, it should still occupy a place in the armamentarium of fracture surgeons for the management of fractures of the femoral shaft.

    Operative Techniques

External Fixation

External fixation using percutaneous pins inserted proximal and distal to the fracture gained initial popularity for the stabilization of fractures of the femoral shaft during World War II. This method provided excellent bony fixation and wound access as well as permitted early patient ambulation. However, it was extremely controversial at the time, with some authors reporting excellent results but others publishing high rates of nonunion, pin-tract infection, and knee stiffness.230

    The pins of external fixators often tether the quadriceps muscle to the femoral shaft. The resultant scarring can cause a permanent loss of motion of the knee. This problem was compounded with early external fixation designs that used transfixion pins that exited the thigh on both the medial and lateral surfaces.166,249 There remain few, if any, indications for the use of transfixion pin frames for fractures of the femoral shaft. The lateral half-pin external fixator designs, pioneered by Wagner,319 have been shown to provide adequate bone fixation and stabilization for most complex femoral shaft injuries84,98,99,123,154 (Fig. 27-13). As with other long-bone stabilization, the rigidity of femoral external fixators depends mainly on the pin diameter.84 As long as a half-pin at least 5 mm in diameter is used, adequate stiffness of nearly all commercially available frames can be achieved. Laterally placed frames are stiffest in the mediolateral plane, whereas anteriorly placed frames are stiffest in the sagittal plane.

Fig. 27-13

    Published series of external fixation of the femur report mixed results. Some authors have judged that the return of 90° of knee flexion is an acceptable result and, therefore, report a high percentage of excellent functional outcomes with this technique.98,156,319 Other investigators have reported decreases in the functional range of motion of the knee at follow-up.11,125,156 These differences are due to many factors, most notably the method of pin insertion, the number and type of external fixation pins, and the severity of the soft-tissue injury accompanying the fracture.

    One comparative study between external fixation and interlocking intramedullary fixation for closed fractures of the femoral shaft disclosed distinctly superior clinical results with the intramedullary technique, although the severity of injuries between the two treatment groups was not identical.241 The high rate of fracture union was equivalent in the two groups, but the external fixation group had complications of knee stiffness and pin-tract infection.241

    Pin-tract infection complicates up to 50% of the reported cases of external fixation of the fractured femur, undoubtedly because of pins traversing the iliotibial band and the broad muscle belly of the vastus lateralis. This complication must be accepted as a routine problem inherent with the use of this method. Although it can be lessened with good pin insertion technique, it cannot be eliminated.46,99,125,132

    External fixation of the femoral shaft reportedly has been used most often in high-energy injuries in which rapid, rigid fracture stabilization is required because of the patient's associated injuries.48 Today, the major indication for using external fixation for the femoral shaft is grade III open fractures (Fig. 27-14). This technique provides adequate bony stabilization, even in comminuted injuries, and permits excellent wound access for debridement and dressing changes. In the severely contaminated or high-energy open fracture, external fixation is the treatment of choice because the risk of infection with internal fixation can be prohibitive. The slightly increased prevalence of fracture nonunion and decreased range of motion of the knee reported with this technique may be due, in part, to the severity of injuries studied.99,156 No controlled studies exist that compare the results of similar injuries treated with external fixation and other treatment methods.

    Circular or small-wire external fixators (Ilizarov) used in limb lengthening and the correction of post-traumatic deformity obstruct access to the thigh for the multiple debridements and dressing changes required with these grade III fractures and, thus, are poor choices for initial fracture treatment. If these techniques are required later, previous external fixation with half-pin frames does not preclude their use.

    Because intramedullary nailing techniques have demonstrated more predictable fracture healing and improved clinical results with closed injuries, external fixation is not indicated in the routine treatment of closed fractures of the femoral shaft.241 In certain clinical situations, such as the multiply injured patient who cannot tolerate prolonged anesthesia or the patient with a closed fracture of the femoral shaft and an associated vascular injury,285 external fixation may be the safest and most expedient method with which to stabilize the fracture. In these instances, it usually is considered as temporary fixation and is replaced by internal fixation once the emergency situations have been resolved.11,48 However, caution should be exercised if the external fixator is used as a temporary fixation device.11 The prevalence of infection in the femur after internal fixation (either plate or intramedullary nail) following the removal of an external fixator is unknown. Caution should be exercised in internally fixing a fracture in the presence of colonized pin tracts of a temporary external fixator.

Plating

During the 1960s and 1970s, the treatment concepts of rigid internal fixation of diaphyseal fractures followed by early limb rehabilitation gained wide acceptance. Dissatisfaction existed with the results of nonoperative treatment of femoral shaft fractures because of the prolonged hospitalization, high costs, fracture shortening, malunion, delayed union, and joint stiffness reported with these methods.103,137,247,318 Open reduction with plating of femoral shaft fractures was espoused in an effort to improve these results, and the clinical results of plating compared favorably with those of closed treatment or limited internal fixation.300

    This technique requires experience and operative skill to anatomically restore the alignment of a comminuted femoral shaft fracture without further devitalizing the fracture fragments through dissection. Evacuation of the fracture and at least partial devascularization of the femoral cortex are inevitable with plating of the fracture. Some authors apply plating to all fractures of the femoral shaft,82,287,300,330 whereas others limit its use to those fractures that are not amenable to intramedullary nailing, with or without cerclage wiring.160,271,291,330 The goal of the operative procedure is fracture stability. Early in the history of plating of femoral fractures, multiple plates were applied to the femoral diaphysis to obtain more secure fixation. These were referred to as 90-90 plates, because they were applied 90° from one another on the anterior and lateral cortices to enhance rotational stability.209,271,300 Improvements in plate strength and design permitted fracture site compression and allowed single plating of fractures of the femoral shaft. Less surgical dissection is required with single compared with double plating.203,330

    Open reduction and plating overcome the difficulties encountered with skeletal traction with respect to the restoration of femoral length and rotational alignment. Direct visualization of the fracture fragments facilitates an anatomic or near-anatomic reduction. This technique improves the range of motion of the knee, compared with the results obtained with skeletal traction.82,203 This improvement is attributed to both the rigid fixation achieved with the compression techniques of the ASIF group and early rehabilitation of the limb. However, despite this clinical improvement, 20% to 30% of patients still have major residual loss of knee motion, generally attributed to excessive scarring of the quadriceps muscle.246,348 Careful dissection of the vastus lateralis muscle combined with early postoperative knee rehabilitation can minimize knee contracture.287

    Another advantage of this technique is prompt mobilization of the patient with a shorter hospital stay compared with that required for skeletal traction. The benefits of immediate stabilization of long-bone fractures on pulmonary function were recognized only after open reduction with internal fixation of femoral shaft fractures was studied.

    Although this method addresses some of the problems encountered with skeletal traction treatment, an array of new complications has become apparent. Failure of fixation occurs in 5% to 10% of the reported cases, with many requiring reoperation.4, 160, 203, 286, 291, 300, 330 Fixation failure more than 6 months after surgery indicates a nonunion. Fatigue fracture of the plate can be salvaged easily in most cases by intramedullary nailing of the nonunion.286

    The prevalence of infection is higher with plating of fractures of the femoral shaft than with conservative treatment methods or closed intramedullary nailing.18,160,216,246,336 Devitalization of fracture fragments naturally occurs with injury. However, further iatrogenic tissue and bone necrosis can occur with the dissection for open reduction, a variable dependent on the care and experience of the surgeon. Tissue necrosis from excessive dissection can create an environment that is less favorable for fracture union and more favorable for infection after surgical contamination.330 Most studies concerning plating of femoral shaft fractures demonstrate overall rates of healing between 90% and 95%.203,300,330 This figure is decreased somewhat when open fractures are added to the investigation. Infection has complicated zero to 11% of the reported cases.109, 134, 148, 190, 207, 228, 342 Ruedi and Luscher300 reported a large series (126 comminuted fractures over 6 years) of femoral shaft fractures treated with open reduction and plating. Although they reported 92% good or excellent final results, 9% of cases lost fixation because of nonunion, 9% required bone grafting for delayed union, and 6% became infected. Most of these complications required reoperation. These authors strongly recommended routine bone grafting of comminuted femoral shaft injuries treated with open plating.300

    In a more recent series, Riemer and colleagues286 reported improved results when minimal dissection and routine bone grafting were used. Of 141 fractures treated with a single AO large-fragment plate and cancellous bone grafting, only ten plates failed and only one surgical wound infection was recorded. Fracture union occurred at an average of 17.2 weeks. Despite excellent final knee motion in nearly all cases, rehabilitation was slow in most patients. Contraindications to plating in the multiply injured patient were considered to include coagulopathy, preexisting skin infection, cardiac instability, and severe head injury with uncontrollable and fluctuating intracranial pressure measurements.

    This technique requires an extensive surgical exposure of the lateral aspect of the femur. The entire leg is draped free with the patient positioned at the ipsilateral edge of the operating table. The vastus lateralis muscle is reflected anteriorly with ligation of the perforating vessels, and the major proximal and distal fragments are mobilized sufficiently to obtain an anatomic reduction. Ten- or 12-hole dynamic compression plates with a minimum of five screws in both the proximal and distal fragments are used routinely. Bone forceps hold the plate to the bone without additional elevation of the muscles. A minimal number of intrafragmental screws (preferably through the plate) are inserted to prevent excessive damage to the soft tissues. All medial cortical defects are grafted, and large suction drains are inserted deep in the wound. Perioperative antibiotics should be used to minimize the chance of infection.348

    Active range of motion exercises for the knee are encouraged soon after surgery, but forceful strengthening exercises are avoided until fracture healing is evident. Full weight bearing is postponed until complete radiographic union is present. This delay in weight bearing for 3 to 5 months is a major disadvantage of plating compared with closed reamed intramedullary nailing.

    The popularity of this technique has decreased since its peak in the early 1970s.112,115 With the advent of improved intramedullary techniques in the 1980s, open reduction and plating no longer was considered the preferred treatment option for femoral shaft fractures. Interlocking nailing controls femoral length and rotation without the risks of tissue devitalization, quadriceps scarring, blood loss, and infection from plating. The only remaining advantage for open reduction inherent to this open plating technique over closed intramedullary nailing is that open plating does not require the wide spectrum of specialized operating room equipment and radiology personnel that are necessary for closed intramedullary nailing.

    Because the clinical results with interlocking nailing are superior to those with open reduction, few indications remain to treat a fracture of the femoral shaft with open plating. Fractures that involve the distal metaphyseal-diaphyseal junction of the femur still may require extensive open reductions, especially when intercondylar extension is present (Fig. 27-15). An 'indirect reduction' technique has been advocated by the ASIF group to obtain fracture stabilization of these complex injuries without excess dissection, surgical manipulation, and anatomic reduction of the comminuted fracture fragments.33,210,287 Further study of this surgical technique is necessary to see whether it affords decreased rates of nonunion and infection when compared with previous open reduction methods (Fig. 27-16).

Fig. 27-15

Fig. 27-16A+B. reducerea indirecta a unei fracturi cominutive in 13 distala. Se practica minima disectie a fragmentelor cominutive. Dupa reducerea anatomica si fixarea fragmentelor intraarticulare se aplica lama placa 95 grade pt a obtine reducerea fragmentelor diafizare. Sistemul de compresie ASIF se aplica invers folosindu-l la refacerea lungimii femurului. C. Incidenta AP cu OS finala cu lag-screw de mentinere a fragmentelor mari. Succesul acestei tehnici depinde de minima disectie a zonei diafizare faracu minima devascularizare a fragmentelor osoase cominutive.

Intramedullary Nailing

The straight, tubular anatomy of the femoral shaft is ideally suited to intramedullary fixation. The centrally located isthmus allows for endosteal purchase both proximally and distally by an intramedullary rod. The loading conditions of the femur by gravitational, muscular, and ligamentous forces also are favorable for intramedullary fixation.9 The femur normally is loaded in compression, bending, and torsion. Both bending and torsion loads generate a combination of tensile, compressive, and shear stresses in the bone. Compared with other internal and external devices, such as plates and external fixators, intramedullary nails are closer to the center of motion of the body and, thus, are subjected to lesser loads. In addition, in fractures stabilized with cortical contact of the major proximal and distal fracture fragments, the bone share of loading increases as healing progresses. This mechanical property of the nail-bone composite is distinctly different from the load shielding inherent with plate fixation and has several beneficial effects. First, the intramedullary nail is loaded less than a plate, making it less likely to fail in fatigue. Second, the fracture callus is loaded progressively, stimulating healing and remodeling. Finally, the cortical osteopenia usually evident from the stress shielding of plates is avoided with intramedullary implants.

    Intramedullary nailing has many theoretic and practical advantages over the other forms of internal and external fixation. Although specialized instrumentation and radiographic facilities are needed for closed nailing, nails are inserted with relative ease without the extensile exposures and dissection required for plate application. Because the fracture hematoma is not evacuated with closed nailing, the early action of local cellular and humoral agents critical to normal fracture healing is not disturbed (Fig. 27-17). Therefore, closed nailing constitutes a form of 'biological' fixation of the femur. The lesser surgical dissection carries the added benefits of a lower infection rate and less quadriceps scarring.

    Intramedullary nails provide predictable restoration of shaft alignment. In simple midshaft fractures, large-diameter nails that fill the medullary cavity automatically correct the normal alignment of the femur. Similar restoration of anatomic length and alignment is possible with comminuted fractures and those proximal or distal to the midshaft but requires more technical precision.

    Early functional use of the extremity is feasible after most cases of intramedullary nailing. Patient mobilization out of bed within 24 hours of surgery is the norm. As load-sharing implants, nails allow for early weight bearing after most fractures. Only severely comminuted and distal shaft fractures may require protected weight bearing during the early stages of fracture healing. The minimal surgical scarring of the thigh musculature after nailing enhances early recovery of quadriceps function and knee motion. This rapid rehabilitation that is normally evident after nailing decreases the length of hospitalization and the total period of disability, yielding obvious economic benefits.

    The rapid fracture healing that occurs after intramedullary nailing can be attributed to several factors. Nails allow cyclic compressive loading across the fracture site, which has a propitious effect on callus formation and remodeling. The closed insertion of nails causes little or no damage to the periosteal vasculature, which plays a dominant role in fracture healing. In addition, marrow elements and cortical reamings extravasate into the fracture hematoma during closed nailing. Such reamings serve as osteogenic, osteoconductive, and, perhaps, osteoinductive stimuli to fracture healing.83 Thus, biomechanical and biological factors combine to create an excellent milieu for the healing of shaft fractures after closed nailing.

    Nailing also is associated with a lower prevalence of refracture than are other forms of internal and external fixation. Shaft fractures after closed nailing predictably heal with abundant callus formation and little or no osteopenia of the major fracture fragments. Because of the greater diameter of the callus and the neocortex at the fracture site, the strength of the bone actually may be greater than normal. Although nail extraction routinely is not recommended for 18 months, safe removal as early as 6 months is possible in selected young adults because of rapid healing and remodeling. No protection in the form of casts or delayed weight bearing is necessary after nail extraction.56

    Specific clinical studies comparing the results of intramedullary nailing with other nonoperative and operative treatments consistently have demonstrated the superiority of intramedullary fixation. The data show fewer cases of malunion, improved function, earlier return to work, shorter hospitalization, less fracture shortening, and more rapid healing with intramedullary nailing.70,163 Fewer complications of treatment occur, except for those related to infection after open nailing.

    The history of intramedullary nailing of femoral shaft fractures is long and rich. Fifty years after Küntscher's revolutionary work on intramedullary fixation, his cloverleaf nail remains the benchmark for intramedullary implants. The original Küntscher nail had a V-shaped cross-sectional design that was modified to the current cloverleaf shape as instrumentation was developed for its closed insertion over a guide pin. Many additional refinements in the Küntscher system have been introduced over the years, but the basic concept and system remain unchanged.

