Method and device for use in osteotomy

Method and device to be used in osteotomy in securing two separated parts of a bone in relation to each other before and after removing an excessive part thereof. After removing and/or holding/keeping apart tissue like muscles, tendons, skin and so on, a longitudinally shaped fixation device is applied atop of a site of said bone (B) where the excision is to be performed. The device is secured with the use of one or more nails or screws at one first end thereof with the use of a hole or holes providing a snug fit to the bone as well as the device. The fixation device is secured at its other second end with the use of one or more elongated holes or slots in the longitudinal direction of the fixation device, which holes once the bone portion to be excised is taken away, provide for movability of the bone ends thus created towards each other. This is temporarily achieved by using prefabricated gliding pins and guiding holes in the respective parts fixing a cutting guide to the fixation device enabling a controlled cutting of a part of bone to be excised. After cutting the bone to a preferred configuration the bone ends created are pushed towards and into contact with each other whereafter a screw is driven into a prefabricated hole in the fixation device to transversely penetrate and snugly fit the taxation device and both bone ends together, keeping a steady state, during which at least one screw is snugly fitted to the other second end of the bone such as to finally keep the bone ends together in order to heal.

FIELD OF INVENTION

The present invention relates generally to a method and a device adapted for use in connection with a surgical osteotomy, and more specifically a device for use during a bone-shortening operation for the treatment or correction of deformity related to excessive bone length.

BACKGROUND AND PRIOR ART

It is known to the art the difficulties to treat a bone fracture near a joint. Prior known methods and arrangements in this context have not safeguarded all necessary requirements when it comes to accuracy in fixation of bone parts using methods including a cutting sequence. In unfortunate circumstances a poor accuracy may later on affect the healing process as well as the rigidity of the bone parts when a normal healing period or process has passed, with possible further convalescence or re-operation required.

The present invention is described in connection with fracture disorders related to the wrist, particularly those that result in misalignment between a first part of a bone named radius, and another part of a bone named ulna, causing interference, for instance in the sigmoid notch of the wrist.

The invention is not restricted to this application and can be used when treating bones of the elbow, knee, and ankle. These applications may require a change in the shape of the inventive device related to each specific application, but the same principles are used irrespective of the site of the misalignment. However, the major use of the invention is expected to be for treating deformities and disorders of the distal radial ulnar joint.

The treatment of joint misalignment has been a problem because of the frequency of the injury disorders and the difficulties in correct treating.

The object of the invention is to restore an alignment between the radius and the ulna in order to prevent arthritis and to relieve pain as well as to minimize the impaction and pressure between the ulna and the carpus of the wrist. Misalignment between the radius and the ulna can result from injury or idiopathic conditions where the ulna is excessively long in relationship to the radius. Injuries that result in a fracture or dislocation of the radius can end up producing a radius that is too short in relationship to the ulna that allows the prominent distal end of the ulna to impact and apply excessive pressure to the carpus of the wrist, the triangular fibre cartilage that covers the distal end of the ulna.

There are essentially five general groups of options available for treatment of misalignment between the radius and the ulna or the joint referred to as the distal radius ulnar joint, these are:(1) Complete excision of the distal end of the ulna,(2) Partial excision of the distal end of the ulna,(3) Excision of the ulna and replacement with a prosthetic joint,(4) Fusion between the radius and the ulna with excision of a segment proximal to the fused joint to create a false joint, and(5) Shortening of the ulna.

Excision of the distal end of the ulna can relieve the pain resulting from arthritic joints or increased pressure and impaction between the ends of the ulna and the carpus, but it results in an unstable joint, which frequently increases instability of the ulna that produces additional symptoms for which no treatment options can subsequently restore the action of the destroyed joint.

Partial excision of the end of the ulna strives to relieve the pressure between the ulna and the carpus while still allowing some portion of the joint to reserve a normal relationship and rotation between the radius and the ulna. Unfortunately, many patients experience significant pain because the normal cartilage and joint contacting between the triangular cartilage and ulna have been removed.

