Step It Up to Level Up: After Anterior Cruciate Ligament Reconstruction, Do Individuals Reach Internationally Recommended Physical Activity Levels and How Do These Levels Compare With Uninjured Controls? A Systematic Review and Meta-Analysis.

OBJECTIVE: Anterior cruciate ligament reconstruction (ACLR) leads to high rates of knee post-traumatic osteoarthritis (PTOA). Physical activity may mitigate PTOA risk but levels after ACLR have not been extensively studied. We aimed to review self-reported and device-measured physical activity levels in individuals with ACLR and compare them with international guidelines, and with uninjured controls. DATA SOURCES: MEDLINE, Embase, Scopus, Google Scholar, Cochrane Library, Web of Science, and SPORTDiscus were searched from inception to 22 June 2023. MAIN RESULTS: Of the 5391 studies identified on our initial search, 15 satisfied the inclusion criteria for analysis (N = 544 individuals with ACLR). Across all studies, the average physical activity levels for individuals with ACLR were 343 ± 185 moderate-to-vigorous physical activity (MVPA) min/wk and 8453 ± 233 steps/day. In studies measuring the proportion of individuals with ACLR reaching MVPA guidelines, 147/213 (69%) achieved ≥150 min/wk. Of those using step counts, 22/85 (26%) achieved ≥10 000 steps/day. Individuals with ACLR engaged in less physical activity than uninjured controls (SMD = -0.37 [95% CI = -0.60 to -0.15]; P < 0.001). CONCLUSIONS: Individuals typically meet recommended MVPA, but not steps, after ACLR. Optimal volume, type, and weight-bearing nature of physical activity should be further investigated given the beneficial role of moderate mechanical loading in knee health. Our findings suggest that steps per day may represent a potentially modifiable prevention target and may help guide the future development of tailored physical activity guidelines for PTOA prevention after ACLR. PROSPERO REGISTRATION NUMBER: CRD42022330699.