A bio-inspired condylar knee joint for knee prosthetics

Abstract

This paper presents a novel bio-inspired condylar prosthetic knee joint developed at the University of Bristol. The bio-inspired condylar joint mimics the structure and biomechanics of the human knee joint. The joint contains an inverted parallelogram four-bar mechanism combined with a cam mechanism. The joint has a favourable mechanical advantage compared with a hinge joint. The joint is also compact and robust. An adultsized prototype joint has been designed and tested. The prototype joint contains a long cable for the ligaments with a mechanism for adjusting preload. Compared with other prosthetic joints, the condylar joint has the advantages that it is simple and closely mimics human biomechanics. This paper presents the design of the new artifi cial knee joint and some of the test results. The joint can be used in artifi cial legs and also for knee implants. A rapid prototyping procedure is also presented that enables a custom-sized prosthetic knee joint to be made very quickly and from just a few key dimensions. This process has the potential to improve the quality of surgical implants.