Pelvic Limb Kinematics and Surface Electromyography of the Vastus Lateralis, Biceps Femoris, and Gluteus Medius Muscle in Dogs with Hip Osteoarthritis

Objective: To measure the activity patterns of the vastus lateralis (VL), biceps femoris, and gluteus medius (GM) muscle at a walk in sound dogs and dogs with hip osteoarthritis (OA). Animals: Dogs (n = 10) with hip OA and 7 clinically sound dogs. Methods: Self-reflective markers and a high-speed camera system were used for kinematic measurements and surface electrodes were used for the electromyography (EMG). All measurements were performed on walking dogs. Maximal, minimal, and mean values of the joint angles were evaluated, together with the surface EMG data. Results: In all muscles investigated, mean activity was significantly decreased during the early swing phase in dogs with hip OA. The VL and GM muscle of the clinically worse pelvic limb had significantly higher activity than the contralateral pelvic limb during early stance. Conclusion: The muscles investigated were significantly affected by hip OA. This finding suggests that there is a more distinct resting phase of the muscles during swing and a higher activity during early stance.