Instruments and techniques for orienting prosthesis components for joint prostheses

A modular system for long bone arthroplasty comprising:

• an array of prosthesis components, an array of anchor components and an array of coupler components, wherein a selected component of each of the arrays of prosthesis, anchor and coupler components are engageable to provide an arthroplasty assembly,
• wherein the position of the prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component, and
• wherein the position of the anchor component relative to the coupler component can be varied in two dimensions on a plane that is perpendicular to the central engagement axis of the coupler and prosthesis components,
• wherein the coupler component is selected from an array consisting of a plurality of coupler components, each coupler component comprising a prosthesis component engagement side and an opposite anchor component engagement side, the sides bounded by a lateral edge that is one of cylindrical, frustoconical and frustohemispherical, and comprising a surface treatment comprising texturing to encourage bony ingrowth or ongrowth, wherein the coupler component is configured to interchangeably engage both a convex prosthesis component and a concave prosthesis component, wherein the array of coupler components has variably positioned anchor engagement features and each of at least two of the plurality of coupler components comprises at least one anchor engagement feature that is off-center from the central engagement axis of the coupler component,
• wherein the anchor component is selected from an array consisting of a plurality of anchor components each comprising a proximal portion having a proximal surface for contacting at least a portion of the coupler component and a distal portion for positioning within bone, the proximal portion having an angle of inclination of from about 120 to about 145 degrees and comprising a coupler component engagement feature, and wherein coupler component engagement feature includes a female taper recessed into the planar proximal surface that is complementary to and configured for receiving the complementary male taper on the coupler component,
• wherein the prosthesis component is selected from an array consisting of a plurality of prosthesis components each having a generally elliptical cross sectional shape and comprising on a first side a bone articulation surface that is either convex or concave, and comprising on an opposite second side an engagement feature for engagement with the coupler component, and,
• wherein, when one of each of the selected prosthesis, anchor and coupler components are engaged and the coupler and anchor components are recessed into bone, the assembly achieves alignment of the bone articulation surface of the prosthesis component with the bone that is anatomically similar to a native long bone.

A modular system for long bone arthroplasty comprising:

• a generally disc shaped coupler component comprising:
• a prosthesis component side and an opposing anchor component side and a central axis;
• a lateral edge that bounds the prosthesis component and anchor component sides, the lateral edge comprising a surface treatment comprising texturing to encourage bony ingrowth or ongrowth;
• on the prosthesis component side, a recess having a substantially planar floor and a sidewall that is defined by the lateral edge and at least one prosthesis component engagement feature;
• the anchor component side being substantially planar and comprising at least one anchor engagement feature extending from a surface and radially offset from the central axis by from about 1 mm to about 8 mm, wherein the shape of the coupler component is selected from cylindrical, frustohemispherical, and frustoconical;
• a prosthesis component comprising on a first side a bone articulation surface is a convex head and has a generally elliptical cross sectional shape, wherein a ratio of the axes of symmetry of the convex head is from 0.85 to 1, and comprising on an opposite second side an engagement feature for engagement with the coupler component, wherein the at least one prosthesis component engagement feature is a tapered sidewall, and wherein the at least one anchor engagement feature is a male taper, and wherein the coupler component further comprises at least a second prosthesis component engagement feature that comprises at least one circumferential tooth on the tapered sidewall adjacent to a recess at the base, wherein the engagement features of the prosthesis and coupler components are concentrically aligned;
• and
• an anchor component comprising a proximal portion having a planar proximal surface for contacting at least a portion of the planar surface of the anchor component side of the coupler component and a distal portion for positioning within a bone, the proximal portion comprising on its planar proximal surface a coupler component engagement feature, wherein the anchor component is a stem having an overall length, proximal portion length, distal portion length, proximal portion girth, and distal portion girth, and wherein the coupler component engagement feature comprises a female taper recessed into the planar proximal surface that is complementary to and configured for receiving the complementary male taper on the coupler component, and wherein at least a portion of the proximal portion of the stem comprises surface treatment to encourage bony ingrowth,
• wherein the generally disc shaped coupler component is configured to interchangeably engage both a convex prosthesis component and a concave prosthesis component.