    The Küntscher nail served as the impetus for the development of many other nails. These alternative intramedullary rods and nails have not consistently reproduced the outstanding results of the Küntscher nail. The Rush rod, first applied in the 1930s to femoral shaft fractures, is a curved, round pin that is inserted in such a fashion as to create a dynamic force within the bone.302 Proper application of the Rush rod requires an accurate assessment of the muscular forces on the bone with an attempt to oppose these intrinsic forces with the bent rod. Similar flexible fixation is achieved with Ender pins.106 These thin, stainless steel rods, originally designed for peritrochanteric fractures, have been widely used for shaft fractures. They can be inserted through either the greater trochanter or the femoral condyles, depending on the location of the fracture. Although satisfactory results are obtainable for simple transverse and short oblique fractures and for fractures with unicortical comminution, complex patterns involving long oblique, spiral, distal, and comminuted fractures tend to shorten over the pins. Adjunctive fixation in the form of cerclage wires, limited plate fixation, external fixation, cast bracing, or postoperative traction may be required.257,258 When adequate fixation is achieved, healing occurs rapidly.

    The Rush rod and Ender pin systems have numerous problems. As internal splints, they provide little resistance to axial loads. Postoperative shortening and malalignment are common, especially in complex fractures.164 Despite techniques such as stacking multiple nails in the canal and diverging the rods in the proximal and distal fragments, the anatomic results have been poorer than those of interlocking nails. Rod irritation and resultant knee or hip pain may necessitate early implant removal. Because of the inherent design and technical problems with these small-diameter rods, they seldom are used for the treatment of shaft fractures in adults. Some authors recommend that they be used only in patients with femora with small medullary canals (á8 mm), in fractures below noncemented femoral prostheses, or in fractures in young children requiring intramedullary fixation that avoids open physeal plates.144 However, the efficacy of Ender nails in such selected cases has not been proven.

    Two noncannulated nails have been widely used in North America. The Hansen-Street diamond-shaped nail has a tapered end and, thus, can be inserted with or without reaming.146 The flanged Schneider nail incorporates the double I-beam principle in its design and is very strong. The four flanges along the length of the nail provide improved rotational control of the fracture fragments. The graduated sawtooth configuration of the ends of the nail acts as a self-broach during its insertion without prior reaming. Either antegrade or retrograde insertion is possible. Both the Hansen-Street and the Schneider nails are intended for use without guide pins. Although excellent results are reported for these nails in simple fractures, their usefulness is limited in more complex injuries311,337 (Fig. 27-18).

Fig. 27-18 Telescoparea unei fracturi oblice in 13 medie in jurul unei tije Schneider nealezata. Cele 7 grade de varus se atribuie punctului lateral de intrare al tijei la nivelul trohanterului precum si localizarii proximale a fracturii. 

    The Samson fluted rod was designed specifically to strengthen the nail and improve its rotational fixation of fractures. It possesses a closed, circular cross-sectional configuration with circumferential external flutes that cut into the endosteal cortical surface. A system of extenders that attach to the end of the nail precludes the need for a large inventory of various-length nails. Compared with other nails of comparable diameter, the bending strength of the Samson nail is 40% to 80% greater and the torsional rigidity is 230% to 3000% greater.10 The nail was developed mainly for comminuted fractures and cases of nonunion in which resistance to torque is critical for successful healing. In one report, postoperative loss of rotatory alignment of 20° to 30° occurred in six patients with comminuted fractures.127 Early weight bearing should be deferred in fractures with Winquist III or greater comminution. Although good results are attainable with this implant, its stiff properties increase the risks of comminution of cortical bone during its insertion. Overreaming of the canal by several millimeters often is necessary to prevent such comminution. This very stiff nail also can stress-shield the fracture and retard normal healing. More flexible, slotted nails have supplanted the fluted nail at most centers.

    The Huckstep nail was designed mainly for use in unreliable patients in Third World countries.152,153 It is a very strong square nail with 4-mm holes drilled every 1.5 cm along its length. Locking screws inserted through targeting jigs can stabilize comminuted fractures. The stiffness of the nail in torsion, bending, and tension is much greater than that of most other commercially available nails. Despite many improvements in its design over the last 15 years, its use is still limited.

    The Küntscher cloverleaf nail is the most popular nail in general use. Although minor modifications, such as tapered ends, closure of the slot, and placement of locking holes, have been developed, the basic design has remained unchanged over 50 years. The cloverleaf configuration permits closed insertion over a guide pin. The longitudinal grooves of the nail also permit reconstitution of the endosteal vasculature. The slot in the Küntscher nail decreases its torsional rigidity. The nail tends to compress circumferentially as it is driven into the canal. Küntscher believed that the elastic rebound of the nail on the endosteal surface was responsible for rigid fixation. Such elastic impingement does occur to a minor extent, but the fixation of most Küntscher nails is due to their multiple sites of contact over a long segment of the endosteum of the proximal and distal fragments.

    Although the original Küntscher nail was straight, most current designs are prebent for the antecurvature of the femoral shaft. The prebent design eases nail insertion and minimizes posterior gapping and distraction of the fracture site.

    The Küntscher nail can be inserted without reaming the canal, but the risk of incarceration of the nail is high. The elastic recoil of the nail on the endosteum at the isthmus of the shaft can make further insertion or extraction impossible. Therefore, its unreamed use should be restricted.

    Küntscher emphasized certain prerequisites for nailing.182 Fixation must be sufficient so that the major fracture fragments will not distract. The rigidity of the fixation should allow for early function. Finally, whenever feasible, the closed technique is preferred to lessen wound problems and to decrease the time to fracture union.

    Although no experimental data have proved the optimal rigidity and strength of intramedullary nails, clinical experience has shown that the cloverleaf, open-slot design yields predictably good results in most cases.32,89,370 Union rates of 98% to 99% with infection in less than 1% of cases are standard. Midshaft fractures of the femur healed clinically and radiographically by 12 to 24 weeks after standard closed nailing.14,308,332 Shortening and malrotation remain problems of standard Küntscher nails applied to complex fractures,370 but the overall results are as good as or better than those obtained with other nonlocking, intramedullary nails.

    Historically, the major limitation of all nailing systems has been their poor results in comminuted midshaft fractures and in fractures at the proximal or distal aspects of the shaft (Fig. 27-19). The axial and rotatory loads are not neutralized by most nails, and postoperative shortening and malrotation are troublesome complications. Although Küntscher and others had conceived of locking screws for such fracture patterns, widely available locking nail systems have been used only in the last decade. Most locking nails have a cloverleaf cross-sectional design with one proximal hole and two distal holes for locking of the major fracture fragments (Fig. 27-20). Transfixion screws are inserted under radiographic control using one of a variety of techniques. Screws in just the proximal hole or the distal holes yield a 'dynamic' fixation for fractures with potential instability in axial compression and rotation. Static locking with screws in both proximal and distal fragments is indicated in fractures in which both shortening and malrotation are possible.

Fig. 27-19 Initial reducere anatomica cu ulterioara telescopare si scurtare de 1,5 cm datorita unei tije subdimensionate. Sunt specifice fracturilor oblice, cominutive in 13 distala.  

Fig. 27-20 Designul unor tije (A-proximal; B-distal). Tije: ASIF, Grosse-Kempf, Russel-Taylor, Zimmer, Alta.

    Locking of the fracture fragments to the nail appears to have no deleterious effect on the rapid healing that is evident after simple Küntscher nailing. Most series of interlocking nailing report a 97% to 100% rate of union.8,88,175,176,355,372 Routine static locking of all fractures eliminates postoperative loss of fixation secondary to unrecognized fracture comminution, which occasionally occurs after unlocked nailing (Fig. 27-21). Various interlocking nails now form the foundation for most intramedullary fixation systems used in North America. The clinical outcome has been found to be similar regardless of which interlocking nail system is used. A report comparing the Grosse-Kempf, Russell-Taylor, and Synphes interlocking nails demonstrated no difference in the pain, limp, range of motion, or time of union of the fractures.68 Minor design differences can influence the versatility of the various systems and the likelihood of prominent screw heads, but all commercially available nails appear to yield essentially comparable results.

Fig. 27-21 Fractura Winquist tip II tratata cu tija blocata dynamic. B)Se observa, la 4 saptamani, scurtarea. Cominutia fracturii a fost subestimata iar o tija blocata se impunea pt a preveni aceasta complicatie

Biomechanics of Interlocking Nailing. The optimal biomechanical conditions for fracture healing are still unknown. Therefore, the goals of interlocking nailing of femoral fractures are not to influence the normal cascade of fracture healing as much as to provide a stable nail-bone construct during the healing process. This construct should allow full loading of the bone and early functional recovery of the limb. The biomechanical demands placed on the intramedullary nail vary depending on fracture location and comminution, patient size, bone morphology, and other parameters. Thus, modifications in interlocking nail design are needed to meet these various mechanical settings.

    Insertional Properties of Intramedullary Nails. The antegrade insertion of intramedullary nails can result in iatrogenic bursting of either the proximal or distal fracture fragments. Several factors have been shown to predispose to this complication.

    The average antecurvature of the femoral shaft in an adult has a radius of curvature of about 110 cm.138 Interlocking nails are prebent to conform to this average. If there is a mismatch in the curvatures of the femoral shaft and nail, increased hoop stresses are generated in the femoral canal during nail insertion. Because overreaming of the canal is performed routinely during interlocking nailing, such mismatches are of little clinical significance except in cases of severely abnormal femoral antecurvature.

    A second cause of increased hoop stresses and possible bursting during nail insertion is an errant entrance portal for the nail. An anterior starting hole in front of the pyriformis fossa results in distortion of the nail and increased stresses within the canal.165,345,346 An excessively lateral entrance portal can cause eccentric placement of the nail and medial comminution of the proximal fracture fragment. The entrance portal should be located in line with the longitudinal axis of the femoral canal in both the mediolateral and anteroposterior planes.

    The clinical problem of iatrogenic comminution has been largely eliminated by the routine use of overreaming and smaller-diameter, nonslotted nails.

    In Situ Properties of Interlocking Nails. Long bones are loaded in bending, compression, and torsion. Interlocking nails are capable of restoring adequate stiffness and strength of the fractured femoral shaft in all three of these planes of loading.

    A fractured femur fixed with a standard intramedullary nail measuring 12 to 14 mm in diameter is 50% to 70% as stiff as an intact femur in bending.164 This restoration of bending stiffness occurs regardless of whether a slotted or nonslotted nail design is used. Fractured femora fixed with static locking of the nail fail at about four times body weight.164 Cadaveric studies have demonstrated that when this load is exceeded, failure occurs by either proximal screw cut-out through the trochanters or bending of the nail at the fracture site. The Brooker-Wills interlocking nail failed at a lower load of 1.5 times body weight by the distal fins cutting through the metaphyseal bone. The torsional stiffness of the nail is much less than that of the intact femur, with slotted nails being only 3% as stiff and nonslotted nails about 50% as stiff. This torsional flexibility of interlocking nails does not result in rotational instability of the fracture because any rotational deformation of the femur with loading is corrected by the spring-back effect provided by locking of the major fracture fragments.

    Considerable controversy surrounds the issue of slotted versus nonslotted interlocking nails.95 The presence of a longitudinal slot beginning at the distal end of the nail and extending up to or within a few centimeters of the proximal tip has several effects on the mechanical properties of the nail. First, the slot permits elastic impingement of the compressed nail on the endosteal surface of the bone. Küntscher and others have postulated that this tight interference fit with the femoral canal minimizes malrotation and shortening of the fracture. Slotted nails also have been easier traditionally to manufacture. In addition, the slot decreases the torsional stiffness by 15- to 20-fold compared with nonslotted nails,344 decreases the fatigue strength of the nail,9 and decreases the amount of metal around the locking screw holes. Thickening the nail wall of slotted nails can lessen this problem, but also diminishes any chance of elastic impingement of the nail on the proximal and distal fracture fragments.

    Closed-section, nonslotted nails have experienced a renewed popularity. They markedly increase the amount of metal around the screw holes, lessening the risk of metal fatigue. Cold working of the screw holes also has been used to strengthen the metal around them. By varying the wall thickness, the bending stiffness of nonslotted nails can be changed to mimic that of slotted nails, thus lessening the risk of damage to the femur during insertion of an overly stiff nail. Such splinting of the distal fracture fragment has been described, especially in elderly patients in whom large-diameter nails are used.7 Change in the cross-sectional design to a delta configuration and in the wall thickness have improved the mechanical strength of these small-diameter, nonslotted nails (Fig. 27-22). Such implants now are widely regarded as the interlocking nails of choice for most femoral shaft fractures.

Fig. 27-22 Tija Russel-Taylor standard (sus) si delta (jos)

    The necessary number of screws for distal locking has been studied for midshaft fractures. In a cadaveric femur model, no significant difference in torsional rigidity or axial load to failure was noted when one as opposed to two distal screws were used.133 A parallel clinical series revealed no differences in time to union or complication rate in cases with one versus two distal locking screws. The judicious use of one screw probably is warranted, but a single screw may not provide adequate stabilization of distal-third fractures. The Brooker-Wills distal locking fins also are inadequate and provide insufficient resistance to axial compression.20

    Fatigue Properties of Interlocking Nails. Fatigue failure through the midportion of a standard, large-diameter (12- to 15-mm) nail or a thick-walled, smaller-diameter nail is rare. Deformation and breakage is more common at the proximal or distal ends of interlocking nails. Several factors may predispose to failure at these locations. First, overreaming of the medullary canal and the use of undersized interlocking nails leads to little contact of the nail on the endosteum and concentration of loading at the proximal and distal screw sites. The holes in the nails decrease the amount of metal and the strength of the nail to an appreciable degree. Most manufacturers now thicken the nail wall, widen the proximal nail diameter, or cold work the holes to enhance the nail fatigue life at these sites. Despite these improvements, fatigue failure can occur if fracture healing is delayed or early excessive loading is permitted.

    The most common site for fatigue failure is at the most proximal of the two distal locking holes for most interlocking nails (Fig. 27-23). Finite element analysis of interlocking nails has revealed that if a fracture is located within 5 cm of this hole, stresses are generated in the nail above its endurance limit63 (Fig. 27-24). Once fracture healing has proceeded sufficiently to restore 50% of the normal stiffness of the distal femur, the stresses are diminished below that of the endurance limit of the nail. Improvements in nail design, such as nonslotted cross sections, cold working of the holes, and thicker nail walls, have lessened the prevalence of nail fatigue at this level. Nevertheless, infraisthmal fractures stabilized with interlocking nailing should be managed with delayed weight bearing until bridging callus is evident on radiography.

    Another weak area of certain interlocking nails is at the proximal weld between the cylindrical and slotted portions of the nail. In one study, prototypical nails were welded at this junction, and fatigue failure was common when the nails were used for high subtrochanteric fractures and cases of nonunion.113 The manufacturing process of partially slotted nails has been changed, and proximal welds no longer are present in most nail systems. Implant failure in cases of delayed union of proximal-third fractures now involves mainly screw breakage.

SPECIAL SITUATIONS

Simple transverse and short oblique midshaft fractures without associated fractures or soft-tissue injuries are managed readily by closed interlocking nailing. Many fractures of the femoral shaft, however, are more complex in their fracture anatomy, location, or associated injuries. Therefore, most shaft fractures necessitate some modification of the standard nailing technique. The following common situations alter the specific preferred treatment of shaft fractures.

Comminution

Comminution is a sign of a high-energy injury. Comminuted fractures are associated with a greater blood loss into the thigh and, frequently, with open-fracture wounds. The prevalence of systemic complications, such as fat embolism, also is higher. The Winquist classification of comminution is based on the degree of circumferential fragmentation of the shaft369,370 (see Fig. 27-6). It was designed to evaluate the feasibility of achieving a stable surgical construct with intramedullary fixation. Nondisplaced comminution of the proximal or distal fragments may not be apparent on the diagnostic radiographs, and only become manifest during the intraoperative or postoperative period.59

    The presence of fracture comminution traditionally has complicated the decision making on preferred treatment. Simple cloverleaf nails have been found to be contraindicated for type III and type IV comminuted fractures because of the risk of shortening of the fracture around the nail. Small-diameter nails fail to fill the canal, allowing even type I and type II comminuted fractures to telescope around the nail. Before the advent of interlocking nails, standard cloverleaf nails supplemented with cerclage wiring of major cortical fragments were widely used for comminuted fractures (Fig. 27-25). This method requires wide exposure with a system of wire passage and wire tightening. A minimum of two wires are used for each major fragment, the soft-tissue attachments of which should not be disturbed. A variety of materials have been recommended for cerclage. Stainless steel, 16- or 18-gauge wire results in negligible disruption of the periosteal blood flow and little necrosis of the underlying bone. Parham bands, with their wider diameters, are easy to use and effectively stabilize cortical fragments of variable sizes.263 However, they interrupt blood flow over a 1-cm length of bone and should not be used.

