Osteonics Corp.

Marc G Weissman

Mark A Kester

Michael E Wolak

Adam C Bastian

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.

Patellar implant component and method

A knee prosthesis in which engagement between the femoral component and the tibial component of the knee prosthesis takes place at a contact area along articular surface areas including complementary medial-lateral surface profile contours having a single medial-lateral articular radius defining an arcuate profile, and anterior-posterior surface profile contours along the femoral component and the tibial component, the anterior-posterior surface profile contour of the femoral component having an essentially constant anterior-posterior articular radius throughout regions of the femoral component which contact the tibial component within a primary range of flexion, the center of the anterior-posterior articular radius being located along a line extending laterally between the medial and lateral attachment points of the collateral ligaments of the knee, such that the contact area along the articular surface areas is maintained at a maximum throughout at least the primary range of flexion for minimizing stresses in the tibial component and better balancing tension in the collateral ligaments during articulation of the knee prosthesis at least within the primary range of flexion, and further including an eminence projecting from the tibial component toward the femoral component, and a follower on the femoral component for engaging the eminence for controlled restraint of the femoral component during a limited portion of the primary range of flexion.

Knee prosthesis with increased balance and reduced bearing stress

An instrument system and method are disclosed for preparing a distal femur for the implant of a femoral component of a knee prosthesis by the removal of natural bone in the intercondylar area of the distal femur to prepare a femoral notch, including a patella recess, subsequent to establishing distal, anterior and chamfer surfaces at the distal femur. The instrument system includes a femoral notch cutting guide for placement over the distal, anterior and chamfer surfaces of the prepared distal femur, and a femoral notch cutting punch. The femoral notch cutting punch is engaged with a first guideway in the femoral notch cutting guide to remove natural bone from the intercondylar area and establish the patella recess, and subsequently is engaged with a second guideway in the femoral notch cutting guide, transverse to the first guideway, to remove natural bone from the intercondylar area and complete the femoral notch.

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Derby, CT, United States of America

Marc G Weissman