Joint prosthesis and device for making a drilling in at least one joint head

• US 5,800,557 A
• Filed: 01/06/1997
• Issued: 09/01/1998
• Est. Priority Date: 05/02/1994
• Status: Expired due to Fees

• Current Assignee: Laghaollah Elhami
• Original Assignee: Laghaollah Elhami
• Inventors: Elhami, Laghaollah
• Primary Examiner(s): Willse, David H.
• Application Number:
  US08/732,347
• Time in Patent Office: 603 Days
• Field of Search: 623/22, 623/23, 623/19, 606/67, 606/66, 606/65
• US Class Current: 623/23.12
• CPC Class Codes: A61B 17/1753 for fixing pins through femoral hip prostheses
• CPC Class Codes: A61B 17/746 the longitudinal elements coupled to a plate opposite the femoral head
• CPC Class Codes: A61B 17/748 with means for adapting the angle between the longitudinal elements and the shaft axis of the femur
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• 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 2002/30113 circular
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30289 helically-coiled
• 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 2002/30364 Rotation about the common longitudinal axis
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3052 unrestrained in only one direction, e.g. moving unidirectionally
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30566 Helical springs
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30672 : temporary
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30795 : Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• 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 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/30919 : Sleeves
• 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 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 2230/0006 : circular
• 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 a joint prosthesis with a cap having a supporting surface, a telescopic arrangement having a telescopic component on a cap side and a telescopic component on a holder side and connected to a holder for securing to a bone surface, wherein the supporting surface is formed by an inner surface of the cap which is at least approximately shaped to fit the bone head. A restricting device acts dependently upon the direction so as to allow the cap to be moved in relation to the holder in a direction away from the socket and to prevent or at least hamper movement towards the socket. Also disclosed is a surgical device for making a drilling with a bush to accept an instrument and a system connected to the bush to accept the joint head at least partially; the median longitudinal axis of the bush is brought into relation with the periphery of the joint head in order to facilitate the positioning of the device in relation to the bone system.

Claims

1. A joint prosthesis for a joint head of a joint, which head cooperates with a joint cavity, said prosthesis comprising:

a cap having a contact surface adapted to abut the joint head, and having an outer surface which is at least approximately shaped as a spherical cap;

a telescopic arrangement having a first telescopic member linked with the cap and projecting from the cap, and a second telescopic member which is in telescopic engagement with said first telescopic member, said telescopic arrangement being sized and arranged so as to pass through a drilling in the joint head and bone regions adjacent thereto when in an implanted state, and

a supporting member attached to said second telescopic member and designed for fixation to a bone surface of a bone located opposite to the joint head,

wherein the first telescopic member is guided for sliding movement in relation to the second telescopic member in a direction away from the joint cavity,

wherein said contact surface is defined by an internal surface of the cap, which internal surface is at least approximately adapted to the shape of the joint head, and wherein said prosthesis comprises restraining means the operation of which is dependent on the direction of the forces acting thereon so as to permit changes in position of the cap with respect to the supporting member in the direction away from the joint cavity, and to at least impede changes in position of the cap with respect to the supporting member in the direction towards the joint cavity in comparison with the changes of position in the direction away of the joint cavity.

2. The joint prosthesis of claim 1, wherein said restraining means is designed to prevent changes in position of the cap with respect to the supporting member in the direction towards the joint cavity.

3. The joint prosthesis of claim 1, wherein said telescopic arrangement is designed so that the joint prosthesis, in its implanted state, at least partly permits biomechanical movements of the joint head and joint neck relative to the bone carrying the joint head and joint neck.

4. The joint prosthesis of claim 3, wherein said telescopic arrangement has a flexibility permitting biomechanical movements of the joint head and joint neck relative to the bone carrying the joint head and joint neck.

5. The joint prosthesis of claim 1, wherein the internal surface of the cap is at least approximately shaped like a spherical cap.

6. The joint prosthesis of claim 1, wherein said supporting member is comprised of a supporting plate which is attached to the end of the second telescopic member remote from the cap.

7. The joint prosthesis of claim 1, wherein said second telescopic member is pivotally connected to said supporting member.

