The Impact of Spacer Adjustment for SACH Foot in Below-knee Amputees on Hip Joint and Low Back Force

• Main Authors: Guan-Xun Chen, 陳冠勛
• Other Authors: Chen-Sheng Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/37440035673098386005

碩士 === 國立陽明大學 === 物理治療暨輔助科技學系 === 101 === SACH foot is a non-joint foot without natural ankle function. Below-knee amputees exhibit drop foot in late swing phase due to lack of active dorsiflexion. To solve that, clinical guidance suggests to shorten the spacer for a smooth gait. However, this causes leg length discrepancy and induces asymmetry of hip joint and overload of L5/S1 joint force. As a result, the early hip osteoarthritis and low back pain were found in clinics. Therefore, this research aimed to investigate the influence of different prosthesis spacers on hip joint and L5/S1 joint force. This research recruited 10 subjects using leg length for normalization under four different spacers (0%, 1%, 2%, and 3%) for gait analysis. Vicon system and force plate were respectively conducted to collect kinematic data and ground reaction force. A mathematic software Matlab was employed to create a mathematical model for evaluating symmetry and force of hip joint and low back force of L5/S1 joint. Results showed that model validation was passed achieved with excellent correlation coefficient (r=0.96) and root mean square of less than 0.025 N. Model analysis demonstrated that vertical maximal hip joint force in symmetry index is the best at 1% group (4.94%). Moreover, vertical maximal L5/S1 joint force is lower at 0% group (0.703BW) and 1% group (0.728BW) than other adjustments. This study concluded that the 1% of spacer shortage would be better for the symmetry of hip joint force and the lower L5/S1 joint force.