Effect of early hip decompression on the frequency of avascular necrosis in children with fractures of the neck of the femur.

Twenty-eight per cent of 32 children with fractures of the neck of the femur developed avascular necrosis. It occurred in three of the four type I fractures, in five of the 11 type II fractures, in one of the 12 type III fractures and in none of the five type IV fractures. We studied the effect of early hip decompression on the frequency of avascular necrosis. It had no apparent value in type I fractures. To increase the statistical power of our analysis of displaced type II and III fractures we combined our cases with similar cases from other series. Twenty-two (41 per cent) of the 54 combined cases treated without hip decompression developed avascular necrosis while only three (8 per cent) of the 39 combined cases treated with early hip decompression developed avascular necrosis. This difference was statistically significant. This finding supports the use of early hip decompression as a means of reducing the frequency of avascular necrosis in displaced type II and III fractures. Our findings also indicate that the complications of nonunion, malunion and premature closure of the proximal femoral physis are minimized by accurate reduction of displaced fractures, routine use of internal fixation for all fractures and avoidance of permanent physeal damage by internal fixation devices.