GB2414936A

GB2414936A - Fracture reduction apparatus

Info

Publication number: GB2414936A
Application number: GB0412798A
Authority: GB
Inventors: Ravi Kumar Khetrapal
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-09
Filing date: 2004-06-09
Publication date: 2005-12-14
Also published as: GB0412798D0

Abstract

A device for reducing bone fragments and maintaining them in reduction includes a tape passer (part 1 in fig.1) This allows a strap 6 to be passed around a fractured bone 5 A and B traversing the fracture. The strap 6 can be drawn securely around the bone by means of tensioning device 15.

Description

24 1 4936

FRACTURE REDUCTION APPARATUS

The present invention relates to apparatus to reduce fractures in bones, for example prior to surgical fixation. More particularly, but not exclusively, it relates to apparatus to reduce and maintain in reduction fragments of bones weakened by osteoporosis or the like.

Orthopacdic surgeons are frequently called upon to deal with fractures of long bones such as the femur, tibia and humerus. Surgical fixation of such fractures is an almost daily procedure for a surgeon responsible for trauma care. The effectiveness of a procedure such as "pinning" a fracture is often dependent on achieving a good reduction at the fracture site before any nails, plates and the like are implanted to reinforce the bone. A poorly aligned fracture, particularly one involving mt;itiple laments, may heal badly and/or lead to impaired limb function after healing.

Fractures of weight bearing bones, especially around the hip and femur, arc often encountered with patients whose bones are weakened, Ior example by conditions such as osteoporosis, or by secondary tumours. ('onventional instruments lor fracture reduction comprise metal clamps to grip the bone securely above and below the fracture(s). However, weakened bone such as osteoporotic bone could easily be crushed by tightening such clamps, and in such cases it may often be necessary to accept a suboptimal reduction rather than risk further damage to the bone. This is far from satisfactory.

Even for patients with robust bones, the conventional clamps may not be fully effective with complex fractures having a higher degree of comminution, and where the fracture is near a joint rather than in midshaft.

Conventional clamps, being opaque to X-rays, may obscure visualization of a fracture site, hindering the procedures of inserting and fixing devices such as intramedullary nails. They may even, in some cases, physically obstruct the surgeon's access to the required parts of the bone.

It is therefore an object of the present invention to provide apparatus for reducing and maintaining in reduction bone fragments which obviates the above disadvantages.

According to a first aspect of the present invention, there is provided a device for reducing bone fragments and maintaining them in reduction, comprising strap means disposable around a fractured bone traversing the fracture and tightening means adapted to draw the strap means securely around the bone.

Prelerably, said tightening means is operable to draw the strap means gradually and controllably around the fracture.

Advantageously, the device is provided with fastening means to maintain the strap means in position once the tightening means has drawn it securely around the fracture.

Preferably, the strap means comprises an elongate strip of tough, bendable plastics material.

The strap means is advantageously provided with a plurality of aperture means, optionally arranged in a row, extending longitudinally of the strap means.

Said aperture means may be provided with circumferential reinforcing means, optionally of metal.

Said aperture means are preferably adapted to receive said tightening means and/or fastening means of the device.

Preferably, the tightening means comprises means to engage with the strap means adjacent a first end thereof, means to engage with the strap means adjacent a second end thereof remote from the first, and means to urge said engagement means together.

Advantageously, means is provided to urge each said engagement means towards the other.

The engagement means may comprise elongate rod means passable through a selected aperture means of the strap means.

The urging means may then comprise nut means engaged with a thread extending around the rod means.

The device may comprise a single said rod means passable through a respective aperture means adjacent each end of the strap means.

The device is preferably provided with first plate means, apertured for passage of the rod means therethrough and disposable between each urging means and an adjacent portion of the strap means.

The device may also be provided with second plate means apcrtured for passage of the rod means therethrough and disposable adjacent a face of each said portion of the strap means remote from the urging means.

Each said plate means may be provided with one or more supplementary aperture means, so spaced that fastening means of the device, such as a nut-and-bolt fastening means, may be passed therethrough and through corresponding aperture means of the strap means.

Preferably, the device is provided with strap passer means with which the strap means may be guided around a fractured bone.

Said strap passer means may comprise elongate rigid generally partcircular channel means, through which the strap means may be passed.

