Artifical joint system

• US 4,904,264 A
• Filed: 10/24/1985
• Issued: 02/27/1990
• Est. Priority Date: 05/08/1984
• Status: Expired due to Fees

• Current Assignee: Fried. Krupp Gesellschaft mit beschrankter Haftung
• Original Assignee: Fried Krupp GmbH (Thyssenkrupp AG)
• Inventors: Scheunemann, Rudiger
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): Isabella, David J.
• Application Number:
  US06/795,493
• Time in Patent Office: 1,587 Days
• Field of Search: 623/16-23, 128/924
• US Class Current: 623/23.57
• CPC Class Codes: A61B 17/742 having one or more longitudinal elements oriented along or parallel to the axis of the neck
• CPC Class Codes: A61B 17/744 the longitudinal elements coupled to an intramedullary nail
• CPC Class Codes: A61F 2/30 Joints
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3601 for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices non-prosthetic internal fixation devices for the femoral head or neck A61B17/74
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/3672 Intermediate parts of shafts
• CPC Class Codes: A61F 2/3676 Distal or diaphyseal parts of shafts
• CPC Class Codes: A61F 2/4607 of hip femoral endoprostheses
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30289 helically-coiled
• CPC Class Codes: A61F 2002/30291 spirally-coiled, i.e. having a 2D spiral cross-section
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30782 : inclined obliquely
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30886 : externally-threaded
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 : Necks
• CPC Class Codes: A61F 2002/365 : Connections of heads to necks
• CPC Class Codes: A61F 2002/3652 : Connections of necks to shafts
• CPC Class Codes: A61F 2002/368 : with lateral apertures, bores, holes or openings, e.g. for reducing the mass, for receiving fixation screws or for communicating with the inside of a hollow shaft
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• 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 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section

Abstract

The invention relates to an artificial joint system which, by a combination of defined pretension in the implant in the resection plane and a wholly or partially resorbable shaft or clamping system connects, after a transition period after implantation, the intermediate member of the implant with the remaining bone in the resection plane and the shaft required in the long bone during the transition period decomposes at the surface or the clamping system of the intermediate member deomposes to such an extent that unphysiological force transmission into the bone through the shaft of the implant or through the clamping system is no longer possible.

Claims

1. An artificial joint system for cement-free implantation into a bone provided with a resection plane and a bore for accommodating at least a portion of the artificial joint system, the artificial joint system comprising:

an implant comprised of an intermediate member having a contact face provided thereon, which contact face engages the resection plane of the bone when the artificial joint system is implanted therein, and having at least one pin positioned on and protruding from the contact face, which at least one pin has a threaded section; and

a clamping device comprised of a shaft having defined therein at least one threaded bore for receiving and threadedly engaging the at least one pin,

wherein the artificial joint system has a surface and is provided, along at least a portion of the surface thereof adjacent to the bone, with a transition structure, the transition structure comprising a matrix which is at least partially resorbable and a plurality of projecting members, which plurality of projecting members extend perpendicularly outwardly and away from said at least a portion of the surface of the artificial joint system adjacent to the bone, are one of flexible metallic wires and flexible fibers, are surrounded by and embedded in the matrix, have a shape which is one of a pin shape, a helical shape, and a wavy shape, and have a modulus of elasticity corresponding to the modulus of elasticity of the bone tissue which surrounds same when the artificial joint system is implanted.

2. The artificial joint system according to claim 1, wherein at least one of the shaft and the intermediate member has a core, which core is biocompatible and is made of one of a metallic material and a composite material, and wherein the plurality of projecting members are durably anchored to the core.

3. The artificial joint system according to claim 1, wherein the plurality of projecting members extend parallel to one another.

4. The artificial joint system according to claim 1, wherein each of the plurality of projecting members has a structure which permits each of the plurality of projecting members to exhibit a uniform tension and strength over its length.

5. The artificial joint system according to claim 1, wherein the plurality f projecting members are spaced apart from one another in an irregular pattern.

6. The artificial joint system according to claim 1, wherein the plurality of projecting members are spaced apart from one another and adjoining projecting members are separated by an interstice defined therebetween which is large enough to accommodate the growth of bone tissue therein.

7. The artificial joint system according to claim 6, wherein each said interstice is filled with said matrix selected from the group consisting of a material which is at least partially resorbable, a bioactive material, an osteogenesis-inducing material, and mixtures thereof.

8. The artificial joint system according to claim 1, wherein the plurality of projecting members have lengths which vary from one another.

9. The artificial joint system according to claim 1, wherein the plurality of projecting members have thicknesses which vary from one another.

10. The artificial joint system according to claim 1, wherein each of the plurality of projecting members has a wavy shape and the plurality of projecting members are arranged in an offset pattern with respect to one another.

11. The artificial joint system according to claim 1, wherein each of the plurality of projecting members has the form of a helix.

12. The artificial joint system according to claim 11, wherein each helix has a shape which is one of a cylindrical shape, a conical shape, and a parabolic shape, and a pitch which is at least equal to the thickness of each projecting member.

13. The artificial joint system according to claim 2, wherein the plurality of projecting members are flexible fibers, each flexible fiber being provided with an inner core which is fixedly attached to the core of said at least one of the shaft and the intermediate member, whereby shear forces are accommodated.

14. The artificial joint system according to claim 1, wherein each of the plurality of projecting members has a thickness of less than 800 μ

.

