[Reconstruction of large femoral defects in exchange operations following artificial hip replacement]

Loosening of the implant is one of the most serious complication in case of total hip replacement. It is caused by the growth of a secondary cancellous channel and in destroyed bone cement. From 1981 to 1986 we operated 63 patients to exchange a loosened hip prosthesis. With 15 patients we have seen a severe damage of the femur shaft. Big parts of the bone tube were missed. To insert the new stem we had to reconstruct the proximal femur and the calcar region by autogenous cortico-cancellous bone grafts in seven cases. In three cases a large defect of the lateral femur cortex was reconstructed by extended cancellous bone graft. In five cases we found a cominuted fracture of the femur shaft. The osteosynthesis was performed by plating. The screws were inserted through the bone into the stem. They find a very strong grip in the polyacetal material. 14 of 15 patients operated in this manner could achieve a walking ability. Most of them improved one step higher in the evaluation scheme according to Merle d'Aubigne. One patient suffering from a septic loosening showed a severe exacerbation with septicemia and ended in a disarticulation of the hip joint. The so called isoelastic prosthesis gives a chance to reconstruct the femur tube. It allows unhindered calcification of bone graft and acts as a forming model for new bone. With this we are able to restore the movement of hip joint as well as weight bearing and working ability of the limb. Additional osteosynthesis is possible to perform.(ABSTRACT TRUNCATED AT 250 WORDS)