Abstract
Introduction
Peri-acetabular-osteotomy (PAO) was initially described for the correction of acetabular dysplasia. Anteverting PAO is an established treatment for acetabular retroversion. By reviewing a large cohort, we aimed to (1) Test whether PAO outcome is equivalent in different types of deformity (classic dysplasia vs. retroversion) and (2) Determine whether outcome in acetabular retroversion is different between impinging-only hip and hips with combined pathology (impingement & dysplasia).
Methods
A single-centre, retrospective cohort study was performed on a group of patients (n=183) with acetabular retroversion (n=90) or lateral-under-coverage dysplasia (n=93) treated with PAO. Acetabular deformity was defined on pelvic radiographs and 3-D CTs using a number of parameters. Hips with retroversion, were sub-divided into combined pathology - retroversion with dysplasia (lateral centre-edge [LCEA] < 25°), or retroversion-only (LCEA≥25°). The mean age at time of the procedure was 29+/−7 years and most hips were in females (n=171). Complication (as per Dindo-Clavien)-, re-operation-, hip preservation rates and patient-reported-outcome measures were measured using the Non-Arthroplasty-Hip-Score (NAHS).
Results
At 2±1 years of follow-up, 5 hips underwent THA (2 dysplastics; 3 retroversion). Major complication rate was 2% for dysplastics and 5% for retroversions (p=0.9). Similar re-operation rates were seen (4% Vs. 8%, p=0.1). Better NAHS was seen in dysplastics compared to retroversions post-operatively (83Vs.73; p=0.001) but not pre-operatively (59 vs 57; p=0.2). ΔNAHS was inferior in retroversions (25 Vs.16, p=0.02). No difference in complications (p=0.1), re-operations (p=0.4) nor post-operative NAHS (76Vs71; p=0.3) were identified between retroversion-only and retroversion-combined pathology cases.
Conclusion
A PAO is as safe for retroversion as it is for dysplasia. This is the case for retroverted acetabulae showing either features of combined pathology or impingement-only. However, the pre-operative NAHS was inferior in retroversion and the improvement was not as great as dysplastic hips, illustarting that the impingement process has a detrimental effect on outcome.
