Effects Of Treadmill-based Gait Biofeedback Intervention On Overground Biomechanics After Acl Reconstruction: A Preliminary Study

Cueing an increase in peak vertical ground reaction force (vGRF) using real-time gait biofeedback (RTGBF) acutely mitigates the stiffened-knee gait strategy in patients with an anterior cruciate ligament reconstruction (ACLR) by increasing peak knee flexion angle (KFA) and peak knee extension moment (KEM). However, it remains unknown if gait modifications cued using treadmill-based RTGBF transfer to overground gait. PURPOSE: To determine the effects of a treadmill-based RTGBF intervention on vGRF, KFA and KEM collected during overground walking in ACLR individuals. METHODS: 19 individuals 6-60 mo. post ACLR were randomized to RTGBF (n=8; 21.9±5.1 years) or sham RTGBF (n=11; 22.2±5.1 years) and received 18 intervention sessions over a six-week period. Using visual biofeedback, the RTGBF group was cued to increase peak vGRF to 1.12 body weights (i.e., average peak vGRF of uninjured controls) while the sham group was cued to maintain step length. vGRF, KFA and KEM were collected in the ACLR limb throughout stance phase during overground walking at baseline, 6 weeks, and 8 weeks post-intervention. Functional waveform analyses compared within- and between-group changes over time. RESULTS: In the entire cohort, the RTGBF group demonstrated increased KFA throughout stance from baseline to 8 weeks (7-101%) and between 6 and 8 weeks (1-56%, 91-101%). The sham group exhibited increased KFA in late stance from baseline to 8 weeks (86-101%). vGRF and KEM were not statistically different between timepoints within or between groups. We identified four participants that were considered potential outliers (i.e., peak treadmill vGRF that exceeded the RTGBF vGRF target or extremely slow gait speed [<1.0 m/s]). Therefore, we performed a sensitivity analysis including the remaining individuals (RTGBF: n=6; sham: n=9). Similar KFA increases in the RTGBF group were observed from baseline to 8 weeks (13-45%) and from 6 to 8 weeks (1-56%, 95-101%). Between-group differences in KFA existed as the sham group had greater KFA at baseline (1-75%), 6 (1-71%, 84-101) and 8 weeks (1-37%). CONCLUSION: Treadmill-based RTGBF interventions may elicit changes in KFA overground in ACLR individuals. Future studies should assess the long-term biomechanical effects of treadmill-based RTGBF on different transfer tasks. The research presented in this abstract was funded by the Arthritis Foundation.