NZ547561A

NZ547561A - Intramedullary nail

Info

Publication number: NZ547561A
Application number: NZ547561A
Authority: NZ
Inventors: Andre Schlienger; Markus Buettler; Peter Senn
Original assignee: Synthes Gmbh
Priority date: 2003-12-19
Filing date: 2003-12-19
Publication date: 2009-09-25

Abstract

An intramedullary nail 1 having a proximal half 2, a distal half 3 suitable for being inserted into the medullary canal, and a central axis 4, the distal half 3 being provided with at least three transverse bores 5 6 7 suitable for receiving locking screws 10, whereby A) the distal half 3 is provided along the central axis 4 with at least a proximal transverse bore 5 having a bore axis 15, a central transverse bore 6 having a bore axis 16, and a distal transverse bore 7 having a bore axis 17, B) the bore axis 16 of the central transverse bore 6, which extends between the proximal transverse bore 5 and the distal transverse bore 7, is spaced at a shortest distance "a" from the bore axis 15 of the proximal transverse bore, C) the bore axis 16 of the central transverse bore 6, which extends between the proximal transverse bore 5 and the distal transverse bore 7, is spaced at a shortest distance "b" from the bore axis 17 of the distal transverse bore 7, and D) the condition a # b is applicable, and wherein E) the bore axis 15 16 17 of at least one of the N transverse bores 5 6 7 located in the distal half 3 is spaced at a distance YN > 0 from the central axis 4.

Description

547561 Intramedullary nail The invention relates to an intramedullary nail.

From FR 1,031,128 CARRIERI an intramedullary nail is known which has a plurality of transverse bores, particularly in its distal half. A disadvantage of this 5 known intramedullary nail is the fact that all of the transverse bores are spaced at the same distance from one another and that they are oriented in the same direction. Thus, a central transverse bore lying between two other transverse bores will function as a centre of rotation for the connection between a bone fragment and the intramedullary nail, which is undesirable.

It is an object of the invention to create an intramedullary nail with a plurality of distal locking bores that is capable, once the distal locking screws have been inserted, of stabilising the bone fragment held in place by said locking screws and of preventing it from tipping over relative to the nail axis, this being done in a more optimal manner than would be possible with the use of conventional intramedullary nails, or to at least provide the public with a useful alternative.

According to one aspect of the invention, there is provided an intramedullary nail having a proximal half, a distal half suitable for being inserted into the medullary canal, and a central axis, the distal half being provided with at least three transverse bores suitable for receiving locking screws, whereby A) the distal half is provided along the central axis with at least a proximal transverse bore having a bore axis, a central transverse bore having a bore axis, and a distal transverse bore having a bore axis; B) the bore axis of the central transverse bore, which extends between the proximal transverse bore and the distal transverse bore, is spaced at a shortest distance "a" from the bore axis of the proximal transverse bore; C) the bore axis of the central transverse bore, which extends between the proximal transverse bore and the distal transverse bore, is spaced at a shortest distance "b" from the bore axis of the distal transverse bore; and D) the condition a t b is applicable, wherein E) the bore axis of at least one of the N transverse bores located in the distal half is spaced at a distance yN > 0 from the central axis.

INTELLECTUAL PROPERTY OFFICE OF N.Z 2 0 AUG 2009 547561 ' 2 The advantages achieved by the invention reside essentially in the fact that the intramedullary nail of the invention with locking options provided in its distal half allows to significantly reduce the freedom of the bone fragment held in place by the locking screw to tip over with respect to the nail axis.

In one particular embodiment of the invention, the bore axis of at least one of INTELLECTUAL PROPERTY OFFICE OF N.Z. 2 0 AUG 2009 RECEIVED 547561 2 a, from the centra! axis, in particular, the bore axis of the central transverse bore may be spaced at a distance yi > 0 and the bore axis of the proximal transverse bore may be spaced at a distance y2 > 0 from the centra! axis (4). in another embodiment the distance "a" ts in the range of between 0.6 (a+b) 5 and 0.9 (a+b), and preferably in the range of between 0.7 (a+b) and 0.8 (a+b). The distance "b" may be in the range of between 0.6 (a+b) and 0.9 (a+b), and preferably in the range of between 0.7 (a+b) and 0.8 (a+b).

In a further embodiment, two or. more of the transverse bores (5, 6, 7) provided in the distal half (3) intersect one another at least partially. in a further embodiment, displaying a number N > 3 of transverse bores, the features A, B, C, D of claim 1 are true of any sub-combination of three transverse bores.

Typically, the sum L = (a+b) is in the range of between 20 mm and 35 mm, preferably in the range of between 24 mm and 30 mm.

In the following, the invention and improvements of the invention wiil be illustrated in greater detail with referecne to the partially diagrammatic representations of several embodiments.

