Carpometacarpal (cmc) joint arthoplasty implants and related jigs, medical kits and methods

Abstract

Thumb carpometacarpal (CMC) joint implants include a trapezium implant defining an articulating surface and a cooperating first metacarpal implant with a base portion of the first metacarpal defining an articulating surface. The first metacarpal base articulating-surface is configured to articulate against the trapezium implant articulating surface.

1 . A thumb Carpo-MetaCarpal (CMC) joint implant, comprising:
 a trapezium implant defining an articulating surface; and   a cooperating first metacarpal implant with a base portion of the first metacarpal defining an articulating surface, wherein the first metacarpal base is configured to articulate against the trapezium implant articulating surface.   
   
   
       2 . An implant according to  claim 1 , wherein the trapezium implant comprises at least one substantially rigid downwardly extending anchoring member configured to reside in a channel formed in a target trapezium. 
   
   
       3 . An implant according to  claim 2 , wherein the at least one anchoring member is a plurality of transversely spaced apart keels extending at least a major portion of a length or width dimension of the trapezium implant. 
   
   
       4 . An implant according to  claim 3 , wherein the trapezium keels are sized to extend only a portion of the length or width of the trapezium implant, and wherein the keels extend transversely or longitudinally closer to one outer perimeter surface than the opposing outer perimeter surface. 
   
   
       5 . An implant according to  claim 1 , wherein the trapezium implant comprises a projecting portion that forms the articular surface, and wherein the first metacarpal base portion has a recessed cavity that matably receives the projecting portion of the trapezium implant, thereby allowing articulating motion between the trapezium implant and the first metacarpal base. 
   
   
       6 . An implant according to  claim 1 , wherein the trapezium implant is a unitary rigid body. 
   
   
       7 . An implant according to  claim 1 , wherein the trapezium implant and the first metacarpal implant define a total thumb CMC joint replacement. 
   
   
       8 . An implant according to  claim 1 , wherein the trapezium implant has a projecting portion that extends outside the bounds of the trapezium into the CMC cavity to define a substantially convex articular surface, and wherein the first metacarpal implant base portion has a socket with a substantially concave cavity sized and configured to matably receive the projecting portion of the trapezium implant. 
   
   
       9 . An implant according to  claim 1 , wherein the first metacarpal implant base portion has a projecting portion that extends outside the bounds of the first metacarpal into the CMC cavity to define a substantially convex articular surface, and wherein the trapezium implant has a socket with a substantially concave cavity sized and configured to matably receive the projecting portion of the metacarpal base portion. 
   
   
       10 . An implant according to  claim 1 , wherein the first metacarpal implant comprises an elongate intramedullary body that is attachable to the base portion. 
   
   
       11 . An implant according to  claim 1 , wherein the base portion has a locking member that is matably attachable to the elongate intramedullary body. 
   
   
       12 . An implant according to  claim 1 , wherein the first metacarpal implant has an elongate intramedullary body that merges into the base portion, wherein the elongate body is rigid, and wherein the articular surface of the base portion material comprises a polymer. 
   
   
       13 . An implant according to  claim 12 , wherein the base portion has a thickness defined to substantially fill a target articulating cavity of the CMC joint. 
   
   
       14 . An implant according to  claim 1 , wherein the trapezium implant has at least one anchoring member with a substantially planar downwardly extending body merging into a lower portion that is substantially circular in cross-section 
   
   
       15 . A medical kit for thumb CMC joint arthroplasty, comprising:
 at least one thumb trapezium implant; and   at least one thumb first metacarpal intramedullary stem implant;   whereby, in position, the thumb first metacarpal intramedullary implant and the trapezium implant articulate against each other.   
   
   
       16 . A kit according to  claim 15 , further comprising:
 a plurality of base members having different sizes and/or shapes, each of the base members configured to serially attach to the first metacarpal intramedullary stem implant, whereby, in position, the attached base member of the intramedullary implant and the trapezium implant articulate against each other.   
   
   
       17 . A medical kit according to  claim 15 , wherein the at least one trapezium implant comprises at least one downwardly extending anchoring member configured to reside in local bone of a target trapezium. 
   
   
       18 . A medical kit according to  claim 16 , further comprising a plurality of trial trapezium implants, wherein the trials have a substantially planar bottom surface devoid of any downwardly projecting anchoring member or the trials have at least one downwardly extending anti-rotational post. 
   
   
       19 . A medical kit according to  claim 15 , further comprising at least one trapezium implant jig configured to define a bone preparation guide or template for preparing a target trapezium to accept the trapezium implant. 
   
   
       20 . A medical kit according to  claim 15 , wherein the trapezium implant jig comprises at least one downwardly extending slot, and a plurality of holding apertures. 
   
