Return to Sport in Professional Athletes After Cartilage Restoration Surgery of the Knee: A Systematic Review and Meta-Analysis Demonstrates Gender Inequality and the Need for Improved Reporting

Objective: To synthesize the literature concerning return to sport (RTS) and related outcomes after cartilage restoration surgery of the knee in professional athletes.

Design: Cochrane, PubMed, and OVID/Medline databases were queried for data pertaining to RTS after knee cartilage surgery in professional athletes. Demographic information, cartilage lesion characteristics, and RTS-specific information were extracted. Freeman-Tukey Double-Arscine Transformations with Dersimonian-Laerd random-effects estimators were constructed to quantitatively describe the cumulative incidence of RTS, while heterogeneous data described narratively.

Results: Eleven studies (476 athletes; mean age 27.5 ± 2.1 years; 96.6% male) were included. Nine (81.8%) studies investigated a form of microfracture as treatment, with 6 (54.5%) performing isolated microfracture. The remaining studies investigated osteochondral allograft transplantation and mosaicplasty. More than half (n = 6; 54.5%) did not report cartilage lesion location or size. The pooled RTS rate was 84.3% (95% CI: 75.4%-91.8%) at a mean 39.9 (range, 12-104) weeks postoperatively. In 6 studies reporting competition level, a trend toward returning to a lower than pre-injury level was observed. The definition of RTS was only provided in 6 (54.5%) studies, while the criteria for RTS was only reported in 2 (18.2%) studies, suggesting limited transparency. One study reported an objective imaging assessment of reparative tissue, while none reported formal RTS testing protocols or minimum RTS timeline.

Conclusion: Although the majority of professional athletes are reported to achieve a successful RTS after cartilage restoration surgery of the knee, the literature predominantly reflects microfracture treatment. Current limitations in this literature include a substantial lack of female representation and infrequent reporting of cartilage lesion characteristics, rehabilitation and RTS criteria, and objective imaging assessments of reparative tissue.