Hip preservation surgery for borderline and frank dysplasia: an overview of systematic reviews.

Purpose: To identify, synthesise, and critically appraise findings of systematic reviews and/or meta-analyses on hip preservation surgeries for borderline and/or frank dysplasia with or without concomitant femoroacetabular impingement (FAI). Methods: A search, following the PRISMA guidelines, was conducted using Medline and Embase on 19/04/2023. Findings extracted from eligible studies were tabulated and synthesised. Results: The search identified 477 references. Nineteen were eligible for data extraction: nine reported on arthroscopy, five reported on periacetabular osteotomy (PAO), one reported on shelf acetabuloplasty, and one reported on Chiari osteotomy, while two compared arthroscopy versus PAO, and one compared PAO versus rotational acetabular osteotomy (RAO) versus eccentric acetabular osteotomy (ERAO). The nomenclature and lateral centre edge angle (LCEA) thresholds to define hip dysplasia varied widely across included studies. All hip preservation surgeries provided good outcomes, with the Harris hip score (HHS) being the most commonly reported clinical score. Using the AMSTAR checklist for risk of bias, no systematic reviews were rated as high quality; ten were rated as moderate quality; six were rated as low quality; and three were rated as critically low quality. Conclusions: Most published systematic reviews on hip preservation surgery are of moderate or low quality, and there is high heterogeneity among them regarding outcomes reported, follow-up periods, and definitions of dysplasia. The authors recommend the following thresholds and nomenclature for dysplasia: LCEA < 20° for frank dysplasia, 20°-25° for borderline dysplasia, and >25° for no dysplasia. Although all hip preservation surgeries can provide good outcomes, it is challenging to conclude which surgery provides the best outcomes and to determine if treatment options are dependent on LCEA.