WO1994028812A1

WO1994028812A1 - Bone fracture fixation apparatus

Info

Publication number: WO1994028812A1
Application number: PCT/GB1994/001292
Authority: WO
Inventors: Kevin Hardinge
Original assignee: Kevin Hardinge
Priority date: 1993-06-15
Filing date: 1994-06-15
Publication date: 1994-12-22
Also published as: AU6934394A

Abstract

Bone fracture fixation apparatus comprising: a cable and a cable securing device, said cable securing device having at least one guide means adapted to receive a portion of the said cable and deformably operable to capture the said cable therein. A second aspect of the invention incorporates a bone plate into the cable securing device. A cable, typically, has a second end which is operable to abut onto the said guide means so that only the thin end of the said cable need be secured. The securement is, typically, by means of deformation of the cable guide means affected by means of a crimp. The invention is advantageous, inter alia, to fracture fixation and fixation of the trochanter during artificial hip replacement.

Description

BONE FRACTURE FIXATION APPARATUS

The present invention relates to bone fracture fixation apparatus and, in particular, to bone fracture fixation apparatus incorporating a cable as the fixation means.

Co-pending U.K. Patent application Nos. 9312271.1 and No. 9403167.1 disclose respectively means for non-invasive fixing of a bone plate in position that

utilises cable encerclase of the bone and bone plate to fix the plate, and bone

fixator apparatus comprising; a bone fixating member, at least one cable guide

means extending at least partially over, through, under or around the said fixating member and cable cooperating with the said guide means to securedly fix the said fixating member to a bone wherein the cable has as least two ends at least one

of the ends being wider than the said guide means so that in use the said wider

end securely abuts onto one of the said cable guide means. The present application combines the aforementioned priority applications.

Internal bone fixation plates are used for the reduction or retention in the

reduced position of fracture. Fractures occur when an external force acts on the bone and in healthy bones the bone consistency can usually withstand the forces applied to it by plates and screws both during corrective surgery and thereafter.

However, in certain instances the bone may not be able to withstand the forces applied to it by the plates and screws, for example, a long bone, such as

a femur, which has been used to hold the stem of a total hip replacement, and fractured because of loosening of the stem within the femur. Subsequent attempts to apply a plate to the fractured bone have proved problematic. The screws can

abut into the stem of the hip replacement and also damage already weakened

bone.

Thus, it has been difficult to carry out revision operations on fractured bones previously supporting the stems of a joint replacement and it has often not

been possible to fix the fracture without interfering with the stem of the joint

replacement.

It is an object of the present invention to overcome these problems.

It is a further object of the present invention to provide a non-invasive means for fixing bone plates.

It is a still further object of the present invention to provide a non-invasive means for fixing bones.

It is a still further object of the present invention to provide a non-invasive

simple way of securing bones after joint revision and replacement operations.

According to a first aspect of the present invention there is provided bone fracture fixation apparatus comprising: a cable and a cable securing device, said

cable securing device having at least one guide means adapted to receive a portion of the said cable and deformably operable to capture the said cable therein.

Typically, the cable has two ends, one of which ends is thickened so that

it will not pass through or be received in the said guide means. Preferably, the cable securing device comprises a crimpable member . The crimpable member accommodates the said cable and may then be crimped to securedly

accommodate the cable therein.

By this means only one end of a cable need be fixed by deformation of the < said guide means, the widened end being designed to abut onto the said guide means and thus abuttingly secured as oppose to deformably secured.

Typically, the said guide means is in the form of an aperture. The apparatus may be used with a bone plate which is adapted to be secured to a bone by a cable using the said cable securing device. Alternatively, the cable securing device may comprise a bone plate which has guide means deformably

operable to capture the said cable.

According to a second aspect of the present invention there is provided bone fracture fixation apparatus comprising: a cable and a cable securing device, the said cable securing device incorporating a bone plate having at least one guide means extending at least partially over, through, under or around the said

bone plate for accommodating the said cable and means for fixing the cable with respect to the said bone plate.

