Biomechanical asymmetries differ between autograft types during unplanned change of direction after ACL reconstruction.

Nine months after anterior cruciate ligament (ACL) reconstruction, athletes who undergo surgery using a bone‐patellar‐tendon‐bone (BPTB) autograft demonstrate higher loading asymmetries during vertical jumping than those with a hamstring tendon (HT) autograft. These asymmetries may transfer into sporting movements with a greater ACL injury risk. The aim of this study was to compare between‐limb asymmetries in knee mechanics and task performance during an unplanned 90° change‐of‐direction (CoD) task in male field sport athletes reconstructed with BPTB or HT autografts. Seventy‐eight male multidirectional field sport athletes with either a BPTB (n = 39) or HT (n = 39) autograft completed maximal unplanned CoD trials in a three‐dimensional motion capture laboratory at approximately 9 months post‐surgery. A mixed‐model 2x2 ANOVA (autograft type x limb) was used to compare variables related to ACL injury risk (e.g., internal knee moments) and performance (e.g., completion time) between autografts and limbs. Statistical parametric mapping was used for a waveform comparison throughout stance, supplemented with a discrete point analyses of peak knee moments and performance variables. Interaction effects were found at the knee joint, with BPTB demonstrating greater asymmetries than HT in knee extension moment (p < 0.001); resultant ground reaction force (p < 0.001); peak knee external rotation moment (p = 0.04); and knee adduction (p = 0.05), medial rotation (p < 0.001), and flexion (p < 0.001) angles. No differences were found between autografts for any performance variable. BPTB demonstrated greater lower‐limb biomechanical asymmetries than HT during CoD, which may influence knee loading and longer‐term outcomes and should thus be targeted during rehabilitation prior to return to play. [ABSTRACT FROM AUTHOR]