8. The joint prosthesis of claim 7, wherein said second telescopic member is connected to said supporting member by means of a hinge having a hinge axis which is substantially perpendicular to the longitudinal extension of said telescopic arrangement and substantially perpendicular to the longitudinal extension of the supporting member.

9. The joint prosthesis of claim 8, wherein said hinge is designed for being sunk in said drilling.

10. The joint prosthesis of claim 7, wherein said second telescopic member is connected to said supporting member by means of a hinge having a hinge axis which is substantially perpendicular to the longitudinal extension of said telescopic arrangement and substantially parallel to the longitudinal extension of the supporting member.

11. The joint prosthesis of claim 7, wherein said second telescopic member is elastically spring-supported on the supporting member.

12. The joint prosthesis of claim 7, further comprising locking means for selectively stiffening the pivotal connection between the second telescopic member and the supporting member.

13. The joint prosthesis of claim 12, wherein said second telescopic member is elastically spring-supported on the supporting member;

and

wherein the spring-elastic support means of the second telescopic member comprises a leaf spring leaning against the second telescopic member and the supporting member, and wherein the locking means is comprised of an angled plate, which is interchangeable with said leaf spring.

14. The joint prosthesis of claim 1, wherein said telescopic arrangement is equipped with at least one flexible member at least partially permitting biomechanical movements of the joint head.

15. The joint prosthesis of claim 14, wherein said flexible member is placed in a distance from the internal surface of the cap corresponding to about one to three times an inner diameter of the cap.

16. The joint prosthesis of claim 14, wherein said flexible member is designed to prevent twisting motion.

17. The joint prosthesis of claim 14, wherein said flexible member is selected from the group comprising a spring adapted to prevent torsion, a flexible shaft, a wire mesh shaft, a spring joint and a flexible insert.

18. The joint prosthesis of claim 14, wherein said flexible member is integrally connected with said first telescopic member.

19. The joint prosthesis of claim 1, wherein at least one of said telescopic members is made of at least two parts disposed substantially one behind the other in the longitudinal direction of the telescopic arrangement, said parts being mutually engaged in a manner preventing twisting motion and being adapted to be secured against spontaneous releasing.

20. The joint prosthesis of claim 1, wherein said restraining means comprises automatic, direction-dependent coupling means.

21. The joint prosthesis of claim 1, wherein said restraining means is selected from the group consisting of snap-in locking means, detent means and spring-loaded restraining means.

22. The joint prosthesis of claim 21, wherein said restraining means has at least one outstanding protrusion on one of said telescopic members, said protrusion being disposed so as to lockingly engage a contacting surface on the other one of said telescopic members when said first telescopic member is attempted to be displaced relative to said second telescopic member in the direction towards the joint cavity, but to allow displacement of said first telescopic member relative to said second telescopic member in the direction away from the joint cavity.

23. The joint prosthesis of claim 22, wherein said protrusion consists of at least one spring member one end of which is in fixed connection with said one telescopic member and the other end of which is free to move and is biased in radial direction.

24. The joint prosthesis of claim 22, and comprising a ring adapted to be pulled over said protrusion for at first holding back the protrusion and for automatically releasing the protrusion upon said telescopic members having been inserted into each other.

25. The joint prosthesis of claim 22, wherein said contacting surface comprises a plurality of saw-tooth shaped recesses.

26. The joint prosthesis of claim 22, wherein said contacting surface is defined by a coating into which said protrusion is adapted to dig itself.

27. The joint prosthesis of claim 1, and comprising spring biasing means for biasing said first telescopic member in the direction away from the joint cavity.

28. The joint prosthesis of claim 27, wherein said spring biasing means comprises at least one tractive spring one end of which is attached to said first telescopic member and the other end of which is attached to one of said second telescopic member and said supporting member.

29. The joint prosthesis of claim 27, wherein said spring biasing means also defines said restraining means.

30. The joint prosthesis of claim 27, wherein one of said telescopic members is a male member having an external shoulder, and the other of said telescopic members is a female member having an internal shoulder, and wherein a biasing spring is disposed between said shoulders.

31. The joint prosthesis of claim 30, wherein said male telescopic member comprises a pair of detachably interconnected coaxial parts one of which is attached to the cap and the other of which is provided with said external shoulder.

