WO1992012683A1

WO1992012683A1 - Single-use locking fastener device and bone support device

Info

Publication number: WO1992012683A1
Application number: PCT/EP1992/000050
Authority: WO
Inventors: Guido Danieli
Original assignee: Confida S.A.S.
Priority date: 1991-01-15
Filing date: 1992-01-13
Publication date: 1992-08-06

Abstract

The present invention relates to a single-use locking fastener device suitable to be interposed between two elements (19, 20) of a hinge of a bone support device (13) for supporting bone fragments. The device has a first part (18) formed by a material softer than the material of the two elements (19, 20) of the hinge, so that it is deformable upon fastening the hinge for improving the locking ability of the hinge. The first part (18) comprises a central hole (22) for housing a bolt (21) which fastens the hinge. The present invention also relates to a bone support device (13) for supporting fragments of bone, in particular of fractured bones of the human body. The invention achieves a high stability locking for the hinges of the bone support device.

Description

SINGLE-USE LOCKING FASTENER DEVICE AND BONE SUPPORT DEVICE

The present invention relates to a single-use locking fastener device suitable to be interposed between two elements of a hinge of a bone support device for supporting bone fragments. The present invention also relates to a bone support device comprising the single-use locking fastener device.

The invention is suitable for supporting fragments of bone, in particular of fractured bones of the human body. Said fractured bones must be kept in a selected relative position, so as to allow the natural process of healing of the bone fragments in the best possible manner.

More in particular, the device comprises a first member adapted to be rigidly connected to the first of said bone fragments and a second member adapted to be rigidly connected to the second of said bone fragments. More in particular, the rigid couplings are provided by means of threaded means which penetrate in adapted holes provided in the bone fragments. The device furthermore comprises an adjustable articulated central body which is connected to the first member and to the second member. The articulated central body allows to adjust the relative position of the first member with respect to the second member and to rigidly lock this relative position in an indifferent position and particularly at a point which is particularly suitable to obtain the perfect healing of the bone fragments. For indifferent position it is meant a position which can be chosen with continuity among all possible positions. In particular, the relative arrangement of the two fractured bone fragments and therefore the corresponding relative arrangement of the first and second members are performed by a surgeon, who can control the position of the two bone fragments by virtue of detection means such as for example X-rays. Since said detection means allow to detect the position of the two bone fragments on a single plane, at least two different detections, taken along two different planes of exposure to radiation, are required, so as to verify that the position of the two bone fragments is correct in the three spatial dimensions. Said two detections can be performed on two planes which are inclined at 90° with respect to one another.

The above is in summary the main field of industrial application of the invention; said field, however, does not constitute a limitation of the scope thereof, since the device according to the invention, in particular as described and claimed hereinafter, can be advantageously used in any other equivalent field in which fractured bone fragments must be knitted, keeping them in a selected indifferent relative position.

It is known from PCT patent application N° WO 90/07305, a bone support device in which four hinges are used for adjusting the relative position of the first member with respect to the second member and to lock this relative position in an indifferent position.

However this known device entails some problems since the four hinges may slide for the high stresses caused for example by the movements for walking on a fractured leg. In fact, according to this known device, the locking effect of the fastened hinges is entrusted to friction only.

The present invention provides, in a first aspect, a single-use locking fastener device suitable to be interposed between two elements of a hinge of a bone support device for supporting bone fragments, said bone support device being of the type comprising a first member adapted to be rigidly connected to the first of said bone fragments, a second member adapted to be rigidly connected to the second of said bone fragments, and an adjustable articulated central body connected to said first member and to said second member, said articulated central body allowing to adjust the position of said first member with respect to said second member in an indifferent position and to rigidly lock said indifferent position; said locking fastener device having a first part formed by a material softer than the material of said two elements of said hinge, so that it is deformable upon fastening said hinge for improving the locking ability of said hinge; said first part comprising: a central hole for housing a threaded means which fasten said hinge, a flat side lying on a plane which is perpendicular to the axis of said hole, said flat side being suitable to be engaged by a first complementary seat arranged on the first element of said hinge.