Preferably, the means for fixing the said cable with respect to the said bone

plate comprises a crimpable member. The crimpable member may be incorporated as part of the bone plates but, preferably, comprises a separate member which accommodates the said cable and which may be crimped to securedly accommodate the cable therein.

Typically, the crimpable member has at least one guide means adapted to

receive a portion of the said cable and is deformably operable to capture the said cable therein.

Typically, the cable has two ends, one of which ends is thickened so that it will not pass through or be received in the said guide means.

By this means only one end of a cable need be fixed by deformation of the said cable securing device or crimp as the widened end is designed to simply abut onto the said guide means and thus abuttingly secured as oppose to deformably secured.

Typically, the said guide means is in the form of an aperture.

As an alternative, the thickened end of the cable may not be received in the

said separate crimpable member and, in this configuration, it rιay or may not be received in the said guide means on the bone plate depending upon the construction thereof.

Previously, in the fixation of the trochanter during artificial hip replacement,

a bulky securing device has been located on the upper surface of the trochanter in order to produce the required fixation. Unfortunately, the bulkiness of the device causes irritation to overlying soft tissue and also the adjoining abductor

muscles.

Such a device may also hinder muscle movement and through a combination of discomfort, muscle weakening and hindered muscle movement the patient frequently has a limp and suffers discomfort. Thus, the first aspect of the

present invention provides a considerable improvement to currently available fixation systems and, allows fixation of the trochanter by means of a cable and securement of the cable by the securing device in a position removed from the

trochanter results in a greatly improved technique.

Preferably, the securing device in such applications has at least two channels each adapted to receive at least one cable end and deformably operable

to capture cable therein.

Preferably, the channels are fully enclosed in the body of the holding device and form a hole passing therethrough for accommodating cable and, by crimping,

securing the same therein. According to a third aspect of the present invention there is provided a method of bone fracture fixation comprising the following steps:

(a) locating a cable in position over opposing fractured bone surfaces,

(b) threading the cable through a securing device, and

(c) tensioning the cable to achieve the required compression of the

opposed bone surfaces, and crimping the securing device to secure at least one end of the cable.

If cable with a thickened end is used only one crimping step is necessary,

the thickened end being abuttingly secured, but if standard cable is used two crimping steps will be necessary to secure the cable at both ends.

In a preferred operation, the cable is located to oppose the relevant bone surfaces and the un-thickened cable end is then threaded through the securing device channel or hole. The bone surfaces are then compressed using a cable tensioner and upon obtaining the required compression the securing device is crimped at the appropriate point. The tension is maintained throughout this step so that after the next step, the cutting of the cable at the end of the un-thickened cable, the tension in the cable being released the cable retracts into the channel.

The result is the non-protrusion of the cut ends of the cable into soft tissue which provides a significant decrease in soft tissue irritation. Overall the use of the

invention offers great advantages during surgery wherein short operating time and a simpler method result, not only because of the alleviation of the necessity of using screws and other invasive securing methods, but also by use of the cable with the thickened end thus cutting down on the necessary crimping steps.

Preferably, the said guide means comprises a hole passing through the cable securing device or a groove passing thereover.

Preferably, the said cable guide means are spaced at intervals and along the said bone plate when found therein.

Preferably, in such embodiments, the said guide means comprise a hole

passing substantially laterally and at least partially through the said bone plate or a groove passing substantially laterally and at least partially over the said bone

plate.

Preferably, the said bone plate is an elongate member shaped in the longitudinal direction to be close fitting with the bone to which it is applied and shaped in the lateral direction to be sufficiently curved to accommodate lateral curvature of the bone.

Typically, the plate has spaced longitudinally therein cable guide means extending in a lateral direction designed to accommodate bone encircling cable therethrough.

The cable guide means may- pass across a fenestration of the plate so that

a compression device can be introduced to crimp the cable guide means thus securing the cable in the plate and simultaneously securing the plate on the bone

surface. However, preferably, spaced arcuate grooves are located along one

longitudinal edge of the bone plate adjacent one end of the groove or holes. Preferably, the grooves or holes are spaced in pairs and the arcuate indentations are adjacent each of the said pairs on one side thereof.

