We report the results of a long-term follow up study of Chiari pelvic osteotomy for early stage coxarthrosis with severe acetabular dysplasia. The subiects were 14 hips in 14 Ninomiya-type 2 patients. The average age at the time of operation was 23.7 years and the average follow up term after operation was 13 years and 6 months. Twelve hips underwent only Chiari procedure and 2 hips underwent Chiari procedure combined with varus osteotomy. The clinical result showed improved pain and total JOA score (pain: from 23.9 to 33.6 points, total: form 73.9 to 85.4 points). The radiographic assessment showed that only one hip progressed in stage.
