[Para-articular surgical interventions of the hip--a mechanical problem].

From the analysis of a case report the author draws the following conclusions: Combining a perfect reduction with a valgus intertrochanteric osteotomy and a stable fixation ensures almost certainly against non union and probably against a high rate of avascular necrosis in cases of subcapital fractures of the neck of the femur. However, increased compressive stresses must be expected in the joint, above all in obese patients or if the joint surfaces are not congruent. Therefore, unloading is recommended and a secondary varus intertrochanteric osteotomy should be carried out as soon as bony union is achieved. Pauwels' intertrochanteric osteotomy constitutes a sensible treatment of osteoarthritis of the hip and gives amazingly long term good results if the weight bearing surfaces of the joint can be increased and the articular pressure is thus considerably reduced. The cyst in the femoral head results from fractures of cancellous trabeculae subjected to stresses which are beyond of functional adaptation.