Exhibition of Postural Time-Force Parameters in Varying Severity of Osteoarthritis of Knee During Performing Sit-To-Stand Testing| Biomed Grid

Background: Knee osteoarthritis (OA) is an irreversible leading cause of disability in elder. Clinical and research assessment for knee osteoarthritis often use radiographic finding to determine the disease severity. But recently research found that radiographic diagnosis couldn't reflect the functional activity of life capacity of patient with knee osteoarthritis. Load distribution influence functional capacity of patient with knee osteoarthritis. It is important to know the correlation between performance and functional capacity of knee osteoarthritis patients. Purpose: In this study, a sit-to-stand task was chosen to compare the force-plate measured time-force parameters and weight bearing asymmetry degree in knee osteoarthritis patients with different functional severity. Method: Study content sit-to-stand performance task and Lequesne severity index questionnaire. Forty-nine subjects participated in this study and were categorized into four groups (normal, mild functional limited OA knee patient, moderate functional limited OA knee patient, severe functional limited OA knee patient) according to Lequesne severity index questionnaire grading which assesses the functional disability of knee osteoarthritis patients. Sit-to-stand performance used a four-load cell force-plate to detect ground reaction force during movement. Then four parameters (sit-to-stand total time, the ground reaction force, the moving rate of center of force (COP), and asymmetry index) which measured by force-plate were compared with the Lequesne severity index questionnaire grading. One-way ANOVA was used to compare the four parameters difference between four groups. Results and discussion: Compared with the normal subjects, the knee osteoarthritis patients take more time to stand up (p=0.003). Insufficient lower extremities extensors muscle strength (p=0.039), slower COP moving rate (p<0.001) were also found. The asymmetry index has shown the discrepancy between normal subjects and OA knee patients which showed weight shifting to their sound side. There was a good correlation between the patient's Lequesne severity index and asymmetry index. Conclusion: Objective assessment of the OA knee patient's functional performance reflects the patient's subjective assessment of their functional ability. OA knee patients shown a tendency of slow sit-to-stand movement, weakness lower extremities extensor muscle strength, poor posture control and weight shifting to sound side associated with reduced functional performance