A joint prosthesis assembly, includes a joint prosthesis body (1) made of a first biocompatible non-resorbable material and an anchoring element (2-5) made of a second biocompatible non-resorbable material. The anchoring element (2-5) is arranged to allow rotation of an end portion of the joint prosthesis body (1) with respect to the anchoring element (2-5) when in situ.