[Cervico-acetabular impingement after femoral neck fracture]

Six cases of femoral neck-acetabular impingement following fracture of the femoral neck are reported. To our knowledge, this complication has not previously been described in the literature. A bony prominence at the level of the former fracture site following primary or secondary valgus position of the femoral head showed a conflict with the acetabular rim causing pain and limited motion. In four patients this impingement was posterior, between the femoral neck and the acetabulum in extension with external rotation, and in two patients it was anterior in flexion with internal rotation. A detailed description of the symptoms, diagnostic procedures and treatment options is presented.