Long-term results of Chiari pelvic osteotomy in patients with developmental dysplasia of the hip: indications for Chiari pelvic osteotomy according to disease stage and femoral head shape

Abstract

BackgroundWe evaluated the long-term results of Chiari pelvic osteotomy for developmental dysplasia of the hip (DDH) after follow-up of 10years or more. The indications for Chiari osteotomy were assessed based on the results. MethodsWe evaluated 74 hips in 69 patients treated for DDH with Chiari osteotomy. The average postoperative follow-up period was 13years. The mean age at the time of surgery was 32years (range 6–64 years). The disease was classified into two stages based on joint space measurements on radiographs: an early stage (36 hips) in which the mean age at surgery was 21years (range 6–48 years) and an advanced stage (38 hips) in which the mean age at surgery was 41years (range 18–64 years). Femoral head shape was classified into two types based on measurements of the sphericity of the femoral head: spherical (33 hips) or flat (41 hips). Clinical manifestations were evaluated according to Japanese Orthopaedic Association (JOA) hip scores. The joint space was measured on radiographs as an index of the progression of osteoarthritis. We attempted to identify factors that affected the long-term results of Chiari osteotomy, especially in regard to disease stage and femoral head shape. ResultsThe mean total JOA score was 72 preoperatively and 87 at final follow-up. It had improved in 66 hips and was worse in 7 hips. All of the worse cases were at the advanced stage at the time of surgery, and in 6 of the worse cases the femoral head was spherical. Hips with advanced DDH and a spherical femoral head had poor outcomes and exhibited joint space narrowing postoperatively. ConclusionsEarly DDH is considered a good indication for Chiari pelvic osteotomy because of the good results at 10years or more. Even with advanced DDH, a flat femoral head predicts a good surgical outcome, but patients with a spherical femoral head may experience early progression to osteoarthritis.