Kinematics observed during ACL injury are associated with large early peak knee abduction moments during a change of direction task in healthy adolescents

Funding Information: The authors have no conflicts of interest that would bias or otherwise affect the current study, but would like to acknowledge The Icelandic Centre for Research (http://rannis.is) for funding through the following grants: 120410021, 903271305, 1203250031, and 185359051 and National Institutes of Health (grant: R37-HD037985). The Football Association of Iceland has supported the lead author (HBS) with a travel grant. No funding source was involved in the design or execution of the study, the data analysis, interpretation of results, or the decision to publish the results. Funding Information: The authors have no conflicts of interest that would bias or otherwise affect the current study, but would like to acknowledge The Icelandic Centre for Research ( http://rannis.is ) for funding through the following grants: 120410021, 903271305, 1203250031, and 185359051 and National Institutes of Health (grant: R37‐HD037985). The Football Association of Iceland has supported the lead author (HBS) with a travel grant. No funding source was involved in the design or execution of the study, the data analysis, interpretation of results, or the decision to publish the results. Publisher Copyright: © 2020 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals LLC on behalf of Orthopaedic Research SocietyCluster analysis of knee abduction moment waveforms may be useful to examine biomechanical data. The aim of this study was to analyze if the knee abduction moment waveform of early peaks, consistent with anterior cruciate ligament injury mechanisms, was associated with foot-trunk distance, knee kinematics, and heel strike landing posture, all of which have been observed during anterior cruciate ligament injuries. One hundred and seventy-seven adolescent athletes performed cutting maneuvers, marker-based motion capture collected kinetic and marker data and an 8-segment musculoskeletal model was constructed. Knee abduction moment waveforms were clustered as either a large early peak, or not a large early peak using a two-step process with Euclidean distances and the Ward-d2 cluster method. Mediolateral distance between foot and trunk was associated with the large early peak waveform with an odds ratio (95% confidence interval) of 3.4 (2.7–4.4). Knee flexion angle at initial contact and knee flexion excursion had odds ratios of 1.9 (1.6–2.4) and 1.6 (1.3–2.0). Knee abduction excursions had an odds ratio of 1.8 (1.1–2.4) and 1.8 (1.4–2.4), respectively. Heel strike landings and anteroposterior distance between foot and trunk were not associated with the large early peak waveform with odds ratios of 1.2 (0.9–1.7) and 1.1 (0.8–1.3), respectively. The knee abduction moment waveform is associated with several kinematic variables observed during ACL injury. The results support intervention programs that can modify these kinematics and thus reduce early stance phase knee abduction moments.Peer reviewe