Modular humeral head and related methods
Provided is an improved humeral head assembly for a shoulder prosthesis.
1. A humeral head assembly, comprising:
an articular body including a convex articular surface and a coupling portion, the coupling portion on a side of the articular body opposite the convex articular surface, the coupling portion including a first recess and a second recess that extend from the first recess, and two continuous zones of eccentricity adjustment,
wherein the first recess is bounded by the two continuous zones of eccentricity adjustment provided on opposite sides of the second recess, wherein each of the two continuous zones extend between two ends wherein each end is formed by a stop that includes curved protrusions that extend to peaks disposed into the first recess, and each of the two stops defining an end for each of the two continuous zones; and
a coupler including a first portion configured to mate with the coupling portion and a second portion opposite the first portion, the second portion configured to mate with another member of a joint prosthesis; wherein
the first portion of the coupler is configured to be placed in a first configuration against the coupling portion in which the coupling portion circumferentially overlaps a portion of the coupler and a rotational position of the coupler is adjustable along first of the two continuous zones to allow for selection of different amounts of eccentricity along the first continuous zone; and,
wherein the first portion of the coupler is configured to be placed in a second configuration against the coupling portion in which the coupling portion circumferentially overlaps the portion of the coupler and the rotational position of the coupler is adjustable along second of the two continuous zones to allow for selection of different amounts of eccentricity along the second continuous zone.
2. The humeral head assembly of claim 1 , wherein the peaks of the stops extend about one-quarter of the width of the first recess from the continuous zones toward the second recess.
3. The humeral head assembly of claim 1 , wherein the continuous zones are symmetric about a line connecting the peaks of the stops.
4. The humeral head assembly of claim 1 , wherein the articular body comprises indicia on the side of the articular body opposite the convex articular surface, the indicia indicating the amount of eccentricity at predetermined spaced apart locations of each of the two continuous zone.
5. The humeral head assembly of claim 1 , wherein the first portion of the coupler comprises a tapered protrusion that couples with the articular body by an interference fit.
6. The humeral head assembly of claim 1 , wherein the second portion of the coupler is tapered.
7. The humeral head assembly of claim 1 , wherein the coupler comprises a collar disposed between the first portion and the second portion thereof, the collar comprising a protrusion configured to be positionable at least along the continuous zone.