Abstract: A joint prosthesis and a joint prosthesis organ comprising a cup-shaped element having two parts. One part (1) is a ring which may be connected to the cup-shaped second part (2) with use of click-joint elements (2',2") which are such that ring and cup-shaped part are allowed to rotate freely relative to each other. Described is that said ring may be formed such as to hamper luxation; the ring therefore may partially have an enlarged height. The surgeon using a joint prosthesis according to the invention on a patient has the possibility to rotate the ring with respect to the cup-shaped part until an optimal position is reached. If necessary the two parts may then be fixed to each other using separate means for fixation.