Back to results
US 5,593,450 AGranted
Oval domed shaped patella prosthesis
AssigneeJohnson & Johnson Professional, Inc.
InventorsRichard D. Scott, Thomas S. Thornhill, John Slamin
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeJohnson & Johnson Professional, Inc.
InventorsRichard D. Scott, Thomas S. Thornhill, John Slamin
Estimating the term…
An improved knee prosthesis disclosed that includes a patella for positioning in a trochlear groove formed by two condyles of a femoral component. The novel patella of the disclosure has an elliptical outer periphery and presents an articulating surface to the femoral component for sliding engagement with a trochlear groove formed between the condyles of the femoral component. A side opposite the articulating surface has extending therefrom three posts which enhance the attachment of the patella prosthesis to the patella bone. In one embodiment of the invention an undercut area which is cut into the bone contacting surface of the prosthesis presents an overhang or undercut to the bone in order to enhance cement fixation. The overhang is formed by an outer defining wall which is positioned at an angle to a bottom surface of the recessed overhang area of between 50.degree. and 75.degree..
In a knee prosthesis having a femoral component that includes two condyles as articulating surfaces, a tibial component that articulates with respect to said femoral component and a patella prosthesis for sliding engagement with a groove formed between said condyles, the improvement comprising said patella prosthesis having a non-circular outer periphery and a contact surface of substantially constant spherical radius terminating at said non-circular periphery for contacting said groove in sliding engagement.
In a knee prosthesis having a femoral component that includes two condyles as articulating surfaces, a tibial component that articulates with respect to said femoral component and an ultra high molecular weight polyethylene patella prosthesis for sliding engagement with a groove formed between said condyles, the improvement comprising said patella prosthesis having a non-circular outer periphery and a first side for contact with said groove, said first side having a convex surface terminating at said non-circular periphery, said convex surface defining a substantially constant spherical radius of curvature for contacting said groove in sliding engagement, a second bone contacting side having extending therefrom at least three posts for fixation of said patella prosthesis to a resected patella bone and said bone contacting side further including an undercut area defined by an angularly position wall that defines an angle with a bottom of said undercut area of between 50.degree. and 75.degree..
Dependencies are inferred from the claim text.