Whole Body Vibration Acutely Decreases Medial Tibiofemoral Contact Force During Walking Following Anterior Cruciate Ligament Reconstruction.

Investigating the loading environment of the tibiofemoral joint is critical following anterior cruciate ligament reconstruction (ACLR), given these individuals incur a high risk of post-traumatic osteoarthritis (PTOA). Whole-body vibration (WBV) and local muscle (LMV) vibration acutely improve isometric quadriceps function and gait biomechanics linked to PTOA development, but it is unclear how vibration affects tibiofemoral contact and quadriceps forces during walking. Participants with unilateral, primary ACLR were randomized to control (n = 21, time since ACLR = 23 ± 15), WBV (n = 25, time since ACLR = 27 ± 15), or LMV (n = 23, time since ACLR = 31 ± 16) groups, and walking biomechanics were assessed before and immediately following the respective interventions. Peak medial, lateral, and total tibiofemoral contact forces, as well as rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis forces, were compared between groups and across time with 2 × 3 repeated measure ANCOVAs while controlling for gait speed and time since ACLR. Medial contact force decreased following WBV (mean difference = -0.219, p = 0.001, d = -0.643) but was unaltered by LMV. Peak lateral contact, total contact, and quadriceps forces were unaltered by WBV or LMV (p > 0.05). Greater medial contact forces during gait have been implicated in the development of idiopathic osteoarthritis, and individuals with ACLR often exhibit signs of limb overloading in the later stages of recovery (e.g., > 2 years post-ACLR). WBV may offer a targeted strategy to reduce PTOA risk in those who overload the ACLR limb by decreasing medial knee compartment loading.