CONTRA-LATERAL KNEE JOINT FUNCTION IN MODERATE KNEE OSTEOARTHRITIS: AN ELECTROMYOGRAPHIC INVESTIGATION OF KNEE MUSCLE CO-CONTRACTION

Abstract

Unilateral knee osteoarthritis (OA) often progresses to bilateral disease, yet studies focused on joint function during walking often test the symptomatic knee only. The thesis objectives were: i) identify whether co-contraction between the contra-lateral limb of an OA group (CONTRA) and asymptomatic controls (ASYMP) are different, ii) identify whether knee joint biomechanics were different between groups, and iii) quantify inter-limb co-contraction differences in a healthy control group. Muscle activation was recorded in 20 individuals with moderate OA and 20 asymptomatic individuals for the gastrocnemii, hamstrings and quadriceps after 6 minutes of walking. Co-contraction indices were calculated for loading response, midstance and terminal stance, as well as gait biomechanical variables in the sagittal and frontal planes. Co-contraction was not different in between groups, however gait biomechanics were. Results suggest from a co-contraction perspective, the contra-lateral knee in individuals with unilateral symptomatic moderate knee OA is behaving similar to a healthy limb.