J Am Acad Orthop Surg, Vol 18, No 4, April 2010
David M. Foulk, MD and Brian H. Mullis, MD A simple hip dislocation is one without fracture of the proximal femur or acetabulum. Complex fracture-dislocations involve the acetabulum, femoral head, or femoral neck. The incidence of posttraumatic arthritis is much lower in simple dislocations than in fracture-dislocations. The most common mechanism of injury is a high-energy motor vehicle accident, which is usually associated with other systemic and musculoskeletal injuries. The hip should be reduced emergently in an atraumatic fashion. For acetabular fracture, intraoperative stress views may be necessary to evaluate for instability and to determine whether surgical fixation is required. The appearance of a concentric reduction on plain radiographs and CT does not rule out intra-articular hip pathology; such injury may contribute to long-term degenerative changes. Other complications of hip dislocation include osteoarthritis, osteonecrosis, and sciatic nerve injury. Indications for surgical management include nonconcentric reduction, associated proximal femur fracture (including hip, femoral neck, and femoral head), and associated acetabular fracture producing instability. Surgical management ranges from formal open arthrotomy to minimally invasive hip arthroscopy. Hip arthroscopy has become popular for treating intra-articular hip pathology, including loose bodies, chondral defects, and labral tears.