   
       21 . A medical kit according to  claim 20 , wherein the at least one downwardly extending slot merges into a keyhole on a medial to lower portion of the jig. 
   
   
       22 . A medical kit according to  claim 20 , wherein the jig comprises a top portion that merges into a downwardly extending side portion, with the side portion being substantially orthogonal to the top portion, and wherein the jig at least one downwardly extending slot is configured to continuously extend from the downwardly extending portion upward and across the top portion to define a substantially horizontal slot extending through a top surface of the jig thereby providing a cutting guide to allow a cutting member to form a channel in local bone of the trapezium that receives the anchoring member. 
   
   
       23 . A medical kit according to  claim 15 , further comprising at least one first metacarpal bone broach sized and configured to enter an intramedullary canal of a target first metacarpal bone to size and/or prepare the bone for the first metacarpal stem implant. 
   
   
       24 . A medical kit according to  claim 15 , wherein the at least one trapezium implant has a projecting portion that extends outside the bounds of the trapezium into a CMC cavity to define a substantially convex articular surface, and wherein the first metacarpal implant has a socket with a substantially concave cavity sized and configured to matably receive the projecting portion of a corresponding trapezium implant. 
   
   
       25 . A medical kit according to  claim 15 , wherein the trapezium implant has at least one anchoring member with a substantially planar downwardly extending body merging into a lower portion with a larger shape in an end view thereof. 
   
   
       26 . A jig for a thumb arthroplasty procedure, comprising:
 a rigid body having a substantially planar top segment that merges into a substantially planar downwardly extending side segment; and   at least one slot extending across at least a portion of the top segment and down into at least a portion of the side segment, whereby the slot is sized and configured to define a cutting guide for a target trapezium.   
   
   
       27 . A jig according to  claim 26 , wherein the slot is substantially straight and substantially horizontal across the top segment and substantially vertical along the side segment. 
   
   
       28 . A method for treating and/or repairing a thumb in a patient, comprising:
 implanting a trapezium implant so that the trapezium implant defines surface of a joint in a patient; and   implanting a first metacarpal implant into the first metacarpal so that the first metacarpal implant defines surface of the joint in the patient whereby the first metacarpal implant articulates against the trapezium implant.   
   
   
       29 . A method according to  claim 28 , further comprising before the step of implanting the trapezium implant:
 preparing the target trapezium for receiving the trapezium implant by planarizing the natural articular surface of the target trapezium, then forming a channel in the target trapezium; and   trying different size trapezium trials to determine a proper size trapezium implant for the patient.   
   
   
       30 . A method according to  claim 28 , further comprising, before the step of implanting the trapezium implant, temporarily affixing a jig with at least one drilling and cutting channel guide to the trapezium, and drilling and cutting at least one channel into the target trapezium using the jig drilling and cutting channel guide. 
   
   
       31 . A method according to  claim 28 , wherein the first metacarpal implant comprises an elongate intramedullary stem and an attachable base member with a socket, the method further comprising, before the step of implanting the first metacarpal implant;
 trying different size base members to select a base member that substantially fills the CMC cavity.   
   
   
       32 . A method according to  claim 31 , further comprising attaching the selected base member to the metacarpal stem. 
   
   
       33 . A method according to  claim 28 , wherein the trapezium implant has at least one anchoring member with a substantially planar downwardly extending body merging into a lower portion that has a larger cross-sectional configuration that the substantially planar body. 
   
   
       34 . A method according to  claim 33 , wherein the lower portion has a substantially circular cross-section. 
   
   
       35 . A thumb arthroplasty implant, comprising:
 a first implant member having an upper surface; and   a cooperating second implant member with a base portion defining a lower surface thereof, wherein the first implant upper surface faces the second implant lower surface, and wherein the first implant member is configured to articulate with respect to the second implant member.   
   
   
       36 . An implant according to  claim 35  wherein the first implant member comprises at least one substantially rigid downwardly extending anchoring member configured to reside in a channel formed in a target bone of the hand. 
   
   
       37 . An implant according to  claim 36 , wherein the at least one anchoring member is a plurality of transversely spaced apart keels extending at least a major portion of a length or width dimension of the first implant member. 
   
   
       38 . An implant according to  claim 35 , wherein the second implant member has an elongate intramedullary body for placement in the first metacarpal of a thumb, wherein the base portion is matably attachable to the second implant member, wherein the elongate body is rigid, and wherein the lower surface of the base portion comprises a polymer. 
   
   
       39 . An implant according to  claim 35 , wherein the first implant member has at least one anchoring keel member with a substantially planar downwardly extending body merging into a lower portion that is substantially circular in cross-section. 
   
   
       40 . An implant according to  claim 35 , wherein at least one of the first implant member or the base portion of the second implant member is provided in a plurality of different sizes.