Fifty two of 53 Chiari pelvic osteotomies performed between 1974 and 1991 were reviewed clinically and radiographically with an average follow-up of 10.5 years.
In more than 46 per cent of cases, the osteotomy was performed on a dysplastic painful hip with severe osteoarthritis. Major complications were rare. The Chiari's osteotomy fixation screw was removed in 16 cases. Technically, the average displacement was 22 mm. A ascending osteotomy, related to the level of the osteotomy (p = 0.001), provided good displacement.
The functional results were very good or good in 65 per cent of the patients and lasted more than 10 years. Seventy five per cent of the hips were pain free. Radiographically, the center edge angle and the femoral head covering were corrected by the procedure. Degenerative changes of the hip joint were improved or stabilized in 63.5 per cent of the cases. Fifteen hips had undergone secondary total hip replacement, seven during the first five years and 8 after 13 years.
Factors associated with a positive outcome included: age under 30 at the time of surgery (80 per cent of survivorship up to 15 years of follow up), low stage (I or II) of osteoarthritis, and a technically perfect Chiari osteotomy. The outcome of initial stage III or IV initial osteoarthritis were not as long lasting. Chiari osteotomy functional results were good for the initial 10 years, after this time they deteriorated quickly.
Chiari pelvic osteotomy is an alternative procedure to early total hip replacement for severe painful dysplastic hips with low stage of osteoarthritis in young patients.