475 FO25 – Cluster analysis of cutting technique: a valuable approach for assessing anterior cruciate ligament injury risk?

Background Despite extensive efforts to pinpoint singular biomechanical risk factors for anterior cruciate ligament (ACL) injuries, research findings are still inconclusive. By combining multiple biomechanical variables, cluster analyses could help us identify safe and risky cutting technique strategies. Objective To identify cutting technique clusters and assess their association with ACL injury risk. Design Prospective cohort study. Setting Biomechanical laboratory. Participants 786 female elite handball and football players, including players with and without a previous and future ACL injury. Interventions All participants performed a sport-specific cutting task while 3D biomechanics were recorded. ACL injuries were registered prospectively for 8 years. To identify different cutting techniques with distinct biomechanical features, we employed a K-means clustering algorithm on data subsets involving different numbers of kinematic variables and different sports. Adjusted rand indices (ARI) were used to assess the impact of the identified cutting technique clusters on ACL injury risk. Main Outcome Measurements Kinematics of the identified cutting technique clusters and the clusters' association with ACL injury risk. Results We found no clearly distinguishable cutting technique clusters, as evidenced by average silhouette scores (ASS) of less than 0.5 (Table). There was some evidence of cluster existence in the subset involving both sports and five variables (ASS = 0.36), but these clusters were of no relevance for ACL injury risk (ARI = 0.00). Rather, they could be attributed to sport-related differences (ARI = 0.84) (Figure). The subset involving only handball players and five variables scored highest among the handball subsets (ASS = 0.20). However, the identified clusters were not associated with ACL injury risk (ARI = 0.00). Conclusions No safe or risky cutting technique strategies could be discerned among female elite handball and football players. Cluster analysis of cutting technique did not prove to be a valuable approach for assessing ACL injury risk.