Removal of the distal ulna and replacement with a prosthetic joint allows for correction of the length of the ulna at the time of joint replacement, and may be satisfactory in older patients, but in younger, active patients the action between the metal surface of the ulna will cause destruction of the normal cartilage of the radius, with which it articulates. The loss of cartilage from the radius can result in recurrence of pain in the patient.

Arthrodesis of the joint and the creation of a false joint proximalis by removing a segment of bone have been referred to as the Sauve-Kapandji procedure. Although this can relieve symptoms of pain because the joint is fused, the rate of arthrodesis is unreliable and the false joint below can cause instability, clicking, and pain that is very difficult to treat because the resected bone can cause instability and pain.

Shortening osteotomies have been developed to preserve the normal joint and restore the correct alignment between the radius and the ulna. However, a failure to properly coat the bone surfaces of the osteotomy can result in delayed healing or a non-union.

A few major techniques have been developed, which include both a transverse osteotomy, as well as an oblique osteotomy. A comparison study demonstrated that transverse osteotomies require 21 weeks to heal while the oblique osteotomies healed in 11 weeks. (Reference Rayhack J M, Gasser S I, Latti L L, Ouellette E A, and Maline E L: Precision oblique osteotomy for shortening of the ulna, JHS 1993, Vol. 18A: 908-18). Oblique osteotomies can be performed either with or without the use of a lag screw through the plate and across the osteotomy to improve the compression. Providing a lag screw across the osteotomy site substantially improves the compression of the site and enhances bone healing. It is difficult to compress the bones, as there are other tissues attached to the bone that prevent the compression.

Few major techniques for providing the bone compression involve making an unguided or free hand bone cut followed by the application of a plate. This requires multiple assistance to guide the bone ends together while the osteotomy is performed.

The other method is to use a cutting guide and then apply a device with a compression screw system to bring the bone ends together. The freehand technique has a high margin of error and if the bone surfaces are not cut parallel, there is poor coaptation of the bones and a high rate of non-union. Also, the amount of bone removed is very imprecise. The technique that uses a cutting guide with the compression screw requires that the cutting guide be removed before applying the final plate implant. This technique will result in loss of alignment once the cutting guide is removed, as the final implant in the bone being cut cannot be visualized, and if the cutting guide provides any errors because of the way the device is assembled, significant problems may occur. The cutting guide from this device blocks and prevents the surgeon or physician from viewing the structures around the bone and injury to the bony structures by the saw can occur. Finally, this device uses two separate screws for compression of the osteotomy that cannot be compressed at the same time. As a result, misalignment between the bone surfaces often occurs.

Contrary hereto, according to the invention, a method of oblique osteotomy for the bone shortening is described, which allows for lag screw compression through the plate and can be performed while the plate is already attached to the bone, thus preventing loss of alignment.

The osteotomy can be directly visualized while the plate is in place in order to make sure that the physician can ensure that the cuts are accurate and that all soft tissues around the bone can be protected. A single central screw compression is all that is needed between the bone ends created to optimise the healing of the osteotomy.

SUMMARY OF THE INVENTION

The object of the invention is to provide implantable means for bone shortening to restore joint alignment, which overcomes the problems associated with the known art.

The means according to the invention has three functions, (1) bone shortening with an oblique osteotomy, (2) compression screw fixation across the osteotomy, and (3) stabilization with a plate implant that is applied to the bone prior to making the osteotomy. The plate implant is applied to the bone with an excavated or recessed portion of the plate centered over the site where the osteotomy is desired. The plate is compressed to the bone. Pressure is applied to the plate using one or more screws in the distal three holes of the plate. Fixation guides are arranged on the side of the plate and the surgeon selects the width of the bone to be removed based on a cutting guide to be applied in said fixation guides.

Two, three, or arbitrarily millimetres thick bone wafers can be removed with the guides that will be available. The surgeon can protect the soft tissues with retractors on either side of the bone and directly visualize while the cuts are completed. At one to two centimetres proximal to the proximal end of the plate a screw is inserted through one cortex—a 3.5-millimeter screw is inserted through one cortex of the bone to be used as a post for compressing the osteotomy.

