Patellofemoral Cartilage Restoration: A Systematic Review and Meta-analysis of Clinical Outcomes

Background: Many surgical options for treating patellofemoral (PF) cartilage lesions are available but with limited evidence comparing their results. Purpose: To determine and compare outcomes of PF cartilage restoration techniques. Study Design: Systematic review and meta-analysis. Methods: PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines were followed by utilizing the PubMed, EMBASE, and Cochrane Library databases. Inclusion criteria were clinical studies in the English language, patient-reported outcomes after PF cartilage restoration surgery, and >12 months’ follow-up. Quality assessment was performed with the Coleman Methodology Score. Techniques were grouped as osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocyte cell–based therapy, bone marrow–based therapy, and scaffolds. Results: A total of 59 articles were included. The mean Coleman Methodology Score was 71.8. There were 1937 lesions (1077 patellar, 390 trochlear, and 172 bipolar; 298 unspecified). The frequency of the procedures was as follows, in descending order: chondrocyte cell–based therapy (65.7%), bone marrow–based therapy (17.2%), OAT (8%), OCA (6.6%), and scaffolds (2.2%). When compared with the overall pooled lesion size (3.9 cm 2 ; 95% CI, 3.5-4.3 cm 2 ), scaffold (2.2 cm 2 ; 95% CI, 1.8-2.5 cm 2 ) and OAT (1.5 cm 2 ; 95% CI, 1.1-1.9 cm 2 ) lesions were smaller ( P < .001), while chondrocyte cell–based therapy lesions were larger (4.7 cm 2 ; 95% CI, 4.1-5.3 cm 2 ; P = .039). Overall, the instability pool was 11.9%, and the anatomic risk factors pool was 32.1%. Statistically significant improvement was observed on at least 1 patient-reported outcome in chondrocyte cell–based therapy (83%), OAT (78%), OCA (71%), bone marrow–based therapy (64%), and scaffolds (50%). There were no significant differences between any group and the overall pooled change in International Knee Documentation Committee score (30.2; 95% CI, 27.4-32.9) and Lysholm score (25.2; 95% CI, 16.9-33.5). There were no significant differences between any group and the overall pooled rate in minor complication rate (7.6%; 95% CI, 4.7%-11.9%) and major complication rate (8.3%; 95% CI, 5.7%-12.0%); however, OCA had a significantly greater failure rate (22.7%; 95% CI, 14.6%-33.4%) as compared with the overall rate (6.8%; 95% CI, 4.7%-9.5%). Conclusion: PF cartilage restoration leads to improved clinical outcomes, with low rates of minor and major complications. There was no difference among techniques; however, failures were higher with OCA.