Investigation of the Relationship Between Isokinetic Muscle Strength and Functional Performance in Patients with Knee Osteoarthritis

Abstract

Objective: The aim of this study was to examine the relationship between knee flexor and extensor isokinetic muscle strength and physical performance, functional level and quality of life in individuals with knee osteoarthritis (OA). Methods: The study were included individuals diagnosed with OA. Knee extensor and flexor muscle strength of the individuals was measured by isokinetic device (60°/sec and 180° angular velocities). 30 second chair stand, timed up and go, stair climb and 6 minute walk test were applied for physical performance. Western Ontario and McMaster University Osteoarthritis Index (WOMAC) was used for functional status and Short Form-36 (SF-36) was used for quality of life. Results: Eighty participants, 61 women and 19 men, participated in the study. The mean age of the participants was 56.98+-7.71 years. A low-moderate relationship was found between isokinetic knee extensor and flexor muscle strength with physical performance tests (r=0.29 to 0.53; p<0.05). While there was low-moderate relationship between extensor muscle strengths and WOMAC (r=-0.29 to -0.41; p<0.05), low negative relationship was found between flexor muscle strengths and WOMAC (r=-0.29 to -0.32; p<0.05). While there was low-moderate relationship between extensor muscle strengths and SF-36's physical function, physical role difficulty, and pain parameters (r=0.28 to r=0.45, p<0.05), low correlations were found with flexor muscle strengths (r=0.25 to r=0.38, p<0.05). Conclusion: This study showed that knee extension and flexion muscle strength is an important parameter that can affect the physical performance, functional level and quality of life of individuals with OA.

Keywords

• knee osteoarthritis
• muscle strength
• physical performance
• quality of life