Once the bone wafer has been removed, a compression screw device is attached to the plate with the aim of bringing the bone ends thus created together for achieving perfect conditions for coaptation of the leg or bone.

A unique feature of the plate is that it functions both as a drill guide, incorporated in the plate, as well as providing the guide for the osteotomy and device for compressing the bone surfaces.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As can be seen from the set of drawings above briefly described, the preferred embodiment of a device, according to the invention, is here shown used in a treatment sequence (FIGS. 1 through 10) using a method according to the invention. The steps of said sequence will in the following be described with reference to all parts involved.

Thus, inFIG. 1aa section of a bone B is shown, which due to for instance a misalignment problem (as discussed above), is prone to be shortened. In connection thereto a fixation device1is arranged, here arranged parallel to, above and adjacent to said bone section or portion B.

In order to provide an enabling disclosure,FIGS. 1band1cshow a specific part having cavities13aand13b. Important to note, is the countersink made in the cavity13a, being provided with a slight slant to provide for a relatively easily handled screw joint, which is important for practical reasons after having performed a saw cut (see below).

Furthermore,FIG. 2shows that the fixation device1has been brought into close contact with a surface of the bone portion B. For illustrative purposes, four screws2,2′ are used, on the one hand in a set of three screws2, and on the other hand in a set of one separated screw2′ and two nails3, each nail3shown in the vicinity of its related cavity5.

Cavities or holes4are arranged and adapted for the first set of three nails2and a cavity or a slot13ais adapted for said separated nail2′. Between these sets2;3,2′ are said cavities5and adjacent said slot13ais a further hole or slot13b.

The two nails3are as shown aimed to be arranged in said cavities5, which probably best can be described as elongated slots in said fixation device1, the purpose of which will be described more in detail below. Also the cavity13afor the separated screw2′ is, as previously mentioned, designed in an elongated fashion.

As is illustrated inFIG. 3each of the three screws2, and the separated screw2′ shown inFIG. 2, have been finally tightened and fixed as well as each of the nails3have been driven into a position in which they are tightly fixed to cortex of the bone B.

As can be seen from allFIGS. 1athrough3, said fixation device1includes two holes6, which are arranged transversely to each axis of the holes or cavities4,5and13aof said device. The holes6are aimed for a temporary coaction with an arrangement formed as a cutting guide7, which, here shown at a distance from the fixation device1, is provided with guiding slots8for a saw blade.

FIG. 4shows the fixation device1and the cutting guide7in coaction together with a saw blade9, for excising an excessive part of the bone section or portion B shown.

As seen from an opposite side of the cutting guide7, arranged as illustrated inFIG. 4,FIG. 5shows the excision operation completed with an excised bone portion10as a separated part and with the saw blade9in its final position.

FIG. 6in turn shows how, after excision of the excessive bone portion10, both bone end surfaces11and11′ thus created are pushed together by applying a force F, however this may be done only after a temporarily release of the screw2′ (illustrated by an arrow) in its elongated and slantedly designed hole13a.

Thereafter, the bone end surfaces11and11′ are to be fixed in relation to each other and this is done by using an additional screw12, which is obliquely arranged in relation to a main direction of the bone, however transversely arranged to each of the bone end surfaces11and11′ thus created.

According toFIGS. 7athrough7fthree different alternatives are illustrated in order to exemplify how to bring the bone ends11and11′ together.

In all three alternatives one leg20in the pair of pliers P is attached to one of the holes6for the cutting guide7discussed above.

More precisely one leg is arranged in the one of the holes6situated most close to a cavity or a hole12afor the screw12to be obliquely arranged relative to said axis of the bone B.

The other leg21aof said pair of pliers is in each of the alternatives illustrated applied differently.

According toFIGS. 7aand7bthe leg21ais applied behind the two nails3to enable the bone end surfaces11and11′ to be forced together, while according toFIGS. 7cand7dsaid leg21bis hooked around the screw2′, arranged in the cavity13aafter the same has been suitably loosened as shown.

