Limitations in predicting outcome following primary ACL reconstruction with single-bundle hamstring autograft — A systematic review

Abstract Background Anterior cruciate ligament reconstruction (ACLR) is one of the most well studied and performed procedures in the world. Thus, it would be useful to develop a tool to predict patient outcomes post-operatively to allow clinicians to optimise management. Purpose To identify and summarise factors predictive of graft failure and patient-reported outcome (PROM) measures at minimum two years after ACLR with single-bundle quadruple hamstring autograft via the anteromedial portal technique. Methods Studies reporting IKDC, KOOS, Lysholm and graft failure in ACLR were systematically reviewed. A methodological score was applied to these studies, with those above the mean analysed further. Only those reporting primary predictors of patient outcomes following ACLR were included. Results Twenty-six studies satisfied our inclusion criteria. Fourteen scored above the mean 20 Downs and Black score (18.4) and were considered higher level evidence. The higher quality papers reported that younger age, female sex, higher BMI, smoking history and activity levels predicted poorer outcomes. High-grade tears of the menisci or full-thickness cartilage defects were identified as predictors of poorer PROMs. None of the factors investigated by more than a single paper were unanimously significant in predicting the outcome of ACLR. Conclusions The evidence surrounding predictors of outcome was inconsistent in design, methodology and reporting of results, hindering our ability to draw conclusions regarding the validity of the reported relationships. However, this systematic review identified several patient demographics, concomitant injuries, and surgical factors that could be investigated further in future prospective studies to create a definitive predictive model.