ISOKINETIC TORQUE LEVELS IN HEMOPHILIAC KNEE MUSCULATURE

Abstract

This study was to measure peak torques generated by knee extensors and flexors in hemophilia patients, describe flexor to extensor ratios, record the point in the arc of motion where peak torque was achieved, correlate results with age, degree of hemophilic arthropathy and presence of flexion contracture, and compare results with reports on healthy subjects. Patients (47) (94 knees) with severe hemophilia were tested with a Cybex II isokinetic dynamometer at a speed of 30.degree./s. Height, weight, thigh girths and passive knee range of motion were recorded. Standing roentgenograms of the knee were evaluated to assess degree of arthropathy. Subjects were divided into groups by age and degree of arthropathy. Descriptive statistics were generated for all groups. Average peak extensor and flexor torque was similar for adolescents and adults. Increasing degree of arthropathy was associated with significant decreases in both extensor and flexor torque, an increase in flexor to extensor ratios and increasing knee flexion contractures. Across all groups, flexor to extensor ratios were abnormally high, particularly in patients with type IV arthropathy. The point in arc of motion where peak torques occurred did not differ significantly across groups. For all ages, mean peak extensor and flexor torques were less than values reported in the literature for healthy subjects. The profound decrease in torque produced by knee musculature in hemophilia patients, particularly those with more severe arthropathy and knee flexion deformity, was demonstrated.