A Hip-Knee Joint Coordination Evaluation System in Hemiplegic Individuals Based on Cyclogram Analysis

Inter-joint coordination analysis can provide deep insights into assessing patients’ walking ability. This paper developed a hip-knee joint coordination assessment system. Firstly, we introduced a hip-knee joint cyclogram generation model that takes into account walking speed. This model serves as a reference template for identifying abnormal patterns in the hip-knee joints when walking at different speeds. Secondly, we developed a portable motion capture platform based on stereovision technology. It uses near-infrared cameras and markers to accurately capture kinematic data of the human lower limb. Thirdly, we designed a hip-knee joint coordination assessment metric DTW-ED (Dynamic Time Wrapping - Euclidean Distance), which can score the subject’s hip-knee joint coordination. Experimental results indicate that the hip-knee joint cyclogram generation model has an error range of [0.78 \(^{\circ }\) , 1.08 \(^{\circ }\) ]. We conducted walking experiments with five hemiplegic subjects and five healthy subjects. The evaluation system successfully scored the hip-knee joint coordination of patients, allowing us to differentiate between healthy individuals and hemiplegic patients. This assessment system can also be used to distinguish between the affected and unaffected sides of hemiplegic subjects. In conclusion, the hip-knee joint coordination assessment system developed in this paper has significant potential for clinical disease diagnosis.