    The slow healing observed after open intramedullary nailing and cerclage also can be attributed to the disruption of the fracture hematoma. Removal of the scaffolding of the fracture hematoma with its complement of cytokines and growth factors lessens the initial inflammatory and subsequent proliferative stages of fracture healing. Combined with the surgical devascularization of the cortex, this violation of the fracture hematoma invariably has a measurable, deleterious effect on the speed of fracture healing.

    The clinical results with cerclage wiring are satisfactory but clearly inferior to those of closed static interlocking nailing.378 The early Seattle experience with 245 comminuted fractures revealed an infection and nonunion rate of less than 1% and a shortening and malunion rate of only 5%.370 The good results were attributed to routine delay of weight bearing until advanced healing of the fracture was evident on radiography.

    Interlocking nails have supplanted other therapies for comminuted fractures. These nails fill the medullary canal of the proximal and distal fragments, thereby restoring femoral alignment. Reduction of the comminuted fragments is unnecessary because abundant callus engulfs them (Fig. 27-26 and Fig. 27-27). Serial radiographs usually demonstrate progressive lessening of the angulation and translation of displaced cortical fragments as fracture healing proceeds. Such consolidation of these fragments is due to the hydrostatic effect of the surrounding muscles and the organization of the fracture callus. Persistent displacement of butterfly fragments has no deleterious effect on function except for the rare situation in which the fragment is buttonholed into the quadriceps muscle or through the iliotibial band. Fragments displaced more than 2 cm from the medullary canal do not contribute to the healing fracture and are not incorporated in the fracture callus.86 Static locking of the major fracture fragments prevents postoperative shortening and malrotation of the fracture. The high prevalence of unexpected comminution has led many authors to recommend routine static locking of all femoral shaft fractures.59 The published results with interlocking nails are superior to those of other treatments.163,349,378 Wiss and coworkers372 reported a 98% union rate without any infection in a large series of comminuted and rotationally unstable fractures.

    A specific variant of comminuted fractures, the segmental fracture, involves a double-level fracture of the shaft. The proximal fracture may approach the subtrochanteric region, and the distal fragment may approach the supracondylar region of the bone. As high-energy fractures, the individual fractures may be comminuted and each fracture must be assessed for its degree of instability. The good results achieved with closed interlocking nailing eclipse those attainable with other therapies for segmental fractures.368,378 Although technically demanding, the closed technique usually is applicable and yields predictably good results.

Proximal and Distal Fractures

When the fracture is a distance proximal or distal to the isthmus of the medullary canal, the feasibility of achieving stable fixation with a conventional intramedullary nail diminishes. Failure of the nail to fill the canal of either the proximal or distal major fragment, especially for fractures at the junction of the metaphysis and diaphysis, leads to postoperative instability in both axial compression and rotation. Fracture angulation also is possible during surgery if the nail is driven eccentrically out of alignment with the longitudinal axis of the canal. Such operative malalignment is especially a problem with distal fractures in which the nail is driven into the medial or lateral condyles, resulting in either a valgus or varus deformity, respectively. The mechanical demands on the nail also are increased. Subtrochanteric and high proximal-third fractures are subjected to major muscular forces and high concentrations of tensile forces along the lateral cortex.310 Supracondylar fractures have similar load concentrations in both the sagittal and frontal planes.

High Proximal-Third and Subtrochanteric Fractures. High proximal-third and subtrochanteric fractures encompass a wide spectrum of proximal femoral fractures, and the distinction between these two areas often is blurred. The biomechanical stresses of this area historically have led to separation of these injuries from pure femoral shaft fractures, because the rates of nonunion and hardware failure are higher in this region than in any other in the femur.310 The anatomical relationships of the fracture lines and the continuity of the proximal femoral fracture fragment must be understood to conceptualize the appropriate therapy for an individual injury within this region.

    Classification of these fractures has undergone refinement through the years. Simplistic and outdated classifications, like that of Fielding and Magliato,111 were based merely on the distance below the lesser trochanter. The Seinsheimer classification,317 which is widely quoted, and the AO classification239 use the details of the obliquity of fracture lines and the degree of comminution of the medial femoral cortex to differentiate between their fracture types. Although these classifications helped orthopaedists understand that fractures with medial comminution have higher rates of varus collapse and failure of fixation, their usefulness was related to proximal femoral fractures treated with open reduction and plating. With closed interlocking techniques, the specifics of the fracture pattern below the lesser trochanter has little or no bearing on the treatment, diminishing the applicability of these accepted classification schemes. For conceptual purposes, fractures of the proximal third of the femur can be widely differentiated into those with the proximal fragment intact to a level below the lesser trochanter, those with the proximal fragment intact but with dissociation of the lesser trochanter, and those subtrochanteric fractures with proximal extension into the intertrochanteric region.

    Proximal-third fractures usually are high-energy injuries of young adults. In this patient population, the proximal femoral fragment generally is intact to a level below the lesser trochanter, creating a true subtrochanteric fracture, often with distal extension into the femoral isthmus and beyond. In older patients, proximal extension into the greater trochanter and intertrochanteric region is more common. Because the method of fracture stabilization depends on the integrity of the proximal fragment, the clinician should look specifically for fractures involving the greater or lesser trochanter in the radiographic assessment. Fracture extension into one or both of these areas often precludes the use of conventional intramedullary nails. Multiple radiographic views may be necessary to demonstrate longitudinal fracture lines that can displace during nail insertion and preclude adequate interlocking fixation.

    Treatment decisions can be difficult with this spectrum of injuries. Nonoperative methods of traction and cast bracing are poor choices for proximal femoral fractures because they inadequately counteract the deforming muscular forces around the hip. Because this area is prone to varus collapse, patients who are permitted to ambulate before fracture consolidation have unacceptably high rates of varus malunion. Condylocephalic rods, such as Ender rods, have been used for proximal-third femoral fractures, but their poor mechanical properties and questionable stability restrict their usefulness. Their insertion is technically difficult, and postoperative bracing or continued traction often is required to maintain alignment. For these reasons, these devices have fallen out of favor for the fixation of proximal femoral fractures.144

    Open reduction with plating has been advocated by many investigators. The 95° condylar screw or blade plate (Fig. 27-28) has the advantage of providing excellent purchase on the proximal fragment.30,96,173,174,224,245 These designs obtain multiple screw fixation of the head and neck fragment as opposed to the standard 135° or 150° compression hip screw devices. The barrel of the hip screw devices often enters the fracture site, and this device usually gains proximal fragment fixation only with the proximal large lag screw. Although advances in metallurgy have increased the strength of the sliding hip screw designs, rotational control of the proximal fragment is lacking because of this single screw purchase. Therefore, unlike intertrochanteric fractures, the 95° devices unquestionably provide better fixation than do the more familiar hip screws for proximal-third femoral fractures.96 However, good results have been obtained with either device when reconstruction of the medial buttress of the proximal femur has been obtained.186,238,320

    The technique of open reduction has changed substantially over the past decade. Once, rigid internal fixation with anatomical restoration of the fracture anatomy was desired. Although this gained superior stability, it created the need for increased dissection of the fracture, rendering more of the fragments avascular. Bone grafting was recommended in most of these procedures, especially if the medial wall was comminuted, as a stimulant to fracture healing. Recently, the so-called 'indirect' reduction methods have been popularized.174 These techniques sacrifice anatomic restoration of the fracture fragments to ensure their viability. The medial soft tissues and fragments are left relatively undisturbed, permitting fracture healing through natural external callus. Bone grafting, and the need to dissect medially for its placement, usually are unnecessary with these techniques. Because of the decrease in iatrogenic damage within the zone of injury, these methods theoretically can produce a higher rate of fracture healing with a decrease in the prevalence of infection and hardware failure. Good comparative studies of these two techniques (extensive open reduction and rigid fixation vs. indirect reduction and fixation) are not available224; however, a decrease in these complications has been reported.174 Further study is necessary to determine whether plating by indirect reduction methods for subtrochanteric fractures provides a safeguard against the complications that are inherent with any plating of the femur.353

    The Zickel nail was designed for subtrochanteric and high proximal-third shaft fractures. It is a rigid, short, noncannulated, prebent nail through which a triflanged nail is inserted into the femoral head and neck.382 Accurate placement of the nail can be difficult, especially in patients with anatomic variations of the proximal femur and in those with comminution of the greater trochanter. Nevertheless, its design decreased the biomechanical lever arm inherent in this area, and good results have been reported.27 However, its design did not permit axial or rotational control of the distal fragment, and, although insertion by closed technique has been reported,281,305 open reduction and cerclage wiring of the fracture routinely is required to obtain stability.280 Furthermore, a major complication of the device occurred with nail extraction, where a disturbingly high rate of refracture of the femur was noted, often at a level different from that of the original fracture.255 Because of this complication, the Zickel nail is contraindicated in young patients and should be considered only for older patients or those with pathologic fractures. This device represented a great advance in the late 1970s, but it has largely been replaced by other intramedullary designs and is implanted only rarely today.

    Interlocking intramedullary nailing is the treatment of choice for subtrochanteric fractures and fractures of the proximal third of the femur in which the lesser trochanter is in continuity with the proximal fragment.5,45,259,371,380 The oblique interlocking screw obtains excellent purchase on the medial cortex, usually just anterior to the lesser trochanter, providing excellent stabilization of the proximal fragment (Fig. 27-29). Interlocking nails available today are much stronger than early designs and are less susceptible to device deformation and failure in spite of the large biomechanical stresses of this region.220 A correct starting portal in the piriformis fossa is mandatory, because placement too lateral in the greater trochanter will shift the proximal fragment into varus malalignment and will drive the nail into the medial femoral cortex, possibly increasing fracture comminution. Many investigations have demonstrated the superiority of the interlocking nail over open plating and the Zickel nail in the treatment of subtrochanteric fractures.45,245,320,371 With closed interlocking nailing, the biomechanical stresses of the subtrochanteric region no longer threaten the security of the fixation, and the results of these fractures approach those seen with midshaft femoral injuries. Once grouped as a separate and more complex injury than midshaft fractures, subtrochanteric fractures with the proximal fragment intact to a level below the lesser trochanter no longer exhibit such clinical difficulty. Plating of femoral fractures with an intact proximal fragment to a level below the lesser trochanter generally should be considered a choice of treatment second to interlocking nailing.353

    The Gamma nail, a short intramedullary hip screw,205,322 has been advocated for intertrochanteric and subtrochanteric fractures of the femur. The published results of this device vary widely,36,120,197 and its applicability to subtrochanteric fractures remains controversial. Because of the relatively high rates of refracture of the femoral shaft below the tip of the implant reported in large studies of hip fractures,204,274,365 this device cannot be recommended for subtrochanteric fractures.

    For subtrochanteric fractures in which the lesser trochanter is dissociated from the proximal fragment but the remainder of the proximal femur remains intact, interlocking nails with the standard oblique interlocking screw are unable to provide fixation. Interlocking nails with the proximal screws directed into the neck and head of the femur are required (Fig. 27-30 and Fig. 27-31). Because of the complexity of this surgery, patient numbers in published series using this technique are relatively small compared with the large patient populations in investigations using standard interlocking techniques. Nevertheless, for this injury, the results of these studies have been promising, despite an increase in the technical difficulty of nail insertion.37,169,327 Because the piriformis fossa lies posterior to the femoral neck, anteversion is built into these devices to ease correct placement of these proximal interlocking screws. If the proximal fragment has fracture extension into the area of nail insertion, then the nail can displace posteriorly through the fracture site. Fractures into the piriformis fossa, therefore, are relative contraindications to intramedullary nailing and open reduction with plating should be considered. Further discussion regarding these difficult intertrochanteric/subtrochanteric fractures is found in Chapter 26.

Fig. 27-31Tija de reconstructie Russel-Taylor

Supracondylar Fractures. Infraisthmal and supracondylar fractures pose problems similar to those of proximal fractures. Infraisthmal fractures, defined as fractures extending from the isthmus of the medullary canal to the supracondylar region, include most distal-third shaft fractures. These fractures are notorious for a high complication rate after plating and screw fixation, especially when rigid fixation is not achieved.336 The major loading of this region of the femur, along with the inadequacy of endosteal purchase on the distal fragment, also results in a higher nonunion rate with interlocking nails than is seen in midshaft fractures. Despite these obvious mechanical limitations, the results with interlocking nails are superior to those of closed treatment and those of plating.286

    Supracondylar fractures present additional mechanical and technical problems. Traction and cast bracing are hampered by a tendency toward varus and internal rotational deformity. Malunion is common.286 Good results are attainable with the 95° angled blade plate or screw plate if there is close adherence to the ASIF principles of rigid fixation. Placement of the blade plate in all three planes must be precise. Double plating (lateral and medial) is indicated in unstable fractures with extensive medial comminution.304 Bone grafting and delayed weight bearing normally are required as part of the postoperative regimen. The indirect reduction technique with minimal exposure of any comminuted fragments can be especially useful in the AO type A3 and C3 injuries.33

    A major complication of plating of distal-third shaft fractures is refracture after removal of the plate. Refracture is especially likely if supplemental interfragmental lag screws were used for the initial internal fixation.38 Cortical atrophy under the plate and the stress riser effect of the screw holes combine to result in refracture with minor trauma in nearly 10% of cases in which plates are removed, regardless of the timing of plate removal. Refracture can be treated easily by closed intramedullary nailing.

    The Zickel supracondylar device was designed specifically for the problem of comminuted distal fractures in osteoporotic bone.383,384 The flexible, sled-shaped ends of the Zickel nails are inserted through the medial and lateral condyles up into the medullary canal. The ends are tapered for ease of insertion, and closed insertion under fluoroscopic control is feasible in most cases. The nails are anchored to the condyles with screws. Although a high union rate is obtained with these implants, shortening of the fracture around the nails does occur. Because of its poor mechanical properties, use of the Zickel supracondylar device should be limited to low supracondylar fractures in the elderly.

    A cannulated, prebent interlocking nail called the GSH (Green, Seligson, Henry) supracondylar nail has been designed specifically for low infraisthmal and supracondylar fractures200 (Fig. 27-32). It is inserted in a retrograde fashion through an entrance portal in the intercondylar notch of the distal femur. When the nail is inserted using a closed technique, rapid fracture healing can be expected. Severe osteopenia of the distal femur may necessitate supplemental external fixation with a cast brace. Nail breakage remains a problem and modifications in the nail design, including larger-diameter nails, small locking holes, and a nonfenestrated central portion to the nail, have been recommended.155 The exact role of this nail in the management of AO type A and type C supracondylar/intercondylar fractures will not be clear until larger clinical studies are available.200

    Interlocking nails with distal screw fixation yield excellent results for most distal fractures (Fig. 27-33). They are the preferred implant for most infraisthmal fractures and for selected supracondylar fractures. Two distal locking screws are needed to ensure sagittal plane stability. The risk of implant failure through the most proximal of the distal screw holes mandates delayed weight bearing until fracture healing has progressed.63 The Brooker-Wills nail with locking fins in place of distal locking screws has been used extensively for these distal-third shaft fractures.47 However, technical problems with insertion limit the usefulness of this nail for distal-third fractures as well as for any shaft fractures.23 A more detailed description of supracondylar fractures is provided in Chapter 30.

Open Fractures

Open fractures of the femoral shaft often result from high-energy accidents and frequently are accompanied by injuries to multiple organ systems.15,74,76 Open fractures of the femur traditionally have been treated with debridement and skeletal traction. Clinical research in the last several decades has demonstrated that several major benefits can be derived from a more aggressive surgical approach.

    Retrospective studies in the 1970s and 1980s demonstrated that the multiply injured patient's chance of survival was increased by immediate fixation of long-bone fractures.122,163,218,288,289,314 A randomized prospective study by Bone and colleagues34 showed that immediate stabilization of femoral shaft fractures in the multiply injured patient resulted in a decreased prevalence of adult respiratory distress syndrome, fewer days in the intensive care unit, and decreased hospital costs. These investigations heightened the awareness of orthopaedists and trauma surgeons to the importance of early orthopaedic intervention in their patient populations.

