Published in:
01-11-2012 | Symposium: Papers Presented at the 2011 Meeting of the International Hip Society
What Factors Predict Failure 4 to 12 Years After Periacetabular Osteotomy?
Published in: Clinical Orthopaedics and Related Research® | Issue 11/2012
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Background
The goal of periacetabular osteotomy (PAO) is to delay or prevent osteoarthritic development in dysplastic hips. However, it is unclear whether the surgical goals are achieved and if so in which patients. This information is essential to select appropriate patients for a durable PAO that achieves its goals.
Questions/purposes
We therefore (1) determined hip survival rates; (2) determined how many preserved hips were functionally unsuccessful after PAO; and (3) identified demographic, clinical, and radiographic factors predicting failure after PAO.
Methods
We retrospectively reviewed 316 patients (401 hips) who had PAO between December 1998 and May 2007. We evaluated radiographic parameters of dysplasia and osteoarthritis and obtained WOMAC scores. Through inquiry to the National Registry of Patients, we identified conversions to THA. Risk factors for conversion to THA were assessed. Minimum followup was 4 years (mean, 8 years; range, 4–12 years).
Results
The overall Kaplan-Meier hip survival rate was 74.8% at 12.4 years. A WOMAC pain score of 10 or more, suggesting clinical failure, was observed in 13% of preserved hips at last followup. Higher age, preoperative Tönnis grade of 2, incongruent hip, postoperative joint space width of 3 mm or less, and postoperative center-edge angle of less than 30° or more than 40° predicted conversion to THA.
Conclusions
PAO preserved three of four hips with most functioning well at 4- to 12-year followup. When planning surgery, surgeons should attempt to achieve hip congruence and a center-edge angle of between 30° to 40° to improve the durability of PAO.
Level of Evidence
Level II, prognostic study. See Instructions for Authors for a complete description of levels of evidence.