Fractures of the posterior wall of the acetabulum.

Only 30% of posterior-wall acetabular fractures involve a single large fragment. The majority are multifragmentary or have areas of impaction. Unsatisfactory clinical results occur in more than 80% of patients treated non-surgically. Operative management usually offers the best chance of preserving long-term joint function, but only if an anatomically reconstructed acetabulum can be achieved without complication. The keys to surgical success include maintaining the viability of the fracture fragments and the femoral head itself, using bone grafts and buttress plating to support elevated and comminuted fragments, and protecting the neurovascular structures at risk. Complications can include sciatic nerve injury (incidence, 3% to 18%), heterotopic ossification (7% to 20%), and osteonecrosis of the femoral head (5% to 8%). Despite the relative simplicity of this acetabular fracture, unsatisfactory outcomes after surgical repair of the posterior wall occur in at least 18% to 32% of cases, results that are worse than for most of the other more complex acetabular fracture patterns.