In the case of surgically dressed necroses of the hip condyle and coxarthroses a condition was found after fracture of the pelvis or after dislocation of the hip joint in 7.2% of the cases. In 13.2% of the cases a trauma was found anamnestically. It was subdivided into fractures of the acetabulum, fractures of the pelvic girdle, dislocations, and fractures of the pelvic brim on the basis of the system of Judet and Engler as well as Feldkamp. Fractures of the pelvic brim through muscular traction, traction of the ligament, and direct trauma were discussed. The most frequent delayed consequences arising after dislocations of the hip joint and fractures of the acetabulum are: necroses of the head of the femur, coxarthroses, pseudarthroses, and myositis ossificans. The pathogenesis of the delayed injuries resulted from: capsular and vascular lesions, damage to cartilage with fractures in the spongiosa region, incongruence of the surface of the joint, insufficiency of the static structure of the pelvic ring, deposit of calcium salt outside the bone. In some cases the progress of the necrosis could be arrested by means of osteotomy and spongiosa filling. The rate of necrosis increases in proportion to the period between the time of occurrence of the accident and reposition (limit of 6 h). Even though about half the pelvic girdle fractures show good results with conservative treatment, in the case of fractures of the acetabulum a reconstruction as far as possible continuous and without stages is to be aimed at. In many cases the development of a myositis ossificans cannot be prevented.