Biomechanical assessment of CAD/CAM and hand-cast prostheses for transtibial amputees

Pressures between the residual limb and the prosthetic socket for a transtibial amputee are speculated to play a critical role in socket fit and comfort, as well as residual limb tissue health. The purpose of this research was to compare quality of fit, interface pressures and gait characteristics of sockets manufactured utilizing (1) Computer-aided Design and Manufacturing (CAD/CAM) methods, versus (2) traditional hand-cast techniques. This is the first study that has compared hand-cast and CAD/CAM sockets utilizing the combined measures of interface pressure and quantitative gait assessment. Four amputees were assessed while wearing each socket, on two separate testing days. There were no evident relations between socket type and changes in interface pressure, though there is some evidence that gait symmetry is improved with CAD/CAM sockets. Comfort scores were not directly related to interface pressures, indicating that prosthetists should take care when relying on patient feedback to determine quality of socket fit.