Total shoulder prosthesis system

• US 4,550,450 A
• Filed: 07/24/1984
• Issued: 11/05/1985
• Est. Priority Date: 07/24/1984
• Status: Expired due to Fees

• Current Assignee: James G. Kinnett
• Original Assignee: James G. Kinnett
• Inventors: Kinnett, James G.
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): Prizant, James
• Application Number:
  US06/634,482
• Time in Patent Office: 469 Days
• Field of Search: 3/1.91, 128/92 C
• US Class Current: 623/20.11
• CPC Class Codes: A61F 2/40 for shoulders
• CPC Class Codes: A61F 2/4003 Replacing only the epiphyseal or metaphyseal parts of the humerus, i.e. endoprosthesis not comprising an entire humeral shaft replacing only the epiphyseal or metaphyseal parts of the femur A61F2/3601
• CPC Class Codes: A61F 2/4081 Glenoid components, e.g. cups
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30902 laterally or radially
• CPC Class Codes: A61F 2002/4018 Heads or epiphyseal parts of humerus
• CPC Class Codes: A61F 2002/4088 Acromial components
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0004 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0026 trapezoidal
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium

Abstract

A total shoulder replacement arthroplasty system which encompasses replacement of the articular surface of the humerus and adjacent glenoid articular surface with a humeral component having a convex surface and a shallow trapezoidal fixation keel to avoid violation of the medullary cavity by the prosthesis and with a concave overmounted glenoid component having a similar keel. The inferior aspect of the acromion is resurfaced with an acromial component for replacement of the acromial clavicular joint, providing mechanical advantage of a fulcrum for abduction and forward flexion of the humerus, and preventing superior migration of the humerus.

Claims

1. A total shoulder replacement prosthesis system for replacement of the articular surface portions of the humerus and glenoid and resurfacing of a portion of the acromion, comprising a humeral prosthesis component having a convex main body portion shaped to provide a complex generally hemispherical head formation defining a generally ovaloid rear face disposed generally perpendicular to a center axis of the component and a convex pseudo-hemispherical articulating front surface extending forwardly from the rear face, the humeral component having a fixation keel projecting integrally from the body portion from the mid region of said rear face for a distance substantially not greater than the maximum depth dimension of the pseudo-hemispherical head formation to be implanted on the proximal humerus portion of a shoulder and having a non-round cross-sectional configuration, a glenoid component formed of a two-part assembly of a rigid member and an articular member of plastic material shaped to provide a shallow concave articular surface to articulate with the front surface of the humeral component and having rounded corners bounding the concave surface and a rearwardly facing well and deflectable shouldered catch projections to nestingly receive a flat confronting face of the articular component in said well and interlock with said catch projections, said base member of the glenoid component having a rearwardly projecting integral fixation keel of similar shape and depth of projection as the humeral component keel to be implanted on the scapular portion adjacent the humerus, and an acromial component to be fixed on a resurfaced portion of the inferior aspect of the acromion formed as a two piece assembly of a rigid backing member and a plastic generally oval shaped facing member having a shallow concave articular front face and a rear face secured against a confronting face of the backing member, interfitting catch formations projecting from one to the other of the acromial component members to interlock them together, and the backing member having fixation projection formation means to be implanted in the resurfaced acromion portion.

2. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said humeral component is of substantially trapezoidal configuration in side elevation.

3. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said humeral component is of substantially trapezoidal configuration in side elevation and has a pair of parallel planar sides.

4. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said humeral component is of substantially trapezoidal configuration in side elevation and has a pair of parallel planar sides and rearwardly converging top and bottom planar surfaces with one of the two latter surfaces extending perpendicular to the rear face of the humeral component.

5. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said glenoid component is of substantially trapezoidal configuration in side elevation.

6. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said glenoid component is of substantially trapezoidal configuration in side elevation and has a pair of parallel planar sides.

7. A shoulder replacement prosthesis system as defined in claim 1, wherein the fixation keel of said glenoid component is of substantially trapezoidal configuration in side elevation and has a pair of parallel planar sides and rearwardly converging top and bottom planar surfaces with one of the two latter surfaces extending perpendicular to the rear face of the humeral component.

8. A shoulder replacement prosthesis system as defined in claim 1, wherein said formation means of the acromial component are a pair of spaced apart substantially cylindrical peg formations having indentations along the cylindrical surface thereof.

9. A shoulder replacement prosthesis system as defined in claim 1, wherein said formation means of the acromial component are a pair of spaced apart substantially cylindrical peg formations having annular grooves at plural axially spaced positions along the cylindrical surface thereof.

10. A shoulder replacement prosthesis system as defined in claim 4, wherein said formation means of the acromial component area a pair of spaced apart substantially cylindrical peg formations having indentations along the cylindrical surface thereof.

11. A shoulder replacement prosthesis system as defined in claim 4, wherein said formation means of the acromial component are a pair of spaced apart substantially cylindrical peg formations having annular grooves at plural axially spaced positions along the cylindrical surface thereof.

12. A shoulder replacement prosthesis system as defined in claim 7, wherein said formation means of the acromial component are a pair of spaced apart substantially cylindrical peg formations having indentations along the cylindrical surface thereof.

13. A shoulder replacement prosthesis system as defined in claim 7, wherein said formation means of the acromial component are a pair of spaced apart substantially cylindrical peg formations having annular grooves at plural axially spaced positions along the cylindrical surface thereof.

14. A shoulder replacement prosthesis system as defined in claim 1, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of rigid metallic material.

15. A shoulder replacement prosthesis system as defined in claim 1, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of titanium.

16. A shoulder replacement prosthesis system as defined in claim 1, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, their companion base member and backing member are formed of titanium and said humeral compoent is formed of chrome cobalt molybdenum.

17. A shoulder replacement prosthesis system as defined in claim 4, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of rigid metallic material.

18. A shoulder replacement prosthesis system as defined in claim 4, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of titanium.

19. A shoulder replacement prosthesis system as defined in claim 4, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, their companion base member and backing member are formed of titanium and said humeral component is formed of chrome cobalt molybdenum.

20. A shoulder replacement prosthesis system as defined in claim 7, wherein the glenoid component articular member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of rigid metallic material.

21. A shoulder replacement prosthesis system as defined in claim 7, wherein the glenoid component tray member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of titanium.

22. A shoulder replacement prosthesis system as defined in claim 7, wherein the glenoid component tray member and the acromial component facing member are formed of high molecular weight polyethelene plastic, their companion base member and backing member are formed of titanium and said humeral component is formed of chrome cobalt molybdenum.

23. A shoulder replacement prosthesis system as defined in claim 8, wherein the glenoid component tray member and the acromial component facing member are formed of high molecular weight polyethelene plastic, and their companion base member and backing member and said humeral component are formed of rigid metallic material.