Pretest

Introduction

The ball and socket configuration of the hip joint is inherently stable and allows excellent range of motion in all directions. The acetabulum lies between the anterior and posterior columns of the pelvis, and is anteverted 10° to 15° relative to the coronal plane. The femoral head is completely covered by articular cartilage except at the fovea centralis, where the ligamentum teres inserts. The femoral neck is anteverted 15° relative to the transcondylar axis of the distal femur, and the neck-shaft angle is approximately 135°. When treating proximal femoral fractures, the bony anatomy of the upper end of the femur dictates where the internal fixation devices should be placed for maximum purchase in the femoral head. The area of maximum bone density in the femoral head is where the compression and tension trabeculae coalesce in the center of the head, and represents the ideal site for internal fixation devices to be placed. Identification of the trabecular patterns allows the surgeon to estimate the degree of osteoporosis and the likelihood of successful internal fixation, although the subjectivity of evaluating these patterns has made the use of any grading system unreliable.^1,2

The major forces acting on the hip joint are abductor muscle tension and body weight as defined by the joint reaction force. In men, the normal joint reaction forces can be as much as 4 to 7 times body weight, and in women 2.5 to 4 times body weight.^3,4 Stair climbing causes peak hip forces of up to 7 times body weight.¹⁹ Activities of daily living in a bedridden patient can produce forces on the implant equivalent to walking with the use of external supports.³ Nordin and Frankel showed that only ¼ of the total load is supported by the fixation device if bone fragments are allowed to impact. Implants designed for fracture fixation must withstand extremely high loads and varus bending moments.

Blood Supply of the Femoral Head

The primary blood supply to the femoral head comes from the medial and lateral femoral circumflex arteries which form an extracapsular ring about the femoral neck (Slide 1). Ascending cervical branches arise from this network and enter the capsule at its insertion. Dislocations of the hip and fractures of the femoral neck disrupt the vascularity of the femoral head.^6-8 Claffey⁹ has shown that displaced fractures of the femoral head can occur without disruption of the medial femoral circumflex or lateral epiphyseal systems. Early anatomic reduction and internal fixation of displaced femoral neck fractures may restore blood flow in vessels kinked by the displaced fragments. In 20% of specimens, collateral circulation can maintain viability of the femoral head when the medial circumflex and lateral epiphyseal vessels are disrupted.⁸

Slide 1

Dislocations and Fracture-Dislocations

Hip dislocations are the sequelae of high energy trauma and typically occur in younger patients. Avascular necrosis may result in 15% of the cases, and is usually evident within the first year (but may appear up to 3 years after injury). Degenerative arthritis may be the result in up to 75% of patients at long-term follow-up. Associated musculoskeletal trauma may be seen in 30% to 40% of cases.

Pure dislocations generally occur either anteriorly or posteriorly. Anterior dislocations represent 15% of all hip dislocations, and often are associated with femoral head impaction fractures. Posterior dislocations are more common (85% of hip dislocations), and may occur with posterior wall acetabular fractures. In these cases, hip stability needs to be assessed and the size of the posterior wall fragment determined. Posterior hip fracture-dislocations are classified according to Thompson and Epstein¹⁰ into 5 types:

The term "central dislocation" actually implies a displaced acetabular fracture, and should not be used in lieu of the proper description of the fracture of the acetabulum.

The principles of treatment are well outlined and involve immediate reduction of the hip under appropriate anesthesia. Anterior dislocations are reduced by traction, extension, and internal rotation of the femur. Posterior dislocations are reduced by traction in adduction and flexion, followed by gentle abduction and extension of the hip. Post-reduction imaging is required to delineate the presence of osteochondral fragments that may remain incarcerated within the joint. If present, these fragments require removal. The size and location of any fractures of the acetabular rim or femoral head need to be determined. For this reason, post reduction computed tomography (CT)-scanning is recommended.

Following uncomplicated reduction, the patient is treated with protected weight-bearing for 4 to 6 weeks. Operative intervention is necessary if congruent closed reduction cannot be obtained, if an associated posterior wall fracture > 25% of the wall is identified, or if osteochondral debris is present within the joint space.

Femoral Head Fractures

Associated fractures of the femoral head or neck (Epstein type V) occur in 10% of posterior hip dislocations. These injuries have been further categorized by Pipkin into four sub-types: type I, fracture of the femoral head caudad to the fovea; type II, fracture of the femoral head cephalad to the fovea, type III, femoral head plus femoral neck fracture; and type IV, femoral head plus fracture of the acetabular rim.¹¹ CT-scanning is recommended for identification and sizing of the femoral head fragment.