15. The artificial joint system according to claim 2, wherein the plurality of projecting members which are durably anchored to the core by one of an adhesive means, welding, and sintering.

16. The artificial joint system according to claim 1, wherein at least a portion of the surface of the shaft is provided with a material which is one of a bioactive material and an osteogenesis-inducing material, which material is at least partially resorbable.

17. The artificial joint system according to claim 1, wherein the shaft and the intermediate member are at least coated with a first and a second resorbable material, respectively, and wherein the first resorbable material resorbs at a slower rate than that of the second resorbable material.

18. The artificial joint system according to claim 1, wherein the intermediate member is provided with means to facilitate threaded engagement of the pin and the threaded bore of the shaft so as to produce a pretension.

19. The artificial joint system according to claim 1, wherein the shaft has a longitudinal axis and a central internal bore provided therein, which central internal bore extends along the longitudinal axis of the shaft.

20. The artificial joint system according to claim 19, wherein a plurality of perforations are provided in the shaft.

21. The artificial joint system according to claim 20, wherein the perforations are filled with a material selected from the group consisting of a resorbable material, a bioactive material, and osteogenesis-inducing material, and mixtures thereof.

22. The artificial joint system according to claim 1, wherein at least one of the clamping device and the intermediate member are made, at least in part, of a material which is at least one of a bioactive material and an osteogenesis-inducing material, said material being selected from the group consisting of an inorganic material, an organic material, and mixtures thereof.

23. The artificial joint system according to claim 22, wherein said material is selected from the group consisting of tricalcium phosphate, hydroxylapatite, bioglass, a mixture of bioglasses, and mixtures thereof.

24. The artificial joint system according to claim 1, wherein at least one of the clamping device and the intermediate member is coated at least partially with a material which is at least one of a bioative material and an osteogenesis-inducing material.

25. The artificial joint system according to claim 1, wherein the implant further comprises an artificial joint head and wherein the intermediate member is connected to the artificial joint head by one of a screw connection and a taper connection.

26. The artifcial joint system according to claim 1, wherein the intermediate member having said contact face provided thereon has a central bore, which central bore permits bone tissue along the resection plane to grow into the intermediate member.

27. The artificial joint system according to claim 1, wherein the bone has a region of spongy tissue at least proximate to the resection plane thereof and wherein a contact plate is applied to the contact face, the contact plate having a transition structure provided along the surface thereof which engages the resection plane of the bone, the transition structure projecting beyond the resection plane into the spongy tissue region of the bone when the implant is implanted.

28. The artificial joint system according to claim 1, wherein the intermediate member having said contact face provided thereon has a longitudinal axis which extends perpendicularly to the contact face, and wherein the intermediate member is radially symmetrical about the longitudinal axis.

29. A method for implanting an artificial joint system for cement-free implantation into a bone provided with a resection plane and a bore for accommodatnng at least a portion of the artificial joint system, the method comprising:

providing an artificial joint system including an implant comprised of an intemediate member having a contact face provided thereon, which contact face engages the resection plane of the bone when the artificial joint system is implanted therein, and having at least one pin positioned on and protruding from the contact face, which at least one pin has a threaded section; and

a clamping device comprised of one of a shaft and a plate, which one of a shaft and a plate is provided with at least one threaded bore for receiving and threadedly engaging the at least one pin, wherein the artificial joint system is provided, along at least a portion of the surface thereof adjacent to the bone, with a transition structure, the transition structure comprising a matrix which is at least partially resorbable and a plurality of projecting members which extend perpendicularly outwardly and away from said at least a portion of the surface of the artificial joint system adjacent to the bone, said projecting member are one of flexible metallic wires and flexible fibers, are surrounded by and are embedded in the matrix, have a shape which is one of a pin shape, a helical shape, and a wavy shape and have a modulus of elasticity corresponding to the modulus of elasticity of the bone tissue which surrounds same when the artificial joint system is implanted;

resting the contact face on the resection plane of the bone, which resection plane includes a bone cortex portion, so that the contact face rests medially on the cortex portion and engages same under pretension.

30. The method according to claim 29, further comprising

enclosing each of the plurality of projecting members with bone cells so as to connect same to one another with the bone cells, entirely free of connective tissue and without interruption.

31. An artificial joint system for cement-free implantation into a bone provided with a resection plane and a bore for accommodating at least a portion of the artificial joint system, the artificial joint system comprising:

an implant comprised of an intermediate member having a contact face provided thereon, which contact face engages the resection plane of the bone when the artificial joint system is implanted therein, and having at least one pin positioned on and protruding from the contact face, which at least one pin has a threaded section; and

a clamping device comprised of a plate having defined therein at least one threaded bore for receiving and threadedly engaging the at least one pin,

wherein the artificial joint system is provided, along at least a portion of the surface thereof adjacent to the bone, with a transition structure, the transition structure comprising a matrix which is at least partially resorbable and a plurality of projecting members, which plurality of projecting members extend perpendicularly outwardly and away from said at least a portion of the surface of the artificial joint system, are one of flexible metallic wires and flexible fibers, are surrounded by and embedded in the matrix, have a shape which is one of a pin shape, a helical shape, and a wavy shape, and have a modulus of elasticity corresponding to the modulus of elasticity of the bone tissue which surrounds same when the artificial joint system is implanted.