The deformation upon fastening of said flat side of said first part gives rise to an important advantage i.e. the locking effect of the fastened hinge is no more entrusted to friction, but is entrusted to the shear strength of the material which forms said first part.

Furthermore the bone support device can be used many times , simply changing the first part each time.

Preferably said first part comprises: an opposite side which is flat and which lies on a plane which is perpendicular to the axis of said hole, said flat side being suitable to be engaged by a second complementary seat arranged on the second element of said hinge; the surfaces of said first complementary seat and of said second complementary seat being corrugated or rough.

This embodiment is particularly suitable if both the first element and the second element of the hinge are formed of a hard material. In fact in this case said corrugated or rough surfaces deform said first part in a complementary way. For the purposes of this invention, for hard material it is meant for example steel or an alloy based on steel.

Preferably said first part comprises: an opposite side whose edge has such a shape as to fit tightly into a second complementary seat arranged on the second element of said hinge and suitable to prevent rotation between said first part and said second element of said hinge; the surface of said first complementary seat being corrugated or rough.

This embodiment is particularly suitable if said first element of the hinge is formed of a hard material, and if said second element of said hinge is formed of a material softer than the material of said first element and harder than the material of said first part. In fact in this case: (a) said corrugated or rough surfaces of said first complementary seat deform said first part in a complementary way, giving rise to a strong coupling hard/soft material

(b) the particular shape of said edge of said opposite side of said first part is sligtly deformed fitting into said second complementary seat, giving rise to a strong coupling semi-hard/soft material.

For the purposes of this invention by soft material it is meant for example copper or annealed copper and by semi- hard material it is meant for example aluminium or an alloy based on aluminium.

The use of different materials for the first element and for the second element is useful for example for reasons of weight. In fact, if the second element must be substantially bigger than the first element, it will be extremely important to reduce its weight using for example a light alloy.

Preferably said first complementary seat is formed by a second part comprising: a central hole for housing said threaded means which fasten said hinge, a first side supporting said first complementary seat, and lying on a plane which is perpendicular to the axis of said hole; and an opposite side whose edge has such a shape as to fit tightly into a third complementary seat arranged on the first element of said hinge and suitable to prevent rotation between said second part and said first element of said hinge; said first part being formed by a material softer than the material of said second part.

This embodiment is particularly suitable if both said first element and said second element of the hinge are formed of a semi-hard material, if said first part is formed of a soft material, and if said second part is formed of a hard material. In fact in this case:

(a) said corrugated or rough surfaces of said first complementary seat deform said first part in a complementary way, giving rise to a hard/soft material strong coupling

(b) the particular shape of said edge of said opposite side of said first part is sligtly deformed fitting into said second complementary seat, giving rise to a semi-hard/soft material strong coupling,

(c) the particular shape of said edge of said opposite side of said second part is sligtly deformed fitting into said first element of said hinge, giving rise to a semi- hard/hard material strong coupling.

The use of semi-hard material both for the first element and for the second element is useful to further reduce the weight.

Preferably said firs.t part comprises: an opposite side whose edge has such a shape as to fit tightly into a second complementary seat arranged on the second element of said hinge and suitable to prevent rotation between said first part and said second element of said hinge, a layer of adhesive on said flat side; said first complementary seat being formed by a second part comprising: a central hole for housing a threaded means which fasten said hinge, a side supporting said first complementary seat, lying on a plane which is perpendicular to the axis of said hole, and being covered with a layer of adhesive; and an opposite side whose edge has such a shape as to fit tightly into a third complementary seat arranged on said first element of said hinge and suitable to prevent rotation between said second part and said first element of said hinge.

This embodiment is particularly suitable if both said first element and said second element of the hinge are formed of a semi-hard material, if said first part is formed of a soft material, and if said second part is formed of a soft material. In fact in this case:

(a) said surface of said first complementary seat makes an adhesive bond with said first part in a complementary way, giving rise to a strong coupling base for example on an epoxy resin,

(b) the particular shape of said edge of said opposite side of said first part is sligtly deformed fitting into said second complementary seat, giving rise to a semi-hard/soft material strong coupling.

