Archives of Orthopaedic and Trauma Surgery - 2026-04-17 - Journal Article
Periacetabular osteotomy of the hip: an 8-year follow-up of 96 consecutive cases.
Enocson A, Wallensten R, Lundblad H
Topics
Key Takeaway
At median 8-year follow-up after PAO, 22% of hips converted to THA, with age ≥30 years (HR 4.0) and smoking (HR 7.8) as independent predictors of conversion in multivariable analysis.
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Summary
This study evaluated THA conversion rate as the primary outcome after PAO for acetabular dysplasia in 96 consecutive patients (median age 30, 84% female) at a single Swedish center from 2006–2022. At median 8-year follow-up, 22% converted to THA; Cox regression identified age ≥30 (HR 4.0, CI 1.1–15), smoking (HR 7.8, CI 1.7–37), and Tönnis grade 2 OA (HR 31, CI 2.6–384) as independent predictors. An additional 10% required reoperation for non-THA reasons, most commonly nonunion (6.3%), and 43% experienced an adverse event, predominantly transient nerve injury.
Key Limitation
The Tönnis grade 2 hazard ratio of 31 is statistically unstable given extremely wide confidence intervals (2.6–384), reflecting inadequate power to reliably quantify the effect of preoperative OA severity on conversion risk.
Original Abstract
INTRODUCTION
A periacetabular osteotomy (PAO) is a joint-preserving surgical option for treatment of acetabular dysplasia. The procedure aims to prevent, or at least delay, the development of osteoarthritis, and subsequent need for total hip arthroplasty (THA). The conversion rate to THA differs widely in the literature, but most of the studies have few patients, and the follow-up time is often short for THA as an endpoint. The aim of this study was to evaluate the long-term outcome after PAO surgery with the rate of conversion to THA as the primary outcome.
MATERIALS AND METHODS
Patients ≥18 years that underwent a PAO operation at the Karolinska University Hospital in Stockholm, Sweden from 2006 to 2022 were included. Radiological signs of hip osteoarthritis, and the lateral center-edge angle (LCEA) was calculated on pre- and postoperative radiographs or CT-scans. The national Swedish Arthroplasty Register was used to find cases who had a secondary operation with THA.
RESULTS
The number of cases included was 96. Median age was 30 (18–46) years, and 84% ( n = 81) were females. Median follow-up time was 99 (17–227) months (8 years). A total of 21 (22%) cases had a secondary THA. Cox regression analyses identified that age ≥ 30 years and smoking was associated with THA reoperation in both uni- (HR 2.8, CI 1.1–7.3, HR 3.7, CI 1.0–13) and multivariable (HR 4.0, CI 1.1–15, HR 7.8, CI 1.7–37) analyses. Preoperative osteoarthritis (Tönnis grade 2) was weakly associated with THA in multivariable (HR 31, CI 2.6–384) analysis. A total of 10 (10%) cases had an unexpected reoperation due to other reasons than a secondary THA, and the most common reason was nonunion ( n = 6, 6.3%). Forty-four (43%) patients had an adverse event. The most common was a transient nerve injury.
CONCLUSIONS
The PAO procedure is a suitable option in young patients with symptomatic dysplasia of the hip in order to avoid, or at least delay, hip arthroplasty.