The arcs allow a close fitting crimp member to be accommodated therein which crimp member also accommodates the cable which passes through the adjacent groove or hole for crimping engagement of the said cable. If a cable is

used with the thickened end only one side of the crimp need be deformed the other side accommodating the other end of the cable which is abuttingly secured thereto. However, preferably, the thickened end of the cable abuts on to the other longitudinal side of the cable plate and the cable is thereafter threaded through the hole or groove in the cable plate and accommodating adjacent crimp member to be passed around the adjacent bone and then back through the second hole or

groove of the pair and second accommodating hole in the adjacent crimp member which second accommodating hole can be crimped when the correct tension in

the cable is achieved.

Where fenestrations are used they may consist of two semi-ovoid shapes symmetrically aligned to each other and separated by a bridge extending laterally across the plate and containing at least one guide means therein, extending therethrough, so that a compression device introduced to the bridge by way of the

fenestrations may crush the said bridge, effectively fixing the cable in the cable guide means.

The fenestration is of a size that would not materially weaken the plate and

a plurality of paired fenestrations may be located at intervals along the longitudinal axis of the plate according to the number of cable guide means required for securing the plate to the bone.

The plates may be of a stainless steel or other suitable material and are

preferably malleable to allow adaptation of the longitudinal profile to the particular bone requirements.

Similarly, the crimps are also preferably, malleable to allow crimping of the cable.

A further advantage of the encirclage technique described above, in

addition to being compatible with long bones fitted with replacement joint stems, is that it is non-invasive and this leaves bones substantially intact. It therefore does not subject the bone to the forces applied to conventional plate and screw methods.

Embodiments of the invention will now be described by way of the example, with reference to the accompanying ^'drawings in which:-

Fig.1 shows an elevational view of a cable securing device and cable; Fig.2 is a front elevation of a bone plate with fenestrations;

Fig.3 is a side elevation of a bone plate;

Fig.4 is a sectional view of a bone plate;

Fig.5(a) shows a widened end cable;

Fig.5(b) shows a cross-section through a widened end cable and bone

plate;

Fig.6 shows a front elevation of a bone plate with arcuate side grooves;

Fig.7 shows a bone plate crimp and cable during assembly,

Fig.8(a) shows an enlarged plan view of a crimp; and

Fig.8(b) shows a cross-section through a crimp.

In fig.1 the cable securing device 2 comprises two elongate enclosed channels 4,6 adapted to receive cable 8 therethrough, said cable entering at points 10,12 and exiting at points 14,16 respectively.

A cable tensioner (not shown) grips the cable and provides the necessary cable tension to give the required compression of the bone surfaces. When the compression required is obtained the securing device is crimped at points 10 and 12 and while tension is maintained the cable is then cut at points 14 and 16. The

tension being released, the cable retracts into the channel and the securing device is then further crimped for security at points 14 and 16.

Referring to fig. 2 an elongate plate member 1 has at intervals along the

longitudinal axis thereof a plurality of paired semi-ovoid fenestrations 4, having a bridge 22 extending laterally therebetween along the axis of symmetry of the paired fenestrations, the said bridge containing a pair of cable guide means, (transverse port holes, not shown) extending laterally therethrough and further extending through the plate member.

Referring to fig.3 the side of the plate member 18 is shown to have spaced along its length a plurality of pairs of portholes 24, said pairs spaced along its

length at intervals and the said port holes extending laterally through the plate and being substantially circular in cross-section.

Referring to fig.4 a cross-section of the plate 18 is curved to accommodate the bone surface on the underside thereof and the upper surface is also curved closely mimicking the normal bone surface and thus providing more comfort when in contact with soft tissue.

