Bilateral gait biomechanics in individuals with varying levels of kinesiophobia after anterior cruciate ligament reconstruction: a cross-sectional study

To investigate whether bilateral gait biomechanical characteristics differ among individuals with varying levels of kinesiophobia after anterior cruciate ligament reconstruction (ACLR) and healthy controls. This cross-sectional observational study included 36 individuals who were ≥ 12 months post-ACLR and 18 healthy controls. Individuals after ACLR were classified into high- and low-kinesiophobia groups using a predefined TSK-17 cutoff score of 40. A three-dimensional motion capture system synchronized with force platforms was used to quantify bilateral gait biomechanics during self-selected walking, including spatiotemporal, kinematic, and kinetic parameters. Limb symmetry indices (LSIs) were calculated for prespecified bilateral gait variables, and exploratory analyses examined associations between continuous TSK-17 scores and biomechanical outcomes. Compared with healthy controls, individuals after ACLR demonstrated reduced knee flexion–extension range of motion (ROM), with greater reductions in the high-kinesiophobia group than in the low-kinesiophobia group. Specifically, the involved limb had a 10.0° lower knee flexion–extension ROM in the high-kinesiophobia group than in the low-kinesiophobia group (95% CI 5.8–14.2°). The contralateral limb also showed reduced knee flexion–extension ROM compared with healthy controls in both ACLR groups (high-kinesiophobia group: mean difference − 7.3°, 95% CI − 10.7 to − 3.9°; low-kinesiophobia group: mean difference − 6.4°, 95% CI − 9.8 to − 3.0°). Differences in selected joint moments, including hip adduction, knee varus–valgus, and ankle inversion–eversion moments, were joint- and limb-specific among groups. Knee flexion–extension ROM LSI differed among groups, with greater deviations from 100% observed in both ACLR groups than in healthy controls, indicating differences in numerical bilateral symmetry estimates. Exploratory analyses identified no consistent associations between continuous TSK-17 scores and gait biomechanical variables after correction for multiple comparisons. Varying levels of kinesiophobia after ACLR were associated with differences in bilateral gait biomechanics, particularly knee flexion–extension ROM. TSK-17 scores alone may not be sufficient to identify individual gait abnormalities; therefore, integrating psychological assessment with objective gait evaluation may provide a more comprehensive basis for individualized rehabilitation planning.