Intramedullary support strut

• US 6,755,862 B2
• Filed: 07/02/2002
• Issued: 06/29/2004
• Est. Priority Date: 01/03/2000
• Status: Expired due to Fees

• Current Assignee: Orthoscope, Ltd.
• Original Assignee: Orthoscope, Ltd.
• Inventors: Keynan, Ory
• Primary Examiner(s): Robert, Eduardo C.
• Assistant Examiner(s): COMSTOCK, DAVID C
• Application Number:
  US10/188,125
• Publication Number:
  US 20030109932A1
• Time in Patent Office: 728 Days
• Field of Search: 606/63, 606/64, 606/68, 606/89, 606/80, 606/94, 606/104, 606/105, 606/108, 606/170, 606/180, 606/192, 606/198, 623/16.11, 623/17.12, 623/19.14, 623/20.25, 623/20.35, 623/20.36, 623/22.4, 623/22-1-, 623/23.23, 623/23.26, 623/23.27, 623/23.32, 623/23.33, 623/23.45, 623/23.47, 411/82.1, 411/19, 411/32
• US Class Current: 623/16.11
• CPC Class Codes: A61B 17/72 Intramedullary pins, nails or other devices A61B17/744 takes precedence
• CPC Class Codes: A61B 17/7283 with special cross-section of the nail
• 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: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• 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 2/4014 Humeral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic humeral shafts
• CPC Class Codes: A61F 2/4081 Glenoid components, e.g. cups
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30205 conical
• CPC Class Codes: A61F 2002/30215 Stepped cones, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30233 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30408 : Conical threadings
• CPC Class Codes: A61F 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30601 : telescopic
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30738 : Sleeves
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• CPC Class Codes: A61F 2002/30828 : parallel
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/342 : the outer shell having circumferential protrusions parallel to the equatorial plane, e.g. circumferential fins or wings
• CPC Class Codes: A61F 2002/3652 : Connections of necks to shafts
• CPC Class Codes: A61F 2002/369 : Stepped shaft, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0067 : conical
• 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 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00059 : Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00353 : Bone cement, e.g. polymethylmethacrylate or PMMA

Abstract

An intramedullary support strut for a long bone for a range of different applications including anchoring and fixation. The strut is in the form of nested telescopic members. In the retracted configuration, the strut is compact and may be inserted into position aligned with a shaft made in the medullary canal via a portal made in the lateral cortex of the bone. The strut may then be telescopically extended into the medullary canal to provide the required support.

Claims

1. An intramedullary support strut for a long bone consisting of a plurality of elements, said plurality consisting of one terminal, a base member, and at least one extendable element;

the first of said extendable elements being telescopically supported in said base member;

the remaining extendable elements, if any, being telescopically connected to one another, whereby said support strut is extendable from a retracted configuration having a first longitudinal length to an extended configuration having a second longitudinal length;

said support strut being adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone and

being aligned with and extended into said longitudinal cavity.

2. An intramedullary support strut as claimed in claim 1, wherein said strut comprises a cap portion at the terminal end of the base member.

3. An intramedullary support strut as claimed in claim 1, wherein a first ratio of tKe diameter of said strut to said first length is between about 0.5 and about 2.0, and preferably about 1.25.

4. An intramedullary support strut as claimed in claim 1, wherein a second ratio of said second length to said first length is between about 2 and about 10, and preferably about 8.

5. An intramedullary support strut as claimed in claim 1, wherein said strut comprises between 3 and 10, and preferably 8 said telescopic members.

6. An intramedullary support strut as claimed in claim 1, wherein said telescopic members are adapted for sliding longitudinal displacement relative to each other from said retracted to said extended configuration.

7. An intramedullary support strut as claimed in claim 1, further comprising locking means for maintaining said strut in said extended configuration.

8. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises suitable stops between adjacent said telescopic members adapted to prevent relative movement therebetween when said strut is in said extended configuration.

9. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises an inflatable bag having an opening for receiving a suitable liquid, said bag adapted for maintaining said liquid at a suitable pressure.

10. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises at least one semi-rigid bar insertable within said strut when said strut is in said extended configuration.

11. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises a screw or nail for locking the said innermost telescopic member with respect to said long bone, when said strut is in said extended configuration.

12. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises suitable adhesive, including bone cement or biological glue, provided between said strut and said cavity when said strut is in said extended configuration.

13. An intramedullary support strut as claimed in claim 7, wherein said locking means comprises a suitable flowable polymer injected into said strut when said strut is in said extended configuration, said flowable polymer being adapted for setting and hardening in situ.

14. An intramedullary support strut as claimed in claim 13, wherein said flowable polymer is one of PMMA or Silastic.

15. An intramedullary support strut as claimed in claim 7, wherein each said telescopic member is formed as a frustro-conical unit, having the inside surfaces thereof screw-threaded and the distal parts of their outside surfaces threaded to engage with the inside surface of the externally-adjacent telescopic member, wherein to provide said locking means.

16. An intramedullary support strut as claimed in claim 1, wherein said strut is adapted for anchoring a hip or shoulder hemi/total arthroplasty prosthesis.

17. An intramedullary support strut as claimed in claim 1, wherein said strut is adapted for the intramedullary fixation of diaphyseal fractures of long bones.

18. An intramedullary support strut as claimed in claim 1, wherein said strut is adapted for the intramedullary fixation or anchoring of compression screw fixation system for isolated intertrochanteric and subtrochanteric fractures.

19. An intramedullary support strut as claimed in claim 1, wherein said strut is adapted for the intramedullary fixation or anchoring of compression screw fixation system for combined intertrochanteric/subcapital femoral fractures with subtrochanteric fractures.

20. An intramedullary support strut as claimed in claim 1, wherein said strut is adapted for the intramedullary fixation or anchoring of compression screw fixation system for subcapital or proximal humeral fractures not requiring arthroplasty.

21. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and wherein each said telescopic member comprises a substantially circular longitudinal cross-sectional profile.

22. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the meduilary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and wherein each said telescopic member comprises a substantially elliptical longitudinal cross-sectional profile.

23. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and wherein each said telescopic member comprises a substantially triangular longitudinal cross-sectional profile.

24. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and wherein each said telescopic member comprises a substantially rectangular longitudinal cross-sectional profile.

25. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and wherein each said telescopic member comprises a substantially polygonal longitudinal cross-sectional profile.

26. An intramedullary support strut for a long bone comprising at least two telescopic members adapted for longitudinal displacement relative to each other from a retracted configuration of said strut having a first longitudinal length to an extended configuration of said strut having a second longitudinal length, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone, and is characterized in that

said strut comprises in said retracted configuration a transverse profile adapted for enabling said strut to be inserted into said long bone via a suitable lateral portal formed through the lateral cortex of the long bone, such as to enable said strut to be aligned with and extended into said longitudinal cavity;

and

further comprising actuating means for extending said strut from said retracted configuration to said extended configuration.

27. An intramedullary support strut as claimed in claim 26, wherein said actuating means comprises a liquid injected under pressure into said strut via a suitable opening therein.

28. An intramedullary support strut as claimed in claim 27, further comprising an inflatable bag in said strut and in communication with said opening for receiving said liquid and for preventing leakage of liquid therefrom.

29. An intramedullary support strut as claimed in claim 26, wherein said actuating means comprises a feeding wire arrangement comprising a wire having a distal end attached to the distal end of said innermost telescopic member, and a wire feeder for feeding said wire distally with respect to said base member.

30. An intramedullary support strut as claimed in claim 29, wherein said feeding wire is disposed external to said strut.

31. An intramedullary support strut as claimed in claim 29, wherein said feeding wire is disposed internally in said strut, and wherein said wire feeder comprises a spool for feeding said wire to said strut, said spool being operatively connected to a motor means.