The strap passer means may then be slid around the fractured bone, the strap means passed thercthrough, and the strap passer means slid back from around the bone to leave the strap means m situp The strap passer means may comprise two said channel means, so telescopically mounted together that the strap passer means may be expanded as desired to negotiate large or bulky bone fragments such as the femoral trochanters.

A distal one of said channel means may be telescopically mounted externally of a proximal one, so as to facilitate passage of a tip of the strap means from the proximal to the distal channel means.

According to a second aspect of the present invention, there is provided a tool to facilitate passage of strap means, such as a flexible strap, tape or the like, around a bone, particularly a fractured bone, comprising elongate rigid channel means adapted to be disposed around the bone so that the strap means may be passed therealong to surround the bone.

Preferably, the channel means is part-circular, optionally generally semicircular.

The tool may comprise two said channel means, so telescopically mounted together that the tool may be expanded as desired.

According to a third aspect of the present invention, there is provided a method for maintaining a fractured bone in reduction, comprising the steps of providing flexible strapping means, passing a distal end of the strapping means around the fractured bone, drawing the distal end and a proximal end of the strapping means together to tighten the strapping means around the bone, and fastening said ends together.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying figures, in which: Figure 1 is a schematic cross-section of a tape passer embodying the invention in position around a fractured bone, with a tape partially inserted therein; Figure 2 is a radial cross-section of the tape passer and tape shown in Figure 1, adjacent a bone surface; Figure 3 is a scrap cross-section of a part of an alternative form of tape passer; Figure 4 is an elevation of part of the tape shown in Figure 1, Figure 5 is a perspective view of a tensioning device embodying the present invention; Figure 6 is a cross- sectional elevation of the tensioning device shown in Figure 5, engaged with a tape; Figure 7A is a schematic cross-section of the tensioning device and tape shown in Figure 6, mounted around a fractured bone; Figure 7B is a schematic cross-section of the tensioning device, tape and bone shown in Figure 7A, with the tape tightened around the bone; and Figure 8 is a scrap elevation ol the tape shown in Figures 6 to 7B in position around the bone, with the tensioning device removed.

Referring now to the figures and to Figure 1 in particular, a tape passer I comprises an elongate substantially semicircular channel 2 provided adjacent a first open end 3 with a handle 4. Using this, a surgeon may slide the tape passer 1 around a fractured bone S. overlapping the fracture site, so that it extends around a side of the bone 5 remote from the surgeon. A stiff but flexible, elongate tape 6 of X-ray translucent plastics material is then inserted into the first open end 3 and pushed around the channel 2. (Alternatively, the tape 6 may be inserted through an entry slot located below the handle 4). The tape 6 is sufficiently stiff not to buckle when pushed, such that its tip 7 will follow the semicircular channel 2 as shown by arrow 8, ultimately emerging from a second open end 9 of the channel 2, remote from the first 3. The tape 6 is thus disposed around the fracture site of the bone 5 in a generally Ushaped loop. The tape passer 1 is then slid back out from behind the bone 5 and removed, leaving the tape 6 in position.

As shown in Figure 2, the channel 2 has a generally elongate rectangular cross-section, ensuring that the tape 6 extends substantially parallelly to a local surface of the bone 5. A slot I O extends along an entire length of a face of the semicircular channel 2 remote from the bone 5, allowing access to the tape 6 if necessary.

In an alternative, preferred form of tape passer, shown in Figure 3, the channel 2 comprises a proximal section 11 and a distal section 12, connected telescopically. The distal section 12 surrounds the proximal section 11 ensuring that the tip 7 (not shown) of a tape 6 being passed in the direction of the arrow 8 cannot catch on an end of a section 11, 12. This jointed structure allows the tape passer I to be expanded to extend around a large or severely displaced bone fragment.

As shown in Figure 4, the tape 6 is provided with a series of regularlyspaced apertures 13, extending longitudinally along its midline. Each aperture 13 is surrounded by a metal grommet 14 to prevent it fraying in use (see below). Typically, the tape 6 will be one or two centimetres wide, with apertures every centimetre, but these dimensions are not critical.

