Greater knee flexion excursion/moment in hopping is associated with better knee function following anterior cruciate ligament reconstruction
Individuals with impaired knee function after anterior cruciate ligament reconstruction (ACLR) may be at greater risk of developing knee osteoarthritis related to abnormal knee joint movement and loading. The aim of this study was to assess the association between knee biomechanics and knee laxity during hopping and clinically assessed knee function (i.e., patient-reported knee function and hop tests) following ACLR.
Sixty-six participants (23 women, mean age 28 ± 6 years, mean 18 ± 3 months following ACLR) completed a standardized single-leg hopping task. Three-dimensional movement analysis was used to assess knee flexion excursion and body weight/height normalized knee flexion moments during landing for the involved limb. Anterior–posterior knee laxity was assessed with a KT-1000 knee arthrometer. Participants then completed a patient-reported knee function questionnaire and three separate hop tests (% of uninvolved limb) and were divided into poor and satisfactory knee function groups (satisfactory: ≥85% patient-reported knee function and ≥ 85% hop test symmetry). Associations between knee function and hop biomechanics/knee laxity were assessed using logistic regression and interquartile range scaled odds ratios (ORIQR).
Greater knee flexion excursion (ORIQR 2.9, 95%CI 1.1–7.8), greater knee flexion moment (ORIQR 4.9, 95%CI 1.6–14.3) and lesser knee laxity (ORIQR 4.7, 95%CI 1.5–14.9) were significantly associated with greater odds of having satisfactory knee function (≥ 85% patient-reported knee function and ≥ 85% hop test symmetry).
Greater knee flexion excursion/moment during hop-landing and lesser knee laxity is associated with better patient-reported knee function and single-leg hop test performance following ACLR. Patients with lower levels of knee function following ACLR demonstrated hop-landing biomechanics previously associated with early patellofemoral osteoarthritis. Therefore, interventions aimed at improving hop landing biomechanics in people with poor knee function are likely required.
Level of evidence
III, Cross-sectional study.
KeywordsACL reconstruction Biomechanics Hopping Knee function.
We gratefully acknowledge the assistance of Ms. Stacey Telianidis and Ms. Karine Fortin who assisted with data collection.
Luke Perraton was a recipient of a National Health and Medical Research Council (NHMRC) postgraduate scholarship (APP1038378). Adam Bryant and Ross Clark are recipients of NHMRC Career Development Fellowships (R.D.Wright Biomedical, No. 1053521 and 1090415). AC was supported by postdoctoral funding from a European Union Seventh Framework Program (FP7-PEOPLE-2013-ITN; 607510) and is a recipient of an NHMRC Early Career Fellowship (Neil Hamilton Fairley, No. 1121173). The authors have no professional or financial affiliations that may be perceived to have biased the presentation.
Compliance with ethical standards
Conflict of Interest
The authors declare that they have no conflict of interest.
Ethical approval was provided by the University of Melbourne Human Research Ethics committee (ID 1136167).
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