Ankle joint prosthesis and its method of implantation

An ankle joint prosthesis adapted to involve the patient's distal tibia and talus, said prosthesis comprising:

• a tibial component for lateral to medial implanting on a prepared portion of said distal tibia, said tibial component having a top and a bottom surface, said top surface having convex curvature in the anterior to posterior direction,
• a talar component for lateral to medial implanting on a prepared portion of said talus, said talar component having a top and a bottom surface, said top surface having convex curvature in the anterior to posterior direction, said bottom surface having concave curvature in the anterior to posterior direction that is configured so as to compliment and match with the curvature of said prepared portion of said talus,
• a semi-constrained bearing component for lateral to medial implanting between said tibial and talar components, said semi-constrained bearing component having a top and a bottom surface, said bottom surface having concave curvature in the anterior to posterior direction that is complimentary to the curvature of said talar component's top surface, and
• wherein said semi-constrained bearing component top surface and said tibial component bottom surface having complimentary curvature that is configured to aid in providing a defined level of constraint of movement and interaction between said semi-constrained bearing component top surface and said tibial component bottom surface.

A method for laterally to medially implanting an ankle joint prosthesis comprising tibial, talar and bearing components for replacement of the diseased bone associated with articulating surfaces between a patient's distal tibia and talus, said method comprising the steps of:

• making an incision on the lateral side of the ankle and foot adjacent to said joint,
• cutting the patient's fibula at a point above said joint and reflecting the inferior portion of said fibula downward so as to gain access to said ankle joint,
• distracting said ankle joint so as to improve access to said joint,
• making a lateral to medial cut on the end portion of said distal tibia so as to prepare a portion of said tibia by removing said diseased bone and configuring said prepared portion so that it matches the anterior to posterior plane profile of a to-be-inserted tibial component,
• making a lateral to medial cut on the dome portion of said talus so as to prepare a portion of said talus by removing said diseased bone and configuring said prepared portion so that it matches the anterior to posterior plane profile of a to-be-inserted talar component,
• laterally to medially inserting said tibial component in said prepared portion of said tibia,
• laterally to medially inserting said talar component in said prepared portion of said talus,
• laterally to medially inserting said bearing component between said tibial and talar components,
• removing distraction from said ankle joint, and
• replacing said inferior portion of said fibula back into position relative to the proximal portion of said fibula and securing said portions in position.