[Treatment of coxa magna in Perthes disease by pelvic osteotomy (author's transl)].

In M. Perthes a progressive deformation and flattening of the epiphysis is caused by the stress in the hip. In the beginning stages a varisation osteotomie gives a sufficient reduction of the joint pressure and a modelling of the enlarged head by the acetabulum is possible. In later stages a detoriation of the head deformity with fixed adduction contracture can be caused by varisation osteotomie. Enlarging the acetabulum laterally and ventrally and medializing the hip-joint by means of a Chiari pelvic-osteotomy reduces the joint pressure so far, that a restitution of the hip joint with round and congruent joint surfaces can be expected. A lateralisation of the deformed femoral head with a secondary insufficiency of the acetabulum should also be treated by an additional pelvic osteotomy, if in the arthrography the lateral part of the head does not enter the acetabulum in abduction position. In secondary osteochondritis in hip luxation the treatment should be equal. Even an advanced secondary osteoarthritis after M. Perthes could be stopped by pelvic osteotomy over years.