Referring to figs.5(a) and 5(b) a cable 28 having a widened end 30 is shown separately and in use respectively. In use the widened end 30 of the cable abuts on to cable guide means 32 such that only the non-widened end 34 of the cable need be secured in the guide means or in a crimp (not shown) as appropriate. Referring to fig.6 an elongate bone plate 36 has at intervals along the length thereof a series of spaced pairs 38,40, 40,42, 44,46 and 48, 50 extending laterally from one longitudinal side of the bone plate to the other. The said bone plate 36 having formed in one longitudinal side thereof, adjacent each

of the said pairs, arcuate cut-outs 52 to 58. The said arcuate cut outs are designed to accommodate a close fitting crimp member such as that shown in

figures 8(a) and 8(b).

Referring to fig.7, a bone plate 36 is shown with four arcuate cut outs along one longitudinal side thereof and resting against the length of bone 60 which bone is compressed by circumferential cable 62, which circumferential cable has widened end 64 abutting onto hole 38 on the non cut-out longitudinal side of the

said bone plate and passes through the said hole and through an accommodating matching hole 68 in an adjacent crimp 66 accommodated and close fitting with cut

out 52 to pass thereafter around the remote side of the said bone 60 to encircle the bone and pass back through the second hole 40 of the pair and the second hole 70 of the crimp whereafter it may be tensioned and crimped to secure the cable to the bone and bone plate. Similar procedures can be carried out with respect to further pieces of cable and the further pairs of holes in the plate and thus provide an efficient and non- invasive method of fracture fixation using a bone

plate.

Referring to fig.8(a) an enlarged plan view of the crimp 66 shows a segment form which is adapted to be close fitting with arcuate cut outs formed in the side of a bone plate such as 36. Two spaced laterally extending channels 72 and 74 extend from the arcuate side of the crimp to the straight side thereof.

Referring to fig.8(b), a cross-.sectional view of the crimp shows the shape of the channels 72 and 74 which are wider in the interior and toward the base of the crimp and thus allow crimping of the over hanging portion 76 and 78 when cable is accommodated therein. The inside edges of the channel are serrated (not shown) to aid in gripping the cable when the crimp is compressed. Any

suitable crimping device may be used to carry out the abovementioned process. ^"

Various modifications and alterations to the invention are possible without departing from the aforementioned embodiments. In particular, the shape of the

crimp and bone plate can be varied to suit requirements.

It will be appreciated that the manner in which the cable is arranged over the bone surfaces to be opposed will vary depending upon the type, size and

nature of the fracture. It will also be appreciated that all parts described are made of appropriate surgical materials such as stainless steel or other suitable alloys. It will also be appreciated that the above embodiments have been described by way of example only and that many variations are possible. For instance, the

shape of the crimp can be varied depending upon the application and, in particular, depending upon which part of the bone surface it is to be fixed adjacent to. Such an embodiment could be utilised during trochanteric osteotomy where it is necessary to secure the cut trochanter back onto the top of the femur. By passing the cable across the trochanter a number of times depending upon requirements and securing the two ends of the cable using the crimp as described

a simple and effective technique which avoids the use of bulky securement members on the trochanter and thus uses patient comfort and soft tissue damage

results.

Claims

1. A bone fracture fixation apparatus comprising : a cable and a cable securing

device, said cable securing device having at least one guide means adapted to

receive a portion of the said cable and deformably operable to capture the said cable therein.

2. A bone fracture fixation apparatus as claimed in claim 1 wherein the cable has

two ends, one of which ends is thickened so that it will not pass through or be

received in the said guide means.

3. A bone fracture fixation apparatus as claimed in claims 1 or 2 wherein the cable securing device comprises a crimpable member.

4. A bone fracture fixation apparatus as claimed in claim 3 wherein the crimpable member accommodates the said cable and is then crimped to securedly accommodate the cable therein.

5. A bone fracture fixation apparatus as claimed in any preceding claim wherein one end of the cable is abuttingly secured to the guide means and the other end of the said cable is deformably secured to the said guide means.

6. A bone fracture fixation apparatus as claimed in any preceding claim wherein the guide means is in the form of an aperture.