Femoral head fractures are best treated by closed reduction for Pipkin types I, II, and IV. Type III injuries, involving an associated fracture of the femoral neck, require open reduction. An unsuccessful closed reduction should be treated by open reduction. Pipkin types I and II usually require open reduction from an anterior approach and internal fixation with countersunk cancellous or Herbert screws. Type III fractures in young or active patients should be managed by open reduction and internal fixation of the femoral neck, followed by internal fixation of the femoral head fracture. In the elderly, or low functional demand patient, prosthetic replacement is indicated. Type IV injuries may require open reduction with fixation of the femoral head and posterior acetabulum if the hip is unstable.

Hip dislocations with associated femoral head fractures are at high risk for developing avascular necrosis (AVN) and degenerative arthritis. The prognosis for these injuries varies according to type. Pipkin types I and II have the same prognosis as a simple dislocation. Pipkin type IV injuries are similar to posterior fracture-dislocations without a femoral head fracture. Pipkin type III injuries have a poor prognosis.

Epidemiology

The incidence of hip fractures is increasing as the average age of the population increases. The number of hip fractures in the United States doubled from the mid-1960s through the 1980s, and may triple by the year 2050.¹² Presently, 250,000 hip fractures occur in the United States each year, which results in health care costs of over $8.7 billion.¹³

Hip fractures in the elderly generally result from a single fall, and are more common in females than males.¹⁴ The absolute rate of hip fracture was highest for white women, followed by white men, black women, and black men.¹⁵ The intertrochanteric fracture group is slightly older and has a higher morbidity and mortality than those with femoral neck fracture.¹⁶

Risk Factors

Proximal femur fractures predominantly occur in elderly patients with osteoporosis. Numerous factors are related to the high incidence of hip fractures in the elderly, including osteoporosis, malnutrition, decreased physical activity, impaired vision and neurological impairment, poor balance, altered reflexes, and muscle weakness. The risk of infection and other systemic afflictions is increased in these debilitated patients.

Classification

Garden Classification (types I to IV) is determined according to the degree of displacement evident on an anteroposterior radiograph of the hip (Slide 2).¹⁷ These grades correlate with the prognosis for healing and the rates of avascular necrosis or nonunion.

Slide 2

Pauwels Classification is based on the angle of the fracture line with the horizontal plane.¹⁸ More vertical fractures have higher shear stresses and a correspondingly poor prognosis. These fractures are given a higher classification in the Pauwels system. The closer the fracture line is to the horizontal, the less shear force exists on the implant and the fracture site.

Fifty percent of multiple trauma patients are young patients with a femoral fracture and possibly other long bone fractures.^19,20 Twenty percent of young patients with femoral neck fractures have ipsilateral shaft fracture.^20,21 The surgeon often focuses on the femoral shaft fracture and a femoral neck fracture is missed in 40% of these cases.¹⁹ According to Protzman and Burkhatter, the outcome of femoral neck fractures in the young is poor (AVN 80%, nonunion 60%). More recent literature states that the avascular necrosis rate (range, 20% to 30%) and nonunion rate (range, 15% to 20%) in both the elderly and the young are similar.^19,20

Clinical Examination

Signs and symptoms of femoral neck fracture may be minor in patients with incomplete, impacted, or nondisplaced neck fractures. Internal rotation using the Thomas test almost always elicits pain in the hip and groin region when a femoral neck fracture is present. Axial loading, elicited by gently pushing on the patient's heel, may elicit pain. In displaced femoral neck fractures, there is shortening and external rotation of the hip, with the hip held in slight abduction. These patients are in severe pain and any attempt at hip movement elicits pain.

Imaging

Standard anteroposterior (AP) and lateral radiographs are essential. Rotational malalignment may be observed when the major compressive trabeculae in the head do not accurately align themselves despite overall good alignment of cortical shells (Slide 3). The AP radiograph demonstrates varus or valgus deformity. The lateral radiograph must be evaluated to determine the amount of posterior comminution (Slide 4). Currently, magnetic resonance imaging (MRI) is recommended for the evaluation of occult fractures of the femoral neck.

