High variability and lack of standardization in the evaluation of return to sport after ACL reconstruction: a systematic review

Purpose: Return to sport (RTS) after ACL reconstruction (ACLR) has been recognized as an important outcome, which is associated with success of the surgery. This study aimed to assess the methods used to determine return to sport after ACLR in the published literature, report on variability of methods and evaluate their strength in establishing accurate RTS data. Methods: Electronic databases (PubMed, Cochrane Library and Embase) were searched via a defined search strategy with no limits, to identify relevant studies from January 2008 to December 2020 for inclusion in the review. Defined eligibility criteria included studies specifically measuring and reporting on return to sport after ACLR with a clear methodology. Each included study was assessed for the definition of successful RTS, successful return to pre-injury level of sport and for methods used to determine RTS. Results: One hundred and seventy-one studies were included. Of the included studies, six studies (4%) were level of evidence 1 and seventy-two studies (42%) were level of evidence 4. Forty-one studies (24%) reported on return to a specific sport and 130 studies (76%) reported on return to multiple sports or general sport. Sixteen studies (9%) reported on RTS in the pediatric population, 36 (21%) in the adult population and 119 (70%) reported on a mixed-aged population. The most commonly used definition of successful RTS was return to the same sport (44 of 125 studies, 35%). The most common method used to determine RTS was a non-validated study-specific questionnaire (73 studies, 43%), which was administered in various ways to the patients. Time of RTS assessment was variable and ranged between 6 months and 27 years post-surgery. Conclusion: This review demonstrates high variability in defining, evaluating and reporting RTS following ACLR. The findings of this study reveal low reliability and unproven validity of methods used to evaluate RTS and highlight the challenges in interpreting and using RTS data reported in literature. Level of evidence: IV.