Gait Biomechanics Linked To Post-traumatic Osteoarthritis Following Anterior Cruciate Ligament Reconstruction Are Improved With Vibration

Abstract

PURPOSE: Anterior cruciate ligament reconstruction (ACLR) incurs a high risk of post-traumatic knee osteoarthritis (PTOA). Aberrant gait biomechanics contribute to PTOA and are attributable in part to quadriceps dysfunction. Vibration improves quadriceps function following ACLR, but its effects on gait biomechanics are unknown. The purpose of this study was to evaluate the effects of whole body vibration (WBV) and local muscle vibration (LMV) on gait biomechanics in individuals with ACLR. METHODS: 75 volunteers with primary unilateral ACLR (72% females; age 21 ± 3 yr; time since ACLR 27 ± 16 mo) were randomized to WBV, LMV, or Control interventions. WBV and LMV were applied 6 x 1 minute (30Hz, 2g). Walking biomechanics were assessed prior to and following the interventions. Outcomes included the peak vertical ground reaction force (vGRF) and its loading rate, peak internal knee extension and valgus moments, and peak knee flexion and varus angles during the first 50% of stance. vGRF magnitude and rate were normalized to body weight (BW) and moments were normalized as % body weight∗height (%BW∗Ht). ACLR limb change scores (post-pre) for each outcome were compared across groups via one-way ANCOVA controlling for gait speed, time since ACLR, and baseline values. RESULTS: Change scores did not differ across groups for peak knee flexion (p = 0.374) or varus (p = 0.801) angles, vGRF (p = 0.656), or internal valgus moment (p = 0.866). However, changes in vGRF loading rate differed across groups (p = 0.024), with a significant decrease in the LMV group (-3.6 BW/s) that was greater than the changes in the WBV (-0.3 BW/s; p = 0.035) and Control (0.5 BW/s; p = 0.010) groups. Additionally, the change in peak internal extension moment differed across groups (p = 0.016), with a significant increase in the WBV group (0.27 %BW∗Ht) that was greater than the change in the Control group (-0.17 %BW∗Ht; p = 0.005) but not the LMV group (0.01 %BW∗Ht; p = 0.101). CONCLUSIONS: Lower knee extension moments and greater loading rates during gait have been linked to declines in joint health following ACLR. WBV acutely increased the peak knee extension moment and LMV decreased loading rates. These data suggest that vibration has the potential to mitigate aberrant gait biomechanics, and may represent an effective approach for mitigating PTOA risk following ACLR.