Sulzer Brothers Limited

Protek Ag

Gebruder Sulzer, Aktiengesellschaft Protek A.g.

Gebruder Selzer Ag

Peter G Niederer

Otto Frey

Maurice E Muller

The hip joint socket is formed of a socket body of relatively elastic material, for example of plastic, and one or more reinforcement rings which are shrunk fit on the socket body under a prestress. The rings impart rigidity to the hip joint socket. The rings may protrude from the contour of the socket body or may have projections which protrude from the contour of the socket body in order to improve fixation in a cement bed or pelvic cavity.

Hip joint socket

The prosthesis shank is composed of a blade which carries a joint head and a wedge-shaped end piece. The end piece is driven in along a guide in the lateral narrow side of the blade while the blade remains in a fixed position. The wedge-shaped form of the end piece permits fixation of the blade at a predetermined height such that the joint head can be at the level of the trochanter tip.

Shank for a prosthesis

The socket body has an exterior surface which tapers in one direction while anchoring beads on the exterior surface taper in an opposite outward direction. The beads serve to anchor the body within a pelvis. In addition, cross ribs are formed on the anchoring beads with at least some of the ribs being elastic. Upon insertion of the socket, the ribs bend in a direction opposite to the direction of insertion. The two oppositely directed anchoring tapers of the socket body and the beads provide a firm fit of the socket body in a pelvis with a cement-free anchoring. Also, the bent ribs tend to resist withdrawal of the socket from the pelvis.

Joint socket for a hip joint prosthesis

The shank of the prosthesis is provided with a plurality of parallel grooves in order to improve adhesion of the shank in a prepred bone cavity. The grooves are used to improve adhesion either directly to bone tissue or to a cement bed within a bone cavity. The grooves are spaced apart on a center-line to center-line distance of a few millimeters and each has a depth of several tenths of a millimeter.

Joint endoprosthesis

In patients with hypoplastic hip joints, hip joint prostheses with relatively thin and narrow shank blades must be used. For this reason, due to the torque effect of the force acting on the joint head, the danger exists that deformations of the shank blades may occur. This danger is counteracted in that the collar type projection forming the transition between the shank and the prosthesis neck extends in a direction parallel to the prosthesis neck, preferably in a prolongation of the lower edge of the prosthesis neck.

Hip joint prosthesis

The intramedullary stem is provided with a plurality of recesses in the wide sides which are disposed in herring bone fashion. These recesses communicate with a longitudinal groove so that bone tissue material may move into the recesses and grooves during implantation. Apertures may also be provided through the stem so as to provide spaces for the tissue material to collect in a packed manner. Each recess also has a domed shaped pocket on the upper side to receive the material during implantation.

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Zollikofen, Switzerland

Peter G Niederer