Talonavicular joint prosthesis and its method of implantation

A talonavicular joint prosthesis adapted to replace a natural and original talonavicular joint that exists between an anterior-inferior portion of a patient's talus and a superior-posterior portion of said patient's navicular bone after appropriate surgical preparation of said portions of said bones so as to create, with minimal bone resection from said bones, a new joint space to accommodate said prosthesis, said prosthesis comprising:

• a talar component having an inner and an outer surface and a herein defined average thickness, tT, that quantifies an average distance between said talar component surfaces, and wherein said talar component surfaces each having a portion that is parallel and concentric to each other so that said talar component average thickness, tT, assumes a minimum value that is consistent with providing sufficient strength and rigidity in said talar component while also providing for said minimal bones resection from said anterior-inferior portion of said talus, said talar component inner surface is further configured to generally follow an anatomic contour of said anterior-inferior portion of said-talus joint surface to which said talar component is to be attached;
• and
• a navicular component having an inner and an outer surface and a herein defined average thickness, tN, that quantifies an average distance between said navicular component surfaces, and wherein said navicular component surfaces each having a portion that is parallel and concentric to each other so that said navicular component average thickness, tN, assumes a minimum value that is consistent with providing sufficient strength and rigidity in said navicular component while also providing for said minimal bones resection from said superior-posterior portion of said navicular bone, said navicular component inner surface is configured to generally follow an anatomic contour of said superior-posterior portion of said navicular joint surface to which said navicuiar component is to be attached.