    The introduction of interlocking nailing widened the spectrum of femoral shaft injuries that could be stabilized by closed intramedullary techniques. Open fractures often are characterized by severe fracture comminution, bone loss, and a proximal or distal fracture level. Interlocking nails are uniquely suited to handle these fracture patterns, and the results of interlocking nailing have been superior to those of all other previous treatment methods.162,372

    Finally, dissatisfaction existed with the accepted treatment alternatives. Skeletal traction, which permitted little patient mobility, did not allow adequate wound access and was associated with high rates of pulmonary complications in the multiply injured patient.34,288 This method provided the least softtissue and bony stability of all treatment options, factors thought to be important in the control of infection in open fractures.75,76

    Intramedullary nailing by open technique,167,199 open nailing with cerclage wiring,163,351 and open reduction and plating of open femoral shaft fractures18,124,203,290,300 resulted in unacceptable rates of infection, and these techniques were readily abandoned for these injuries. The high rates of infection were attributed to the cumulative effects of bone and tissue necrosis resulting from the injury, contamination introduced at the time of the accident, and further tissue devitalization during surgical dissection.

    The closed insertion of multiple nonreamed intramedullary rods, such as Ender rods,121,207,237,257 theoretically provides an attractive alternative to open reduction, because nonreamed intramedullary nailing disrupts the endosteal vascular supply to a lesser degree than does reamed intramedullary nailing.284 The frequent complications of knee pain, unstable fixation, and malrotation, however, have diminished the popularity of this technique.52,106,144

    External fixation provides excellent bony stabilization, wound access, and early patient mobilization, avoiding most disadvantages of skeletal traction. Unfortunately, in a substantial percentage of open femoral fractures treated with external fixation, decreased range of motion of the knee and pin-tract infection develop, leading to suboptimal results.132,241 However, the prevalence of chronic infection at the fracture site is markedly decreased in injuries treated with this technique, as compared with previously discussed methods.18,21,294,295,358

    Before the 1980s, closed intramedullary nailing was not commonly performed in open femoral fractures.57,77,194 Theoretic reasons to avoid its use include the following: (1) all open fractures are contaminated injuries; (2) all open fractures have some degree of tissue crush, necrosis, and periosteal stripping; and (3) reaming the medullary canal devascularizes the bone further through obliteration of the endosteal blood supply.3,251,284

    Chapman76 suggested that open femoral fractures be treated with delayed intramedullary nailing, usually 5 to 7 days after wound closure. This delay allowed the immune system to control existing fracture-site contamination, decreasing the rate of postoperative infection. He reported no infections with delayed closed intramedullary nailing of grade I and grade II open fractures, which were stabilized initially with skeletal traction.76 Despite these excellent results, delayed nailing failed to provide the benefits of early fracture fixation in the multiply injured patient.

    Winquist and colleagues370 performed immediate and delayed closed intramedullary nailing in open femoral shaft fractures after wound debridement and found it to be a safe technique in grade I and grade II open injuries. They recommended immediate stabilization of these less severe open fractures, because the prevalence of infection (2%) was not affected by the timing of the operative stabilization. These findings have been substantiated by the later investigations of Lhowe and Hansen,194 Brumback and colleagues,57 and others.128,248 Each investigator emphasized the requirement of a thorough wound debridement before intramedullary nailing and stressed the selection of appropriate candidates for the procedure (Fig. 27-34).

    Two major considerations must be evaluated in deciding whether an open femoral fracture is best treated by immediate intramedullary nailing. First, multiply injured patients with an ISS greater than 18 run a high risk of pulmonary complications and benefit from early fracture stabilization on the day of injury.

    Second, the size and contamination of the soft-tissue wound must be accurately assessed. The Gustilo classification of open fractures,130,131 which is used most commonly in assessing soft-tissue injury, defines three specific variables in determining the applicability of intramedullary nailing to a given open fracture: the time after injury; the degree of tissue necrosis, crush, and periosteal stripping; and the magnitude of the wound contamination.

    Because all open fracture wounds are contaminated, and the bacterial flora continues to proliferate over time, the time since injury may be an important factor in the development of wound infection. The longer the contamination remains unchecked, the greater is the risk of infection.292 This is reflected in the Gustilo classification by the categorization of any open fracture in which debridement is delayed more than 8 hours as a grade III open fracture. Brumback and colleagues57 suggested that immediate intramedullary nailing of open femoral fractures was contraindicated if the debridement procedure was performed more than 8 hours after injury. Therefore, a timely, thorough debridement is a prerequisite to immediate intramedullary nailing. With severe soft-tissue injury, the response of the tissues to the bacterial contamination is compromised. Therefore, wounds with minimal tissue crush and periosteal stripping (Gustilo grade I and grade II injuries) carry a lower risk of infection after immediate intramedullary nailing than do those with severe soft-tissue injuries.

    Injuries accompanied by extreme contamination, such as farm accidents, shotgun blasts, and explosions, are considered grade IIIB open fractures and have high rates of infection, regardless of the method of fracture fixation.76 The risk of infection undoubtedly is increased if the contamination occurs in a severely injured soft-tissue environment. The presence of gross contamination in the medullary canal of the major fracture fragments should preclude immediate internal fixation.

    Taking all these factors into account, the following treatment guidelines have been developed. A systemic antibiotic, usually a cephalosporin, is administered, and the patient is prepared for surgery after emergency resuscitation and assessment. Before any external or internal fixation is undertaken, all open wounds are debrided radically and the degree of contamination of the fracture site is assessed. Jet lavage irrigation with a minimum of 6 to 10 L of fluid is used during debridement. Surgical wounds can be closed, but all traumatic wounds are packed open. Regardless of the magnitude of the multiple organ system injury, grade I and grade II open fractures without gross medullary contamination are treated best by immediate intramedullary nailing. The multiply injured patient with an open femoral fracture should be treated with some form of immediate stabilization; a patient with a grade IIIA open femoral fracture can be treated safely with immediate intramedullary nailing, if the debridement is performed within 8 hours of injury. If the debridement is delayed or if a grade IIIB injury is present, then external fixation may be the treatment of choice. No investigation has studied the delayed conversion of external fixation to intramedullary nailing with respect to open femoral fractures. In patients without multiple injuries, grade IIIA and selected grade IIIB open femoral shaft fractures can be placed in temporary skeletal traction, awaiting wound closure. Delayed intramedullary nailing is performed 5 to 7 days after soft-tissue coverage. Isolated open fractures with severe contamination require external fixation.

    For those fractures associated with arterial lesions (grade IIIC) that require repair, external fixation may be the best method of immediate stabilization because it can be applied quickly and then realigned after vascular repair. After revascularization of the limb, this fixation can be converted to an open plating or an intramedullary nailing, even on the day of injury. Plating of grade IIIC open fractures has been suggested because the surgical exposure to the bony injury usually is already performed for the vascular repair.193 A grade IIIC open fracture in an unstable multiply injured patient may be a relative indication for limb ablation, because the critical nature of the patient's condition and other organ system injuries can make limb revascularization a life-threatening procedure.

    When intramedullary nailing is selected as the method of stabilization, it should be performed as a separate operative procedure after wound debridement.57 The nailing is performed through a standard antegrade approach on a fracture table. High rates of fracture union are reported in open femoral fractures treated in accordance with these guidelines. Bone grafting usually is not necessary despite the loss of small devitalized cortical fragments from the injury and debridement.57 Chapman73 has shown closed intramedullary bone grafting to be an excellent technique for segmental bone loss of the femoral shaft. Such surgery is most effective if it is performed several weeks after soft-tissue coverage is achieved.

    Reports in the literature indicate low rates of infection for grade I, grade II, and grade IIIA injuries treated in accordance with these guidelines, but most authors agree that grade IIIB injuries remain a therapeutic problem.57,194 No large series of grade IIIC open femoral shaft fractures exists, but the reported cases document the relatively poor limb function and high prevalence of late infection in these injuries.104

    Nonreamed interlocking nails are being investigated for open femoral fractures. These devices represent a potential advance in the treatment of open femoral shaft fractures because the bone necrosis created by medullary reaming may be diminished. No long-term data on the results with these implants are available. Concern over the durability of these smaller implants has been expressed, yet the early clinical experience has been favorable. Recent concern over reamed intramedullary nail insertion having a potential deleterious effect on pulmonary function has led to an increase in the use of nonreamed nails for both open and closed femoral fractures. Further study is required in this area.

Ipsilateral Femoral Neck and Shaft Fractures

Concurrent ipsilateral femoral neck fractures are reported in 2.5% to 5% of patients with femoral shaft fractures.17,71,114,339,340,373 The wide variability of fracture patterns of the proximal femur and shaft challenges the treating orthopaedist. Since the first description of this complex injury by Delaney and Street in 1953,101 more than 70 methods of treatment have been reported in hundreds of cases.340 There has been a recent resurgence of interest in these injuries.26, 37, 81, 189, 262, 278, 373, 376, 377 Some investigations include only those injuries with ipsilateral femoral neck and shaft fractures,37,141,148,339,373 whereas others expand the category of proximal injuries to include intertrochanteric fractures.17,29,71,114,117 In all published series, femoral neck fractures occur more often in conjunction with femoral shaft fractures than do intertrochanteric injuries, by a ratio of about 7:1.26 Reflecting the high-energy nature of these injuries, associated knee injuries, including patellar fractures, tibial plateau fractures, and intraarticular injuries, often accompany the femoral fractures.26

    Whereas the shaft fractures vary widely in their location and comminution, the neck fractures usually are a vertical shear (Pauwels grade III) pattern373 (Fig. 27-35). The typical neck fracture commences inferiorly at the base of the femoral neck and travels superiorly to the subcapital portion of the neck. Because much of the impact energy of the injury is dissipated at the shaft fracture, the neck fracture usually is minimally displaced and noncomminuted. Therefore, the prevalence of osteonecrosis of the femoral head is low after this combined femoral fracture.26

    Diagnosis of the neck fracture often is delayed because of failure to evaluate the entire femur radiographically when there is a shaft fracture.26,278 About one fourth to one third of neck fractures initially are overlooked, and then subsequently are detected after stabilization of the shaft fracture.26,278 Some do not become apparent until weeks after the patient has been discharged from the hospital.278 Delayed diagnosis is not associated with an increased rate of femoral head osteonecrosis26 and most cases can be salvaged with good functional results by closed reduction and insertion of multiple pins or screws around in situ nails.

    The literature describes some of the femoral neck fractures as iatrogenic injuries created at the time of intramedullary nailing.138,140 It is difficult to separate this group from those that are present before surgery but are recognized only after the procedure. Although an incorrect starting position of the intramedullary nail may increase the likelihood of an iatrogenic neck fracture, it is probable that many of these injuries are not recognized before surgery and then are attributed to, or propagated by, the surgical procedure. Plain radiographs of the proximal femur, preferably with 15° internal rotation of the hip, should be obtained as part of the initial evaluation followed by fluoroscopic evaluation of the hip once the patient is positioned for the nailing procedure.

    Femoral neck nonunion and malunion are more common problems than are osteonecrosis of the femoral head26,37,373 or complications secondary to the shaft fracture. Therefore, it is important to give priority to anatomical reduction and rigid internal fixation of the femoral neck fracture.81 Subcapital and transcervical fractures usually are stabilized with lag screws; fractures occurring at the base of the neck or the intertrochanteric region can be treated best with sliding compression screw devices. The former fixation is compatible with a wide range of treatment options for the femoral shaft, whereas the latter greatly restricts the alternatives for femoral shaft fixation. The historical dilemma in the treatment of these injuries is thus demonstrated: to obtain anatomical reduction and rigid fixation of the neck fracture without compromising the treatment of the femoral shaft fracture.

    Anatomical reduction of the femoral neck usually can be achieved even in the presence of an unstable shaft fracture. Malreduction of the neck fracture results in nonunion in many patients.26,37 Symptomatic varus nonunion has been reported to occur in as many as 18% of these injuries and requires proximal femoral valgus osteotomy to achieve union.373 Fixation of the femoral neck fracture ideally should provide compression across the fracture site. Therefore, devices such as the Ender rod, the Zickel nail,17 and the Williams nail143,150 are poor choices for fixation, despite having been used successfully in the past. These implants tend to distract the femoral neck fracture, possibly increasing the prevalence of nonunion. If rigid, intrafragmental compression of the neck fracture is accomplished, fracture healing within 3 to 6 months can be expected with most fixation techniques.

    The most commonly reported method of fixation is antegrade intramedullary nailing of the femoral shaft fracture combined with multiple pin or screw fixation of the femoral neck fracture.26,189,373 An alternative retrograde technique with insertion of a short nail through the side of the medial femoral condyle has been proposed to allow for more space for accurate insertion of the femoral neck screws.340 However, interlocking nails cannot be readily inserted with this method, compromising fixation in comminuted, oblique, or spiral femoral shaft fractures. Although excellent results have been reported with this retrograde nailing protocol, it has not received widespread acceptance. A different retrograde technique using an intraarticular, intercondylar entrance portal permits the use of standard interlocking nails but remains experimental at this time228 (see Fig. 27-36). Both these retrograde methods must be used cautiously because retrograde nailing imparts a cephalad load in the proximal femur that can lead to varus displacement of a femoral neck fracture.

    Antegrade nailing and screw fixation of an ipsilateral femoral neck and shaft fracture are technically demanding.373 Accurate placement of three or four 6.5-mm cancellous screws is important to prevent obstruction of the intramedullary reamers or passage of the nail (Fig. 27-37). The use of cannulated lag screws assists in precise screw insertion anterior to the nail and centrally in the head and neck of the femur.189 Placement of at least one screw before intramedullary nailing is suggested to prevent displacement of the femoral neck fracture.62 The major complication of this technique has been failure to achieve anatomical reduction of the femoral neck fracture. If the neck fracture is markedly displaced or irreducible, an anterior open reduction with provisional K-wire or screw fixation of the neck should be performed.

Fig. 27-37 Relatia corecta dintre suruburile de col si tija. De remarcat punctul de intrare anterior si traiectul spre cortexul posterior al capului femoral. 

    Although interlocking nailing improved the treatment of the shaft fracture, it was not until the introduction of the second-generation interlocking nails, such as the femoral reconstruction nail, that closed intramedullary fixation could securely stabilize both the proximal and shaft fractures with a single device. The proximal end of the nail is designed to accommodate two smooth-shanked lag screws that gain purchase in the head and neck of the femur (Fig. 27-38). These screws serve both to fix the neck fracture and to lock the shaft fracture. Anteversion of these two screws of about 10° has been designed into these nails to allow passage of the lag screws through the nail and up the femoral neck.

    Biomechanical studies of cadaveric femora demonstrate that the ultimate strength of the reconstruction nail fixation of the neck fracture is higher than that afforded by cancellous screw fixation alone.275 The passage of the locking screws through the nail prevents varus collapse of the neck fragment, which is seen often when only cancellous screws are used. The bending moment on the proximal screws also is decreased by their passage through the nail. Therefore, the mode of failure after fixation of an ipsilateral neck fracture with a reconstruction nail is more likely to be cutting out of the locking screws.275

    Because of the requirement for accurate placement of the proximal screws in the second-generation interlocking nails, these devices are even more technically demanding than is routine interlocking fixation.373 The femoral canal should be overreamed 1.5 to 2 mm larger than the nail to allow for adjustment of the anteversion angle. Because the neck originates anteriorly on the proximal femur, the nail often must be externally rotated 30° to 40° to obtain a bulls-eye screw placement in the femoral head. This may be true even with the built-in anteversion in these nails. If the nail is not driven in a proper distance, only one screw can be inserted into the head and neck.37 The lateral alignment of the proximal screws can be observed on fluoroscopy by the proximal targeting jig. It is critical, therefore, that careful attention be paid to the depth of nail insertion and its rotation in the femur. If inaccurate alignment is noted, the nail should be removed and repositioned, and the alignment of the guide pins for the locking screws should be rechecked. Several series of neck and shaft fractures stabilized with reconstruction nails have reported satisfactory results.

    Femoral shaft fractures also are associated occasionally with hip dislocations, acetabular fractures, or pelvic ring disruptions189,376 (Fig. 27-39). Functional results are optimized by early rigid fixation of all fractures. Emergency reduction of hip dislocations, often with the assistance of a temporary external fixation pin in the proximal femur, is mandatory. If extensile exposure and dissection of the gluteal musculature is necessary for acetabular or pelvic ring fractures, heterotopic ossification between the pelvis and the trochanteric entrance portal of the femoral nail is a serious problem. Prophylactic radiation therapy or indomethacin therapy helps lessen the prevalence of heterotopic ossification in such cases.

