Hop to It! A Systematic Review and Longitudinal Meta-analysis of Hop Performance After ACL Reconstruction

Abstract

Background Hop testing is widely used by clinicians to monitor rehabilitation and decide when to return to sport following anterior cruciate ligament reconstruction (ACLR); however, the trajectory of long-term hop performance has not been summarised. Objective To investigate hop performance change over time after ACLR. Design Systematic review with longitudinal meta-analysis. Data Sources MEDLINE, EMBASE, CINAHL, Scopus, Cochrane CENTRAL and SPORTDiscus to 28 February 2023. Eligibility Criteria Studies with ≥ 50 participants following primary ACLR, with mean participant age of 18–40 years, reporting a quantitative measure of hop performance (e.g. single forward hop distance). Results had to be reported for the ACLR limb and compared with (1) the contralateral limb (within person) and/or (2) an uninjured control limb (between person). Results We included 136 studies of 23,360 participants. Performance was similar across different hop tests, with steep initial improvements in within-person symmetry, tailing off after 18–24 months. ACLR limb hop performance was 5–10% lower compared with the contralateral limb at 1 year post-surgery, with largest deficits observed for vertical hop [87.0% contralateral limb (95% CI 85.3–88.8) compared with single forward hop 93.8% (95% CI 92.8–94.9)]. By 3–5 years, results were similar between ACLR and contralateral limbs. There were limited data for between-person comparisons (n = 17 studies). Exploratory analyses showed deficits in all forward hopping tests to be very strongly correlated with each other [e.g. single forward and triple hop rho = 0.96 (95% CI 0.90–0.99)], though there was discordance in the relationship between single forward hop and vertical hop performance [rho = 0.27 (95% CI − 0.53 to 0.79)]. Conclusions Hop performance is comparable to the uninjured limb by 3–5 years post-ACLR, with the greatest deficits in within-person symmetry present in vertical and side hop tests. Assessment of hopping in multiple planes and comparison with uninjured controls, may provide the most complete evaluation of functional performance.