Abstract
Background: Hip dysplasia is a complex developmental process. Untreated acetabular dysplasia is the most common cause of secondary hip osteoarthiritis. With increased interest in redirectional pelvic osteotomies, the role of the shelf procedure needs to be re-defined.
Aim of the study: to investigate the effectiveness of the shelf procedure in adults with symptomatic acetabular dysplasia by assessing the functional and radiological outcome at a minimum of five years follow-up.
Material and Methods: Seventy-six consecutive adults with symptomatic acetabular dysplasia treated with acetabular shelf augmentation, have been followed up for an average period of 11 years (range: 6–14). The mean age was thirty-three years (range: 17–60 years). The Oxford hip score (OHS) was used for clinical assessment. Centre-edge angle (CEA) and acetabular angle (AA) were measured to determine femoral head coverage. Osteoarthiritis severity was based primarily on the width of the joint space using the De Mourgues classification. Survivorship analyses using conversion to THR as an endpoint were performed. logrank test was used to compare the outcome of the shelf against the variables of age, preoperative osteoarthiritis, preoperative and postoperative AA, CEA angles.
Results: The shelf procedure improved the mean preoperative CEA from 11° (range: 20° to 17°) to 50° postoperatively (range: 30° to 70°) and the mean preoperative AA from 52° (range: 46° to 64°) to 32° postoperatively (range: 18° to 57°). The Mean OHS was 34.6 (hip score maximum: 48). Thirty percent of hips needed THR at an average duration of 7.3 years. Survival analysis using conversion to THR as an endpoint was 86% (CI, 76%–95%) at five years and 46% (CI, 27%–65%) at ten years. The survival in the 44 patients with only slight or no joint space narrowing was 97% (CI, 93%–100%) at 5 years and 75% (CI, 51%–100%) at 10 years. This was significantly higher (p= 0.0007) than the survival in the 32 patients with moderate or severe osteoarthiritis, which was 76% (CI, 55%–89%) at 5 years and 22% (CI, 5%–38%) at 10 years. There was no significant relationship between survival and age (p= 0.37), pre and postoperative centre-edge angle (p= 0.39), or acetabular angle (p= 0.85).
Conclusion: Shelf acetabuloplasty is a reliable, safe procedure offering medium-term symptomatic relief for adults with acetabular dysplasia. The best results were achieved in patients with slight or no joint space narrowing.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
