Prosthetic condylar joints with articulating bearing surfaces having a translating contact point during rotation thereof
A prosthetic joint according to the present invention includes a first implant component for attachment to a first bone and a second implant component for attachment to a second bone. The first implant component has a condylar portion that includes first and second condylar bearing surfaces and similarly, the second implant component has bearing surfaces that receive and are complementary to the first and second condylar bearing surfaces. Each of the first and second condylar bearing surfaces and each of the bearing surfaces of the second implant component has a cross-section in a coronal plane that exhibits two different radii and a contact point is established between the first and second condylar bearing surfaces and the bearing surfaces of the second implant component. The bearing surfaces of the respective implant components are configured such that varus and valgus rotation of the first implant component relative to the second implant component causes the contact point to move outwardly.
1. A prosthetic joint comprising:
a first implant component for attachment to a first bone, the first implant component having a bicondylar portion that includes first and second condylar bearing surfaces, wherein each of the first and second condylar bearing surfaces has a convex shape; and
a second implant component for attachment to a second bone, the second implant component having bearing surfaces that receive and are complementary to the first and second condylar bearing surfaces;
wherein each of the first and second condylar bearing surfaces and each of the bearing surfaces of the second implant component has a cross-section in a coronal plane that exhibits at least two different radii and a contact point is established between the first and second condylar bearing surfaces and the bearing surfaces of the second implant component, the at least two different radii of each respective condylar bearing surface defining the convex shape of the respective condylar bearing surface;
wherein varus and valgus rotation of the first implant component relative to the second implant component causes the contact point to move laterally (outwardly) away from a center of the joint when the second implant component is in near full extension relative to the first implant component.
2. The prosthetic joint of claim 1 , wherein the first bone is a femur bone and the second bone is a tibia bone.
3. The prosthetic joint of claim 1 , wherein the first bone is a humerus bone and the second bone is an ulna bone.
4. The prosthetic joint of claim 1 , wherein the first bone is a tibia bone and the second bone is a talus bone.
5. The prosthetic joint of claim 1 , wherein a medial (inner) radius of each of the first and second condylar bearing surfaces is less than a lateral (outer) radius thereof.
6. The prosthetic joint of claim 1 , wherein the second implant component includes first and second laterally spaced-apart, oblong concavities formed along an upper surface for receiving the first and second condylar bearing surfaces of the first implant component to provide a nested configuration between the first and second implant components, the oblong concavities defining the bearing surfaces of the second implant component.
7. The prosthetic joint of claim 1 , wherein the first implant component comprises a femoral component that includes an intercondylar box and the second implant component includes a tibial insert component that has a constraint post for reception within the intercondylar box.
8. The prosthetic joint of claim 1 , wherein the first implant component comprises a humeral implant component and the second implant component comprises an ulnar implant component, wherein one end of the humeral implant component includes the bicondylar portion that mates with the bearing surfaces that are formed as part of the ulnar implant component.
9. A prosthetic joint comprising:
a first implant component for attachment to a first bone, the first implant component having a bicondylar portion that includes first and second condyles that are spaced apart and define first and second condylar bearing surfaces, respectively, wherein each of the first and second condylar bearing surfaces has a convex shape; and
a second implant component for attachment to a second bone, the second implant component having concave shaped bearing surfaces that receive and are complementary to the first and second condylar bearing surfaces;
wherein each of the first and second condylar bearing surfaces and each of the bearing surfaces of the second implant component has a cross-section in a coronal plane that exhibits two different radii and a contact point is established between the first and second condylar bearing surfaces and the bearing surfaces of the second implant component, the at least two different radii of each respective condylar bearing surface defining the convex shape of the respective condylar bearing surface;
wherein during a prescribed movement between the first and second implant components, the contact point moves outwardly away from a center of the joint when the second implant component is in near full extension relative to the first implant component.
10. The prosthetic joint of claim 9 , wherein the prescribed movement comprises a varus or valgus motion.
11. The prosthetic joint of claim 10 , wherein the prosthetic joint is selected from the group consisting of: a prosthetic knee joint, a prosthetic elbow joint, and a prosthetic ankle joint.