Design and fabrication of a passive-function, cylindrical grasp terminal device.

To assist upper extremity amputees with achieving stable grasps of cylindrical tools, this article describes the development and testing of a prosthetic device for recreational kayak paddling. Initial development included participation of a non-amputee expert kayakist. Subsequent testing of the device used a pseudo-prosthesis for testing on a non-amputee subject, followed by qualitative feedback on the device from a unilateral transradial amputee. The device was evaluated by exploring whether subjects could independently don the terminal device, apply the paddle and use it in a pool and on a river. A semi-hinged, two hemi-cylinder sleeve was designed to be fitted onto a kayak paddle. The terminal device's frame, a second (larger) semi-hinged two hemi-cylinder sleeve, attached the device to the prosthesis. This second sleeve had internal edges that prevent lateral shifting. This component allowed smooth paddle rotation while preventing lateral shift and maintaining grasp. The non-amputee subject was successful at donning the pseudo-prosthesis and paddling. Similarly, the amputee subject was also able to don the prosthesis and paddle using the device. The design reported here is a viable option for fabricating a cylindrical grasp, passive function terminal device for kayaking. It is adaptable to other cylindrical grasp functions such as lifting an exercise weight.