Using a Mathematical Model to Analyze Joint Forces of People with Below-Knee Amputation

• Main Authors: Yu-Cheng Hung, 洪友誠
• Other Authors: Chen-Sheng Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/57375890309127627474

碩士 === 國立陽明大學 === 物理治療暨輔助科技學系 === 98 === Due to lose function of the ankle joint and foot, people with below-knee amputation exhibit abnormal gait and consequently affect biomechanics performance. The asymmetry gait predisposes to cause secondary disorders such as osteoarthritis, osteoporosis, and low-back disease on them after prolonged walking. To obtain normal gait for people with below-knee amputation, the expensive, keel made by elastic carbon fiber prosthetic foot, “Flex-Foot”, was developed. However, there’s limited evidence showed the effects on joint forces from knee to low-back joint between the Flex-Foot and the SACH foot. To investigate the differences on ground reaction forces and joint forces from knee to low-back between normal people and people with below-knee amputation with different prosthetic foot, this study conducted a software Matlab and mathematical model to analyze biomechanics from knee to low-back joint force for people with below-knee amputation with self-selected speed. We also used force plates and motion-analysis system for gathering data to compare the differences of ground reaction force, the knee, hip, and L5/S1 joint forces. We also recruited a normal subject as a comparison. The result indicated that people with below-knee amputation have higher vertical forces in ground reaction force, knee joint, and hip joint force on the sound limb than the affected limb. People with below-knee amputation also suffered larger medial-lateral vibration and joint force in L5/S1 joint. Additionally, they would use the forward forces by hip and L5/S1 joint to compensate the lacked, push-forward forces made by ankle and foot. In the different effects on prosthetic foot, wearing Flex-Foot made the lower limbs’ forces more symmetry, and it also decreased peak joint forces and vibration in vertical and antero-posterior direction in L5/S1 joint during walking. According to the results, the joint forces of people with below-knee amputation were different from the normal people, and wearing Flex-Foot would make bilateral lower limb joint forces more symmetry and decrease forces in L5/S1 joint.