The Journal of Bone and Joint Surgery (American). 2009;91:2169-2179.
doi:10.2106/JBJS.H.00994
© 2009 The Journal of Bone and Joint Surgery, Inc.
Medium-Term Outcome of Periacetabular Osteotomy and Predictors of Conversion to Total Hip Replacement
Anders Troelsen, MD, PhD1,
Brian Elmengaard, MD, PhD1 and
Kjeld Søballe, MD, DMSc1
1 Orthopaedic Research Unit, University Hospital of Aarhus, Buildings 7B (A.T. and B.E.) and 1B (K.S.), Tage-Hansens Gade 2, DK-8000 Aarhus, Denmark. E-mail address for A. Troelsen: a_troelsen{at}hotmail.com. E-mail address for B. Elmengaard: brianelm{at}dadlnet.dk. E-mail address for K. Søballe: kjeld{at}soballe.com
Investigation performed at the Orthopaedic Research Unit, University Hospital of Aarhus, Aarhus, Denmark
Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from the Danish Rheumatism Association. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.
A commentary is available with the electronic versions of this article, on our web site (www.jbjs.org) and on our quarterly CD-ROM/DVD (call our subscription department, at 781-449-9780, to order the CD-ROM or DVD).
Background: Little is known about medium or long-term results of periacetabular osteotomy and which factors predict a poor outcome in terms of conversion to total hip replacement. The aims of this study were to assess the medium-term outcome following periacetabular osteotomy and to analyze what radiographic and patient-related factors predict a poor outcome.
Methods: One hundred and sixteen periacetabular osteotomies performed by the senior author from December 1998 to December 2002 were eligible for inclusion. Data were assessed through database inquiry and evaluation of radiographic material. The mean duration of follow-up was 6.8 years. At the time of follow-up, we conducted an interview, performed clinical and radiographic examinations, and asked the patients to complete the Western Ontario and McMaster Universities Osteoarthritis Index and the Short Form-36 questionnaires. We performed a Kaplan-Meier survival analysis, and we used a Cox proportional hazards model to identify factors predicting a poor outcome.
Results: With conversion to total hip replacement as the end point, the Kaplan-Meier analysis showed a hip survival rate of 81.6% (95% confidence interval, 69.7% to 89.3%) at 9.2 years. At the time of follow-up, the median physical component score on the Short Form-36 was 48.31, the median mental component score on the Short Form-36 was 57.95, and the median Western Ontario and McMaster Universities Osteoarthritis Index total score was 84.44. The median pain score on the visual analog scale was 0 at rest and 1 after fifteen minutes of normal walking. When adjusting for preoperative osteoarthritis, we identified seven factors predicting conversion to total hip replacement. Preoperative predictive factors were severe dysplasia on conventional radiographs and computed tomographic scans, reduced acetabular anteversion angle on computed tomographic scans, and the presence of an os acetabuli (calcification of a detached labrum). Predictive factors identified on the immediate postoperative radiographs were a small width of the acetabular sclerotic zone and excessive lateral and proximal dislocation.
Conclusions: Periacetabular osteotomy can be performed with a good outcome at medium-term follow-up, suggesting that it may be applied by experienced surgeons with satisfactory results. To further improve the outcome, focus should be on the potential negative influence of parameters that are easily assessed, such as the preoperative grade of osteoarthritis, the presence of an os acetabuli, and severe acetabular dysplasia.
Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

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