The incidence and pattern of knee injury associated with dislocation of the hip.

A retrospective survey of 135 posterior dislocations and fracture-dislocations of the hip was carried out in order to define the pattern of associated knee injuries. Thirty-five patients had sustained a significant injury to the knee, of which twenty-five were clearly attributable to a direct blow on the front of the knee (fractured patella, traumatic chondromalacia, fractures of femoral and tibial condyles) and ten were compatible with valgus, varus or rotational forces (medial, lateral and cruciate ligament tears). The second type of injury has not been widely recognised but it is important that it should not be overlooked.