[Joint-preserving osteotomy in segmental femur head necrosis].

Joint-preserving osteotomies for segmental necrosis of the femoral head are clinically important, as necrosis often occurs in relatively young people in whom one is hesitant to perform femoral head replacement. The principle in all joint-preserving osteotomies is to remove the necrotic area from the zone subject to load, thereby guarding against indentation of the joint surface. The most universal and most frequently indicated osteotomy is intertrochanteric valgus flexion osteotomy with ventral capsule resection. The result of the operation depends mainly on the extent of the necrosis. If the angle of the necrosis is under 200 degrees, the hip joint can be preserved with great precision and in a good enough state to allow joint replacement to be postponed for many years.