Ipsilateral Femoral Shaft and Intercondylar Fractures

An intercondylar fracture of the distal femur rarely accompanies a fracture of the femoral shaft. When the combination does occur, two distinct types can be identified: (1) the intercondylar fracture that does not propagate proximally to be contiguous with the shaft fracture, and (2) the intercondylar fracture that forms a distal extension of the shaft fracture.

    These injuries traditionally have been treated by a variety of techniques, including open reduction of both fractures with a single plate, open reduction of both fractures with two separate plates, and open reduction of the intercondylar fracture and intramedullary nailing of the femoral shaft injury. Interlocking nailing has provided the ideal opportunity to combine the stabilization of these two injuries, especially in cases of nondisplaced intercondylar fractures.

    Interlocking nails have been used successfully to treat high supracondylar fractures of the femur and segmental fractures of the femur with supracondylar components.85,190,350,379 The applicability of this technique to ipsilateral fractures of the shaft and distal femur depends on whether the distal screws of interlocking nails can provide fixation of both the femoral shaft fracture and the supracondylar and intercondylar fractures. Therefore, this technique is dependent on the fracture pattern. Lateral and oblique radiographs of the distal femur are recommended to rule out fractures of the femoral condyles in the coronal plane (the so-called Hoffa fracture). Because the plane of these fractures parallels the interlocking screws, reduction and stabilization of this fracture variant by interlocking nailing is tenuous, and other methods should be selected.

    The intercondylar fracture must be stabilized initially with cancellous lag screws placed anteriorly or posteriorly in the femoral condyles. Anatomical reduction of the articular fracture is imperative and may necessitate open reduction. Open reduction through a parapatellar arthrotomy provides the best visualization of the fracture site. Nondisplaced fractures can be treated with percutaneous cancellous screw fixation under image intensifier control (Fig. 27-40 and Fig. 27-41). Our experience with a limited number of these fractures indicates that rotational malalignment of the femoral condyles is common, and an arthrotomy should be performed to check visually the reduction of the articular surfaces. Central placement of the screw in the condyles will obstruct the passage of the interlocking nail, leaving the distal interlocking screws too proximal for adequate condylar fixation. The preferred number of lag screws depends on the fracture pattern. The nailing should be performed after fixation of the intercondylar fracture with two screws to prevent possible displacement of the intercondylar fracture. If further lag screw placement is needed, it should be performed after nail insertion. Standard interlocking nailing then is performed carefully, with attention paid to reaming into the intercondylar portion of the femur. This reaming is necessary to prevent spreading of the intercondylar fracture on insertion of the nail. An intramedullary nail of sufficient length to extend down to the subchondral bone of the intercondylar notch is inserted so that the distal interlocking screws act to stabilize both the intercondylar fracture and the interlocking nail to the distal femur. Because the stability obtained with this method depends on the fracture geometry and the purchase of the lag and locking screws, the postoperative rehabilitation must be individualized to each injury. Weight bearing on intercondylar fractures should be postponed for at least 6 weeks after fixation.

    If the distal fracture is too comminuted or too low, or if it has fracture lines in the coronal plane, then fixation with this method is contraindicated. Open reduction and plate fixation are used in such cases. Acceptable results have been reported with both the open plating and interlocking nailing with adjuvant screw fixation techniques in these rare injuries.66,374

Pathologic Fractures

Pathologic fractures involve the femoral shaft much less frequently than they do the proximal femur. Most are transverse or short oblique fractures sustained with minor violence. Pathologic fractures should be suspected if there is any scalloping or erosion of the cortex at the fracture site. The history of minor trauma along with the radiographic evidence of pathologic bone usually leads to a presumptive diagnosis of pathologic fracture. Excluding osteoporosis, most pathologic fractures are secondary to metastatic disease. Primary benign and malignant tumors of the femoral shaft are rare.

    Pathologic fractures entail both diagnostic and therapeutic challenges. If the primary diagnosis is unknown, biopsy is mandatory. A biopsy technique should be selected that minimizes any seeding of the adjacent tissues with tumor. Biopsies of most metastatic tumors are taken at the time of skeletal fixation. As with all bone tumors, careful histologic and radiographic correlation is needed for a correct diagnosis.

    The goal of treatment, especially for fractures through metastases, is rigid stabilization of the femur, affording immediate pain relief and early weight bearing. Prompt surgical stabilization of pathologic fractures facilitates nursing care, reduces hospital costs, and provides a beneficial psychological effect on the patient. If no preexisting oncology-related problems, such as hypercalcemia, dehydration, or pulmonary insufficiency, are present, surgery should be performed as expeditiously as possible. Traction and cast bracing necessitate prolonged bed rest without predictable pain relief or healing of the pathologic fracture. Plating is associated with slow healing and requires prolonged protection from weight bearing (Fig. 27-42). The open exposure of plating risks major hemorrhage in certain highly vascular tumors. Further growth of the tumor also can compromise plate fixation.

    Despite these limitations of plating, satisfactory functional results have been reported. Broos and associates49 used anterior and lateral plates supplemented with polymethylmethacrylate to stabilize ten pathologic fractures of the femoral shaft. In their combined series of 48 pathologic femoral fractures, 75% of patients recovered the ability to walk. These investigators considered contraindications to surgical stabilization to include a survival expectancy of less than 4 weeks, a premorbid general condition that precluded a safe general anesthesia and surgery, and complete mental deterioration of the patient to the point at which pain relief was not an issue.

    Intramedullary nails achieve most of the therapeutic goals for pathologic fractures. Small, well-localized lesions near the isthmus are manageable with conventional nails. Large lesions with extensive bone loss, lesions proximal or distal to the isthmus, and multiple lesions in the shaft require adjunctive fixation with locking screws or polymethylmethacrylate. A variety of techniques have been described for the use of bone cement.181 Whatever construct or technique is used, rigid fixation must be the goal. Intramedullary nails do not preclude the early use of radiation therapy for shrinkage of the tumor. The Zickel nail is especially well designed for pathologic fractures in the subtrochanteric region.

    In a series of 43 femora with metastatic lesions, Sangeorzan and colleagues305 reported good results with prophylactic Zickel nailing of impending subtrochanteric and proximal shaft fractures. A modified closed nailing technique was used to minimize blood loss and operative time. Eighty percent of the patients walked on the leg within 4 days after the nailing. The average length of survival after surgical stabilization is 9 to 12 months in most published series.49,305

    Controversy still surrounds the issue of the need and timing for prophylactic nailing of metastatic lesions without fracture of the shaft (Fig. 27-43). Radiographic guidelines have been developed based on retrospective clinical studies.221 Prophylactic nailing is recommended if (1) the ratio between the width of the metastasis and the bone is greater than 0.6, (2) the axial cortical destruction is greater than 30 mm in length, or (3) the cortical destruction is greater than 50% of the circumference of the shaft. Smaller lesions in the subtrochanteric region are especially likely to act as stress risers for pathologic fractures (Fig. 27-44).

    Pathologic fractures also can be due to Paget disease.129 The femur is the most common bone fractured in Paget disease. The usual transverse fracture located in the subtrochanteric or proximal third level of the bone occurs most frequently in the late stages of the disease. Fractures in the early stages of Paget disease may hemorrhage excessively. The treatment of pagetoid fractures can be difficult. Traction treatment is associated with varus malunion and refracture.129 Intramedullary nailing is preferred in most cases but can be technically demanding. A short nail may be required to prevent penetration of a deformed shaft. Fracture healing, however, proceeds rapidly. In the presence of severe deformity of the shaft, other treatment options, including corrective osteotomies, plates, or traction, can be chosen.

Fractures in Elderly Patients

Although proximal femoral and distal femoral fractures far outnumber femoral shaft fractures in elderly patients, the incidence of shaft fractures in this group is increasing with the aging of the American population. Most shaft fractures in the elderly are caused by low-velocity injuries from falls at home. Associated injuries are few. The osteopenic cortical bone often is comminuted despite the low-velocity mechanism of injury.235 The goal of treatment is similar to that of hip fractures in the elderly and should include sufficiently rigid fixation of the fracture to allow full weight bearing on the leg. The osteopenic diaphysis with a large medullary canal is not amenable to stabilization with either plating or external fixation, and intramedullary nailing appears to offer superior functional results over other forms of fixation.6,151,235

    Moran and coworkers,235 in a series of 24 patients with a mean age of 77 years, noted rapid healing of femoral shaft fractures treated with statically locked nails. They used large-diameter nails in their patients, nearly all of whom were women. As would be expected in such an elderly population, perioperative complications, including decubitus ulcers, urinary tract infections, and congestive heart failure, were common, and 4 of the 24 patients died after surgery. Alho and associates6 reported similar results, with an additional complication of postoperative shortening of the femur by more than 2 cm in more than half their 15 patients treated by dynamically locked nails.

    Perioperative complications from intramedullary nailing of shaft fractures in elderly patients can be minimized by careful adherence to several technical principles. The status of the ipsilateral hip joint must be assessed by perioperative radiographs because many elderly patients have preexisting hip pathology. Moran and coworkers identified 5 of their 24 patients as having either osteoarthritis or previous hip fracture that limited hip adduction and required modification of patient positioning during nailing of the shaft fracture. One of the patients had marked bowing of the shaft, which also necessitated a change in the nailing technique. The capacious canal is filled best with a large-diameter nail, and static locking is imperative to prevent shortening around the nail. Distal locking screw purchase can be compromised by the osteopenic bone in the distal femoral metaphysis. Fully threaded locking screws are preferred, and a locking bolt on the medial end of the screw can prevent postoperative loosening and backout of the screw. Moran and coworkers235 supplemented their distal locking screws with intramedullary polymethylmethacrylate in several cases.

    Late complications after nailing also are more common in elderly patients. The large, stiff nail can create a stress riser effect in the proximal femur and predispose to subsequent femoral neck or peritrochanteric fracture.235 Careful placement of the entrance portal and precise reaming of the canal lessen the likelihood of such proximal femoral fractures.

Gunshot Fractures

Gunshots are a common mechanism of injury for femoral shaft fractures in most large urban communities. Most are small-caliber, low-velocity injuries. The effect of a small-caliber missile on the tubular bone of the diaphysis is different from that on metaphyseal bone.

    Four fracture patterns have been identified after gunshot wounds to the femur.325 The 'drill hole' fracture characteristically occurs in the distal femoral metaphysis secondary to a direct impact of the missile on the cancellous bone. The butterfly fracture results from a direct hit of the bullet on the diaphysis with variable degrees of cortical comminution. An incomplete fracture is caused by nicking or incomplete bone penetration of the missile. In this last fracture, the impaction of a small cortical fragment can weaken the bone even though the femoral diaphysis is sufficiently intact to allow for full weight bearing. The fourth pattern is a spiral fracture, which can occur proximal or distal to one of the three other patterns. Although this fracture traditionally has been attributed to the fall that some patients report after being shot, it probably is due to a stress riser operating on the loaded femur at remote distances from the site of missile impact.325

    For most gunshot fractures of the femoral shaft, the preferred treatment is the same as if the fracture were closed.43 No formal debridement of the fracture site or coring of the entrance hole is necessary.149 Closed interlocking nailing is performed in a standard fashion. The preferred timing for nailing is unaffected by the presence of the bullet tract, although other gunshot injuries to the thorax, abdomen, or head may alter the timing of nailing. The results are comparable to those obtained with closed fractures28,192,375 (Fig. 27-45). Infection rates are similar to those seen after nailing of closed fractures. Immediate nailing of these fractures decreases the cost of hospitalization and subsequent care in this often unreliable patient population.28,192 The principles of management of high-energy gunshot injuries differ significantly. High-velocity rifle injuries and close-range shotgun blasts are associated with extensive soft-tissue cavitation and necrosis, and, therefore, should be considered grade III open fractures. Thorough debridement of the fracture with removal of all foreign material and open wound care are imperative. External fixation or traction is indicated if the soft-tissue wound is extensive and bone is exposed in the open wound. Delayed internal fixation after soft-tissue coverage facilitates fracture management in selected cases.43

INTRAMEDULLARY NAILING: TECHNIQUES AND PITFALLS

Timing of Surgery

The relative merits of early versus delayed nailing for femoral fractures have been studied extensively over the last 40 years. Early work suggested more rapid fracture healing with delayed fixation.80,185,326 Other studies refuted these claims,107,256 and most recent clinical and laboratory investigations support the concept that delaying the timing of intramedullary nailing has no beneficial effect on fracture healing.

    A more salient argument for early nailing is its advantageous effect on prompt patient mobilization and pulmonary function, especially in the multiply injured patient.

    Retrospective investigations by Goris,122 Meek,218 Johnson,161 Riska,288,289 and Seibel314 and their colleagues demonstrated improved survival for the multiply injured patient who received fracture fixation within 24 hours of injury. The improvement resulted from a lower prevalence of sepsis due to a decrease in the rate of pulmonary insufficiency. Lozman and associates199 reported a randomized prospective investigation that verified the beneficial effects of early fracture fixation with respect to the pulmonary and cardiovascular systems. Poole and coworkers272 found no increased risk of pulmonary or cerebral complications from early femoral fixation in a series of patients with head trauma and long-bone fractures.

    Bone and colleagues34 published the results of a randomized prospective study at Parkland Memorial Hospital on both isolated femoral fractures and femoral fractures in patients with multiple organ system injury. All patients had femoral shaft fractures and received either early or delayed fixation. No patient with an isolated femoral fracture (ISS á 18) had pulmonary insufficiency, but 23% of those with isolated injuries treated by delayed fixation (more than 72 hours after injury) had abnormal arterial blood gases as compared with 10% of those whose fractures were stabilized within 24 hours. The length of hospital stay and hospital costs were decreased in the immediate fixation group. In the multiply injured population, the differences between the immediate and delayed stabilization groups were even more pronounced. Compared with those treated with delayed fixation, multiply injured patients undergoing immediate femoral stabilization had lower prevalences of pulmonary insufficiency and adult respiratory distress syndrome, fewer days in the intensive care unit, fewer days on ventilatory support, shorter hospital stays, and lower total costs for inpatient care.

    Reaming of the femoral nail results in increased intramedullary pressure and variable amounts of embolization of bone marrow contents to the lungs. Wenda and colleagues360 measured increases in intramedullary pressure up to 200 to 600 mm Hg during reamed nailing compared with only 70 mm Hg during nonreamed nailing. The triglycerides and other marrow elements cause the release of various mediators in the lungs that increase pulmonary capillary permeability.260,261,360 The magnitude of the embolization as measured by echocardiography appears to be much greater when reamed nailing is performed compared with nonreamed nailing.253,360 No clinical studies have documented the importance of these observations on the pulmonary function of patients, but they have led some investigators to recommend the routine use of nonreamed nails, especially in multiply injured patients.12,261 Until further studies clearly demonstrate a better risk-benefit profile for nonreamed nails, reamed nailing remains our preferred technique. The results of all these studies over the last 25 years make it apparent that immediate fixation of femoral shaft fractures provides the optimal environment for patient recovery.97,122,199 Immediate fixation of femoral shaft fractures at our institutions is preferred for isolated shaft fractures and is mandatory, except in the most extenuating of circumstances, for femoral fractures in the multiply injured patient.

Preoperative Planning

The clinical results of closed interlocking nailing are largely a function of meticulous preoperative and intraoperative planning. As with any complex surgical procedure, close attention to details is imperative for a successful result.136 Weller and coworkers359 poetically noted that 'most complications happen, when the surgeon-either pressed by time or out of an unjustifiable artistic liberality-deviates from the regular technique.' Preoperative anticipation of technical problems can save the surgeon considerable time in the operating room.

    Diagnostic radiographs must be of sufficient quality to assess the extent of fracture comminution. Longitudinal fissures in the proximal or distal fracture fragments can be missed with suboptimal radiographs (see Fig. 27-21). Such nondisplaced comminution can influence the choice of locking screws or, in cases of fractures extending into the hip or knee joints, the preferred fixation implant. Biplanar radiographs of the knee and an anteroposterior radiograph of the pelvis are part of the standard evaluation of a femoral shaft fracture and assist in ruling out associated hip injuries and ligamentous injuries around the knee.

    The geometry and dimensions of the femur can be assessed on the plain radiographs. The medullary width of the isthmus on the anteroposterior radiograph is a good measure of the probable width of the nail to be used. For simple Küntscher nailing, a nail with a diameter 2 mm greater than the radiographic medullary diameter is optimal. Filling of the medullary canal is less critical in cases in which static interlocking nailing is required.

