The invention relates to a prosthesis comprising first and second prosthesis parts connected for mutual movement which are characterized by a locking element for locking respectively releasing the prosthesis parts relative to each other. The parts are preferably connected for mutual movement by an artificial...http://www.google.co.uk/patents/US5895429?utm_source=gb-gplus-sharePatent US5895429 - Leg prosthesis with lockable knee joint