In the drawings: Fig. 1 is a perspective view of the intramedullary nail; 2 0 Fig. 2 is a side view of the intramedullary nail of Fig. 1; Fig. 3 is a side view of the intramedullary nail of Fig. 2 rotated by 90° with respect to Fig. 1; Fig. 4 is a perspective view of a modified intramedullary naii; Fig. 5 is a side view of the intramedullary nail of Fig. 4; and Followed by page 3 547561 3 Fig. 6 is a side view of the intramedullary nail of Fig. 5 rotated by 90° with respect to Fig. 4.

The first embodiment of ari intramedullary nail 1 as shown in Figs. 1-3 has a proximal half, a distal haif 3 suitable to be inserted into the medullary canal, and 5 a central axis 4. in addition, the intramedullary nail 1 is provided with a cannulation 8 extending over its entire length. The distal half 3 is provided with three transverse bores 5, 6, 7, for the reception of locking screws 10. The proximal transverse bore 5 has a bore axis 15, the central transverse bore 6 a bore axis 16, and the distal transverse bore 7 a bore axis .17. The bore axis 16 10 of the central transverse bore 6, which extends between the proximal transverse bore 5 and the distal transverse bore 7, is spaced at a shortest distance "a" = 16 mm from the bore axis 15 of the proximal transverse bore 5, and at a shortest distance "b" =11 mm from the bore axis 17 of the transverse bore 7. in addition, the condition a ^ b is applicable. The sum L = (a+b) is 27 15 mm. The diameter of the intramedullary nail 1 is D = 10 mm.

The second embodiment of an intramedullary nail 1 as shown in Figs. 4 - 6 has essentially the same features as the first embodiment, but is provided with the following additional or divergent parameters: The bore axis 15 of the transverse bore 5 is spaced at a distance yi = 0.5 mm 20 from the central axis 4. .The bore axis 16 of the transverse bore 6 is equally spaced at a distance y2 = 0.5 mm from the central axis 4, but on the opposite side thereof.

Claims

547561 What we claim is:

1. An intramedullary nail having a proximal half, a distal half suitable for being inserted into the medullary canal, and a central axis, the distal half being provided with at least three transverse bores suitable for receiving locking screws, whereby A) the distal half is provided along the central axis with at least a proximal transverse bore having a bore axis, a central transverse bore having a bore axis, and a distal transverse bore having a bore axis; B) the bore axis of the central transverse bore, which extends between the proximal transverse bore and the distal transverse bore, is spaced at a shortest distance "a" from the bore axis of the proximal transverse bore; C) the bore axis of the central transverse bore, which extends between the proximal transverse bore and the distal transverse bore, is spaced at a shortest distance "b" from the bore axis of the distal transverse bore; and D) the condition a ^ b is applicable, and wherein E) the bore axis of at least one of the N transverse bores located in the distal half is spaced at a distance yN > 0 from the central axis.

2. The intramedullary nail as claimed in claim 1, wherein the bore axis of the central transverse bore is spaced at a distance yi > 0 from the central axis.

3. The intramedullary nail as claimed in claim 1 or 2, wherein the bore axis of the proximal transverse bore is spaced at a distance y2 > 0 from the centra! axis.

4. The intramedullary nail as claimed in any one of the claims 1 to 3, wherein "a" is in the range of between 0.6 (a+b) and 0.9 (a+b).

5. The intramedullary nail as claimed in claim 4, wherein "a" is in the range of between 0.7 (a+b) and 0.8 (a+b).

6. The intramedullary nail as claimed in any one of the claims 1 to 3, wherein "b" is in the range of between 0.6 (a+b) and 0.9 (a+b). INTELLECTUAL PROPERTY OFFICE OF N.Z. 2 0 AUG 2009 RECEIVED 547561 r 5

7. The intramedullary nail as claimed in claim 6, wherein "b" is in the range of between 0.7 (a+b) and 0.8 (a+b).

8. The intramedullary nail as claimed in any one of the claims 1 to 6, wherein two or more of the transverse bores provided in the distal half intersect one another at least partially.

9. The intramedullary nail as claimed in any one of the claims 1 to 8, wherein with nails displaying a number N > 3 of transverse bores, the features A, B, C, D of claim 1 are true of any sub-combination of three transverse bores.

10. The intramedullary nail as claimed in any one of the claims 1 to 9, wherein the sum L = (a+b) is in the range of between 20 mm and 35 mm.

11. The intramedullary nail as claimed in claim 10, wherein the sum L = (a+b) is in the range of between 24 mm and 30 mm.

12. The intramedullary nail as claimed in any one of the claims 1 to 11, wherein the nail is provided with a cannulation extending coaxially to the central axis over its entire length.

13. An intramedullary nail substantially as herein described with reference to Figures 1 to 6.

14. An intramedullary nail as claimed in any one of claims 1 to 12 and substantially as herein described with reference to Figures 1 to 6. INTELLECTUAL PROPERTY OFFICE OF N.Z. 2 0 AUG 2009 RECEIVED