    Preoperative measurements of femoral length and the ideal length of the anticipated nail are necessary. Inadvertent lengthening or shortening of the femur during nailing can occur easily, especially in Winquist type IV comminuted fractures. Clinical measurement of the contralateral uninjured femur from the tip of the greater trochanter to the lateral aspect of the knee joint provides useful surface landmarks for correct length. Radiographic measurement of the contralateral femur with a nail of known length taped to the lateral surface of the thigh yields a more precise determination of normal femoral length. With this technique, problems with radiographic magnification are obviated, and both the preferred length of the nail and its precise depth of insertion into the distal fragment are easily calculated. Alternatively, the Küntscher ossimeter, which corrects for radiographic magnification, can be used. Some interlocking nailing systems offer radiographic templates that can be used for measuring nail size and position for complex fracture patterns. A stock of standard cloverleaf nails and interlocking nails of at least 4 cm greater and lesser length and of at least 2 mm greater and lesser width than the preoperative measurements should be available in the operating room (Fig. 27-46).

    If closed nailing is not to be performed on an emergent basis, the patient's leg is placed in balanced suspension traction using a proximal tibial pin. Preoperative distraction of the major fracture fragments should be ensured by the application of 25 to 40 lb of traction weight. If surgery is postponed for more than 3 to 5 days, radiographic documentation of fracture distraction using a lateral radiograph of the femur is advisable. Simple transverse fractures with spiked bone ends are especially difficult to reduce if surgery is delayed, and overdistraction of the fracture fragments of at least 5 to 10 mm should be sought.

    A systemic antibiotic, usually a first- or second-generation cephalosporin, is administered 30 minutes before skin incision and is continued for 24 hours after the surgery.

Patient Positioning

After the induction of general anesthesia, careful attention must be focused on patient positioning on the fracture table. Correct patient positioning often makes the difference between a successful and an unsuccessful nailing. If difficulty in achieving a closed reduction using a tibial pin is anticipated, a distal femoral pin should be inserted before positioning of the patient. Distal femoral shaft fractures are especially troublesome to reduce with tibial traction because of the deforming effects of the gastrocnemius muscle and the posterior knee capsule. A distal femoral Steinmann pin is inserted as far distal and anterior in the femoral condyles as feasible, thereby permitting direct longitudinal traction on the distal fragment without interfering with placement of the distal locking screws. Fluoroscopic guidance of this distal femoral pin is advisable to prevent penetration into the knee joint. If this pin blocks full insertion of the nail into the distal fragment, or placement of the distal screws, it can be extracted safely after partial insertion of the nail into the canal of the distal fragment. A traction bow similar to that used for skull traction and a modified technique using half-pins as joysticks also have been recommended for very distal fractures.350

    Femoral nailing can be performed with the patient in either the supine or lateral position on the fracture table.1 The supine position is preferable in patients with multiple injuries, especially associated pulmonary injury, unstable spine or pelvic fractures, or contralateral femoral fracture (Fig. 27-47). The supine position also is preferred for the insertion of second-generation nails when unobstructed visualization of the femoral head and neck on anteroposterior and lateral fluoroscopy is needed. Ventilatory assistance of patients with compromised pulmonary function can be impaired if a lateral position is used. A lateral position also can increase the risk of fracture displacement and further soft-tissue damage in patients with unstable pelvic and spinal injuries. However, access to the entrance portal of the nail in the trochanteric fossa often is limited using the supine position. The lateral position permits easy exposure of the entrance portal but does require slightly more time for patient positioning. Obese patients are ideal candidates for the lateral position.

    Closed reduction is achieved easily with the supine position, and problems of rotatory malalignment are encountered less frequently than with the lateral position. The trunk and pelvis of the patient are tilted away from the injured leg, providing a degree of adduction of the hip. The affected hip is flexed about 15° and the opposite leg is extended. The vertical post stabilizes the pelvis and the proximal femur. Satisfactory rotatory alignment is achieved in most cases by allowing the suspended leg to hang perpendicular to the floor. Attempts to judge the correct rotation based on the radiographic appearance of the fracture fragments usually are inaccurate. If necessary, the anteversion can be assessed on the fracture table, and the distal fragment can be rotated to restore the normal torsion of the femur. Proximal-third fractures tend to angle in varus orientation with the patient supine on the table, and adjustments in patient positioning, including switching to the lateral decubitus position, may be necessary in such cases. A long incision often is required for adequate exposure, especially in obese patients.

    When the lateral position is chosen, both vertical and longitudinal posts on the Maquet table are used to hold the pelvis during the reduction and nailing of the femur. The hip is slightly adducted and moderately flexed to improve the reduction of the fracture and enhance access to the trochanter. Traction is applied through the proximal tibial or distal femoral pin with the knee flexed a minimum of 60°. Traction through a foot plate with the knee extended can stretch the sciatic nerve and should be avoided. Internal rotation of 10° to 15° in relation to the floor usually guarantees correct rotatory alignment of the fracture fragments. A common error is to allow the leg to rotate externally on the fracture table, resulting in a 20° to 30° external rotational malalignment. Although most patients will accept this degree of malrotation, every effort should be made to prevent it. Extension of the contralateral leg allows for unimpeded free movement of the C-arm of the image intensifier (Fig. 27-48).

Fig. 27-48

    Satisfactory reduction of the fracture must be obtained in both the anteroposterior and lateral planes before preparation and draping of the leg. In the lateral position on the table, the proximal fragment tends to flex and adduct in relation to the distal fragment. A crutch can be used to support the proximal fragment and correct any residual mediolateral angulation or displacement. Gentle pressure with a crutch or lead-gloved hand is applied on the anterior thigh to confirm that any anteroposterior translation at the fracture can be corrected. Any residual minor displacement of the fracture fragments can be reduced during surgery. If near-anatomical reduction is not radiographically evident, however, adjustments in the position of the patient and the extremity must be made before draping. It may be necessary to release the traction and perform a formal manipulation of the extremity. Sufficient traction for slight distraction of the fracture aids in achieving reduction and passage of the guide pins. If cyanosis or mottling occurs in the leg, pressure on the anterior aspect of the hip by the vertical post should be relieved.

    An alternative nailing technique without the use of a fracture table has been recommended for selected fractures.24,214 Distraction of the acute fracture is accomplished through half-pins inserted into the proximal femur and the femoral condyles using an AO femoral distractor. Anatomical studies demonstrate that the proximal pin can be placed safely distant from the femoral artery and nerve and still not block the insertion of the nail. Although reduction must be achieved by manipulation during the procedure, satisfactory alignment can be obtained in most cases. This technique can be useful for multiply injured patients in whom the manipulation of positioning on the fracture table involves major risk. It is uncommon, however, for concomitant injuries to be of such severity as to preclude the safe use of a fracture table.

    Poor patient positioning before preparation and draping of the limb can create numerous intraoperative problems. It is advisable to spend whatever additional time is required to ensure that a reduction and distal targeting are achievable.

Reaming and Nailing Maneuvers

Excessive radiation exposure to the surgeon's hands and body are a major concern with closed intramedullary nailing. Studies have shown that the greatest dose of radiation to the dominant hand occurs during nail insertion and distal targeting.91,191 Although the total accumulated dose is low, every effort should be made to minimize the use of fluoroscopy during reduction, reaming, nailing, and locking of the fracture. Lead aprons and thyroid shields, along with lead-impregnated glasses, are always advisable. Continuous imaging during nailing and locking is unnecessary, and split-second spot images suffice. The x-ray tube should not be in proximity to the patient because this enhances the scatter radiation to the surgeon. The surgeon and assistants should stand back away from the image intensifier whenever live imaging is being performed.

    The lateral incision extends from 1 cm distal to the tip of the greater trochanter superiorly for 8 to 10 cm. If proximal locking is anticipated, the incision is carried distally an additional 3 to 4 cm. Longer incisions are required in patients with bulky soft tissues. The fascia lata and the fibers of the gluteus maximus are divided in line with the skin incision. The interval between the abductor tendon insertion on the greater trochanter and the pyriformis tendon is identified, and the gluteus medius and minimus are freed from the underlying hip capsule. The trochanteric or piriformis fossa is visualized by retraction of the abductor muscles anteriorly.

    Accurate positioning of the entrance hole is critical.165 The anterior bow of the shaft curves up to the posterior tip of the greater trochanter. Therefore, the beginning awl should be inserted just posterior to the midline of the trochanter and just medial to the prominence of the trochanter in the trochanteric fossa (Fig. 27-49). Such placement ensures that the hole will be aligned with the longitudinal axis of the medullary canal in both the sagittal and coronal planes. An entrance portal anterior to the midpoint of the trochanter can result in perforation of the anterior cortex of the proximal femur. A laterally placed portal at the tip of the trochanter frequently leads to eccentric reaming and medial comminution of the proximal fragment. Varus malalignment of the fracture, especially in proximal shaft fractures nailed with the patient in a supine position, also can be a complication of an entrance hole in the trochanteric tip. Varus reduction is observed commonly in second-generation reconstruction nailing of proximal femoral fractures and can result in errant placement of the locking screws high in the femoral head. Medial placement of the entrance portal must be prevented in adolescent patients, who may be prone to osteonecrosis of the femoral head secondary to iatrogenic damage to the vascular arcade at the base of the femoral neck. Excessive medial placement of the awl can create a stress riser in the femoral neck. After full insertion of the diamond-tipped awl, its position should be visualized in both planes with the fluoroscope. Any deviation from the trochanteric fossa must be corrected before reaming of the canal. When the supine patient position is used, the entrance hole can be difficult to make with a sharp-tipped awl. A Steinmann pin can be drilled into the proximal femur under image intensifier control in such cases and the hole made over the pin with a cannulated reamer.105

Fig. 27-49

    Initial reaming of the proximal fragment is performed with the 6-to 9-mm hand reamers. This preliminary reaming improves the freedom of movement of the bulb-tipped guide pin as it is being passed into the medullary canal of the distal fragment. The guide pin is controlled with a T-handle chuck. Passage of the guide pin across the fracture site into the distal fragment can be facilitated by a small curve at the tip of the guide pin (Fig. 27-50). If residual translation of the fracture fragments is present, direct external pressure on the thigh with a crutch or lead-gloved hand may be needed. Alternatively, a small-diameter (8- to 10-mm) Küntscher nail inserted into a previously reamed proximal fragment can be manipulated as a lever to improve alignment with the guide pin inserted through the nail. Commercially available cannulated guides also are available to control the proximal fragment during guide pin insertion. Passage of the guide pin into the distal fragment by one or more of these reduction maneuvers is almost always possible. Open reduction for guide pin passage should be reserved for the rare case of an irreducible fracture or incarceration of bone fragments in the medullary canal.

Fig. 27-50

    Fractures of the distal third of the shaft pose a special reduction problem. In the supine position, the distal fragment angles posteriorly and must be supported with a crutch or by an unscrubbed assistant. In the lateral position, the distal fragment sags into valgus angulation. If full correction of this angulation is not achieved before guide pin insertion, the nail may be driven into the medial femoral condyle, resulting in an unsatisfactory valgus malalignment, or into the lateral femoral condyle, resulting in a varus malalignment. The guide pin should be aimed directly at the intercondylar notch on the anteroposterior view of the femur before reaming and nailing of the distal fragment. Radiographic verification of proper pin position in both planes is imperative at this stage of the operation.

    After full insertion of the guide pin, the length of the remaining pin is measured from its tip to the trochanter and subtracted from the total length of the guide pin. Using the preoperative measurement of ideal nail length along with this measurement, the preferred-length nail is chosen. For Winquist type IV comminuted fractures, adjustments in the longitudinal traction may be needed to restore the femur to its normal length.

    Flexible reamers, starting with a 9-mm end-cutting reamer, are used to enlarge the medullary canal (Fig. 27-51). The reamers are passed across the isthmus until no further resistance is encountered. Reaming of the distal fragment down to the anticipated distal tip of the nail is unnecessary and can compromise the purchase of the nail on the cancellous bone of the distal third of the shaft. If there is a segmental bone loss or comminution in the shaft, the reamers should be pushed, not powered, across the defect to prevent any damage to the soft tissues of the thigh. Reaming proceeds at 0.5-mm increments until endosteal cortical contact of the reaming heads over a segment of 2 to 3 cm of both the proximal and distal fragments is achieved. Such cortical contact is not feasible or necessary for proximal and distal shaft fractures, which are stabilized with interlocking nails. The canal is overreamed at least 0.5 mm for simple cloverleaf nails and 1 mm for interlocking nails. Failure to ream the canal to a diameter slightly greater than that of the nail can result in nail incarceration or iatrogenic comminution of the fracture. Distal-third fractures especially require a minimal 1- to 1.5-mm overreaming of the proximal fragment to accommodate the variable degree of anterior femoral bow that might be present. If the reaming head jams in a tight canal, it can be extracted by driving it out with the bulb-tipped guide pin. External pressure on the thigh for fracture alignment is helpful to prevent eccentric cortical reaming during passage of the reamer into the distal fragment. At the completion of reaming, the 3-mm bulb-tipped guide pin is exchanged for the 4-mm straight guide pin through a plastic medullary tube.

    The design of the medullary reamer can be important in influencing the amount of marrow embolization to the lung during the reaming maneuver. In an intact femur model in sheep, Pape and colleagues261 showed that the AO reamer design resulted in a significant increase in pulmonary artery pressure and pulmonary capillary permeability damage compared with other reamers. These transient changes in the lungs were attributed to the cylindrical design of the AO reamer, which tends to occlude the canal (Fig. 27-52). Improvements in reamer design should be forthcoming soon.

    In the presence of segmental bone loss after an open fracture, transmedullary bone grafting during delayed nailing occasionally is indicated. Bone particles removed during the reaming maneuver are mixed with autogenous cancellous bone graft from the iliac crest. This morselized graft can be inserted through a chest tube and deposited throughout the area of bone loss before nail insertion.

    The preselected interlocking nail then is driven over the 4-mm nail guide pin into the proximal fragment. Perfect correction of fracture alignment is necessary as the nail is passed across the fracture into the distal fragment. The handle on the driver is held firmly to ensure that the prebent curve of the nail is aligned properly with the anterior bow of the femur. Once the nail has entered the canal of the distal fragment for a distance of 3 to 4 cm, the rotatory alignment of the limb is checked and the traction is adjusted to restore normal femoral length. The nail then is driven fully into the distal fragment until the lateral flange of the driver or the proximal targeting jig impacts on the tip of the greater trochanter. The diagonal hole of the interlocking nail should be centered on the intertrochanteric region, and the distal holes should be aligned in the coronal plane. Incomplete insertion of the nail results in errant placement of the proximal locking screw into the femoral neck. If the distal holes of the nail are aligned more in the sagittal plane, elastic or plastic deformation of the nail in torsion may have occurred during its insertion into a tight canal. Such torsional deformity of the nail occurs more frequently with thin-walled, slotted nails. More overreaming of the canal or exchange to a smaller-diameter nail is indicated in such cases.

Proximal Locking

The decision to lock the proximal fragment, the distal fragment, or both to the nail is based on the preoperative and intraoperative assessment of the fracture. If the fracture is too far proximal, too far distal, too oblique in its anatomy, or too comminuted to be afforded stability by an unlocked cloverleaf nail, then locking screws are indicated. The broad guidelines recommended by Winquist and coworkers370 are used at our centers (Fig. 27-53). Studies at the Shock Trauma Center have demonstrated that it is wise to err on the side of locking whenever there is any doubt about the stability provided by an intramedullary nail.59,60 It is apparent that fixation with static interlocking reduces the prevalence of postoperative fracture complications without increasing the low risk of femoral nonunion. At our centers, only the simplest, transverse midshaft fractures are considered appropriate for nailing without static locking of the major fracture fragments.

Fig. 27-53 Terapia preferata in fracturi de diferite tipuri functie de anatomie, localizare si cominutie.

