Dynamic Electromyographic Activities of Lower Extremity Muscles in Patients with Osteoarthritis of the Knees

J Korean Assoc EMG Electrodiagn Med 2004;6(1):45-51.
Published online May 10, 2004.

Abstract

Objective: To investigate the characteristics of electromyographic activities in individuals with knee osteoarthritis using dynamic electromyography (dEMG) Method: dEMG activities of eight muscles of lower extremities in 15 patients and 16 healthy controls were measured during walking. dEMG activities were divided according to four phases of a gait cycle (Phase 1, heel strike - foot flat; Phase 2, foot flat - toe off; Phase 3, toe off - midswinig; Phase 4, midswing - terminal swing). Duration of each phase to duration of one gait cycle (%) and normalized integrated electromyography (NIEMG) of each muscle (%) were compared between patients and controls. Results: Patients showed longer duration of phase 2 and shorter duration of phase 3 than controls (p<0.05). The NIEMGs of vastus medialis and those of peroneus longus during phase 1 were smaller and larger, respectively, in patients than in controls (p<0.05). The NIEMGs of tibialis anterior during phase 3 and those of medial gastrocnemius during phase 4 were larger and smaller, respectively, in patients than in controls (p<0.05). Conclusion: Duration of gait cycle and dEMG activities of the lower extremities of the individuals with knee osteoarthritis were different from those of healthy subjects.

Key Words: Knee osteoarthritis, Dynamic EMG, Gait