A Systematic Review and Meta-Analysis of Regenerative Therapies for Hip Cartilage Lesions and Their Outcomes.

Abstract

Chondral lesions of the hip in young, active patients are a recognised cause of pain, functional limitation, and early osteoarthritis. Although regenerative cartilage repair techniques are well established in the knee, hip-specific evidence remains limited. This systematic review and meta-analysis evaluated clinical outcomes and predictors of success following surgical and biologically augmented treatments for hip cartilage lesions. A systematic search of PubMed, OVID MEDLINE, and EBSCOHost was conducted in December 2024 to identify prospective and retrospective case series and comparative studies reporting outcomes following surgical or biologic interventions. Functional outcome was primarily assessed using the modified Harris Hip Score (mHHS), and failure was defined as conversion to total hip arthroplasty (THA). Random-effects meta-regression was used to evaluate predictors of endpoint mHHS and change-from-baseline mHHS (ΔmHHS), while failure outcomes were analysed using Kaplan-Meier survival analysis and Cox proportional hazards regression. 27 studies comprising 30 intervention arms and 1059 patients were included. Cell-based and scaffold-assisted techniques, including autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, autologous matrix-induced chondrogenesis, and micro-fragmented adipose tissue transplantation, demonstrated the highest adjusted endpoint mHHS values (>87). In contrast, microfracture and commercial fibrin glue were associated with inferior functional outcomes and higher THA conversion rates (7.1-12.9%). Meta-regression identified intervention type as the primary determinant of outcome, with increasing defect size independently associated with poorer endpoint mHHS. Improvements in ΔmHHS were influenced by age, defect size, and follow-up duration, although findings were limited by potential model overfitting. Survival analyses demonstrated high overall THA-free survivorship, with increasing age emerging as the consistent predictor of failure. Biological restoration techniques appear to outperform reparative strategies for short-term functional outcomes in hip cartilage lesions. Intervention type, defect size, and patient age remain key determinants of success, underscoring the need for high-quality comparative studies with long-term follow-up.PROSPERO registration:CRD420250644934.