SLIDE 3		SLIDE 4

Treatment: Basic Principles

The treatment of femoral neck fracture depends primarily on the age of the patient and the degree of displacement. All patients must be evaluated medically and their condition optimized.²² The timing for internal fixation of femoral neck fractures remains controversial.^23,24,25 Rates of AVN and nonunion are decreased by fixation within 12 hours after injury.^25,26,27 However, some studies have not shown an increase in the rate of AVN or nonunion with delayed fixation up to a week.²³ Because of the theoretical advantages, we advocate stabilization of the fracture as soon as the patient has been evaluated medically and is stable.

Treatment: Nondisplaced Fractures

Nondisplaced or minimally displaced femoral neck fractures are at low risk (0% to 5%) for avascular necrosis or nonunion,²⁸ and are treated with internal fixation to prevent further displacement and the risks of avascular necrosis and nonunion.²⁹

Treatment: Displaced Fractures

Displaced femoral neck fractures are treated according to the age and demands of the patient. These fractures are at high risk for AVN and nonunion, averaging 30% and 15%, respectively.^23,30-39 In healthy patients under 75 years, the treatment of choice is reduction and internal fixation. Patients physiologically over 75 years should be considered for prosthetic replacement to avoid a secondary operation. A prosthetic replacement also may be desired in a patient with severe hip disease in conjunction with a femoral neck fracture.

Options for Prosthetic Replacement

The choice of prosthetic device depends on the activity of the patient and the degree of hip disease. In a non-ambulatory patient, a one-piece uncemented hemiprosthesis may be used. This prosthesis has been shown to be unsatisfactory in more active patients, because of thigh pain and acetabular protrusion.⁴⁰ In moderate demand patients, such as nursing home or household ambulators, a cemented bipolar prosthesis has been proven to be adequate and has led to excellent results.⁴¹ In an active, healthy, high-demand patient, regardless of age, open reduction and internal fixation is the procedure of choice because this patient is capable of withstanding a secondary operation if the fixation fails. A total hip replacement is the treatment of choice in displaced or nondisplaced femoral neck fractures with concomitant severe osteoarthritis, rheumatoid arthritis or cancer. Dorr has shown that total hip replacement outperforms bipolar replacement in relieving hip pain, but the total hip replacement does have a higher rate of postoperative complications with dislocation rates up to 12% if used in femoral neck fractures with concomitant hip disease.⁴²

Evaluation of Reduction

Poor reductions prevent re-establishment of blood supply to the femoral head and decreases the amount of bony apposition at the fracture, leaving poor mechanical stability after fixation. Garden43 showed that valgus reduction > 20° is associated with higher rates of AVN. Any degree of varus deformity following reduction is associated with increased rates of AVN and nonunion.19 Anterior-posterior angulation of > 10° should not be accepted, particularly in osteoporotic bone because of the potential for further displacement. On the lateral radiograph, the surgeon should pay particular attention to the degree of posterior comminution. Both Garden and Banks have shown that fractures with marked posterior comminution have a high incidence of nonunion.23,44,45 If closed reduction within acceptable parameters cannot be obtained, the surgeon should proceed to open reduction when the patient is not a candidate for arthroplasty. If the patient is a candidate for arthroplasty, the treatment plan for reduction and fixation must be abandoned and the surgeon must proceed with prosthetic replacement.

Surgical Technique: Multiple Cannulated Pins

Multiple pins, popularized by Knowles, is a simple and effective technique for fixation of femoral neck fractures. This technique can be done using percutaneous local anesthetic or an open technique. Mechanical studies show that stability at the fracture site is maximized by 3 to 4 pins placed either in a triangular or boxed configuration (Slide 5). Care must be taken to place multiple pins or screws at a 130° to 135° angle. Positioning them at a higher angle (140° to 145°) places multiple holes at or below the lesser trochanter. This has been shown to result in a 20% incidence of subtrochanteric fracture.⁴⁶

Slide 5

Complications: Nonunion

Nonunion occurs in 2% to 22% of femoral neck fractures and generally becomes apparent within 1 year.^30,32,44,47 Nonunion may or may not be accompanied by AVN. If nonunion occurs, MRI is suggested to evaluate the vascular supply to the femoral head before continuing with treatment options. In the elderly community ambulator, nonunion is treated by total hip replacement. In younger patients, nonunion is treated with a valgus osteotomy and repeat fixation. Most nonunions have some varus deformity, and a valgus osteotomy and fixation are essential to apply compression loads at the fracture site and promote healing. An intertrochanteric osteotomy will realign the proximal femur into a valgus position.

Complications: Osteonecrosis

Most studies report rates of AVN in displaced femoral neck fractures of 10% to 20%. If the patient is asymptomatic, no further treatment is indicated. If collapse of the osteonecrotic fragment has occurred and the patient is symptomatic, total hip arthroplasty is indicated.

