Psychological predictors of anterior cruciate ligament reconstruction outcomes: a systematic review

PURPOSE: Lack of return to sport following anterior cruciate ligament (ACL) reconstruction often occurs despite adequate restoration of knee function, and there is growing evidence that psychological difference among patients may play an important role in this discrepancy. The purpose of this review is to identify baseline psychological factors that are predictive of clinically relevant ACL reconstruction outcomes, including return to sport, rehab compliance, knee pain, and knee function. METHODS: A systematic search was performed in PubMed, Google Scholar, CINAHL, UptoDate, Cochrane Reviews, and SportDiscus, which identified 1,633 studies for potential inclusion. Inclusion criteria included (1) prospective design, (2) participants underwent ACL reconstruction, (3) psychological traits assessed at baseline, and (4) outcome measures such as return to sport, rehabilitation compliance, and knee symptoms assessed. Methodological quality was evaluated with a modified Coleman score with several item-specific revisions to improve relevance to injury risk assessment studies in sports medicine. RESULTS: Eight prospective studies were included (modified Coleman score 63 ± 4.9/90, range 55-72). Average study size was 83 ± 42 patients with median 9-month follow-up (range 3-60 months). Measures of self-efficacy, self-motivation, and optimism were predictive of rehabilitation compliance, return to sport, and self-rated knee symptoms. Pre-operative stress was negatively predictive, and measures of social support were positively predictive of knee symptoms and rehabilitation compliance. Kinesiophobia and pain catastrophizing at the first rehabilitation appointment did not predict knee symptoms throughout the early rehabilitation phase (n.s.). CONCLUSIONS: Patient psychological factors are predictive of ACL reconstruction outcomes. Self-confidence, optimism, and self-motivation are predictive of outcomes, which is consistent with the theory of self-efficacy. Stress, social support, and athletic self-identity are predictive of outcomes, which is consistent with the global relationship between stress, health, and the buffering hypothesis of social support.