Self-reported walking difficulty influences gait characteristics in patients with medial compartment knee osteoarthritis.

BACKGROUND: To differentiate gait strategies per knee osteoarthritis and self-reported walking difficulty during self-selected regular and fast gait speeds. We hypothesize that knee osteoarthritis gait characteristics during self-selected regular and fast gait speeds will be most accentuated by the osteoarthritis and walking difficulty group, followed by osteoarthritis and no walking difficulty, and least in the control group. METHODS: Prospective study of community-dwelling older adults (n = 39) who walk at functional speeds (≥1.0 m per second) were age and sex matched across the three groups. Gait strategies including knee excursion and moments, muscle activation and co-contraction, and limb dynamics (linear acceleration and jerk) were compared between groups during self-selected regular and fast gait speed trials. Significant group differences were defined as P < 0.05 and an effect size greater than small. FINDINGS: Based on walking difficulty, adduction moments (P-range = 0.00-0.03; effect size range,r = 0.42-0.52) and lateral quadriceps-gastrocnemius co-activations (P = 0.01;r = 0.36) were significant during regular gait speeds; and extension (P = 0.03;d = 0.59) and adduction (P-range = 0.00-0.02;d = 0.86;r = 0.40) moments were significant during fast trials. Per knee osteoarthritis presence, adduction moment(P = 0.01;r = 0.49), medial-quadriceps (P = 0.00;d = 1.04;r = 0.61), lateral-hamstrings (P = 0.04;d = 0.55), medial-gastrocnemius (P = 0.02;r = 0.40), medial quadriceps-hamstrings (P = 0.02;r = 0.38), medial quadriceps-gastrocnemius (P = 0.00;r = 0.56), and all limb dynamics (P = 0.00-0.01;d = 1.13-1.18;r = 0.35-0.47) were significant during regular gait speeds. Extension excursion (P = 0.02;d = 0.63), adduction moment (P = 0.01;d = 0.85) and medial-quadriceps (P = 0.01;r = 0.38) were significant during fast trials. INTERPRETATION: Many gait strategies during regular speeds that differ per walking difficulty and knee osteoarthritis attenuated at fast speeds. Perhaps gait training at fast speeds for those with knee osteoarthritis related walking difficulty is biomechanically and functionally beneficial.