Dysplastic acetabula were augmented during total hip replacement by superolateral autografts. In cases of primary arthroplasty these were taken from the excised femoral head and in revision surgery from the iliac crest. Two or (usually) three small grafts were used to facilitate revascularisation; they were fixed with lag screws to the roughened iliac bone above the acetabulum. We reviewed 84 hips (63 primary arthroplasties and 21 revisions) more than five years (mean 10.1) after operation. All but one of the grafts showed consolidation within three months and they had become structurally integrated with the iliac bone, as evidenced by the trabecular reorientation. Resorption, which has caused early socket failure when large bone grafts have been used, did not occur.

In acetabular dysplasia, fixation of the acetabular component of a cemented total hip prosthesis may be insecure and superolateral bone grafts are often used to augment the acetabular roof. We used finite element analysis to study the mechanical importance of the lateral acetabular roof and found that the lateral acetabular rim plays an important role in the load transfer of the pelvic bone. When the superlateral rim was lacking, the load shifted to the posterosuperior rim and to the area of pubic support, and the stresses in all materials, especially in the cement and in the trabecular bone, increased greatly. At the cement-bone interface the tilting component of the shear stress increased threefold. In a model in which the dysplastic acetabulum was augmented by a rigidly fixed, load-transmitting bone graft, the stresses were considerably diminished.

We report a series of 50 patients under 70 years of age who had an ununited femoral neck fracture treated by a Pauwels abduction osteotomy. At an average follow-up of 7.1 years, seven patients had required prosthetic replacement and 37 others were reviewed in detail. In these patients the Harris hip score averaged 91. Twenty-two hips showed radiographic evidence of avascular femoral head necrosis, but only three of these had been replaced. For active patients with non-union of a femoral neck fracture, Pauwels osteotomy provides a high proportion of good results even in the presence of avascular necrosis of the head, providing there has been no collapse. If osteotomy fails, prosthetic replacement is still possible.