Zimmer Gmbh

Sulzer Orthopedics Inc.

Roger Scherrer

Marco A H Heggendorn

Matthias Schäpper

Cosimo Donno

Vincent Leclercq

Ren&eacute; Brack

Marco Heggendorn

A knee prosthesis has a femoral component with a medial condyle defining a constant bearing spacing relative to a central sagittal component plane SP, and a lateral condyle defining divergent bearing spacing from the central sagittal component plane along an extension-to-flexion path. High congruence between the medial articulation surfaces creates a pivot point for external rotation at the medial contact area, while lower congruence in the lateral articulation surfaces allows the lateral femoral condyle to track anteriorly and posteriorly during flexion. The amount of lateral condyle bearing spacing divergence is calculated to produce a substantially linear anteroposterior motion profile of the lateral femoral condyle upon the lateral tibia articular surface throughout a wide range of flexion.

Femoral knee prosthesis with diverging lateral condyle

An orthopaedic knee joint prosthesis () provides guided motion in a wide range of motion, and in both extension and flexion. In flexion, a tibial bearing component () shifts to a first position in which a posterior cam () formed in a femoral component () engages a tibial spine () coupled to a tibial component (). Contact between the posterior cam and the spine guides the motion profile of the knee joint prosthesis throughout a wide range of flexion movement. In extension, the bearing component shifts to a second position in which an anterior cam () formed in the femoral component engages the spine. Contact between the anterior cam and spine guides the motion profile of the knee joint prosthesis throughout a wide range of extension. The anterior and posterior cams, mobile bearing component, and tibial component-mounted spine cooperate to facilitate guided flexion and extension of the knee joint prosthesis throughout a wide range of motion.

Knee prosthesis with guided extension and flexion

The invention relates to a base component for a tibial implant, comprising a lateral compartment (), a medial compartment () and an anterior connection portion () which connects the lateral compartment () and the medial compartment () to one another at anterior. A portion () open to posterior is provided between the lateral compartment () and the medial compartment (). The lateral component () and the medial component () each have a lower side and an upper side, with at least one of the lower sides being configured for the fastening of the base component to the tibia. A marginal web () is formed at at least one of the compartments (), starting from the upper side, said marginal web forming a receiving shell for a meniscus component () of the tibial implant together with the upper side of the compartment. The height of the marginal web () in a posterior region is reduced with respect to other regions of the marginal web () at at least one of the two compartments (). The invention furthermore relates to a tibial implant and to a knee prosthesis.

Base component for a tibial implant

One or both of the condyles in a femoral component for a partial or total knee prosthesis includes a J-curve with a plurality of distinct radii, such as 5 or more radii. The centers of the radii are arranged along an arcuate path extending anteroposteriorly so that successively larger radii are serially arranged along the arcuate path from the posterior side of the femoral component to the anterior side. The femoral component provides a high degree of stability throughout the range of motion of the knee prosthesis, and facilitates a close approximation to the motion of a natural knee.

J-curve for a femoral prosthesis component

A tibia part for a knee joint prosthesis. The prosthesis includes a tibia bearing surface for the support of a bearing body and a bore for the reception of a guiding element. A cut-out for the rear cruciate ligament is provided in the tibia bearing surface and the bore is formed in such a manner that it can, depending on the design of the guiding element, receive the latter either rotationally fixedly relative to the tibia part or rotatably relative to the tibia part.

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Schallhauser, Switzerland

Roger Scherrer