Bombelli’s valgus-extension osteotomy for osteoarthritis due to acetabular dysplasia: results at 10 to 14 years

Severe osteoarthritis due to acetabular dysplasia (n= 17) was treated with valgus-extension osteotomy, and the patients’ clinical outcomes 10–14 years after operation were evaluated according to clinical factors (Japanese Orthopaedic Association hip score; JOA score) and by roentgenography. The mean JOA score 10 years or later had improved by 22 points compared with the preoperative score. On roentgenography, joints which had preoperative roof osteophyte had better postoperative formation of roof osteophyte. The JOA score was higher in the 12 joints which had osteophyte 5mm or longer than in those joints with osteophyte that was 5mm or shorter. Postoperative joint space widening occurred in 15 joints (88.2%) 3–6 months postoperatively, and it reached the maximum at 3–5 years. In patients who had a large bone cyst in the femoral head preoperatively, the cyst collapsed, and deformation of femoral head occurred after operation, but remodeling of the joint surface occurred naturally and the congruity improved. In the 6 joints in which the preoperative acetabular head index was less than 60% and the acetabular angle was larger than 30°, the JOA score at 10 years or later was lower than that of the other joints. Based on these findings, valgus-extension osteotomy was evaluated as a useful surgical method for advanced or terminal osteoarthritis in young or middle-aged patients. Predictive factors for longterm prognosis would be the preoperative length of roof osteophyte, joint space widening, and the degree of femoral head covering.