7. A bone fracture fixation apparatus as claimed in any preceding claim wherein the apparatus incorporates a bone plate which is adapted to be secured to a bone by the cable using the said cable securing device.

8. A bone fracture fixation apparatus as claimed in any preceding claim wherein the cable securing device comprises a bone plate which has guide means deformably operable to capture the said cable.

9. A bone fracture fixation apparatus comprising: a cable and a cable securing device, the said cable securing device incorporating a bone plate having at least one guide means extending at least partially over, through, under or around the said bone plate for accommodating the said cable and means for fixing the cable with respect to the said bone plate.

10. A bone fracture fixation apparatus according to claim 9 wherein the means for fixing the said cable with respect to the said bone plate comprises a crimpable member.

11. A bone fracture fixation apparatus according to claims 9 or 10 wherein the crimpable member is incorporated as part of the bone plate.

12. A bone fracture fixation apparatus according to claim 10 wherein the crimpable member comprises a separate member which accommodates the said cable and which may be crimped to securedly accommodate a cable therein.

13. A bone fracture fixation apparatus according to claims 10 to 12 wherein the crimpable member has at least one guide means adapted to receive a portion of the said cable and is deformably operable to capture the said cable therein.

14. A bone fracture fixation apparatus according to claims 9 to 13 wherein the cable has two ends, one of which ends is thickened so that it will not pass through or be received in the said guide means.

15. A bone fracture fixation apparatus according to any of claims 9 to 14 wherein one end of the cable is abuttingly secured and the other end is deformably secured.

16. A bone fracture fixation apparatus according to any of claims 9 to 15 wherein the guide means is in the form of an aperture.

17. A bone fracture fixation apparatus according to claims 14 to 16 wherein the thickened end of the cable is not received in the said separate crimpable member.

18. A bone fracture fixation apparatus according to claim 17 wherein the thickened end of the cable is received in the said guide means on the bone plate.

19. A bone fracture fixation apparatus according to claim 16 wherein the thickened end of the cable is not received in the said guide means on the bone

plate.

20. A bone fracture fixation apparatus according to any preceding claim adapted to be used for fixation of the trochanter during artificial hip replacement.

21. A bone fracture fixation apparatus according to any preceding claim wherein the trochanter is fixed by means of a cable.

22. A bone fracture fixation apparatus according to any preceding claim wherein the cable is secured by the securing device in a position remote from the

trochanter.

23. A bone fracture fixation apparatus according to any preceding claim wherein the securing device has at least two channels each adapted to receive at least one cable end and deformably operable to capture cable therein.

24. A bone fracture fixation apparatus according to claim 23 wherein the channels are fully enclosed in the body of the holding device and form a hole passing therethrough for accommodating cable and, by crimping, securing the same therein.

25. A method of bone fracture fixation comprising the following steps:

(a) locating a cable in position over opposing fractured bone surfaces,

(b) threading the cable through a securing device, and

(c) tensioning the cable to achieve the required compression of the opposed bone surfaces, and crimping the securing device to secure at least one end of the cable.

26. A method of bone fracture fixation according to claim 25 wherein a cable with

a thickened end is used such that only one crimping step is necessary, the thickened end being abuttingly secured.

27. A method of bone fracture fixation according to claim 25 wherein standard

cable is used such that two crimping steps are necessary to secure the cable at

both ends.

28. A method of bone fracture fixation according to claim 25 or claim 26 wherein

the cable is located to oppose the relevant bone surfaces and the un-thickened cable end is then threaded through the securing device channel or hole.

29. A method of bone fracture fixation according to claims 25 to 28 wherein the bone surfaces are compressed using a cable tensioner and upon obtaining the required compression the securing device is crimped at the appropriate point.

30. A method of bone fracture fixation according to claim 28 wherein the tension is maintained throughout the crimping step so that the cutting of the cable at the end of the un-thickened cable causes the cable to retract into a channel in the said securing device causing non protrusion of the cut ends of the cable into soft

tissue.

