Traumatic posterior dislocation of the hip--prognostic factors influencing the incidence of avascular necrosis of the femoral head.

To elucidate the factors important for development of avascular necrosis of the femoral head following traumatic posterior dislocation of the hip, 98 adult patients with 100 hip dislocations were reviewed after a minimum follow-up of 5 years. Avascular necrosis of the femoral head was found in only 4.8% of the hips reduced within 6 h, but in 52.9% of the hips reduced more than 6 h after the injury. Dislocations were classified according to Stewart and Milford [11]; a significantly higher incidence of avascular necrosis was found in grade-III and -IV dislocations than in grade-I and -II dislocations. We could not demonstrate any benefit from skeletal traction or non-weight bearing. The age of the patients was of no importance.