A ball and socket joint for implanting in the body is provided wherein the sooket portion of the joint can have various orientations with respect to the patient's anatomy, and the orientation used for a particular patient can be selected and / or changed in situ, that is, during or after implantation of the joint. In addition, the configuration of the joint, e.g., constrained versus semi-constrained, as well as the materials making up the socket portion of the joint, e.g., plastic versus metal, can be selected and / or changed in situ.