    Proximal locking is performed easily using a proximal targeting device that attaches firmly to the proximal tip of the nail. This targeting jig must be screwed tightly into the internal thread at the proximal tip of the interlocking nail. Most interlocking nails are designed for a 6-mm fully threaded screw that passes diagonally from the greater trochanter to the lesser trochanter at a 45° angle to the nail. The near cortex is overdrilled to 6 mm, whereas the far cortex at the level of the lesser trochanter is drilled to 5 mm. A fully threaded, fluted screw of appropriate length then is inserted. If the nail is manufactured with an internal thread for this screw, then resistance is encountered as the screw is passed through the nail. The screw must be sufficiently long to gain a firm purchase of the far cortex. Insertion of this diagonal screw is predictable as long as the targeting device is attached snugly to the proximal end of the nail.

Distal Locking

Distal locking for control of length, rotation, or both of the distal fracture fragment is performed in nearly all cases. It is the major technique, over and above standard closed nailing, that must be mastered for a successful interlocking nailing. Over the last decade, several distal targeting techniques have been introduced, tested, and often discarded.31,135,217 Nail-mounted targeting jigs are available with most interlocking systems. Both the Grosse-Kempf and the Russell-Taylor nails possess internal threads in the proximal tip of the nail to which the jig is attached. Theoretically, the device can be preassembled before nail insertion so that, when it is reattached after nail insertion, perfect alignment of the jig with the holes is achieved. However, deformation of the nail during insertion invariably makes adjustment of the holes of the jig under fluoroscopic guidance necessary. The time needed for such adjustment can be lengthy, and even with precise alignment of the holes of the jig and the nail, slight movements of the jig during drilling of the holes often cause errant placement of the holes. Most nail-mounted targeting devices have been replaced by alternative techniques for distal targeting.50,51,202

    Various hand-held targeting devices also are available (Fig. 27-54). Most involve a drill sleeve attached to a long handle that often is radiolucent. The drill sleeve is introduced down to the lateral cortex through a small percutaneous wound over the lateral thigh. Fluoroscopic alignment of the nail hole with the drill sleeve permits accurate targeting. Because of the sloping surface of the distal femur and the long handle of the targeting device, a delicate touch is required to prevent loss of precise positioning.

    We perform most of our distal targeting using a free-hand technique. A 3- to 4-cm incision is made in the lateral thigh directly over the two distal holes of the nail. The iliotibial band is split in line with the skin incision, and the vastus lateralis muscle is retracted anteriorly off the intermuscular septum. Sufficient periosteum is elevated off the cortex to permit unimpeded use of the awl and drill. The radiology technician adjusts the position of the C-arm to align the radiation beam perfectly with one of the distal holes. A perfect circle should be visualized through the hole. The tip of a straight, long-handled awl is rested on the lateral cortex so that its point lies in the center of the hole (Fig. 27-55). The fluoroscope is turned off, and the shank of the awl is brought up directly in line with the C-arm.191 Constant pressure is maintained on the awl handle to prevent skidding of the awl tip on the bone. With the use of a mallet, the tip of the 6-mm-diameter awl is driven through the lateral cortex into the hole of the nail. Repeated fluoroscopic imaging confirms accurate placement of the awl (Fig. 27-56). The awl is removed, and a 4.5- or 5-mm drill bit is used to drill the far cortex (Fig. 27-57). Alternatively, the drill bit can be used primarily to center the hole without using the awl. Most interlocking systems provide either partially or fully threaded, self-tapping, 5- to 6.25-mm screws for distal locking (Fig. 27-58).

    Two distal screws are inserted routinely to prevent toggling of distal fractures in the sagittal plane. Biomechanical studies have demonstrated, however, that there is no significant difference in the torsional rigidity or axial load to failure when one as opposed to two distal 6-mm screws are used with slotted nails for midshaft or proximal fractures.133 Limited clinical studies confirm the adequacy of a single locking screw for most proximal and midshaft injuries, although migration of the simple distal locking screw can occur.133 If any doubt concerning the stability of fixation exists, two locking screws are preferred.

Surgical Technique for Reconstruction Interlocking Nailing

The second-generation, or reconstruction, nails were developed to address the unique anatomical and biomechanical demands of complex femoral fractures, including subtrochanteric fractures, impending pathologic fractures of the proximal femur, and ipsilateral femoral shaft and neck fractures. All such nails are designed to permit the placement of one or more screws into the femoral head and neck. The Russell-Taylor reconstruction nail is typical of these second-generation nails. Its proximal sliding screws neutralize rotational and shear forces and provide excellent purchase of the femoral head and neck. The closed-section design of this nail decreases torsional shear at the fracture site and reduces torsional rotation of the nail during insertion. Small-diameter (delta) reconstruction nails have an increased wall thickness that enhances their bending strength. The proximal 8 cm of all reconstruction nails have an expanded diameter to provide the additional strength needed for the proximal lag screws. The two self-tapping, partially threaded proximal screws are 8 and 6.4 mm in diameter, respectively. Sliding of these screws within the holes in the nail is possible to accommodate any postoperative settling of a peritrochanteric or neck fracture.

    The surgical technique for standard interlocking nailing must be modified in several important ways for successful insertion of the reconstruction nail. The patient positioning must be supine to allow for unobstructed fluoroscopic visualization of the anteroposterior and lateral projections of the femoral head and neck (Fig. 27-59). The involved leg is adducted and slightly flexed on the fracture table, whereas the contralateral leg is positioned either in extension and abduction or in flexion and external rotation to permit unimpeded movement of the image intensifier. With a distal femoral traction pin, rotational alignment of the femur usually is restored by allowing the knee to flex with the foot pointing to the floor.

Fig. 27-59

    Through the standard incision and approach, the curved awl or cannulated reamer is introduced into the trochanteric fossa. High subtrochanteric fractures are subjected to deforming muscle forces that often abduct the proximal fragment. A bone hook on the tip of the greater trochanter or a commercially available cannulated alignment device can be used to adduct the trochanteric fragment, thereby avoiding varus nailing of the fracture. If the reconstruction nail is being used for an ipsilateral femoral neck and shaft fracture, preliminary reduction and provisional screw or pin stabilization of the neck fracture should be performed before the reaming and nailing maneuvers.

    After insertion of the bulb-tipped guide rod, precise determination of the preferred nail length must be calculated. The depth of the chosen nail may have to be adjusted to ensure accurate placement of both proximal screws, so careful selection of a proper-length nail is imperative. The medullary canal then is overreamed a minimum of 1 mm greater than the selected nail diameter. The proximal 8 cm of the proximal femur is reamed to 15 mm for the expanded portion of the reconstruction nail.

    The nail then is inserted to the proper depth to allow for placement of both proximal screws in the femoral head and neck. This depth can be determined by placement of the drill sleeves into the proximal drill guide and extrapolation of the eventual location of the screws by fluoroscopic inspection of the position of the sleeves (Fig. 27-60). The nail should be driven to a level allowing the most inferior of the two proximal locking screws to be placed just superior to the inferior (medial) cortex of the femoral neck. Proper rotation of the nail also must be confirmed at this time. The 8° anteversion in the proximal holes in the nail accommodates the normal anteversion of the neck, but the proximal femoral fragment often sags, necessitating further external rotation of the drill guide below the horizontal level to prevent proximal screw placement posterior to the femoral neck. Oblique fluoroscopic C-arm views can assist in ensuring accurate rotation of the drill guide.

Fig. 27-60

    Using the multiple drill sleeves, a 3.2-mm threaded guide pin then is drilled through the most distal of the proximal locking holes to a level about 5 mm from the subchondral bone of the femoral head (Fig. 27-61). If anteroposterior and oblique lateral views on the fluoroscope demonstrate errant position of the guide pin, it is extracted and the nail is repositioned appropriately in the femur. Anterior placement of the screws in the femoral head must be avoided. The pin for the superior 6.4-mm screw then is placed similarly and its position is confirmed on fluoroscopy (Fig. 27-62). Standard drills and taps are used over the calibrated guide pin before screw insertion. Tapping is especially indicated for dense bone in young patients. Routine distal targeting techniques are used.

  Fig. 27-61   Fig. 27-62

    Depending on the fracture pattern, quality of the bone, and purchase of the proximal locking screws, protected weight bearing may be indicated after surgery. Dynamization of the statically locked reconstruction nail usually is not necessary.

Postoperative Care and Rehabilitation

After closed femoral nailing, all patients should be mobilized out of bed as promptly as feasible. Even the mere act of sitting up in bed or in a chair diminishes the risk of pulmonary complications, especially in the patient with multiple injuries. A major advantage of interlocking nails is that relatively pain-free mobilization is possible even with highly comminuted fractures. Supplemental external support in the form of traction or cast bracing rarely is necessary. Dynamically locked nails with equivocal purchase on the unlocked fragment may need protection against malrotation until the patient's muscle tone and strength return. This is especially true for distal infraisthmal fractures that can rotate externally on the nail. The use of a derotation boot in bed usually suffices.

    If rigid fixation of the fracture is achieved, the patient can resume normal muscle activity and joint motion as early as tolerated. Only mild analgesics are required after the immediate postoperative period. Patients are instructed in quadriceps-strengthening exercises and progressive weight bearing. Weight bearing is delayed only in patients with very proximal or distal fractures that are at risk for implant fatigue failure and in patients with ipsilateral extremity injuries, such as knee ligament tears.

    Prolonged therapy under the guidance of a physical therapist usually is not necessary. Full range of motion of the knee can be expected 4 to 6 weeks after a simple nailing. Using dynamic quadriceps strength and isometric strength tests, Mira and coworkers227 confirmed that the early and late range and strength of knee motion are better after nailing than they are after either traction or cast brace treatment.2

    Serial radiographs at 1, 3, 6, and 12 months after nailing should be obtained to document fracture healing and remodeling. Dynamization of the statically locked nail rarely is indicated except in cases of delayed healing at 3 to 4 months after injury.59,60 When indicated, dynamization is accomplished by removal of the screws farthest from the fracture because these screws contribute the least to fracture stability.

    Routine nail removal is not mandatory.226 However, it is advisable in young patients 1 to 2 years after injury if fracture remodeling has proceeded normally. Earlier extraction for relief of trochanteric pain from the proximal screw or proximal tip of the nail is safe if the fracture is healed solidly.56 Distal screw heads are a less frequent source of chronic discomfort. In the presence of delayed fracture healing, removal of only the locking screws causing local symptoms occasionally is indicated. Such screw extraction must be done judiciously to prevent loss of fracture fixation.

    Heterotopic bone develops around the proximal tip of the nail in up to 20% of cases of closed nailing.208,226,333 There is a positive correlation between bone formation and certain patient and fracture variables, including the male gender, the presence of a head injury, a high ISS, and a prolonged stay in the intensive care unit (Fig. 27-63). A prominent tip of the nail above the trochanter theoretically adds to the risk of heterotopic ossification, but clinical studies have not confirmed its importance.208 The presence of an ipsilateral acetabular or pelvic fracture can predispose to heterotopic ossification, especially if an extensile approach through the gluteal muscles is used for surgical fixation. Less than 5% of patients require reoperation with nail extraction and ectopic bone excision for pain or restriction of hip motion.

    AUTHORS' PREFERRED METHOD OF TREATMENT

Our 15-year experience with closed interlocking nailing has convinced us that this technique should be the treatment of choice for nearly all fractures of the femoral shaft. More than 95% of the femoral fractures that we see at our respective institutions-Parkland Memorial Hospital in Dallas and the Shock Trauma Center of the Maryland Institute for Emergency Medical Services System in Baltimore-are nailed. As a reflection of the high-energy nature of most femoral shaft fractures treated at our trauma centers, locking screws are used in nearly all these cases.

    COMPLICATIONS AND PITFALLS

The type and severity of complications often are related to the specific treatment selected for a given fracture. The prevalence of complications has dropped remarkably with recent therapeutic advances, especially closed intramedullary nailing.87

Nerve Injury

The femoral and sciatic nerves escape injury with most fractures of the femoral shaft. The nerves are encased in muscles throughout the length of the thigh and are highly resistant to stretch injuries during blunt trauma. The prevalence of nerve injury is higher with penetrating trauma such as gunshot injuries.

    Injuries to the nerves during treatment of the shaft fracture can arise in several ways. During skeletal traction on a balanced suspension splint, the leg tends to roll into external rotation. If the proximal fibula rests on the splint, compression palsy of the common peroneal nerve can occur, especially in heavily sedated patients or patients with altered states of consciousness. This complication of traction treatment can be prevented by adjusting the position of the leg on the suspension frame, padding the area around the neck of the fibula, and encouraging the patient to move freely in the traction system.

    Intraoperative nerve damage can result either from stretch injury due to excessive traction for a difficult reduction or from direct compression due to poor positioning of the patient on the fracture table. The pudendal and femoral nerves can be compressed by an unpadded post of the table; careful padding of both the horizontal and vertical posts protects these nerves.55,168 The likelihood of a pudendal nerve palsy increases with the magnitude of the intraoperative traction55 (Fig. 27-64). Either sensory or motor branches of the pudendal nerve can be affected, but most palsies are transient. The sciatic nerve is injured more frequently by stretch, especially when longitudinal traction is needed during a delayed nailing. Traction with the hip flexed and the knee extended increases the pull on the nerve and must be avoided.

    Most intraoperative nerve palsies can be prevented. Specific recommendations to prevent the common pudendal palsy include completely relaxing the patient under anesthesia, carefully positioning the patient on the fracture table, minimizing the magnitude and duration of skeletal traction, and avoiding prolonged adduction of the hip on the table post.55

Vascular Injury

Given the large forces required to fracture a normal femoral shaft, it is surprising that major vascular damage does not routinely accompany these fractures. Although the perforating branches of the profundus femoris artery often rupture, resulting in a tense fracture hematoma, damage of any nature to the superficial femoral artery is documented in less than 2% of fractures.22,177 Because of its rarity in civilian practice, vascular injury often is overlooked.

    The femoral vessel can be partially or completely torn, thrombosed, or merely stretched and in spasm. Intimal tears can remain occult until the appearance of late thrombosis.177,296 Although occlusion of a normal superficial femoral artery does not inevitably result in irreversible gangrene because of abundant collateral circulation through the profundus femoris artery, prompt diagnosis and treatment of vascular injuries generally are imperative for preservation of the limb (Fig. 27-65).

Fig. 27-65

    Vascular damage can accompany any fracture pattern but is most common with penetrating trauma. The presence of diminished distal pulses should initiate a diagnostic assessment of the vasculature of the limb. Although Doppler study of the distal vessels may suffice, there should be no hesitation in ordering an arteriogram. The indications for arteriography vary, but the study should be considered seriously in limbs with absent pulses, all fractures secondary to penetrating trauma, and distal fractures at the level of the adductor hiatus. Normal distal pulses do not exclude a serious vascular injury, and repeated examination of the limb is necessary to avoid missing an occult lesion.177

    The treatment of vascular injury should be a complementary team effort by vascular and orthopaedic surgeons. The aim of surgery is to limit the period of ischemia to the shortest possible time by prompt restoration of the arterial flow to the limb. Irreversible muscle ischemia and extensive necrosis develop over a 6- to 8-hour period, depending on the extent of vascular occlusion and the adequacy of intact collateral vessels. The vascular surgeons may restore circulation by creating temporary shunts around both the arterial and venous injuries. Any internal stabilization of the fracture then can be accomplished without a sense of urgency. After fracture fixation, definitive vascular repair by direct anastomosis or grafting can be performed. Such a staged repair is not necessary if a simple, localized laceration to the artery can be repaired quickly. Fasciotomies are indicated if there has been a delay in restoration of blood flow or if compartment swelling is noted.

    Multiple factors must be assessed in deciding on the best management of the fracture. The presence of open wounds, the degree of contamination, the location and comminution of the fracture, the amount of soft-tissue necrosis, and the delay before vascular repair all influence this decision. As a general rule, femoral fractures associated with vascular injuries in civilian practice should be stabilized internally, whereas those from war injuries should be treated on an individual basis. The vascular surgery is simplified by open reduction and internal fixation of the fracture.35

    The added risks of open fracture care are minimal in the closed, noncontaminated, low-energy injuries seen in civilian fractures. War injuries are distinguished by their contaminated wounds and frequent delays in treatment. During the Vietnam War, 30% of acute major arterial injuries had an associated fracture.285 The high infection rate after open fracture fixation in this military population has led to a preference for alternative modes of fracture immobilization, including traction and external fixation. Connolly and associates93 suggested that the arterial suture line is resistant to longitudinal traction by both the elastic properties of the vessels and the tether effect of the surrounding soft tissues. In their series of wartime injuries, fracture instability in traction was not a source of failure of vascular repairs. If extensive soft-tissue dissection is required for the internal fixation of an open fracture, the risks of infection and resultant failure of the vascular repair outweigh any benefits of internal fixation. The decision regarding open versus closed treatment of the fracture should be made jointly by the orthopaedic and vascular surgeons.

