Universal joint prosthesis with cap

• US 4,328,593 A
• Filed: 06/06/1980
• Issued: 05/11/1982
• Est. Priority Date: 12/22/1979
• Status: Expired due to Term

• Current Assignee: Franz Sutter
• Original Assignee: Institut Straumann AG (Straumann Holding AG)
• Inventors: Sutter, Franz, Straumann, Fritz
• Primary Examiner(s): FRINKS, RONALD
• Application Number:
  US06/157,278
• Time in Patent Office: 704 Days
• Field of Search: 3/1.9, 3/1.91, 3/1.912, 3/1.913, 128/92 C, 128/92 CA, 128/92 G
• US Class Current: 623/23.42
• CPC Class Codes: A61B 17/1637 Hollow drills or saws producing a curved cut, e.g. cylindrical A61B10/025, A61B17/1695 take precedence
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence
• CPC Class Codes: A61B 17/1684 for the shoulder
• CPC Class Codes: A61B 17/1686 for the hand or wrist
• CPC Class Codes: A61B 17/32053 Punch like cutting instruments, e.g. using a cylindrical or oval knife A61B17/326 takes precedence; trepans A61B17/1695; for use on the cornea A61F9/007
• CPC Class Codes: A61F 2/30749 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3603 implanted without ablation of the whole natural femoral head endoprosthetic cartilage A61F2/30756
• CPC Class Codes: A61F 2002/30115 circular-O-shaped
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30779 arcuate
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3082 Grooves
• CPC Class Codes: A61F 2002/30851 Multiple threadings
• 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 2002/30879 Ribs
• CPC Class Codes: A61F 2002/30901 longitudinally
• CPC Class Codes: A61F 2002/30902 : laterally or radially
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30919 : Sleeves
• CPC Class Codes: A61F 2220/0008 : Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys

Abstract

A prosthesis for forming the spherical part of a hip joint with a calotte-shaped cap is disclosed. The inner surface of the prosthesis is provided with grooves and ribs which are evenly distributed over the circumference of the inner surface and extend along planes which, in turn, extend through the rotational symmetry axis of the outer cap surface. A sleeve having jacket is provided with holes is rigidly secured at the inner end of the inner cap surface on the cap and projects partly out of the latter. The ribbing of the inner cap surface and the sleeve permit the prosthesis to be firmly and durably secured in an operation on the bone without cement.

Claims

1. A universal joint prosthesis for engaging the head portion of a bone end while retaining the major portion thereof, comprising a cap having a calotte-shaped outer surface terminating in a free edge and an inner surface having a reference osculating surface which is symmetrical about a central longitudinal axis, extending from said free edge defining a concavity in which a bone or the like may be received, the concavity being sufficiently large to contain a major portion of the cancellous bone end of the joint, said inner surface having a plurality of spaced projections, said projections being spaced to define depressions therebetween, said projections and depressions being successively arranged along lines extending from said free edge toward the innermost portion of said inner surface, said lines extending along planes laying in said longitudinal axis, an open ended sleeve attached to said inner surface and arranged coaxially to said axis and extending at least partly beyond the free edge of said concavity and rigidly connected to said cap, said sleeve including a plurality of macroscopic holes extending therethrough, said concavity as well as said projections and depressions extending from said free edge toward a depth where said inner surface converges toward said axis in a direction away from said free edge, wherein said projections and depressions increase the inner cap surface which can bear on a bone after the prosthesis has been inserted at least 50% with respect to the reference osculating surface that would limit the concavity if the projections and depressions and the sleeve are absent.

2. A prosthesis according to claim 1 wherein said inner surface of the cap includes at least twenty depressions distributed over the inner periphery of the cap which extend along planes extending through the longitudinal axis.

3. A prosthesis according to claim 2 wherein said inner surface of the cap further comprises grooves which extend at a right angle to said longitudinal axis.

4. A prosthesis according to claim 1 wherein said inner surface of the cap comprises at least one groove extending along a helix.

5. A prosthesis according to claim 1 wherein said inner surface includes a circular-cylindrical osculating surface having at least part of said depressions.

6. A prosthesis according to claim 5, wherein each of said depressions has a depth in the said inner surface at least 2.5 percent of the diameter of the circular-cylindrical osculating surface.

7. A prosthesis according to claim 5, wherein said inner surface includes a rounded transition area (3d) joining said cylindrical surface and tapering toward said axis (5) in the direction away from said free edge and wherein said projections and depressions extend over at least a part of said rounded transition area.

8. A prosthesis according to claim 1, wherein the said projections and depressions increase the inner cap surface by at least 100% with reference to said osculating surface.

9. A prosthesis according to claim 1, wherein the sum of the inner surface of the cap and the surfaces of said sleeve that can bear on a bone is at least 200% greater than said osculating surface.

10. A prosthesis according to claim 1 wherein the projections and depressions as well as transitions therebetween are, in a cross-section taken across said axis free of sharp corners.

11. A prosthesis according to claim 1 wherein a free end of said sleeve projects beyond said cavity by an amount(s) that is at most 50% of the total length(L) of an interior of said sleeve.

12. A prosthesis according to claim 1, wherein a free end of said sleeve projects beyond said cavity by an amount (s) that is at most 40% of a total length (L) of the interior of said sleeve.

13. A method of securing a prosthesis according to claim 1, to a joint head of a bone comprising:

cutting off an outer layer portion of the joint head to form a pivot having a shape substantially corresponding to the cap concavity and having a diameter slightly larger than a diameter of the reference osculating surface;

cutting a cylindrical slot into the pivot having a shape substantially similar to that of said sleeve; and

pressing the prosthesis onto the pivot with the cap concavity firmly receiving the pivot and the sleeve moving into the cylindrical slot.

14. A method according to claim 13, wherein the pivot and slot have dimensions so that, upon pressing the prosthesis onto and into the pivot and slot respectively, an immediate firm cement free mounting is established between bone of the pivot and slot and the prosthesis.