(c) the particular shape of said edge of said opposite side of said second part is sligtly deformed fitting into said first element of said hinge, giving rise to a semi-hard/hard material strong coupling.

The use of semi-hard material both for the first element and for the second element is useful to further reduct the weight.

Preferably a centre of a curvature of a substantial part of said edge of said opposite part is substantially far from the centre of said hole. This embodiment is particularly useful for obtaining a semi-hard/soft material strong coupling.

Preferably said edge of said opposite part comprises at least one rectilinear part and more preferably two parallel rectilinear parts. This embodiment achieves the strongest semi-hard/soft material coupling.

The present invention relates, for a second aspect, to a bone support device which comprises a single-use locking fastener device as claimed. For a complete description of the general construction, working and advantages of the bone support device, reference is made to PCT patent application N° WO 90/07305.

Further characteristics and advantages of the invention will become apparent from the description of two preferred but not exclusive embodiments of the device, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a perspective view of the bone support device according to the invention; figure 2 is a different perspective view of an enlarged detail of figure 1; figure 3 is a sectional view of an enlarged detail of figure 1 according to a second embodiment of the invention; figure 4 is a sectional view of an enlarged detail of figure 1 according to a first embodiment of the invention; figure 5 is a sectional view of an enlarged detail of figure 1 according to a second embodiment of the invention; figure 6 is a sectional view of an enlarged detail of figure 1 according to a third embodiment of the invention; figure 7 is a sectional view of an enlarged detail of figure 1 according to a fourth embodiment of the invention;

With reference to figures 1 to 7 , the bone support device according to the invention comprises a first member 10 adapted to be connected to the first bone fragment. In particular, the rigid coupling between the first member 10 and the bone fragment is provided by means of screws (not shown) which are engaged by adapted holes 11 provided on the first member 10 and on the second member 12.

The articulated central body 13 connects the first member 10 to the second member 12 and comprises distinct articulation means 14, 15, 16 and 17, to allow the rotation of the first member 10 with respect to the second member

12 on two distinct and perpendicular articulation planes.

The locking fastener device according to the invention has a first part 18 which is formed by annealed copper which is softer than the material both of the first element 19 of the hinges 14, 15, 16 and 17 and of the second element 20 of the hinges 14, 15_έ 16 and 17.

The deformation of the first part 18 upon fastening is simply caused by bolt 21 which can be easily fastened. The first part 18 has a central hole 22 which has a diameter suitable for housing the bolt 21. A flat side 23 of the first part 18 lies on a plane which is perpendicular to the axis of said hole 22, said flat side 23 is engaged by a first complementary seat 24 arranged on the first element 19 of the hinges 14, 15, 16 and 17.

With particular reference to figures 1, and 4, and according to the first embodiment of the invention, said first part 18 is made of annealed copper, said first element 19 and said second element 20 are made of stainless steel. An opposite side 9 of said first part 18 is flat and lies on a plane which is perpendicular to the axis of said hole 22, said flat side 9 is engaged by a second complementary seat 25 arranged on the second element 20 of the hinges 14, 15, 16 and 17. The surfaces of the first complementary seat 24 and of the second complementary seat 25 have a deep reeding so that during fastening the reedings penetrate respectively into said flat surface 23 and into said flat surface 26.

With particular reference to figures 1, 2, 3 and 5, and according to the second embodiment of the invention said first part 18 is made of annealed copper, said first element

19 is made of stainless steel and said second element 20 is made of a light alloy. An opposite side 26 of said first part 18 has an edge 27 which projects to said second element

20 and which has such a shape as to fit tightly into a second complementary seat 28 arranged on the second element

20 of said hinges 14, 15, 16 and 17. This arrangement prevents rotation between said first part 18 and said second element 20 of said hinge. The surface of said first complementary seat 24 has a deep reeding so that during fastening the reeding penetrates into said flat surface 23.