History of Implants

Treatment of intertrochanteric fractures has advanced greatly since Jewett introduced the triflanged nail in the 1930s.⁴⁸ The shortcomings of fixed nail-plate devices were recognized by the mid 1960s. Sliding devices that allowed impaction of fracture fragments were developed.^18,52 In the 1970s, flexible intramedullary devices for intertrochanteric fracture fixation were introduced in the form of the Ender nail and the condylocephalic nail. The mechanical advantage of these devices derives from their intramedullary position, which places them closer to the resultant force across the hip and reduces the bending movement on the device. In addition, the use of distal sites of insertion decreased operative time and blood loss compared with the proximal sites. Second generation rigid, interlocking, intramedullary devices were introduced in the late 1980s. These devices are also associated with a higher complication rate than the sliding hip screw when used for routine intertrochanteric fractures.

Classification

Intertrochanteric fractures can be classified as stable or unstable. In the stable intertrochanteric fracture, the posteromedial buttress remains intact and collapse of the fracture fragments is minimal. Stability is obtained with reduction and re-establishment of medial cortical contact. In the unstable intertrochanteric fracture, however, a large segment of the posteromedial wall is fractured free with posterior comminution (Slide 6).

Slide 6

Evans and Boyd classification further subdivides the stable fractures into those without comminution, those with minimal comminution, and those with subtrochanteric components.^50,51,52

A modification of Boyd classification is that of Kyle and Gustilo,⁵³ in which four basic intertrochanteric fracture types are recognized (Slide 7).⁴⁷ Type I fractures consist of nondisplaced stable intertrochanteric fractures without comminution. Type II fractures represent stable, minimally comminuted but displaced fractures; these are fractures that, once reduced, allow a stable construct. The unstable type III intertrochanteric fracture - the problem fracture - has a large posteromedial comminuted area Slide 6). The unstable type IV fracture is rare (15% of intertrochanteric fractures) and consists of an intertrochanteric fracture with a subtrochanteric component. The Type IV fracture is the most difficult to fix because of the great forces in the subtrochanteric region of the femur.^53,54

Slide 7

Biomechanics

To correctly apply sliding devices, it is essential to understand the mechanics of the devices and the forces they must withstand.⁵⁵ In a 1935 study, Pauwels¹⁸ concluded that the forces acting on the hip in a single-limb stance amount to approximately three times the body weight applied at an angle of 159° to the vertical plane. This same force acts on any hip fixation device placed across the fracture site.

A sliding device with a screw-plate angle closest to this combined force vector allows optimum sliding and impaction (Slide 8).⁵⁶ Devices of lower angles are subject to lower forces parallel to the sliding axis and higher forces perpendicular to the sliding axis that act to jam or bend the device, thereby preventing impaction. The surgeon cannot place the sliding device at a high angle in small hips or hips with varus deformity. Mechanically, it is desirable to place the sliding fixation device at as high an angle as clinically possible, but still maintain center head placement of the fixation device and prevent cutout.

Slide 8

The ideal position for the nail or screw is the point of coalescence of the tension and compression trabeculae in the center of the femoral head. This is where the best purchase in the bone is obtained with a fixation device. When these trabeculae are absent, the surgeon can expect a higher failure rate with this device. Center head placement within 5 mm of subchondral bone gives the lowest failure rate in unstable intertrochanteric fractures on clinical follow-up (Slide 9). Following anatomic reduction, properly placed sliding devices allow spontaneous impaction and medial displacement of all intertrochanteric fractures into a stable configuration (Slide 10). This allows early mobilization of the patient with weight-bearing in most cases.

SLIDE 9		SLIDE 10

Clinical Examination

The patient is seen with the affected leg externally rotated and shortened. Movement of this leg causes severe pain, and forced attempts of range of motion should not be performed. Kenzora, et al.²² has shown that medical stabilization of the patient is essential prior to surgery and timing of surgery is dictated by the patient's medical condition.⁴⁰

Imaging

A standard anteroposterior and lateral hip radiograph is obtained for evaluation. On the anteroposterior radiograph, a fracture between the greater trochanter and lesser trochanter is seen. The larger the lesser trochanteric fracture, the more unstable the fracture. The surgeon should note the amount of posterior communition on the lateral radiograph. The greater the degree of posterior communition on the lateral radiograph, the more unstable the fracture (Slide 11).