32. The joint prosthesis of claim 1, further comprising means for disabling said restraining means when disassembling the prosthesis.

33. The joint prosthesis of claim 30, wherein said first telescopic member substantially centrically projects from the internal surface of the cap.

34. The joint prosthesis of claim 1, further comprising anti-twist means for preventing rotary motion of the cap relative to the joint head.

35. The joint prosthesis of claim 34, wherein said telescopic members are interconnected in a manner preventing relative twisting of said telescopic members.

36. The joint prosthesis of claim 35, wherein said telescopic members are profiled to provide for twist-proof mutual interconnection of said telescopic members.

37. The joint prosthesis of claim 34, wherein said first telescopic member is placed eccentrically in a predetermined distance from a central axis of the cap.

38. The joint prosthesis of claim 1, further comprising a sleeve adapted to be inserted into said drilling, said sleeve embracing said telescopic arrangement along at least a portion of its longitudinal dimension, when said prosthesis is in an implanted state.

39. The joint prosthesis of claim 1, wherein the telescopic arrangement has a circular outer perimeter at least for a length thereof extending through the cap.

40. The joint prosthesis of claim 1, wherein the cap has a rim which is shaped and disposed to at least prevailingly lie within a plane inclined with respect to a longitudinal axis of the prosthesis at such an angle, that the cap, when implanted, is adapted to overlap the joint head at least approximately evenly.

41. The joint prosthesis of claim 1, wherein the cap is equipped with recesses.

42. The joint prosthesis of claim 1, further comprising at least one insert adapted to be inserted into the cap as an internal part thereof, said insert having an inner surface defining a contact surface which is at least approximately adapted to the shape of the joint head, and said insert being adapted to be selected from a group of inserts differing in at least one of wall thickness and shape.

43. The joint prosthesis of claim 42, wherein said insert has an opening for receiving said first telescopic member.

44. The joint prosthesis of claim 1, wherein said cap includes an upper cap portion which is rotatably mounted on a lower cap portion.

45. The joint prosthesis of claim 1, wherein said cap includes a flattened pole.

53. The joint prosthesis of claim 1, wherein the prosthesis is a hip joint prosthesis for a femoral head which cooperates with an acetabulum.

46. A joint prosthesis for a joint head of a joint, which head cooperates with an joint cavity, said prosthesis comprising:

a cap having a contact surface adapted to abut the joint head, and having an outer surface which is at least approximately shaped as a spherical cap, said contact surface being defined by an internal surface of the cap, which internal surface is at least approximately adapted to the shape of the joint head;

at least one supporting member designed for fixation to a bone surface of a bone located opposite to the joint head; and

at least one restraining means for impeding relative movement between the cap and the supporting member in the direction towards the joint cavity in comparison with relative movement in the direction away of the joint cavity, said restraining means having at least one elastic traction member arranged so as to pass through a drilling in the joint head and bone regions adjacent thereto when in an implanted state, said traction member having one end thereof attached to the cap and having the other end thereof connected to the supporting member, and said traction member biasing the cap in the direction away from the joint cavity.

47. The joint prosthesis of claim 46, wherein said traction member is a spring member.

48. The joint prosthesis of claim 46, wherein at least one stem projects from the inner surface of the cap, and wherein said traction member engages the end of the stem averted from the inner surface of the cap.

49. The joint prosthesis of claim 48, further comprising a sleeve adapted to be inserted into said drilling, said sleeve embracing at least one of said traction member and said stem along at least a portion of their longitudinal dimensions, when said prosthesis is in an implanted state.

50. The joint prosthesis of claim 48, further comprising a sleeve adapted to be inserted into said drilling, said sleeve embracing at least one of said traction member and said stem along at least a portion of their longitudinal dimensions, when said prosthesis is in an implanted state;

and

wherein said insert and said sleeve are firmly interconnected.

51. The joint prosthesis of claim 46, further comprising at least one insert adapted to be inserted into the cap as an internal part thereof, said insert having an inner surface defining a contact surface which is at least approximately adapted to be selected from a group of inserts differing in at least one of wall thickness and shape.

52. The joint prosthesis of claim 46, wherein the prosthesis is a hip joint prosthesis for a femoral head which cooperates with an acetabulum.