32. An intramedullary support strut as claimed in claim 26, wherein said actuating means comprises a suitable reamer having a suitable reamer head at one end thereof rotatably mounted with respect to an innermost telescopic member, wherein rotation of said reamer head and advancement thereof in a distal direction by suitable rotation means automatically opens the said strut.

33. An intramedullary support strut as claimed in claim 32, wherein said rotation means comprises a suitable power tool.

34. An intramedullary support strut as claimed in claim 33, wherein said reamer comprises a flexible reamer driveshaft removably connected to the said reamer head at one thereof, and to said power tool at the other end thereof.

35. An intramedullary support strut as claimed in claim 34, wherein a reaming diameter of said reamer head is at least equal to or greater than the diameter of said base member.

36. An intramedullary support strut as claimed in claim 26, wherein said actuating means comprises a suitable reamer having a suitable reamer head at one end thereof releasably rotatably engageable with respect to an innermost telescopic member, wherein rotation of said reamer head and advancement thereof in a distal direction by suitable rotation means automatically opens the said strut.

37. An intramedullary support strut as claimed in claim 36, wherein a reaming diameter of said reamer head is smaller than the diameter of said innermost telescopic member.

38. A method for the fixation of fractures of long bones, comprising the steps of:

a) providing a support strut comprising at least two telescopic members adapted for longitudinal displacement relative to each other, from a retracted configuration of said strut to an extended configuration of said strut, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone;

b) boring a portal through the lateral cortex of said long bone, such that a cross-sectional profile of said portal is substantially complementary to a transverse profile of said strut, in said retracted configuration;

c) forming said cavity by guiding a reamer into the medullary canal of said long bone;

d) introducing said strut in said retracted configuration into said portal; and

e) expanding said strut to said extended configuration, until distal and proximal parts of a fractured long bone are held together.

39. The method according to claim 38, wherein said support strut is locked in said extended configuration.

40. A method for anchoring a hip or shoulder hemi/total arthroplasty prosthesis, comprising the steps of:

a) providing a support strut comprising at least two telescopic members adapted for longitudinal displacement relative to each other, from a retracted configuration of said strut to an extended configuration of said strut, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of a long bone and for providing therein a mechanical support structure for said long bone;

b) boring a lateral portal on the proximal part of said long bone;

c) forming said cavity by guiding a reamer into the medullary canal of said long bone;

d) joining the outermost telescopic member to a body of a prosthesis;

e) introducing said strut in said retracted configuration into said portal; and

f) expanding said strut to said extended configuration, until said prosthesis is anchored.

41. A method for applying a compressive force between the head and neck of a long bone, in order to fixate a fracture, comprising the steps of:

a) providing a support strut comprising at least two telescopic members and a sleeve formed in the outermost member, said telescopic members adapted for longitudinal displacement relative to each other, from a retracted configuration of said strut to an extended configuration of said strut, wherein said strut is adapted in said extended configuration for accommodation in a longitudinal cavity formed in the medullary canal of said long bone and for providing therein a mechanical support structure for said long bone;

b) boring a portal through the lateral cortex of said long bone;

c) forming said cavity by guiding a reamer into the medullary canal of said long bone;

d) introducing said strut in said retracted configuration into said portal;

e) expanding said strut to said extended configuration, until said strut is anchored in said cavity;

f) introducing a screw or nail of a fracture fixation system into a proximal end of said sleeve, said screw or nail extending into the head and neck of said long bone; and

g) engaging a bolt into a complementary threaded shaft of the distal end of said sleeve, whereby a compressive force is applied to said screw or nail.

42. The method according to claim 41, wherein the fracture to be fixated is selected from the group consisting of isolated intertrochanteric and subtrochanteric fractures, combined intertrochanteric/subcapital femoral fractures with subtrochanteric fractures, subcapital/proximal humeral fractures, or the like.