對於退化性膝關節炎的嚴重程度判斷多以X光等光學影像為判斷基準，但病人的疼痛和僵硬狀態與其軟骨磨損程度並不成正相關。疼痛和僵硬卻會造下肢活動不正常，部分研究會著重於膝蓋的運動分析，認為膝蓋的功能受限為主因。而臨床經驗等復健師，認為主因不再膝蓋上，因此本研究著重於髖關節和腰部的活動，並試圖找出差異性。
本研究首先整合無線多通道慣性感測器和表面肌電圖之量測系統；然後使用於退化性膝關節炎之病人，從所量測的慣性感測訊號經過頻譜分析和四元素，提取步態週期，最後提取特徵，透過統計分析判斷是否有顯著差異.由實驗結果顯示退化性膝關節炎和正常人在步態活動中，其髖關節和腰部姿態有活動受限和過多前傾的現象。研究中所收的四條伸直肌群的肌肉在退化性膝關節炎上不正常活動的現象，透過本研究所提出的特徵方法可知其顯著差異。

For Knee Osteoarthritis (OA) severity is determined optical image, but the wear of cartilage isn’t related to clinical symptoms of pain and stiffness. Some researchers focus on knee movement analysis. They consider that knee movement is highly correlated with pain and stiffness. Some physiotherapists with clinical experience don’t think this. It considers lumbar and hip movement maybe is the reason.
In this study, we integrate the wireless inertial sensing and surface electromyography as a wireless peripheral measurement system first. Then, we acquire the signals from knee OA patients and extract the gait cycle through the spectral analysis and quaternion. In the end, extract the feature to distinguish normal and knee OA group through statistics analysis. The result of experiment hip movement and lumbar anterior are a significant difference. The muscles performance is also a significant difference in this study propose feature method.

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