    The problem of late vascular compromise should be evaluated in all patients with femoral shaft fractures. In a study of 30 patients who had suffered femoral fractures 6 to 20 months before examination, an alarmingly high rate of occult femoral artery injuries was discovered.22 A total of 15% exhibited hemodynamic abnormalities using Doppler ankle-arm pressure indices, all in relation to previously injured limbs. Although most of these subclinical vascular injuries never adversely affect function, major late vascular complications, including false aneurysm, arteriovenous fistula, and thrombosis of an intimal tear, have been described.296

    Most limbs with vascular injuries can be salvaged by prompt repair of the vessels and astute care of the fracture. The key determinants of limb survival include the successful restoration of peripheral flow, the length of delay before repair, the extent of disruption of the collateral circulation, the amount of soft-tissue injury, and the presence or absence of infection.

Infection

Occasionally, infection complicates intramedullary nailing of the femur. The prevalence of infection is related to the technique of intramedullary nail insertion,89,136,178 the use of supplemental fixation of the fracture site, and the presence of open wounds (Fig. 27-66).

    Before the use of operative fluoroscopy, open intramedullary nailing was the standard method of nail insertion.309 It required a moderate exposure and soft-tissue stripping of the fracture site. Reports on the prevalence of infection after the open technique have varied, with most large series documenting this complication in 1.7% to 9% of cases.65,159,167,355 Some authors have contested the observation that infection is more prevalent after open intramedullary nailing as compared with closed nailing.139,187,309,363 The published data, however, appear irrefutable. The series of Winquist and coworkers370 of more than 500 cases of closed femoral nailing yielded a postoperative infection rate of 0.9%. Investigations by King and Rush,175 Rothwell and Fitzpatrick,298 Esser and colleagues,108 Wiss and coworkers,372 and Rothwell,297 each with more than 100 cases of closed intramedullary nailing, documented infection rates of 0.8%, zero, 0.8%, zero, and zero, respectively. When the large series using these two methods are compared, there is little doubt that open intramedullary nailing carries a slight but significant increase in the risk of postoperative infection.118

    Comminuted fractures managed by open nailing are especially at risk for postoperative infection. The multiple fragments oblige the surgeon to use supplemental fixation with cerclage wires. The combined stripping from the high-energy injury and the surgical placement of the cerclage wires devitalizes the cortical fragments. These devitalized fracture fragments serve as an excellent nidus for infection.162,264,351 Interlocking nails, which obviate intrusion into the fracture site for more stability, have largely replaced this technique.

    The final factor that predisposes to postoperative infection after intramedullary nailing is open wounds. When intramedullary nailing is applied to open fractures of the femoral shaft, the prevalence of infection appears to be related to the severity of the soft-tissue injury. Lhowe and Hansen,194 Winquist and colleagues,370 Chapman and Mahoney,77 and Brumback and associates57 all have demonstrated that grade I, II, and III open fractures can be nailed safely with a low risk of infection. Fractures with gross contamination, exposed bone, and extensive soft-tissue necrosis (grade IIIB) carry an unacceptably high risk of infection after nailing, regardless of the treatment method.

    Most patients with infections have purulent drainage from a sinus in the thigh or from the surgical incision in the buttock. Patients who have erythema, swelling, or induration of the thigh weeks or months after intramedullary nailing should be investigated for infection.158,179,201,366 Plain radiographs should be scrutinized for periosteal reactive bone or a radiodense sequestrum at the fracture site. Infected, necrotic cortical fragments can be obscured easily by the radiopaque intramedullary nail. If a sinus is present, a sinogram can be helpful in locating the nidus of the infection. The sinogram usually reveals direct communication with the tip of the intramedullary nail at either the insertion site or the fracture site. Tomography can assist in locating a sequestrum. Computed tomography, ideally performed at the time of sinography, can help in delineating communication of the sinus with different parts of the femur. Unfortunately, computed tomography is subject to distortion from scatter caused by the intramedullary nail. Blood analysis, including a white blood cell count and sedimentation rate, should be obtained to determine the extent of the patient's systemic response to the infection. A technetium or gallium radionuclide scan may assist in diagnosing infection in the area of a healing fracture, but the usefulness of this test in the presence of infection after intramedullary nailing remains in question.266

    Once a deep infection is diagnosed, a decision regarding the advisability of nail removal must be made. Most authors agree with the recommendations of MacAusland and Eaton201 and Patzakis and coworkers,266 who advocate retention of the nail if rigid fracture stabilization is provided by the implant. The fixation provided by the nail is assessed best at the time of debridement of the infection. If no gross motion is discernible in any plane, including rotation, the nail should be left in situ. Because most femoral fractures heal within 4 to 6 months, even in the presence of infection, the patient must be protected from septicemia during that time. Such protection is provided by thorough debridement of all sequestra and infected soft tissue, care of the open wound, and judicious use of antibiotics. Some authors have recommended wound closure over suction-irrigation systems after debridement, but the threat of superinfection has limited the popularity of this technique.266 If the causative agent is sensitive to an oral antibiotic tolerated by the patient, oral antibiotics can be used to suppress the infection during the time to fracture union.266 After adequate fracture healing, the nail can be removed and the endosteal canal should be reamed to remove the infected membrane and bone from the canal. In severe infections, antibiotic-impregnated beads can be placed down the canal after nail removal for further treatment of the infection.

    If rigid fixation is not provided by the nail, several alternatives should be considered. The degree of fracture stability can be augmented either by the insertion of locking screws into an interlocking nail or by the use of a larger-diameter exchange nail. If extensive sequestration of the femoral shaft is present, removal of the nail, radical debridement of the femur, and application of skeletal traction or an external fixator may be necessary (Fig. 27-67). Antibiotic-impregnated bead insertion into the segmental defect may be advantageous. After a period of at least 6 weeks with the patient free from wound drainage, staged reconstruction of the femur can be undertaken. This must be individualized for each case and may require repeated intramedullary nailing, bone grafting, or bone transport.

Delayed Union and Nonunion

In contradistinction to diaphyseal fractures of the tibia, delays in healing of femoral shaft fractures are rare. Delayed union implies a slow healing, longer than what is reasonably expected for a given fracture. Any fracture of the femoral shaft that is not healed by 6 months clearly qualifies as a delayed union. Nonunion signifies a fracture that will not heal without some further intervention. Numerical guidelines for defining delayed union and nonunion remain arbitrary. Most cases of deficient bone healing arise from an insufficient blood supply at the fracture site, uncontrolled repetitive stresses, or infection. Specific factors that predispose to delayed union and nonunion include open fractures, extensile operative stripping of the soft tissues around the fracture site, inadequate fracture stabilization, fracture distraction, infection, and (perhaps) a history of heavy smoking (Fig. 27-68). Even in the presence of one or more of these factors, most femoral shaft fractures heal rapidly after closed intramedullary nailing.

    Once the primary cause of slow healing is identified, the management of delayed union usually is obvious. If dynamic intramedullary nailing has been used, inadequate fracture stabilization may be the cause of delayed union or nonunion. Whereas increased weight bearing may stimulate fracture union in these cases, fractures demonstrating no evidence of callus response at 4 to 6 months after nailing are treated best with a reamed exchange nailing with a larger-diameter nail. Fracture distraction after interlocking nailing can be managed by dynamization of a statically locked nail, bone grafting around a fracture gap, or reamed exchange nailing with a larger-diameter nail (Fig. 27-69). Slight shortening of the extremity is possible after dynamization, even after 6 months of static interlocking. Although weight bearing with fracture impaction after dynamization usually stimulates fracture union, leg-length discrepancy can be accentuated in fractures already stabilized slightly shorter than the noninjured contralateral extremity.60

    Femoral nonunion invariably requires surgical intervention to achieve union. Reamed intramedullary nailing is ideally suited for most cases of nonunion of the femoral shaft. In addition to providing a load-sharing, rigid stabilization of the nonunion site, nailing and reaming stimulate neovascularization of the shaft. A closed technique for reamed nailing is preferred whenever feasible. Webb and associates357 reported a 95% union rate within 20 weeks in a series of 105 cases of femoral nonunion treated by intramedullary nailing. Nearly 80% of the procedures were accomplished without exposing the nonunion site. Four cases of nonunion that did not unite with intramedullary nailing subsequently healed after exchange nailing with a larger nail. The open technique should be reserved for cases of loose or broken plates, synovial pseudarthrosis, and cases of displaced nonunion that cannot be reduced by closed means. Autogenous bone grafting is advisable after excision and open nailing of a synovial pseudarthrosis, but is unnecessary after nailing of most cases of hypertrophic nonunion. When bone grafting is required, the reamings of the canal can be used to supplement graft taken from the posterior iliac crest or the greater trochanter.

    One study investigated the simultaneous correction of leg-length discrepancy in association with therapy for nonunion of the femoral shaft. The technique involves open debridement of the nonunion site with distraction by skeletal traction. After bone grafting the defect, the wound is closed and static interlocking nailing is performed. The authors reported union in 88% of the patients and noted no neurovascular complications with an average lengthening of 2.4 cm.381

    Other techniques, including femoral plating, electrical stimulation, and external fixation with a rigid ring (Ilizarov technique) system, have limited indications for the treatment of cases of femoral nonunion.

Malunion

There is no consensus regarding what represents a malunion of the femoral shaft. An anterior bow is compensated well by hip and knee motion and is tolerated better than either a posterior bow or lateral angulation. Shortening up to 1 to 1.5 cm is compatible with good function. Malunion commonly complicates shaft fractures managed by traction or plaster immobilization. Because of the deforming muscular forces, especially those of the adductors, most cases of malunion after conservative treatment involve internal rotation, varus deformity, and shortening of the femur. The rare malunion after internal fixation usually is secondary to technical errors during the surgery, resulting in fixation of the shaft in a malalignment. Postoperative external rotational deformity can follow intramedullary fixation with small-diameter, unlocked nails.

    External rotational deformities after closed interlocking nailing generally are well tolerated by patients. In an ultrasonic study measuring the torsional deformities of 110 interlocked fractures, Braten and associates41 noted that 21 had external rotational malalignment of 15° or more compared with the opposite normal femur. Only 8 patients expressed complaints related to the deformity and only 3 required reoperation to correct it. The 26 patients with external rotational malalignment of between 10° and 15° had few minor complaints. All the deformities were attributed to incorrect positioning of the limb during the nailing procedure. Careful attention to operative details should limit any rotational malalignment to less than 15°.

    Malunion can result in an abnormal gait, a limb-length discrepancy, and post-traumatic arthritis of the knee. The risks of knee arthritis from a malalignment of the femur have been studied by Kettelkamp and associates.172 Fourteen patients were evaluated using static biomechanical frontal plane analysis of the forces of the knee. An increased force on the tibial plateau was strongly associated with a varus or valgus deformity at the knee. The importance of restoration of lower limb alignment also has been emphasized by many clinical investigators.

    Most cases of severe malunion are readily amenable to corrective osteotomy and intramedullary nailing (Fig. 27-70). Because of translation or shortening at the malunion site, open osteotomy and intramedullary nailing usually is required. Closed osteotomy using a medullary saw under fluoroscopic control is preferable for simple rotational malunion.

Refracture

Refracture through a healed femoral fracture site is a rare event. It can occur, however, at two times during the healing process: during early phases of callus formation or at the time of hardware removal.

    Fractures treated by traction or cast bracing usually heal with abundant callus. Although abundant in quantity, the trabeculae of new bone are not aligned along lines of stress and are prone to fracture with major loading. More than 75% of the cases of refracture reported by Seimon316 occurred within the first 3 to 4 weeks of cast immobilization of the patient. Most were sustained during quadriceps exercises, especially in those patients with limitation of knee motion. Stiffness of the knee lengthens the lever arm acting on the fracture site and, thus, increases loading and predisposes to refracture. After 8 to 12 weeks, stress-induced remodeling of the callus lessens the chance of refracture.

    Although early refracture is negligible after operative fixation, refracture after implant removal is still a serious problem, especially after plate fixation. The biology of fracture healing after plate fixation differs from that after nailing. Rigid plate fixation results in primary fracture healing, with osteonal healing across the small cortical fracture gap. Callus should not be evident on radiography. With primary fracture healing, the strength of the bone at the fracture site is slow to return to normal, depending on the realignment of the newly formed osteons by creeping substitution. Various theories, including stress shielding, osteopenia of the bone beneath the plate, and slow revascularization of the cortical bone, also have been offered to explain the weakness of bone beneath a rigid plate. Premature removal of a plate (before a minimum of 18 months from the time of application) can place the bone in jeopardy of refracture. Breedenveld and coworkers44 noted a 13% refracture rate in 148 shaft fractures, mostly after plate fixation. They advocated routine cancellous bone grafting of all fractures with medial cortical defects.

    The generous callus envelope that develops after closed intramedullary nailing protects the fracture site from refracture after nail removal. Refracture at a different level has been an intraoperative problem during the extraction of Zickel nails. The rigid, prebent design of the Zickel nail can cause transverse fractures several centimeters below the lesser trochanter during nail removal. The risk is high in young patients with normal cortical bone. In a series of 12 patients with refracture during Zickel nail extraction described by Ovadia and Chess,255 all cases of refracture were different from the original fracture in type and site. The authors recommended that the nail, in its current design, not be used for subtrochanteric fractures in young patients.

    Static interlocking of the major fracture fragments to the intramedullary nail does not appear to diminish the abundant callus that is seen with closed nailing or to increase the likelihood of refracture.56,226 Theoretically, a statically locked fracture may have a higher prevalence of refracture secondary to either the stress riser effect of the locking screws or the stress-shielding properties of the statically locked nail. However, bone density studies using computed tomography have revealed that the stress-reducing effects of locked intramedullary nails are small.40 In a series of 214 fractures treated with statically locked nails, Brumback and colleagues56 noted only one case of refracture. In 111 fractures in which the nail was left in situ, no subsequent fractures occurred during 30 months of follow-up. The one case of refracture that occurred in 103 femora from which the nail had been removed after fracture union occurred through the site of the original fracture 6 weeks after removal of the nail. None of the statically locked fractures had been converted to dynamic nailing in either group. The authors concluded that the risk of refracture after statically locked nailing is negligible.56

Implant Complications

In the past, fatigue fracture of implants applied for fractures of the femur was common. With advances in metallurgy and design, along with a fuller appreciation of the major stresses to which any fixation device is subjected, the prevalence has diminished.

    Load-shielding implants such as plates are prone to failure more often than are load-sharing implants such as nails. In a series of 131 comminuted femoral shaft fractures treated with ASIF plating techniques, Ruedi and Luscher300 reported 9 cases of plate loosening or breakage. All 9 fractures had medial cortical defects that increased the bending and tensile loading of the laterally placed plate. The frequency of plate breakage and loosening can be reduced by avoiding fracture distraction, routinely applying bone graft, delaying weight bearing, and using broad dynamic compression plates. Because of the load shielding of the bone by plates, however, breakage remains a problem. A plating that has failed by either loosening or fatigue breakage is treated best by hardware removal and intramedullary nailing.

    Implant failure after intramedullary nailing of a shaft fracture usually is associated with either the insertion of a small-diameter nail or the use of an interlocking nail for a very proximal or distal shaft fracture(see Biomechanics of Intramedullary Nailing). Soto-Hall and McCloy329 noted that plastic deformation (bending) of intramedullary nails occurs mainly with nails that are 10 mm or less in diameter (Fig. 27-71). Newer nails with closed-section designs and thicker nail walls are less prone to plastic deformation and fatigue failure. Nails can deform during surgery when they are inserted through a tight, narrow canal, or after surgery with loading of the leg before fracture union. Complete cracks in the midportion of nails are less common than is plastic deformation (Fig. 27-72). An angulated nail can be managed either by manipulation over the apex of the angle or by open transection of the nail. If the nail is straightened successfully by manipulation alone, routine exchange with a larger-diameter nail is prudent (see Fig. 27-43). A weakened nail can become angulated again with minor loading. A bent nail that has not been straightened successfully by manipulation should not be left in situ, because its extraction after fracture healing may be impossible.