Balancing Risk and Reward in Hip Resurfacing for Developmental Dysplasia of the Hip: A Systematic Review and Meta-Analysis.

Background: As interest in hip resurfacing arthroplasty (HRA) expands to complex pathologies, developmental dysplasia of the hip (DDH) has emerged as a challenging but increasingly considered indication. Although severe DDH often precludes resurfacing because of distorted anatomy, mild cases (Crowe I and II) may provide favorable conditions. This review evaluates outcomes of HRA in mild DDH, compares them with outcomes of total hip arthroplasty (THA) in DDH and HRA in primary osteoarthritis (OA) and assesses the potential of HRA to improve long-term function in this population.

Methods: A systematic search of PubMed, Embase, and Scopus identified studies reporting outcomes of HRA in DDH. Titles and abstracts were screened, followed by full-text review. Data on demographics, outcomes, and radiographic findings were extracted. Pooled complication and survivorship rates were calculated. A random-effects meta-analysis compared revision risk in HRA-treated patients with DDH vs. OA, and in patients with DDH treated with HRA vs. THA. Statistical significance was defined as a 95% confidence interval (CI) excluding 1. A separate meta-analysis compared mean postoperative flexion in patients with DDH treated with HRA vs. THA, with significance defined as a 95% CI excluding 0.

Results: From 65 screened articles, 11 met inclusion criteria, totaling 895 patients and 1,006 hips with DDH. The mean age was 45.26 years, with an average follow-up of 7.06 years. The pooled survivorship was 93%, and the complication rate was 13%. No significant difference in revision risk was found between DDH and OA HRA cohorts, or between HRA and THA in DDH, although both trends favored OA and THA. Patients with HRA-treated DDH had significantly greater postoperative flexion (standardized mean difference -1.21, 95% CI -1.54 to -0.87).

Conclusion: Despite anatomical challenges and a potential for higher revision or complication rates in patients with DDH, mid-term outcomes, including patient-reported outcome, were comparable with those in primary osteoarthritis and THA cohorts. This review supports the selective use of HRA in patients with Crowe I and II DDH, particularly when modern surgical techniques and DDH-specific implants are used.

Level of evidence: Level III, systematic review of Level I, III, and IV studies. See Instructions for Authors for a complete description of levels of evidence.