31. A bone fracture fixation apparatus according to any preceding claim wherein the said guide means comprise a hole passing through the cable securing device or a groove or channel passing thereover.

32. A bone fracture fixation apparatus according to any of claims 7 to 31 wherein the said cable guide means are spaced at intervals and along the said bone plate when found therein.

33. A bone fracture fixation apparatus according to claim 32 wherein the said guide means comprise a hole passing substantially laterally and at least partially through the said bone plate or a groove or channel passing substantially laterally and at least partially over the said bone plate.

34. A bone fracture fixation apparatus according to any of claims 7 to 33 wherein the said bone plate is an elongate member shaped in the longitudinal direction to be close fitting with the bone to which it is applied and shaped in the lateral direction to be sufficiently curved to accommodate the lateral curvature of the bone.

35. A bone fracture fixation apparatus according to any of claims 7 to 34 wherein the plate has spaced longitudinally therein cable guide means extending in the lateral direction designed to accommodate bone encircling cable therethrough.

36. A bone fracture fixation apparatus according to any of claims 7 to 35 wherein the cable guide means passes across a fenestration of the plate so that a

compression device can be introduced to crimp the cable guide means thus

securing the cable in the plate and simultaneously securing the plate on the bone

surface.

37. A bone fracture fixation apparatus according to any of claims 7 to 36 wherein spaced arcuate grooves are located along one longitudinal edge of the bone plate

adjacent one end of the groove or holes.

38. A bone fracture fixation apparatus according to any of claims 31 to 37 wherein the grooves or holes are spaced in pairs and the arcuate indentations are adjacent each of the said pairs on one side thereof.

39. A bone fracture fixation apparatus according to any of claims 37 or 38 wherein the arcuate grooves allow a close fitting crimp member to be accommodated therein which crimp member also accommodates the cable which passes through the adjacent groove or hole for crimping engagement of the said

cable.

40. A bone fracture fixation apparatus according to claim 39 which incorporates a thickened end cable so that only one side of the crimp need be deformed in the

side accommodating the other end of the cable from that which is abuttingly secured thereto.

41. A bone fracture fixation apparatus according to claim 40 wherein the thickened end of the cable abuts onto the other longitudinal side of the cable plate and the cable is thereafter threaded through the hole or groove in the cable plate and accommodating adjacent crimp member to be passed around the adjacent bone and then back through the second hole or groove of the pair and second accommodating hole in the adjacent crimp member which second accommodating hole can be crimped when the correct tension in the cable is achieved.

42. A method of bone fracture fixation according to claims 25, 26, 28, 29 or 30 wherein the thickened end of a cable abuts onto the other longitudinal side of the cable plate and the cable is thereafter threaded through the hole or groove in the cable plate and accommodating adjacent crimp member to be passed around the adjacent bone and then back through the second hole or groove of the pair and second accommodating hole in the adjacent crimp member which second accommodating hole can be crimped when the correct tension in the cable is achieved.

43. A bone fracture fixation apparatus according to any preceding claim wherein the plates are made of stainless steel or other suitable material.

44. A method of bone fracture fixation according to any preceding claim wherein the said components are made of stainless steel or other suitable material.

45. A bone fracture fixation apparatus according to any preceding claim wherein the said components are malleable to allow adaptation thereof to the particular

requirements.

46. A method of bone fracture fixation according to any preceding claim wherein the components are malleable to allow the required adaptation thereof.

47. Non-invasive bone fracture fixation apparatus comprising a bone plate

adapted to be abuttingly secured to a fractured bone surface, securing means operable to secure the said bone plate to the said fractured bone surface, and fixing means to fix the said securing means once the bone plate has been secured to the said fractured bone surface.

48. Non-invasive bone fracture fixation apparatus according to claim 47 wherein the securing means is a cable.

49. Non-invasive bone fracture fixation apparatus according to claims 47 or 48 wherein the fixing means is a crimpable member.

50. Non-invasive bone fracture fixation apparatus according to any of claims 47 to 49 wherein the securing means is a cable having one thickened end thereto for abutting engagement with the fixing means.