Altered sagittal plane kinematics and kinetics during sit-to-stand in individuals with knee osteoarthritis: A systematic review and meta-analysis.

Knee osteoarthritis (OA) progression is associated with an increase in peak external knee flexion torque (EKFT) during gait. However, the difference in the peak EKFT between individuals with knee OA and age-matched subjects was unclear. Therefore, to understand the kinematics, kinetics, and electromyogram characteristics in individuals with knee OA, we conducted a systematic review and meta-analysis of sagittal plane-dominant sit-to-stand (STS) motion. PubMed, PEDro, CINAHL, and Cochrane CENTRAL were used. Fourteen articles (knee-OA group: n = 323, mean age = 65.0 years, mean weight = 79.2 kg; control group: n = 224, mean age = 64.4 years, mean weight = 70.4 kg) were included, and the pooled standardized mean differences (SMDs) were calculated using a random-effects model. Meta-analysis showed that individuals with knee OA present significantly lower peak EKFT (pooled SMD: -1.62; 95% confidence interval [CI]: -2.36 to -0.88), significantly large trunk flexion angle (pooled SMD: 1.04; 95% CI: 0.69 to 1.39), and no significantly lower peak external knee adduction torque despite the significantly larger lateral-lean angle to the less affected side (pooled SMD: 1.04; 95% CI: 0.69 to 1.39). The quality of evidence for all outcomes was very low. The descriptive synthesis indicates that STS motion in individuals with knee OA might be an unsuitable motion strategy for knee muscle activity, force utilization from multiple joints to the knee joint, and their influence on knee joint cartilage, despite their lower peak EKFT. This information can help to better understand movement strategies and to optimize treatment approaches for individuals with knee OA.