A variety of criteria are used to make return to sport decisions after anterior cruciate ligament (ACL) reconstruction.

This systematic review summarized and evaluated prognostic factors and clinical prognostic models for returning to sports after ACL reconstruction.

Independent pairs of reviewers assessed eligibility, extracted data, and evaluated risk of bias and certainty of evidence. A systematic literature search was conducted in key electronic databases. Inclusion criteria: studies published in English, longitudinal cohort or case-control design, reporting outcomes on return to sport or Tegner Activity Score (TAS), participants aged ≥16 years undergoing primary ACL reconstruction, and defined as athletes/sport players or having a pre-injury TAS ≥5. Only associations between predictors and outcomes that were analyzed in ≥3 studies and had consistent results in the same direction in ≥75 % of the studies were considered and reported. Risk of bias was evaluated using the QUIPS or PROBAST tools, and certainty of evidence was evaluated using the GRADE framework.

37 studies (5 low, 6 moderate, and 26 high risk of bias) on prognostic factors and 1 study on prognostic models (low risk of bias), representing 6278 participants, were included. Six prognostic factors were identified and rated as very low certainty evidence: fewer concomitant meniscal injuries, shorter time between injury and surgery, higher jump test scores, better physical functioning, higher muscle strength, and greater psychological readiness to return to sport. Two prognostic models with AUC 0.77–0.78 and 70 % accuracy for predicting return to sport were identified.

There is a very low certainty of evidence that returning to sport is associated with both physical, psychological and demographic prognostic factors. More methodologically sound research on prognostic factors and prognostic models for return to sport in athletes after ACL reconstruction is needed.