In a process of producing an endoprosthesis as a joint replacement especially for knee joints, a reference image for determining contour differences on the femur and the tibia, which are obtained by comparing a corrected preoperative image of the damaged knee joint with a postoperative image, is used as the basis for preparing corresponding femoral and tibial components of the endoprosthesis.

A patellar component of a prosthetic knee joint includes a domed portion having a peak offset from the center of the patellar component for effecting compensation for the displacement of the mechanical joint line upon implant of the prosthetic knee joint so as to enable affixation of the patellar component within the natural patella with sufficient bone coverage while attaining appropriate sliding engagement of the patellar component with a patellar groove in the femoral component of the prosthetic knee joint during articulation of the knee.

A prosthetic joint for replacing a metatarsal-phalangeal joint of a human toe has a head with a convex bearing surface that moves against the concave bearing surface of a base. The base is elliptical and formed by two different radii of curvature with a desired ratio. The head has a generally concave bone confronting surface with four different generally flat surface areas, one surface is horizontal and parallel to the longitudinal axis of the metatarsal bone, another extends approximately perpendicular thereto, and two others extend at angles to the longitudinal axis. The horizontal lower surface allows better distribution of vertical force and helps to resist separation of the head from the bone. The head exterior surface has four different regions formed by four different radii of curvature with desired ratios to one another. These four head surfaces allow the head and base to reproduce pivoting of a healthy toe joint. A method for installing the prosthetic joint is also disclosed.

An improved total knee joint prosthesis having femoral, tibial and patellar components wherein the trochlear groove in the femoral component of the knee joint prosthesis possesses a depth-width ratio that allows the patellar component to sit deeper in the trochlear groove during knee flexion.

A distal femoral knee-replacement component provides additional points of cam action to facilitate a more normal rollback while inhibiting initial translation which could lead to increased wear and sub-optimal patella femoral mechanics. The inventive component preferably includes additional points of cam action, useable separately or together, to prevent early translation at the initiation of flexion, and a distinct point of cam action to prevent a dislocation of the femoral component over the tibial post which often occurs in cruciate-substituting designs. The preferred embodiment includes three distinct point of cam action. The first is preferably located substantially where existing cams are found, namely, at a point spaced apart a slight distance posteriorly relative to the post in full extension. A second point of cam action is located immediately adjacent the posterior aspect of the superior post to minimize and, ideally, prevent anterior translation at the initiation of flexion. The third point of cam action is preferably located more posteriorly to allow enhanced flexion without a dislocation of the cams over the post. The points of cam action may be implemented using any member or combination of elements operative to provide distinct stages of cooperation with the posterior aspect of the superior post. For example, transverse bars may be used which bridge, or partially bridge, the intercondylar space. The members or elements need not be straight across, but may instead be curved, with the post being curved to allows for a rotation, if so desired. The cam structures according to the invention may also be connected to one another forming points of contact as opposed to complete transverse elements such as distinct bars.