Shoulder implant with first and second composite sub-assemblies and improved mounting anchors for establishing a secure joint
The present invention discloses an improved shoulder joint implant assembly including a plastic ball secured to a first joint defining bone end face and a plastic receiver secured to a second joint defining bone end face. Each of the ball and receiver implants are constructed of a composite hardened plastic with a softened cartilage wear surface plastic. A fastener is secured to the first joint defining bone end face and over which is mounted the plastic ball. Anchoring of the receiver is established by a pair of integrally formed and inwardly extending mounting tabs, these further extending into further recess machined cavities in the first bone.
1. A shoulder implant assembly for use with a pair of joint defining bones, said implant assembly comprising:
a spherical shaped member configured to mount in projecting fashion from a retrofitted end of a first of the joint defining bones;
a concave shaped member configured to mount in inwardly recessed fashion from a retrofitted end of a second of the joint defining bones and which seats said spherical shaped member in a joint defining relationship established between the bones;
a pair of mounting tabs adapted to project from a bone contacting surface of said concave shaped member and into the retrofitted end of the second joint defining bone, support pins configured for engagement at surface locations of the second bone and anchoring to said mounting tabs; and
an anchor fastener for mounting said spherical shaped member into a concave shaped seating profile formed in the retrofitted end of the first bone, said anchor fastener further comprising a spike engaging within an elongated and deformable plasticized collar mounted to the first bone at an undercut location in communication with the further concave shaped profile, said undercut location further in alignment with an aperture formed in said spherical shaped member, a pair of semi-spherical undercut engaging portions located within said deformable collar which, upon linear translation of said spike from a direction originating through said aperture in said spherical shaped member, being contacted by said spike and caused to being laterally expanded against said plasticized collar to outwardly deform said collar within the undercut location for mounting said spherical shaped member to the first bone.
2. The assembly as described in claim 1 , each of said spherical shaped member and concave shaped member being constructed of at least one of a composite hardened plastic and a softened cartilage wear surface plastic.
3. The assembly as described in claim 1 , said deformable plastic collar exhibiting exterior threads.
4. The assembly as described in claim 1 , said undercut portions each further comprising an inwardly tapered upper edge profile and collectively defining a pocket for receiving an inserting portion of said spike prior to outward lateral displacement.
5. The assembly as described in claim 1 , at least one of said spherical and concave shape members further comprising a single layer of a composite soft plastic material having rearward extending and integrally formed portions configured so as to precisely match machined interior locations associated with the bone and in preparation for installation thereto.