Once the tape 6 is in position in a loop around the bone 5, it is drawn tightly around the bone with a tensioning device 15, shown in isolation in Figure 5. The tensioning device 15 comprises a threaded stainless steel rod 16 having an elongate stainless steel nut 17 engaged with its thread adjacent each end. Four rectangular reduction plates 18, 19 are provided, each having a first aperture 20 through which the rod 16 extends. A first pair of reduction plates 18 are thus each disposed adjacent a respective nut 17, while a second pair of reduction plates 19 are disposed intermediately between the first pair 18. Each reduction plate 18, 19 also has a second aperture 21, spaced from a respective first aperture 20 by a distance equivalent to the spacing of the apertures 13 of the tape 6. (Note: it is also possible to provide reduction plates 18, 19 with further second apertures 21; in this case, the first 20 and each second 21 aperture of each reduction plate 18, 19 will be arranged in a straight line with the same spacing as for the apertures 13 of the tape 6).

To tighten the tape 6, the tensioning device 15 is mounted thereto as shown in Figure 6. The tensioning device 15 is assembled with the threaded rod 16 extending through each first aperture 20 of each reduction plate 18, 19 and a convenient aperture 13 in each arm of the looped tape 6 (see also Figure 7A). Each arm of the looped tape 6 is thus located between a respective first reduction plate 18, adjacent a respective nut 17, and a respective second, intermediate reduction plate 19.

This also brings each second aperture 21 of the reduction plates 18, 19 into alignment with a respective aperture 13 in each arm of the tape 6. (Note: the reinforcing grommets 14 surrounding each aperture 13 of the tape 6 are here shown with exaggerated thickness for clarity).

The tensioning procedure is shown in Figures 7A and 7B (the second, intermediate reduction plates 19 are omitted from these Figures for clarity). Initially, as in Figure 7A, the tape 6 extends in a relatively loose loop around the fracture site of the bone, here shown comprising two incompletely reduced bone fragments 5A, SB. The tensioning device 15 is operated by turning the elongate nuts 17 with an appropriate open- ended spanner so that they travel along the threaded rod 16, each towards the other. Each nut 17 bears on a respective first reduction plate 18, which in turn urges a respective arm of the looped tape 6 towards the other arm.

The tape 6 is thus gradually drawn more closely around the bone, urging the bone fragments 5A, 5B firmly but gently together. (The surgeon may interrupt tightening the nuts 17 and manipulate the fragments 5A, 5B for optimum reduction if desired).

Ultimately, as shown in Figure 7B, the two arms of the looped tape 6 are brought sufficiently close together that the tape 6 almost completely encircles the shaft of the bone, holding the fragments 5A, 5B securely in reduction. The reduction plates 18, 19 and the tape 6 are fastened together by passing a conventional nut-and-bolt fastening 22 through each second aperture 21 and the respective apertures 13 in the tape 6. (For reduction plates having more than one second aperture 21, a fastening 22 is passed through each).

T he nuts 17 may now be unthreaded, and the rod 16 removed from the first apertures 20. As shown in ldgure 8, this leaves the tape 6 securely and firmly fastened around the bone S. holding the fragments 5A, SO in reduction, but not obstructing access to the bone 5 adjacent the fracture site. (It is often found, for example, that an optimum site for mounting a conventional clamp, adjacent a fracture, coincides with an optimum location for implanting fixation devices). The tape 6 is X-ray translucent, so will not obscure the surgeon's radiological visualization of the fracture while implanting reinforcing plates, intramedullary nails or other orthopaedic fixation devices. The reduction plates 18, 19 may be made of X- ray translucent material if desired, but even if they are made of stainless steel or the like, the flexibility of the tape 6 allows the stack of reduction plates 18, 19 to be folded to one side as desired, for improved visualization of or access to the fracture site.

Once fixation of the fracture is complete, the fastening 22 can be withdrawn, releasing the reduction plates 18, 19 and allowing the loosened tape 6 to be withdrawn from round the bone 5. Alternatively, the tape 6 may simply be severed between the reduction plates 18, 19 and the bone 5, using surgical shears or the like.

Compared to conventional arrangements, the apparatus shown exerts pressure on the bone S over a much wider area. Thus, no part of the bone 5 will be at risk of being crushed, as might occur with existing clamps or those used with osteoporotic or otherwise weakened bone. The tape 6 can also be used to enfold several fragments of a comminuted fracture in a single grasp, rather than requiring a separate clamp member to engage with each fragment. The gradual tightening of the tape 6 around the bone 5 ensures that the alignment of bone fragments can be adjusted and readjusted for optimum reduction, and also lessens greatly the chance of damaging bone by too rapid application (which might occur with a spring- loaded clamp arrangement, for example).

