Rotational acetabular osteotomy shows favorable long-term results for OA secondary to hip dysplasia

Patients with severely deformed femoral heads may experience OA progression within 10 years after surgery.

Performing rotational acetabular osteotomy can provide long-term improvements in pain and function to patients who have early-stage osteoarthritis secondary to developmental hip dysplasia, according to a study by Japanese researchers.

Kunihiko Okano, MD, and colleagues at Nagasaki University, reviewed outcomes for 49 hips of 48 patients treated with rotational acetabular osteotomy procedures to treat early-stage osteoarthritis (OA) secondary to developmental hip dysplasia. Patients averaged 33 years of age at the time of surgery, and 43 patients were women, according to the study, published in Acta Orthopaedica.

All patients had radiographic evidence of early-stage OA, the authors noted.

Preoperatively, patients had a mean Merle d'Aubigné and Postel system clinical score of 13 points, which significantly improved to 17 points at the latest follow-up (P < .001).

"Functionally, excellent or good results were seen in 44 hips, fair results in three hips and poor results in two hips," the authors wrote.

"Radiographically, this procedure gave adequate improvement of femoral head coverage," they noted.

Pain scores significantly improved from an average of 3.1 points preoperatively to 5.6 points (P < .001) at follow-up. Mobility scores significantly decreased, from 5.7 points preoperatively to 5.3 points (P = .007), although walking ability significantly improved from 3.9 points to 5.8 points (P < 0.001), according to the study.

At 13 years mean follow-up, 38 hips showed no change in their osteoarthritic stage and 11 hips showed OA progression. However, two of these 11 hips had "obvious technical failure" and were excluded from subsequent comparisons, the authors noted.

Among the hips with no evidence of OA progression, the femoral head roundness index averaged 55%, significantly different than for the nine hips with OA progression, which had an average roundness index of 68% (P < .001), according to the study.

"In conclusion, early-stage osteoarthritis with a round femoral head is considered a good indication for [rotational acetabular osteotomy] because of favorable results at 10 years and beyond," the authors stated in the study.

"In contrast, patients with a severely deformed femoral head — defined as a round index of more than 64% and early-stage osteoarthritis — may experience progression of osteoarthritis within 10 years after [rotational acetabular osteotomy]," they wrote.

For more information:
Okano K, Enomoto H, Osaki M, Shindo H. Outcome of rotational acetabular osteotomy for early hip osteoarthritis secondary to dysplasia related to femoral head shape: 49 hips followed for 10-17 years. Acta Orthop. 2008;79:12-17.