Ankle prosthesis with simplified adjustment

Abstract

The invention relates to an ankle prosthesis including a talar implant, a tibial implant, and an intermediate implant designed to be mounted to move relative to said talar implant in order to impart mobility to the ankle, said prosthesis further including embedded adjustment structure designed to alternate between a releasing state, in which they allow the intermediate implant to move relative to the tibial implant, and a locking state, in which they hold the prosthesis in the chosen assembly configuration, said prosthesis being characterized in that said adjustment structure can be controlled to be operable while the prosthesis is in the assembled state in vivo.

What is claimed is: 
     
         1 - 13 . (canceled) 
     
     
         14 . An ankle prosthesis comprising:
 a talar implant comprising a contact surface;   a tibial implant;   an intermediate implant comprising an upper portion and a contact surface of complementary rounded shape to the talar implant contact surface, the contact surface of the intermediate implant comprising a reduced width in the mediolateral direction relative to the upper portion, the intermediate implant configured to be:
 interposed between the tibial implant and the talar implant; 
 moved relative to the talar implant in order to impart mobility to the ankle prosthesis; 
 moved relative to the tibial implant at a first time in vivo; and 
 selectively coupled in fixed relation to the tibial implant in any one of multiple positions to inhibit movement of the intermediate implant relative to the tibial implant at a second time in vivo that is different than the first time; and 
   a contact interface formed by the contact surfaces of the talar implant and the intermediate implant being rounded, the contact interface configured to allow the foot to move in plantar and dorsal flexion relative to the leg, the reduced width configured to constrain movement of the intermediate implant in translation along the mediolateral axis at the contact interface.   
     
     
         15 . The ankle prosthesis according to  claim 14 , wherein, at the first time, the intermediate implant is configured to be moved relative to the tibial implant with first and second degrees of freedom, the first and second degrees of freedom being distinct from each other, wherein with the prosthesis extending from the talar implant to the tibial implant along a mean extension axis, the first degree of freedom corresponds substantially to a movement in translation transverse to the mean extension axis and the second degree of freedom corresponds substantially to movement in rotation about the mean extension axis. 
     
     
         16 . The ankle prosthesis according to  claim 14 , wherein a portion of the intermediate implant is configured to be engaged to slide and to move in rotation in a guide member of the tibial implant. 
     
     
         17 . The ankle prosthesis according to  claim 16 , wherein the guide member comprises at least two rails disposed facing each other in order to support the intermediate implant by side edges of the at least two rails. 
     
     
         18 . The ankle prosthesis of  claim 14 , further comprising at least one locking member configured to cause the intermediate implant to be coupled any one of the multiple positions in fixed relation to the tibial implant and to be accessible at an anterior end of the ankle prosthesis. 
     
     
         19 . The ankle prosthesis according to  claim 18 , wherein the locking member is configured to press the intermediate implant against the tibial implant to couple the intermediate implant in fixed relation to the tibial implant. 
     
     
         20 . The ankle prosthesis according to  claim 18 , wherein the locking member is configured to be accessible in vivo. 
     
     
         21 . The ankle prosthesis according to  claim 14 ,
 wherein the contact surfaces are selected from an uninterrupted rounded shape consisting of substantially cylindrically, frustoconically, or spherically rounded.   
     
     
         22 . The ankle prosthesis according to  claim 14 ,
 wherein the contact surface of the talar implant comprises two mediolateral rails disposed facing each other on either side of the contact surface of the talar implant in order to constrain the intermediate implant against moving in translation along the mediolateral axis at the contact interface.   
     
     
         23 . An ankle prosthesis comprising:
 a talar implant comprising mediolateral rails;   a tibial implant;   an intermediate implant configured to be:
 interposed between the tibial implant and the talar implant; 
 moved relative to the talar implant in order to impart mobility to the ankle prosthesis; 
 moved relative to the tibial implant with at least one of a first and second degrees of freedom that are distinct from each other; and 
 selectively coupled in any one of multiple positions in fixed relation to the tibial implant to inhibit movement of the intermediate implant relative to the tibial implant with respect to the at least one of the first and second degrees of freedoms; and 
   at least one locking member configured to press the intermediate implant against the tibial implant an any of the multiple positions thereby allowing the intermediate implant to alternate between being coupled in fixed relation to the tibial implant and being able to move in the at least one of first and second degrees of freedom relative to the tibial implant   wherein the talar implant and the intermediate implant comprise complementary shaped contact surfaces forming a contact interface, the contact interface configured to allow the foot to move in plantar and dorsal flexion relative to the leg.   
     
     
         24 . The ankle prosthesis according to  claim 23 ,
 wherein the mediolateral rails of the talar implant are configured to constrain the intermediate implant against moving in translation along the mediolateral axis at the contact interface.   
     
     
         25 . The ankle prosthesis according to  claim 23 ,
 wherein the contact surfaces are selected from an uninterrupted rounded shape consisting of substantially cylindrically, frustoconically, or spherically rounded.   
     
     
         26 . The ankle prosthesis according to  claim 23 ,
 wherein the contact surface of the intermediate implant has a reduced width in the mediolateral direction relative to an upper portion of the intermediate implant, the reduced width configured to fit between the mediolateral rails and configured to constrain movement of the intermediate implant in translation along the mediolateral axis at the contact interface.   
     
     
         27 . A method of providing an ankle prosthesis, the method comprising:
 coupling an intermediate implant to a tibial implant, the intermediate implant comprising an upper portion and a contact surface;   adjusting in vivo and selecting in vivo a position of the intermediate implant relative to the tibial implant about at least a first degree of freedom;   locking in vivo the selected position of the intermediate implant; and   assembling the intermediate implant to a talar implant, the talar implant comprising mediolateral rails and a contact surface between the mediolateral rails, the contact surface of the talar implant being complementary shaped with the contact surface of the intermediate implant and forming a contact interface, the contact interface configured to allow the foot to move in plantar and dorsal flexion relative to the leg.   
     
     
         28 . The method of  claim 27 , wherein the adjusting in vivo a relative position between the tibial implant and the intermediate implant further comprises: allowing a movement in, at least one of, rotation through a yaw angle, translation along the anteroposterior axis, and translation along a mediolateral axis. 
     
     
         29 . The method of  claim 27 , the intermediate implant further comprising an angularly positional plate,
 wherein the coupling of an intermediate implant to the tibial implant comprises coupling the angularly positional plate of the intermediate implant to the tibial implant.   
     
     
         30 . The method of  claim 29 , wherein the angularly positional plate can slide and move in rotation relative to the tibial implant. 
     
     
         31 . The method of  claim 27 , wherein locking in vivo comprises accessing a locking member along an anteroposterior axis. 
     
     
         32 . The method of  claim 27 , wherein locking in vivo comprises locking in vivo along an anteroposterior axis the selected position between the tibial implant and the intermediate implant.