Avascular necrosis of the capital epiphysis following osteomyelitis of the proximal femoral metaphysis.

In this paper we wish to emphasise the danger of avascular necrosis of the capital femoral epiphysis arising as a late complication of osteomyelitis of the intertrochanteric region. This necrosis is primarily aseptic and is believed to follow interference with the vulnerable vascular channels supplying the capital femoral epiphysis rather than spread of infection into the joint. If, however, the infection is inadequately treated in the early stages, spread of the inflammatory process may inflict further damage to the avascular epiphysis. We believe that awareness of this hazard should prompt the surgeon to be aggressive in the management of infection in this situation. The radiological signs closely resemble those of Legg-Perthes’ disease and, indeed, Kidner (1916, 1923), having observed this similarity in two patients with osteomyelitis of the femoral neck, proposed infection as the cause of Legg-Perthes’ disease. It is interesting to record that Legg (1910) in his original description included among his five patients a child in whom epiphysial necrosis followed a staphylococcal osteomyelitis of the proximal femur. McWhorter (1924) was the first to recognise the distinction between these two varieties of necrosis of the capital epiphysis. He described a patient with staphylococcal osteomyelitis of the femoral neck who at operation was noticed to have a sterile effusion within the hip joint. Although the intra-osseous lesion healed the boy subsequently developed clinical and radiological features resembling Legg-Perthes’ disease.