Characteristics of velocity-controlled knee movement in patients with cervical compression myelopathy: what is the optimal rehabilitation exercise for spastic gait?

ABSTRACT

STUDY DESIGN: The isokinetic strength of knee extensors and flexors was measured at various controlled velocities in patients with spastic paraparesis caused by cervical compression myelopathy. OBJECTIVE: To evaluate leg function objectively in patients with myelopathy. SUMMARY OF BACKGROUND DATA Cervical compression myelopathy causes varying degrees of spastic paresis in the legs and affects the activities of patients. However, the leg function characteristics of the patients have not been fully elucidated. METHODS: Velocity-controlled voluntary knee movements were studied in 39 patients (25 men and 14 women) with compression myelopathy. Their mean age was 60.2 years (range, 44-77 years). The patients were divided into Group A (ambulation without aid, n = 22) and Group AA (ambulation with aid, n = 17). Isometric peak torque values were measured in knee flexor and extensor muscles at 60 degrees of knee flexion, and isokinetic peak torque values were determined in maximal voluntary concentric movements of these muscles at constant angle velocities of 40 degrees, 80 degrees, 120 degrees, 160 degrees, and 180 degrees per second. The relative strength (percentage of isometric peak torque value) of the isokinetic motion was calculated at each velocity. RESULTS: In both groups, the relative strength decreased as the velocity increased, and the degree of reduced strength in the flexors at the high velocities of 160 degrees and 180 degrees per second was significantly greater in Group AA than in Group A (P < 0.05), whereas no significant difference was found in the extensors between the groups. CONCLUSIONS: The results indicate that isokinetic strength at a high velocity may reflect the severity of spastic paresis in the legs resulting from compression myelopathy.