Transposition osteotomy of the acetabulum has been performed since 1956 and is a circumacetabular osteotomy for the dysplastic hip. Of 178 procedures, carried out for osteoarthritis in dysplastic hips, some of which were performed by Nishio himself, we were able to review 102 hips after 2 to 17 years (mean 5.7 years). The clinical result, evaluated according to the Japanese Orthopaedic Association hip score, was exellent (over 90) in 42%, good (80-89) in 26%, fair (65-79) in 23% and poor (less than 65) in 9%. The results depended on the stage of the disease, that is, the more advanced the stage, the poorer the result. No cases have undergone secondary total hip arthroplasty to date. Adequate medialization, as well as good lateral and anterior coverage, was significantly related to achieving good results. An early stage of osteoarthritis in severely dysplastic hips is thought to be the best indication for this procedure.