Slide 11

Treatment: Basic Principles

The most important step in fixation of intertrochanteric fractures is proper placement of the guide pin into the center of the femoral head (Slide 10). After insertion of the screw, the plate should be fixed to the lateral aspect of the shaft with at least four cortical bone screws. In osteoporotic bone, six screws are necessary. Medial fragments may be secured with a lag screw technique, if they can be captured without periosteal stripping and extensive surgery. Biomechanical studies show increased fracture stability when large medial fragments are fixed.57 Image intensification should be used during the final seating of the nail or screw to assure it is well within the femoral head to within 5 mm of subchondral bone.

Postoperative Care

The patient is allowed to sit, as directed by comfort, the day after surgery. If solid fixation is obtained on the second or third postoperative day, the patient is allowed to ambulate on parallel bars with weight-bearing on the injured extremity as tolerated. If the bone is osteoporotic or poor fixation is obtained, delayed weight-bearing is necessary until callus formation is present. Weight-bearing is progressed as tolerated. Radiographs should be taken at weekly intervals for the first 2 weeks to assure proper impaction of the fragments. If there is a subtrochanteric component to the fracture, weight bearing is delayed until callus is seen on the radiograph.

Complications

Complications of intertrochanteric fracture fixation are minimal compared with other hip fractures, if the surgeon uses the device of choice correctly and pays attention to mechanical principles involved. The failure rate with a sliding hip screw should not exceed 10%. Nail breakage is extremely rare with the use of current high technology metals. The infection rate in intertrochanteric fractures should not exceed 1% with the use of prophylactic antibiotics. Avascular necrosis is extremely rare in intertrochanteric fractures, and has not been reported above 1% in any series. The nonunion rate is < 1%. If nonunion does occur, the success rate after simple removal of the device and renailing in a more valgus position with bone grafting is 90%. For this reason, repeated fixation is recommended.^58,59

The most common mode of failure is hip screw cut-out in osteoporotic bone and subsequent collapse into varus. When little bone is left in the femoral head after a failed hip screw, the use of a blade plate is valuable. The plate provides more surface area to resist cut-out through the femoral head.

Treatment of Combined Intertrochanteric Shaft Fractures - Type IV

Second generation interlocking nails may be used in treatment of intertrochanteric fractures combined with femoral shaft extension. The second generation interlocking nail is an excellent form of fixation when the piriformis fossa is intact. When the piriformis fossa is not intact, a hip screw with a long side plate, interfragmentary fixation, and supplementary bone grafting is advisable. In very distal shaft fractures seen in combination with an intertrochanteric fracture and piriformis fossa involvement, a second generation nail is the implant of choice. However, this implant is difficult to use.

Treatment of Reverse-Oblique Fractures

The reverse oblique fracture is a special fracture requiring the same treatment as the intertrochanteric-subtrochanteric fracture. The reverse oblique fracture is difficult to reduce because the adductors and iliopsoas are intact and they pull the distal fragment medial while the proximal fragment is abducted and pulled laterally. Fixation of this fracture is accomplished with a lower angle screw plate so the fixation device does not have to be placed directly through the fracture site. The fracture is reduced with manual traction and held in place with a bone clamp. In this particular fracture configuration, excessive traction may cause further displacement and many times the traction must be released, the fracture rotated slightly, and manually reduced to the side plate. A longer side plate is recommended for this fracture because of its distal extension. A second generation interlocking nail may also be used.

Subtrochanteric Fractures Introduction

Subtrochanteric fractures of the femur account for 10% to 15% of all hip fractures and are among the most problematic to treat. Subtrochanteric fractures occur in the highest stressed region of the body, where compressive forces have been calculated at 1200 psi in the medial cortex below the lesser trochanter and tonsile stresses at 1000 psi.60,61 Such stresses predispose internal fixation of these fractures to a high failure rate and account for the great difficulty in both operative and nonoperative management.

History

As early as 1907, Lambotte⁶² recommended open reduction internal fixation of subtrochanteric fractures using a combination of hip nails and cerclage wiring. Because of the complications with early devices, most surgeons prior to the 1950s attempted treatment of these fractures in traction and plaster immobilization. The majority of cases healed because of the excellent circulation, but with varus deformity and shortening.⁶³ A high medical complication rate also resulted from prolonged bed treatment.

