Association of isokinetic strength with pain and functional status in knee osteoarthritis patients aged 80 years and over / 中华老年医学杂志

ABSTRACT

Objective To evaluate the difference in isokinetic strength of the knee muscles between knee osteoarthritis (KOA) patients aged 80 years and over and matched healthy controls,and to establish the association of isokinetic strength with pain and functional status in patients with KOA.Methods The study enrolled 32 patients aged 80 and over diagnosed with unilateral knee OA and 10 matched controls.Pain was evaluated by the visual analogue scale (VAS),the pain intensity scale and the Lequesne index for patients with knee OA.Functional status was assessed by the Timed Up and Go Test (TUGT),the Five Times Sit to Stand Test (FTSST) and the Timed 10 Meter Walk Test (TWT).Muscle strength was measured using the isokinetic dynamometer Biodex System 4 Pro.Bilateral isokinetic (concentric) knee flexion and extension with the protocol of 60 degrees/sec,180 degrees/sec was also performed.Results The difference in two angular velocities of extensor and flexor peak torques between the knee OA group and the control group was statistically significant (t=2.747,P＜ 0.05).The extensor peak torque was negatively correlated with age,Liquesce index scores,FTSST,TUGT and TWT (r=-0.39～～-0.75,P＜0.05),but had no correlation with the VAS score or the Lequesne index pain score (r=-0.23～ 0.31,P＞0.05).The regression analysis results suggested that the extensor peak torque and the VAS score together were important predictors for the Liquesce index (adjusted R2 =0.41).Conclusions The degree of knee muscle damage is closely related to the functional performance of the muscles in knee OA patients aged 80 years or over.The strength of the quadriceps and the intensity of pain are important predictors of disability for those patients.