While the tape 6 is shown encircling a substantially cylindrical shaft portion of a long bone, it can also be applied adjacent an end of the bone, where the shaft is slightly frustoconical, beginning to flare outwardly towards the condyles. Conventional clamp arrangements would be difficult to locate on both sides of a fracture in such a position on the bone.

In the case of particularly extensive comminution or more complex bone profiles, more than one tape 6 may be applied, generally in parallel or in different alignments. Tapes 6 that are wider than those shown above may also be of use where comminution is extensive.

Claims

1. A device for reducing bone fragments and maintaining them in reduction, comprising strap means disposable around a fractured bone traversing the fracture and tightening means adapted to draw the strap means securely around the bone.

2. A device as claimed in claim 1, wherein the tightening means is operable to draw the strap means gradually and controllably around the fracture.

3. A device as claimed in either claim 1 or claim 2, further comprising fastening means to maintain the strap means in position once the tightening means has drawn it : .. securely around the fracture. ë .- ..

:. . .

4. A device as claimed in any one of the preceding claims, wherein the strap means comprises an elongate strip of tough, bendable plastics material. ë e..

.

5. A device as claimed in any one ol the preceding claims' wherein the strap means is provided with a plurality of aperture means, optionally arranged in a row, extending longitudinally of the strap means.

6. A device as claimed in claim 5, wherein each aperture means is provided with circumferential reinforcing means, optionally of metal. l

7. A device as claimed in either claim 5 or claim 6, wherein the aperture means are adapted to receive said tightening means and/or fastening means of the device.

8. A device as claimed in any one of the preceding claims, wherein the tightening means comprises means to engage with the strap means adjacent a first end thereof, means to engage with the strap means adjacent a second end thereof remote from the first, and means to urge said engagement means together.

9. A device as claimed in claim 8, wherein the engagement means comprise elongate rod means passable through a selected aperture means of the strap means.

10. A device as claimed in claim 9, wherein the urging means comprises nut means : .. engaged with a thread extending around the rod means. . .

- e.

: .

11. A device as claimed in either claim 9 or claim 10, further provided with first plate : means, apertured for passage of the rod means therethrough and disposable between . each urging means and an adjacent portion of the strap means.

I

12. A device as claimed in claim 11, further comprising second plate means apertured for passage of the rod means therethrough and disposable adjacent a face of each said portion of the strap means remote from the urging means.

13. A device as claimed in claim 12, wherein each said plate means is provided with one or more supplementary aperture means, so spaced that fastening means of the device, such as a nut-and-bolt fastening means, may be passed therethrough and through corresponding aperture means of the strap means.

14. A device as claimed in any one of the preceding claims, further comprising strap passer means with which the strap means may be guided around a fractured bone.

15. A device as claimed in claim 14, wherein the strap passer means comprises elongate rigid generally part-circular channel means through which the strap means may be passed.

16. A device as claimed in either claim 14 or claim 15, wherein the strap passer means is adapted to be slid around the fractured bone, the strap means passed therethrough, and : ,. the strap passer means slid back from around the bone to leave the strap means in situ. to. ëe ë

: a.'.

17. A device as claimed in any one of claims 14 to 16, wherein the strap passer means : :. comprises two channel means, so telescopically mounted together that the strap passer .. means may be expanded as desired to negotiate large or bulky bone fragments such as the femoral troehanters.

18. A device as claimed in claim 17, wherein a distal one of said channel means may be telescopically mounted externally of a proximal one, so as to facilitate passage of a tip of the strap means from the proximal to the distal channel means.

19. A device for reducing bone fragments and maintaining them in reduction substantially as described herein with reference to the Figures of the accompanying drawings.

20. A tool to facilitate passage of strap means, such as a flexible strap, tape or the like, around a bone, particularly a fractured bone, comprising elongate rigid channel means adapted to be disposed around the bone so that the strap means may be passed therealong to surround the bone.

21. A tool as claimed in claim 20, wherein the channel means is partcircular, optionally generally semi-circular.

22. A tool as claimed in either claim 21 or claim 22, comprising two said channel means, so telescopically mounted together that the tool may be expanded as desired.

23. A tool as claimed in claim 22, wherein a distal one of said channel means is A. telescopically mounted externally of a proximal one, so as to facilitate passage of a tip : . . of the strap means from the proximal to the distal channel means. :'

24. A tool to facilitate passage of strap means and a bone substantially as described herein ,. with reference to the Figures of the accompanying drawings.