With particular reference to figures 1 and 7, and according to the fourth embodiment of the invention said first part 18 is made of annealed copper, said first element 19 and said second element 20 are made of a light alloy, and said second part 29 is made of stainless steel. An opposite side 26 of said first part 18 has an edge 27 which projects to said second element 20 and which has such a shape as to fit tightly into a second complementary seat 28 arranged on the second element 20 of said hinges 14, 15, 16 and 17. This arrangement prevents rotation between said first part 18 and said second element 20 of said hinge. The surface of said first complementary seat 31 has a deep reeding so that during fastening the reeding penetrates into said flat surface 23. Said first complementary seat 31 is formed by a second part 29. The second part 29 comprises a central hole 30 for housing said bolt 21 which fastens said hinge. The second part 29 comprises a first side 31 which supports said first complementary seat 31, and which lies on a plane which is perpendicular to the axis of said hole 30. The second part 29 also comprises an opposite side 32 whose edge 33 has such a shape as to fit tightly into a third complementary seat 34 arranged on the first element 19 of said hinges 14, 15, 16 and 17, so as to prevent rotation between said second part 29 and said first element 19 of said hinges 14, 15, 16 and 17. With particular reference to figures 1 and 6, and according to the third embodiment of the invention, said first element 19 and said second element 20 are made of a light alloy, said first part 18 and said second part 36 are made of annealed copper. An opposite side 26 of said first part 18 has an edge 27 which projects to said second element 20 and which has such a shape as to fit tightly into a second complementary seat 28 arranged on the second element 20 of said hinges 14, 15, 16 and 17. This arrangement prevents rotation between said first part 18 and said second element 20 of said hinge. The flat side 23 of said first part 18 is covered with a first component of an epoxy adhesive. The surface of the first complementary seat 35 is covered with a second component of an epoxy adhesive. Said first complementary seat 35 is formed by a second part 36. The second part 36 comprises a central hole 37 for housing said bolt 21 which fastens said hinges 14, 15, 16 and 17. The second part 36 comprises a first side 35 which supports said first complementary seat 35, and which lies on a plane which is perpendicular to the axis of said hole 37. The second part 36 also comprises an opposite side 38 whose edge 39 has such a shape as to fit tightly into a third complementary seat 40 arranged on the first element 19 of said hinges 14, 15, 16 and 17, so as to prevent rotation between said second part 36 and said first element 19 of said hinges 14, 15, 16 and 17. Upon fastening said hinges, the first and the second component of the epoxy adhesive are spread and mixed together so that the first part 18 and the second part 36 are firmly fixed together.

Alternatively it is possible to use a single layer of adhesive either on surface 23 or on surface 35. In this case the adhesive contains micro-capsules of an hardener which break upon fastening, releasing the hardener into the adhesive mass.

With particular reference to figure 2, and according to all the embodiments of the invention the edge 27, 33, 39 comprises two parallel rectilinear parts 41.

The device according to the invention may have numerous modifications and variations, all within the inventive concept; particularly the materials may be changed furthermore, all the details may be substituted with technically equivalent elements.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

1. A single-use locking fastener device suitable to be interposed between two elements (19, 20) of a hinge (14, 15, 16, 17) of a bone support device (13) for supporting bone fragments, said bone support device (13) being of the type comprising a first member (10) adapted to be rigidly connected to the first of said bone fragments, a second member (12) adapted to be rigidly connected to the second of said bone fragments, and an adjustable articulated central body (14, 15, 16, 17) connected to said first member (10) and to said second member (12) , said articulated central body allowing to adjust the position of said first member (10) with respect to said second member (12) in an indifferent position and to lock said indifferent position; said locking fastener device having a first part (18) formed by a material softer than the material of said two elements (19,20) of said hinge, so that it is deformable upon fastening said hinge for improving the locking ability of said hinge; said first part (18) comprising: a central hole (22) for housing a threaded means (21) which fasten said hinge, a flat side (23) lying on a plane which is perpendicular to the axis of said hole (22) , said flat side

(23) being suitable to be engaged by a first complementary seat (24, 31, 35) arranged on the first element (19) of said hinge (14, 15, 16, 17) .

