Fractured neck of femur

Fractured necks of femur may be classified as intra- or extra-capsular. The former are either displaced (Fig. 22.8) or undisplaced. Undisplaced intracapsular fractures are generally treated by pinning them in situ with cannulated screws in the operating theatre under X-ray control. The blood supply to the femoral head is somewhat precarious in displaced intracapsular fractures and the risk of avascular necrosis of the femoral head is high. Therefore, these fractures are generally treated with prosthetic replacement of the femoral head in the older age group, which precludes the development of avascular necrosis and allows early relief of pain and early mobilization with full weight bearing from the outset. The other main complication of displaced intracapsular fractures is non-union. The incidence of non-union in these

Figure 22.7. Bimalleolar fracture treated with a plaster of Paris cast.
Figure 22.8. Displaced intracapsular fracture of the left neck of femur.

fractures is higher than other fractures because of the biomechanical disadvantage whereby shearing forces act on the fracture and also due to the fact that synovial fluid has angiogenic inhibiting factors.

Extracapsular fractures usually involve the pertrochanteric, intertrochanteric or subtrochanteric regions of the proximal femur and may be displaced or undisplaced, simple or comminuted. They are usually unstable but because of the risk to the elderly of prolonged immobilization in bed, the accepted form of treatment is usually screw and plate implants, which are designed to allow collapse of the fracture into a stable configuration. The most commonly used implant is a dynamic hip screw (DHS). A proximal femoral nail (PFN) is another option for these fractures. Elderly patients are often unable to co-operate with a non- or partial-weight-bearing regimen postoperatively but the implant allows full weight bearing from the start.

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