Chiari medial displacement osteotomy has been performed for 50 hips diagnosed pre, early and progressive osteoarthritis with acetabular dysplasia since 1977. Of 32 cases, 29 were females and 3 were males with average age of 20.4 years. The average term of follow-up study was 6 years and 3 months. The results were evaluated by the scale for osteoarthritis of the hip joint adopted by the Japanese Orthopaedic Association. Radioogical study was performed in sharp and CE angle, ratio of medial displacement, changing of joint space, ATD and femoral head between pre- and postoperation.
Excellent or good results (over 80 points) were obtained in 28 cases (87.5%), and poor in 4 cases (12.5%). Preoperative coxalgia was remarkably improved from average point of 24.7 to 35.3. The radiological examination showed that the ratio of medial displacement has effective influence on clinical good results.