Intermittent vibrational stimulation can affect the lower limb kinematics three months after anterior cruciate ligament reconstruction: a randomised controlled trial

Anterior cruciate ligament (ACL) injuries often lead to significant gait alterations, with traditional rehabilitation sometimes failing to address these issues. Intermittent vibration stimulation (IVS) can enhance muscle function and reduce pain in knee pathologies. This randomized controlled trial investigated whether IVS affects lower limb kinematics during gait and stair ambulation in individuals three months post-ACL-reconstruction (ACLR). Twenty-seven participants, aged 18-45, were randomly assigned to receive IVS or a sham device. Additionally, 24 healthy participants were recruited to provide normative data. The primary aim was to measure knee sagittal angles during gait at various speeds and during stair navigation. A secondary aim was to assess the sagittal angles of the hip and ankle. Statistical analyses involved a two-way mixed ANOVA. After Benjamini-Hochberg correction, significant group×time interactions were found for minimum knee flexion during normal walking (F(1,25) = 8.50, p = .007, partial η² = 0.254) and slow walking (F(1,25) = 6.32, p = .019, partial η² = 0.208). Post-hoc comparisons at the intervention phase showed greater minimum knee flexion in the IVS group than in the sham group during normal walking (Δ = 4.60°, SE = 1.37°, p = .003, partial η² = 0.309) and slow walking (Δ = 4.67°, SE = 1.37°, p = .003, partial η² = 0.316). First-peak knee flexion showed main effects of time at normal (F(1,25) = 6.47, p = .018, partial η² = 0.206) and slow speeds (F(1,25) = 14.59, p < .001, partial η² = 0.378), driven by within-IVS increases (normal: +1.77°, SE = 0.59°, p = .006, partial η² = 0.264; slow: +2.36°, SE = 0.56°, p < .001, partial η² = 0.423). For fast walking, minimum knee flexion also showed a main effect of time (F(1,25) = 8.17, p = .008, partial η² = 0.246), with a within-IVS increase (+ 2.25°, SE = 0.63°, p = .001, partial η² = 0.340). During stair ascent, minimum knee flexion increased over time (F(1,25) = 6.02, p = .022, partial η² = 0.208), with a within-IVS change of + 2.06° (SE = 0.73°, p = .010). These findings suggest that IVS affects lower limb kinematics during rehabilitation after ACLR. Further research is needed to explore its long-term effects.