No sign of weakness: a systematic review and meta-analysis of hip and calf muscle strength after anterior cruciate ligament injury
Objective We aimed to determine hip and lower-leg muscle strength in people after ACL injury compared with an uninjured control group (between people) and the uninjured contralateral limb (between limbs). Design Systematic review with meta-analysis. Data sources MEDLINE, EMBASE, CINAHL, Scopus, Cochrane CENTRAL and SportDiscus to 28 February 2023. Eligibility criteria Primary ACL injury with mean age 18–40 years at time of injury. Studies had to measure hip and/or lower-leg muscle strength quantitatively (eg, dynamometer) and report muscle strength for the ACL-injured limb compared with: (i) an uninjured control group and/or (ii) the uninjured contralateral limb. Risk of bias was assessed according to Cochrane Collaboration domains. Results Twenty-eight studies were included (n=23 measured strength ≤12 months post-ACL reconstruction). Most examined hip abduction (16 studies), hip extension (12 studies) and hip external rotation (7 studies) strength. We found no meaningful difference in