Design, fabrication, and preliminary results of a novel below-knee prosthesis for snowboarding: A case report.

Snowboarding with a below-knee prosthesis is compromised by the limited rotation capabilities of the existing below-knee prostheses, which are designed for use in normal walking. Based on snowboarding range of motion analyses, a novel below-knee prosthesis was designed with the aim to achieve similar range of motions like able-bodied snowboarders. The new prosthesis allows for passive inversion/eversion, passive plantarflexion/dorsiflexion and additional 'voluntary' plantarflexion/dorsiflexion initiated by lateral or medial rotation of the upper leg and knee. A prototype was built and was subsequently tested on a single subject, a highly professional snowboarder and candidate for the Olympic Winter Games. The movements of the subject were recorded on video, analyzed and compared to the recorded movements of an able-bodied snowboarder, and a snowboarder with a traditional below-knee prosthesis. The results indicated an increased similarity of inversion/eversion and plantarflexion/dorsiflexion between the snowboarder with the new below-knee prosthesis and the able-bodied snowboarder, whereas the snowboarder with the traditional below-knee prosthesis and the able-bodied snowboarder differed considerably. These results indicate that snowboarding with the new prosthesis is more comparable to able-bodied snowboarding. On a subjective basis this is confirmed by the test subject who stated that: "snowboarding with the new prosthesis is like it was before the amputation!".