Following the development of the triflanged nail-plate, internal fixation became more popular although complications remained frequent. In the 1940s, Kuntscher introduced the concept of intramedullary fixation of subtrochanteric fractures with the "Y nail."⁶⁴ The first widely successful intramedullary device was developed by Zickel in the early 1960s.⁶⁵ Clinical series reported failures in less than 5%.^65-67

The AO blade plate used in the 1970s was effective if the medial buttress could be restored and the plate could be used as a tension band. This technique was used in conjunction with the method of indirect reduction promoted by Mast.⁶⁸ The sliding hip screw or nail device was used in high subtrochanteric-intertrochanteric fractures, but implant failure was high in comminuted fractures with shaft extension.⁶⁹ The success of these devices in both subtrochanteric and comminuted intertrochanteric-subtrochanteric fractures has been improved by the use of early bone graft about the highly stressed medial cortex.^68,70

In the early 1980s, closed intramedullary rodding of subtrochanteric fractures with interlocking nails was introduced. Advancements in intramedullary rodding techniques and design have made fixation of subtrochanteric fractures with shaft extension possible. All series of closed interlocking intramedullary nailings have shown a high rate of union, low infection rate, and excellent maintenance of alignment.^71,72-75

Classification

There are several classifications of subtrochanteric fractures, but few have taken into account the mode of treatment or prognosis. The Fielding-Magliato classification describes three fracture types based on the location of the primary fracture line in relation to the lesser trochanter: type I, 1 in. below the lesser trochanter; type II, 2 in. below the lesser trochanter; type III, 3 in. below the lesser trochanter.⁷⁶ Zickel⁶⁶ described six types of subtrochanteric fractures; four are oblique and two are transverse.⁶⁶ Seinsheimer⁶⁹ described the classification that involved types I through IV with a subclassification of A, B, C, with A being the most stable and C being most unstable and comminuted; type I the most proximal and type IV the most distal.⁶⁹ The AO group also has a separate classification system dependent on the degree of comminution; however, in their classification system the lesser trochanter region is always intact.

The classification system presently used at Hennepin County Medical Center is based on treatment and divides subtrochanteric fractures into two types (Slide 12). Type I, or high subtrochanteric fractures, have a fracture into the lesser trochanter. In type II, or low subtrochanteric fractures, the lesser trochanter remains intact and a first generation interlocking nail is used. Both types of fracture may be either simple or comminuted with shaft extension.

Slide 12

Clinical Examination

On presentation, the affected leg is markedly shortened and externally rotated. In the young patient, the surgeon must be aware of accompanying injuries to the pelvis, axial spine, and other long bones. Associated pelvic and long bone fractures were found in 46% of these fractures evaluated at Hennepin County Medical Center.⁷⁷ The patient is also evaluated for hemodynamic instability due to associated blood loss from this high energy fracture.

Imaging

Standard AP and lateral radiographs of the entire femur are sufficient to evaluate most subtrochanteric fractures. When intramedullary fixation is considered, it is frequently helpful to obtain radiographs of the uninjured, opposite femur as well assist with preoperative measurement of limb length and medullary canal diameter.

Treatment

Because high subtrochanteric fractures (type I) have the lesser trochanter fractured off, they must be fixed with either a sliding hip screw or a second generation interlocking nail. In the type I fracture, when the piriformis fossa is fractured, a sliding hip screw is used because the entry point for insertion of an intramedullary nail is lost, making its use difficult. In type I fractures with the piriformis fossa intact, a second generation interlocking rod may be used because the entry point for the intramedullary rod is undisturbed.

On occasion with a very distal femoral shaft fracture, despite piriformis fossa involvement in a type I subtrochanteric fracture, a second generation interlocking nail is indicated. In low, type II fractures with the lesser trochanter and piriformis fossa intact, a first generation interlocking nail is used (Slide 13).

Slide 13

Complications: Varus or Rotational Deformity

Rotational deformity is uncommon after management of a subtrochanteric fracture. When such deformity occurs and is symptomatic, either open or closed derotation osteotomy and intramedullary rodding are performed. Varus malunion is common and requires intertrochanteric valgus osteotomy for correction. A sliding hip screw device or blade plate is used for internal fixation.

Complications: Nonunion

Nonunions that occur in the shaft of the femur are treated with repeat reaming and insertion of a larger interlocked intramedullary rod. Nonunion in the subtrochanteric region is treated with valgus osteotomy, bone grafting, and refixation. Avascular necrosis is rare to nonexistent in subtrochanteric fractures.

Complications: Infection

Acute infection is treated with insertion of tobramycin beads and intravenous antibiotics for a 6-week period. Late infection is treated with removal of the fixation device, insertion of tobramycin beads, and a 6-week course of intravenous antibiotics.

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