2. A device according to claim 1 wherein said first part (18) comprises: an opposite side (9 )which is flat and which lies on a plane which is perpendicular to the axis of said hole (22) , said flat side (9) being suitable to be engaged by a second complementary seat 25 arranged on the second element (20) of said hinge; the surfaces of said first complementary seat (24) and of said second complementary seat (25) being corrugated or rough.

3. A device according to claim 1 wherein said first part (18) comprises: an opposite side (26) whose edge (27) has such a shape as to fit tightly into a second complementary seat (28) arranged on the second element (20) of said hinge and suitable to prevent rotation between said first part (18) and said second element (20) of said hinge; the surface of said first complementary seat (24) being corrugated or rough.

4. A device according to claim 3 wherein said second element 20 of said hinge being formed by a material softer than the material of said first element (19) of said hinge.

5. A device according to claim 3 wherein said first complementary seat (31) is formed by a second part (29) comprising: a central hole (30) for housing said threaded means (21) which fasten said hinge, a first side (31) supporting said first complementary seat (31) , and lying on a plane which is perpendicular to the axis of said hole (30) ; and an opposite side (32) whose edge (33) has such a shape as to fit tightly into a third complementary seat (34) arranged on the first element (19) of said hinge and suitable to prevent rotation between said second part (29) and said first element (19) of said hinge; said first part (18) being formed by a material softer than the material of said second part (29) .

6. A device according to claim 1 wherein said first part (18) comprises: an opposite side (26)) whose edge (27) has such a shape as to fit tightly into a second complementary seat

(28) arranged on the second element (20) of said hinge and suitable to prevent rotation between said first part (18) and said second element (20) of said hinge; said first complementary seat (35) being formed by a second part (36) comprising: a central hole (37) for housing a threaded means (21) which fasten said hinge, a side (35) supporting said first complementary seat (35) , lying on a plane which is perpendicular to the axis of said hole (37); and an opposite side (38) whose edge (39) has such a shape as to fit tightly into a third complementary seat (40) arranged on said first element (19) of said hinge and suitable to prevent rotation between said second part (36) and said first element (19) of said hinge; a layer of adhesive (23, 35) being interposed between said first part (18) and said second part (36) .

7. A device according -fc, ^least one of claims 3 to 6 wherein a centre of a curvature of a substantial part of said edge (27, 33, -39) of said opposite part is substantially far from the centre of said hole (22, 33, 37).

8 . A device according to at least one of claims 3 to wherein said edge ( 27 , 33 , 39 ) of s aid oppos i te part comprises at least one rectilinear part ( 41 ) .

9. A device according to at least one of claims 3 to 6 wherein said edge (27, 33, 39) of said opposite part comprises two parallel rectilinear parts (41) .

10. A device according to at least one of the preceeding claims wherein said first part (18) is made of copper.

11. A device according to claim 10 wherein said copper is annealed.

12 A device according to claim 6 wherein said layer of adhesive is made of an epoxy based adhesive.

13. A device according to claim 5 wherein said second part (29, 36) is made of steel or of an alloy based on steel.

14. Bone support device (13) for supporting bone fragments, comprising a first member (10) adapted to be rigidly connected to the first of said bone fragments, a second member (12) adapted to be rigidly connected to the second of said bone fragments, and an adjustable articulated central body (14, 15, 16, 17) connected to said first member (10) and to said second member (12) , said articulated central body allowing to adjust the position of said first member (10) with respect to said second member (12) in an indifferent position and to lock said indifferent position; and comprising a device according to at least one of the preceding claims.

15. Bone support device according to claim 14 wherein said first element (19) is made of steel or of an alloy based on steel.

16. Bone support device according to at least one of claims 14 and 15 wherein said second element (20) is made of aluminium or of an alloy based on aluminium.

17. Each and every novel feature or novel combination of features herein disclosed.