BACKGROUND: Advanced-stage osteonecrosis and a large area of necrotic bone are known risk factors for failure of transtrochanteric rotational osteotomy of the hip in patients with osteonecrosis. The purpose of this study was to determine whether there are other risk factors for failure of this osteotomy.
METHODS: One hundred and five patients (113 hips) underwent an anterior transtrochanteric rotational osteotomy for the treatment of femoral head osteonecrosis and were followed for a mean of 51.3 months postoperatively. Radiographic failure was defined as secondary collapse or osteoarthritic change. Multivariate analysis was performed to assess factors associated with secondary collapse and osteophyte formation. The Kaplan-Meier product-limit method was used to estimate survival.
RESULTS: Secondary collapse occurred in twenty-seven hips (24%), and fourteen hips (12%) were converted to a total hip arthroplasty. At the time of the most recent follow-up, the hip scores according to the system of Merle d'Aubigné et al. ranged from 6 to 18 points (mean, 15.8 points). Multivariate analysis showed that the stage of the necrosis (III or greater) (hazard ratio = 3.28; 95% confidence interval = 1.49 to 7.24), age of the patient (forty years or older) (hazard ratio = 1.08; 95% confidence interval = 1.02 to 1.14), body mass index (≥24 kg/m2) (hazard ratio = 1.19; 95% confidence interval = 1.03 to 1.38), and extent of the necrosis (a combined necrotic angle of ≥230°) (hazard ratio = 1.08; 95% confidence interval = 1.04 to 1.11) were associated with secondary collapse. Seven of the eighty-six hips without collapse showed progression to osteoarthritis. The survival rate at 110 months was 63.4% (95% confidence interval = 51.1% to 75.7%) with total hip arthroplasty or radiographic failure as the end point and 56.0% (95% confidence interval = 44.6% to 67.4%) with total hip arthroplasty, radiographic failure, or loss to follow-up as the end point.
CONCLUSIONS: Our study showed that age, body mass index, and the stage and extent of the osteonecrosis were determining factors for secondary collapse, unsatisfactory clinical results, and conversion to total hip arthroplasty. These factors should be considered when selecting patients for a transtrochanteric rotational osteotomy.
LEVEL OF EVIDENCE: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.
ORIGINAL ABSTRACT CITATION: “Effects of Age and Body Mass Index on the Results of Transtrochanteric Rotational Osteotomy for Femoral Head Osteonecrosis” (2010;92:314-21).
Investigation performed at the Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul; the Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul; and the Department of Orthopaedic Surgery, Kyungpook National University College of Medicine, Daegu, South Korea
The original scientific article in which the surgical technique was presented was published in JBJS Vol. 92-A, pp. 314-21, February 2010
DISCLOSURE: The authors did not receive any outside funding or grants in support of this research or for the preparation of this work. Neither the authors nor any member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from any commercial entity.
- Copyright © 2011 by The Journal of Bone and Joint Surgery, Incorporated
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