High survival of dome pelvic osteotomy in patients with early osteoarthritis from hip dysplasia.

BACKGROUND: The Chiari osteotomy reportedly has a 60% to 91% survival rate at a minimum 20 years followup. The dome pelvic osteotomy (DPO) has the advantage of allowing a larger weightbearing surface, and congruity in the sagittal plane presumably would reduce the joint contact stress and perhaps increase longevity.

QUESTIONS/PURPOSES: We determined: (1) the survival after DPO at a minimum 25-year followup, (2) patient function, (3) acetabular coverage, and (4) factors influencing conversion to THA.

METHODS: We retrospectively reviewed 50 patients (59 hips) with developmental dysplasia of the hip (DDH) treated with DPO. The preoperative radiographic stages were graded as prearthritis (18 hips), early osteoarthritis (25 hips), and advanced osteoarthritis (16 hips). We performed a Kaplan-Meier survival analysis with THA conversion as the end point. We determined various radiographic parameters reflecting coverage, and compared demographic information for hips without and with THA conversion using multivariate logistic regression analysis. The minimum followup was 25 years (mean, 27.5 years; range, 25-32 years).

RESULTS: Survival for all hips was 63.6% (95% CI, 51-76) at 27.5 years and that for hips with prearthritis and early osteoarthritis before the surgery was 79.1% (95% CI, 63-91). Twenty-one hips (36%) had undergone THAs at a mean 18.3 years (range, 2.5-25 years). At the last followup, pain, walking ability, and acetabular coverage improved. We identified four factors predicting THA conversion: greater age, presence of a preoperative Trendelenburg sign, higher preoperative radiographic osteoarthritis grade, and smaller postoperative acetabular head index (AHI) predicted conversion to THA.

CONCLUSIONS: DPO is a reasonable treatment option for patients with DDH and prearthritis or early osteoarthritis, with high survival at greater than 25 years.