High Rate of Return to Sport for Athletes Undergoing Articular Cartilage Restoration Procedures for the Knee: A Systematic Review of Contemporary Studies

Background: Continued advancements in cartilage surgery and an accumulating body of evidence warrants a contemporary synthesis of return to sport (RTS) outcomes to provide updated prognostic data and to better understand treatment response. Purpose: To perform an updated systematic review of RTS in athletes after knee cartilage restoration surgery. Study Design: Systematic review; Level of evidence, 4. Methods: PubMed, OVID/Medline, and Cochrane databases were queried in October 2023 for studies reporting any RTS outcome after knee cartilage restoration surgery. Meta-analyses with inverse-variance proportion and DerSimonian-Laird random-effects estimators were applied to quantify overall RTS. Comparative proportional subgroup meta-analyses with relative odds ratios (ORs) were constructed to quantify (1) the influence of the procedure on RTS and (2) RTS ability (lower vs same/greater level of play) based on procedure, competition level, and specific sport. Results: A total of 52 studies (n = 2387) were included. The overall pooled RTS was 80.3% (95% CI, 73.3%-86.5%). Matrix-assisted chondrocyte implantation (MACI) (OR, 2.15) and osteochondral autograft transplantation system (OATS) (OR, 1.83) demonstrated the highest likelihoods of RTS at the same/greater level, while microfracture (MF) (OR, 0.78) was the only treatment demonstrating a higher likelihood of RTS at a lower level. The fastest mean RTS was observed after OATS (6.6 ± 2.6 months). Professional athletes demonstrated an OR of 1.01 for RTS at the same/greater level, whereas recreational/amateur athletes demonstrated an OR of 1.63; however, all professional athletes underwent MF, and recreational/amateur athletes who underwent MF demonstrated lower likelihoods of RTS (OR, 0.78), indicating a consistent association between MF and low RTS propensity. Basketball players demonstrated the lowest likelihood of RTS at the same/greater level (OR, 1.1), while American football and soccer were associated with high likelihoods of RTS (OR, 3 and 2.4, respectively) across all procedure types. Conclusion: Cartilage restoration allows for high overall RTS, with OATS and MACI conferring the greatest propensity for RTS, while OATS allowed for the fastest RTS. Undergoing MF was associated with consistently poor RTS ability. This study identified several important associations between the level of RTS and clinically relevant factors when discussing RTS, with recreational/amateur athletes, soccer players, and American football players demonstrating a higher relative propensity to RTS.