OPTIONS

The main complications associated with isolated femoral neck fractures are high rates of nonunion and avascular necrosis of the femoral head. Complications associated with isolated femoral shaft fractures include malunion (i.e., >2 cm shortening, >10-degree varus or valgus alignment, and >20 degrees malrotation) and nonunion. Many authors contend that the complications of the femoral neck trump those of the femoral shaft. They suggest that avascular necrosis is the most significant complication and, therefore, the femoral neck fracture should be treated first.^{4,7, 8} Others suggest that the femur should be treated initially to allow for ease of closed reduction of the femoral neck fracture.^{3,5, 9} What are the most common complications of this injury pattern? In what order should fixation of the fractures proceed?

A large number of the femoral neck fractures associated with shaft fractures are missed (approximately 30%).¹ Many of the femoral neck fractures are nondisplaced at the time of presentation (25–60%).¹ (This may occur because some of the energy that would normally result in a displaced femoral neck fracture is dissipated by the shaft fracture.) In addition, many of these patients have multiple injuries with numerous “distracting” injuries. What is the best method of imaging the hip to avoid missing a fracture?

A spectrum of different hip fractures has been reported with this injury pattern. Hip fractures vary from intertrochanteric fractures to different types of intracapsular neck fractures. The position of the hip (degree of abduction) at the time of injury has been suggested as the determinant of the pattern of hip fracture produced.¹⁰ What is the most common type of hip fracture encountered with this injury? What is the most common type of femoral shaft fracture?

Many different implants and implant combinations have been used to treat this combination of fractures. Implant designs have changed over the time periods of many of the retrospective case series reported in the literature (Table 58-1). For example, the antegrade femoral intramedullary nail has evolved from the unlocked (Küntscher) nail, to the first-generation locked nail, to the second-generation cephalomedullary (or reconstruction) locked nail, and finally to the intramedullary hip screw device. Retrograde femoral nailing has also become increasingly popular since the late 1990s. However, the literature consists of small case series that involve a mixture of different implants from different periods. What are the optimal implants for this fracture pattern?

EVIDENCE

Alho¹ conducted a meta-analysis on 65 studies published between 1970 and 1996 that incorporated 722 cases of ipsilateral hip and shaft fractures. This represents the largest summary of case series reported in the literature. He identified 10 studies (240 fractures) that included useful demographic data. This injury typically occurs in young individuals (mean age, 33 years) and results from a high-energy mechanism (85% motor vehicle accidents). Only 1% of cases occurred in elderly individuals. Approximately 18% of the femoral shaft fractures were reported as open, with a large number of comminuted fractures (i.e., 42% were Winquist type III or IV).¹¹ The majority of shaft fractures occurred in the middle third of the femur (72%). For hip fractures, Alho¹ reports that the majority of cases were femoral neck fractures (61%), with the rest being trochanteric fractures. Shuler and colleagues¹⁰ report on 52 cases of hip fracture with femoral shaft fracture and found 90% to be femoral neck fractures. They found that these hip fractures all tended to extend into the inferomedial neck regardless of the fracture type (i.e., midcervical, basocervical, or pertrochanteric). The extension of the fracture into the inferomedial neck (i.e., femoral calcar) makes it prone to displacement with weight bearing.

Complication rates for femoral neck fractures with an associated femoral shaft fracture tend to be less than with this injury in isolation. Alho¹ quotes an avascular necrosis rate of 5% and no nonunions of 254 fractures (this includes displaced and nondisplaced fractures). For isolated displaced femoral neck fractures, the incidence rate of avascular necrosis is 22.5% and of nonunion is 6%.¹² The reduced rate of avascular necrosis and nonunion seen with the combined injury may result from a greater rate of nondisplaced fractures (up to 60% for the combined injury),¹ perhaps because much of the energy is dissipated through the femoral shaft fracture. Thus, the hip fracture tends to be less comminuted with less injury to the vasculature (i.e., posterior retinacular vessels).

An important consequence of the high rate of nondisplaced femoral neck fractures is that they tend to be missed on initial presentation. Alho¹ states that the diagnosis of the hip fracture was delayed (from 1 day to several months) in 30% of cases. Tornetta and investigators¹³