Acutely Normalizing Walking Speed Does Not Normalize Gait Biomechanics Post-Anterior Cruciate Ligament Reconstruction

Aberrant gait biomechanics in individuals with anterior cruciate ligament reconstruction (ACLR) are linked to posttraumatic osteoarthritis (PTOA) development, indicating a need to normalize gait biomechanics to prevent PTOA. Anterior cruciate ligament reconstruction individuals walk slower than uninjured controls and slower speeds are associated with aberrant gait biomechanics. Yet, it is unclear if increasing walking speed normalizes gait biomechanics post-ACLR.PurposeTo determine the effect of acutely increasing walking speed on gait biomechanics in ACLR individuals compared with their habitual speed and uninjured matched-controls.MethodsGait biomechanics were collected on 30 ACLR individuals (20 females; age, 22.0 +/- 4.2 yr; body mass index, 24.0 +/- 3.0 kg center dot m-2) at their habitual speed and at 1.3 m center dot s-1, a speed similar to controls, and 30 uninjured matched-controls (age: 21.9 +/- 3.8, body mass index: 23.6 +/- 2.5) at their habitual speed. Functional waveform analyses compared biomechanics between: i) walking at habitual speed vs 1.3 m center dot s-1 in ACLR individuals; and ii) ACLR individuals at 1.3 m center dot s-1 vs controls.ResultsIn the ACLR group, there were no statistically significant biomechanical differences between walking at habitual speed (1.18 +/- 0.12 m center dot s-1) and 1.3 m center dot s-1 (1.29 +/- 0.05 m center dot s-1). Compared with controls (habitual speed: 1.34 +/- 0.12 m center dot s-1), the ACLR group while walking at 1.3 m center dot s-1 exhibited smaller vertical ground reaction force (vGRF) during early and late stance (13-28, 78-90% stance phase), greater midstance vGRF (47-61%), smaller early-to-midstance knee flexion angle (KFA; 1-44%), greater mid-to-late stance KFA (68-73, 96-101%), greater internal knee abduction moment (69-101%), and smaller internal knee extension moment (4-51, 88-96%).ConclusionsIncreasing walking speed to a speed similar to uninjured controls did not elicit significant changes to gait biomechanics, and ACLR individuals continued to demonstrate biomechanical profiles that are associated with PTOA development and differ from controls.