Ankle prosthesis for the arthrodesis of the calcaneum

Abstract

A prosthetic ankle assembly including an astragalar component with an upper articular surface that forms part of an ankle joint prosthesis and a lower surface with a shape adapted to engage an upper face of an astragalus. An astragalocalcanean rod is positioned in an astragalocalcanean channel extending from the lower face of the calcaneus to the upper surface of the astragalus. A first end of the astragalocalcanean rod is engage with the lower surface of the astragalar component and a second end of the astragalocalcanean rod is engaged with a lower region of the calcaneus. A distance between the second end of the astragalocalcanean rod is adjustable relative to the lower surface of the astragalar component to adjustably compress the calcaneus against the astragalus.

1 .- 14 . (canceled) 
     
     
         15 . Surgical method for implanting a prosthetic ankle assembly comprising the steps of:
 preparing an upper face of an astragalus of an ankle to engage a lower surface of an astragalar component;   forming an astragalocalcanean bore extending completely through the astragalus and a calcaneus of the ankle between the upper face of the astragalus and a lower face of the calcaneus;   locating the astragalar component on the upper face of the astragalus so that the lower surface of the astragalar component engages the upper face of the astragalus and an upper articular surface of the astragalar component forms part of an ankle joint prosthesis;   inserting an astragalocalcanean rod into the astragalocalcanean bore through the lower face of the calcaneus; and   coupling a first end of the astragalocalcanean rod to the lower surface of the astragalar component so that a second end of the astragalocalcanean rod approximates and engages the lower region face of the calcaneus   so as to progressively compress the calcaneus against the astragalus for performing an arthrodesis between the calcaneus and the astragalus.   
     
     
         16 . The method of  claim 15  wherein the step of locating the astragalar component on the upper face of the astragalus includes receiving an anchor structure of the lower surface of the astragalar component in the astragalocalcanean bore. 
     
     
         17 . The method of  claim 16  wherein the step
 coupling the first end of the astragalocalcanean rod with to the lower surface of the astragalar component includes screwing threads of the first end of the astragalocalcanean rod to complementary threads of the anchor structure. 
 
     
     
         18 . The method of  claim 15  wherein the step of coupling the first end of the astragalocalcanean rod to the lower surface of the astragalar component includes screwing threads of the first end of the astragalocalcanean rod to complementary threads of the lower surface of the astragalar component. 
     
     
         19 . The method of  claim 15  wherein when coupling the first end of the astragalocalcanean rod to the astragalar component, a ring of the second end of the astragalocalcanean rod is pressed against the lower face of the calcaneus. 
     
     
         20 . The method of  claim 15  wherein the first and second ends of the astragalocalcanean rod are linked to each other by a smooth intermediate part, the second end of the astragalocalcanean rod comprising a diameter greater than a diameter of the intermediate part, and
 wherein when coupling the first end of the astragalocalcanean rod to the astragalar component, the diameter of second end of the astragalocalcanean rod engages the lower face of the calcaneus. 
 
     
     
         21 . The method of  claim 15  comprising removing the astragalocalcanean rod from the astragalocalcanean bore through the lower face of the calcaneus after fusion of the astragalar with the calcaneus. 
     
     
         22 . The method of  claim 15  comprising the steps of:
 implanting a tibial component of an ankle joint prosthesis in a distal end of a tibia; and 
 interposing a prosthetic bearing between the astragalar component and the tibial component. 
 
     
     
         23 . The method of  claim 22  wherein the prosthetic bearing is selected from a fixed bearing or a moveable bearing. 
     
     
         24 . The method of  claim 15  comprising arthroscopically locating a bone substance between the astragalus and the calcaneus. 
     
     
         25 . The method of  claim 15  wherein when coupling the first end of the astragalocalcanean rod to the astragalar component, threads of the second end of the astragalocalcanean rod are screwed into the lower face of the calcaneus.