Introduction. Acetabular dysplasia is a common cause of osteoarthritis of the hip. Chiari pelvic osteotomy enables medialization of the center of the femoral head and improvement of coverage over the femoral head for hip dysplasia and prevents or delays progression of degenerative arthritis. We reviewed 104 patients after this augmentation procedure. Patients and methods. Between 1989 and 2000, 167 patients with developmental dysplasia of the hip had undergone the surgery at university hospital. Among them, 104 patients were able to be traced after surgery for more than 10 years. The mean follow-up period was 15.5 years. There were 96 women and 8 men with an average age of 34.3 years at surgery. The average angle of osteotomy was 6.6 degree craniad to the horizontal plane. Ratio of migration of the distal pelvis was 42%. Results. 8 hips were replaced by prosthesis. Setting total hip arthroplasty as an end point, 10-year, 15-year and 20-year survival rate was 99.0, 92.3 and 70.0% respectively. Patients with minimal grade of osteoarthritis at the time of osteotomy preserved 5.4 mm joint space on plain radiographs of last time follow-up. Patients with moderate or severe grade of osteoarthritis at the time of surgery had only 2.5 mm joint space at last. All patients with minimal grade of osteoarthritis could avoid total hip arthroplasty. Conclusion. Chiari pelvic osteotomy can prevent progression of degenerative arthritis in patients with minimal grade of osteoarthritis for more than 15 years

In order to manage painful subluxation/dislocation secondary to cerebral palsy, 12 hips in 11 patients received combined femoral and Chiari pelvic osteotomies with additional soft tissues releases at an average age of 14.1 (9.1-17.8) years. Pain relief, improvement in the arc of movement, sitting posture and ease of perineal care was recorded in all, and these features have been maintained at an average follow-up of 13.1 (8-17.5) years. The improvement of general mobility was marginal, but those who were community walkers benefited the most. Pre-operative radiological measurements have been modified post-operatively to use lateral margin of the neo-acetabulum produced by the pelvic osteotomy. The radiological migration index improved from a mean of 80.6% to 13.7% [p<0.0001]. The mean changes in CE angle and Sharp's angle were 72° (range 56°- 87°) [p<0.0001] and 12.3° (range 9°- 15.6°) [p< 0.0001] respectively. Radiological evidence of progressive arthritic change was seen in only one hip, in which only a partial reduction had been achieved, and there was early joint space narrowing in another. Heterotopic ossification was observed in one patient with athetoid quadriplegia who remained pain free. In seven hips the lateral Kawamura approach, elevating the greater trochanter, provided exposure for both osteotomies and allowed the construction of a dome-shaped iliac osteotomy, while protecting the sciatic nerve. This combined procedure provides a stable hip with sustained pain relief for the adolescent and young adult presenting with pain