Partial or complete prosthetic replacement arthroplasty of the distal radiolulnar joint

Abstract

System, including methods, apparatus, and kits, for replacement of at least one surface region of a distal radioulnar joint using at least one prosthesis. In some embodiments, the system may provide restoration of normal, unconstrained biomechanics of the joint, which may preserve rotation and translation and ensure durability of the joint.

1 . A method of replacing at least a portion of a distal radioulnar joint (DRUJ) formed by a radius and an ulna, the method comprising:
 removing bone from the distal head of the ulna to form a knob on a lateral side of the ulna, while the triangular fibrocartilage complex remains attached to the radius and the ulna;   selecting an ulnar prosthesis having a convex outer surface region opposite a concave inner surface region, and a stem projecting from the concave inner surface region; and   attaching the ulnar prosthesis to the ulna with the knob disposed in the ulnar prosthesis adjacent the concave inner surface region, and the stem extending into the knob toward a medial side of the ulna; and   engaging the convex outer surface region of the attached ulnar prosthesis with the radius or a radial prosthesis attached to the radius.   
     
     
         2 . The method of  claim 1 , wherein the step of removing bone includes a step of removing the entire ulnar portion of the DRUJ. 
     
     
         3 . The method of  claim 1 , wherein the step of removing bone forms a knob having a circular cross section. 
     
     
         4 . The method of  claim 3 , wherein the step of removing bone forms a spherical knob. 
     
     
         5 . The method of  claim 1 , wherein the step of removing bone forms a knob that is shaped to match the inner surface region of the ulnar prosthesis. 
     
     
         6 . The method of  claim 5 , wherein the knob is formed with a tool having an axis of rotation arranged coaxially with the knob. 
     
     
         7 . The method of  claim 1 , wherein the step of removing bone does not remove a most distal tip of the ulna. 
     
     
         8 . The method of  claim 1 , further comprising a step of disposing the ulnar prosthesis over the knob such that the knob is covered by the ulnar prosthesis. 
     
     
         9 . The method of  claim 1 , wherein the stem is disposed in a bore formed in the ulna. 
     
     
         10 . The method of  claim 1 , further comprising a step of attaching a radial prosthesis to the radius, wherein the radial prosthesis is configured to movably engage the convex outer surface region of the ulnar prosthesis. 
     
     
         11 . The method of  claim 1 , wherein the step of attaching the ulnar prosthesis includes a step of disposing a fastener in threaded engagement with the ulnar prosthesis, with the fastener extending to a medial side of the ulna. 
     
     
         12 . A method of replacing at least a portion of a distal radioulnar joint (DRUJ) formed by a radius and an ulna, the method comprising:
 removing bone from a medial side of a distal end portion of the radius to form a circular recess having a diameter;   selecting a radial prosthesis having a concave outer surface region that is sized in correspondence with the diameter of the recess;   attaching the radial prosthesis to the radius with the radial prosthesis disposed in the recess and the concave outer surface region of the radial prosthesis facing away from the radius; and   engaging the concave outer surface region of the attached radial prosthesis with the ulna or an ulnar prosthesis attached to the ulna.   
     
     
         13 . The method of  claim 12 , wherein the step of removing bone is performed while the triangular fibrocartilage complex remains attached to the radius and the ulna. 
     
     
         14 . The method of  claim 12 , wherein the radial prosthesis is attached with an edge portion of the concave outer surface region substantially flush with an adjacent surface region of the radius. 
     
     
         15 . The method of  claim 12 , wherein the step of attaching includes a step of placing a fastener through an aperture of the radial prosthesis and into the radius. 
     
     
         16 . The method of  claim 15 , wherein the fastener is threaded. 
     
     
         17 . The method of  claim 12 , wherein the step of removing bone is performed with a rotating tool having an axis of rotation arranged coaxial with the recess. 
     
     
         18 . The method of  claim 12 , wherein the concave outer surface region is formed of a polymer or cobalt-chrome. 
     
     
         19 . The method of  claim 12 , further comprising a step of attaching an ulnar prosthesis to the ulna, wherein the ulnar prosthesis is configured to movably engage the concave outer surface region of the radial prosthesis. 
     
     
         20 . A method of replacing at least a portion of a distal radioulnar joint (DRUJ) formed by a radius and an ulna, the method comprising:
 selecting a radial prosthesis including a plate portion connected to an articulation portion having a contact site,   forming a recess on a medial side of a distal end portion of the radius such that a radial surface region of the DRUJ is removed;   disposing the articulation portion in the recess such that the contact site has the same medial-lateral position as the radial surface region of the DRUJ before removal;   attaching the plate portion to the radius with one or more fasteners extending through one or more apertures of the plate portion; and   engaging the contact site of the articulation portion with the ulna or an ulnar prosthesis attached to the ulna.   
     
     
         21 . The method of  claim 20 , wherein the articulation portion is composed of a polymer or cobalt-chrome.