Towards a better understanding of the aetiology of Legg-Calvé-Perthes' disease: acetabular retroversion may cause abnormal loading of dorsal femoral head-neck junction with restricted blood supply to the femoral epiphysis.

The most accepted part of the aetiology of Perthes' disease is an intermittent arterial occlusion. Many different reports now also suggest that some mechanical factor plays a role. In search of mechanical differences between normal hips and Perthes hips, many secondary morphologic differences of the proximal femur and the acetabulum are known. Recent research by the author has shown morphological changes of the acetabulum, independent of Perthes' disease in a large part of patients. In particular, retroversion of the acetabulum was found in a large part of adults who suffered from Perthes' disease as a child, and even in children who just developed Perthes' disease. The author suggest a relation of the two entities and hypotheses that due to the acetabular retroversion, there may be an intermittent, movement depending abnormal loading pressure on the dorsal femoral head-neck junction and the local blood vessels, which can lead to insufficient blood supply of the femoral epiphysis and to local necrosis, as these vessels are the only blood supply to the femoral epihysis in children.