Ankle-joint endoprosthesis

Abstract

An endoprosthesis for replacing the ankle joint includes a lower component which is configured to be connected to the ankle bone, an upper component which is configured to be connected to the shin bone, and an intermediate part which forms a slide joint both with the lower and upper components. The intermediate part, which is wedge-shaped in sagittal section, is provided in order to compensate for anatomical or surgical irregularities. The upper component can also be wedge-shaped in frontal or sagittal section.

1 . An endoprosthesis for replacing an ankle joint, comprising: 
 a lower component which is configured to be connected to an ankle bone ( 2 ) and which forms a top slide surface,    an upper component which forms a bottom slide surface and which has an upper connection surface for connection to a resection surface of a shin bone, and    an intermediate part which has two slide surfaces interacting with the top and bottom slide surfaces of the upper and lower components,    wherein the upper component is wedge-shaped in a frontal or sagittal section between its bottom slide surface and its top connection surface or the intermediate part is wedge-shaped in a sagittal section between its slide surfaces.    
   
   
       2 . The endoprosthesis as claimed in  claim 1 , wherein the interacting slide surfaces on the lower component and the intermediate part interact substantially nonrotatably with respect to a vertical axis of the endoprosthesis.  
   
   
       3 . The endoprosthesis as claimed in  claim 1 , wherein the interacting slide surfaces on the upper component and the intermediate part interact rotatably with respect to a vertical axis of the endoprosthesis.  
   
   
       4 . The endoprosthesis as claimed in  claim 1 ,  2  or  3 , wherein the upper component and the intermediate part have a wedge angle of between 1° and 16°.  
   
   
       5 . The endoprosthesis as claimed in  claim 1 ,  2  or  3 , wherein the wedge-shaped component comprises a wedge part having a varying wedge angle and a standard part.  
   
   
       6 . A system of endoprostheses for replacing the ankle joint, comprising a plurality of sets of endoprostheses each set comprising: 
 a lower component which is configured to be connected to an ankle bone and comprises a top slide surface,    an upper component which comprises a bottom slide surface and a connection surface configured for connection to a resection surface of a shin bone, and    an intermediate part which comprises two slide surfaces configured for interacting with the top and bottom slide surfaces of the upper and lower components,    the system comprising sets of normal upper components and normal intermediate parts whose top and bottom faces are substantially parallel and sets of either corrective components which are configured for exchange for the normal upper components and which are wedge-shaped in their sagittal or frontal planes between their top and bottom faces or corrective intermediate parts which are configured for exchange for the normal intermediate parts and which, between their top faces and the overall course of the bottom faces, are wedge-shaped in the sagittal plane as compared to the normal intermediate parts.    
   
   
       7 . The endoprosthesis as claimed in  claim 4 , wherein the wedge-shaped component comprises a wedge part having a varying wedge angle and a standard part.  
   
   
       8 . The endoprosthesis as claimed in  claim 1 ,  2  or  3 , wherein the upper component and the intermediate part have a wedge angle of between 3° and 8°.