Defining sarcopenia in knee osteoarthritis with ultrasonography and evaluation of muscle architecture change by ultrasonography after isokinetic exercise program

Aim: To investigate the effects of isokinetic exercise on pain, muscle strength, functional level and muscle architecture by identifying sarcopenia with ultrasonography in women with knee osteoarthritis. Materials and Methods: 31 female patients with clinical and radiological diagnosis of knee osteoarthritis and a diagnosis of sarcopenia according to the Sonographic Thigh Adjustment Ratio (STAR) algorithm were included in the study. During 3 sessions per week for 6 weeks, the therapy of knee circumference isokinetic strengthening was applied to the patients. Before and after treatment, Rectus Femoris (RF) + Vastus Intermedius (VI) muscle thickness, RF cross-sectional area measurement, Vastus Lateralis (VL) pennation angle, VL muscle thickness, VL fascicle length were assessed by ultrasonography in all patients. Before and after the treatment, hand grip strength, 6 meters walking speed, chair rise test, Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were applied. Results: Significant improvement was observed in STAR values, hand grip strength, 6 meters walking speed, and chair stand test in the pre-treatment and post-treatment comparisons (p<0.001). After treatment, significant differences were observed in muscle architecture in RF + VI muscle thickness, RF cross-sectional area measurement, VL pennation angle, VL muscle thickness, VL fascicle length (p<0.001, p<0.001, p=0.021, p<0.001, p=0.002, respectively). Significant difference wasn't observed in RF echogenicity after treatment (p=0.208). After the treatment, significant increase was observed about 60˚/sec and 180˚/sec peak torque values in the knee extensor isokinetic strengths of the patients (p<0.001). There was a significant decrease in VAS and WOMAC pain scores after treatment (p<0.001, p<0.001). Conclusion: It has been concluded that sarcopenia can be evaluated by ultrasonography, isokinetic exercise provides an increase in muscle strength, and changes in muscle architecture can be evaluated by ultrasonography after isokinetic exercise. Key words: Knee osteoarthritis, isokinetic exercise, rectus femoris, sarcopenia, Sonographic Thigh Adjustment Ratio, ultrasonography.