Last but not least according toFIGS. 7eand7f, said leg21cof the pair of pliers is hooked around an additional nail22, fixed to the side of the bone cortex for this purpose only.

As is conventional, in all three of said alternatives, the pliers and associated legs are used in a manner so as to press the bone ends11and11′ together. After so doing, the pressure of the pliers is upheld while the separated screw2′ in the cavity13ais tightened. The specific design of the elongated cavity13athen makes the achieved position for the slided bone ends11and11′ automatically to lock itself in that position.

Thus the bone end surfaces11and11′ have been brought together and are thereafter, as can be seen inFIG. 8, fixed to each other by using the screw12, however, first after tightening the screw2′ in the cavity13a. Please specifically note the distance “travelled” by the two nails3in their elongated holes or slots5. Said distance is for reasons that are easily realised more or less equivalent to the length of the excised bone portion10.

FIG. 8shows the finally united bone end surfaces11and11′, between which the osteotomy has been performed, and how the bone end surfaces11and11′ just have been secured together by making use of said screw12as well as of retightening the screw2′ in the hole or cavity13a.

Another screw2″, shown apart from the bone portion B and the fixation device1, is to be arranged in a hole13b, arranged further away from the hole or slot-formed cavity13a.

FIG. 9shows the bone portion B and the device1in their final relative positions except for the alternative shown inFIG. 10, where a further screw2′″ is arranged in an opposite end of the elongated slot or hole13a.

As is disclosed on all illustrations, exceptFIG. 4, the fixation device1includes a recess16, which is supposed to be placed facing the part of the bone to be excised during the osteotomy operation. The purpose of the recess16is on the one hand to provide a space in connection to the healing zone, not to cause interference where not needed between natural tissue such as the bone and the fixation device, and on the other hand to make sure that later on, when looking at the healing zone with the aid of X-ray methods, provide for best possible visibility of the healing-zone.

The method according to the invention will hereinafter be described in a consecutive manner. As is completely clear and easily understandable, all necessary and usual preparations normally made in these circumstances also have to be performed when making an osteotomy using the method and device according to the present invention.

Having performed all such necessary measures, the bone on which the osteotomy is to be performed lies relatively open and free to the surgeon.

Initially, thus the device1, according to the invention, is applied to the surface of the bone portion B just above the area where the excision is to be made. Holes in a dimension suitable for the screws2to be used are drilled, using the holes4as a template, whereupon said device1is fixed to the bone surface by said set of three screws2.

In using the device1as a template for drilling purposes it may prove useful to apply a clamp (not shown) around the bone B and the device1, in order to initially be able to properly fix the device1in relation to the bone B.

At an end portion of the elongated hole13a, facing towards the just fixed three screws2, another hole is drilled in the bone B and yet another screw2′ is fixed. Now the device1is properly fixed to the surface of the bone portion B and it is extremely essential that the screws are fixed properly in the three holes4and the hole13abefore the nails3are driven into the bone cortex. Consequently nails3are now driven into the bone cortex at the ends of the elongated slots5situated most close to the cavity or hole13a.

As can be seen from all the Figures, exceptFIG. 4, the holes6are arranged mainly for one purpose only, namely for the attachment of the cutting guide7. EspeciallyFIGS. 3 and 4show how this attachment is preferred and how the saw blade9is applied.

At reference numeral17inFIG. 4is shown a number of alternative slots8adapted to indicate where to place a first cut, and at reference numeral18is also shown a slot where to always make the last cut in order to excise a suitable bone portion10.

After having performed two full through-cuts with the saw blade9, the excessive bone part10is removed and as is shown inFIG. 6, after slightly releasing the screw2′ in the cavity13a, the bone end surfaces11and11′ thus created are forced together by applying said force F as is shown inFIGS. 6 and 7athrough7f. By so doing the thus temporarily loosened bone portion, according toFIGS. 7athrough7f, is forced into contact with its counterpart with fully coinciding bone end surfaces11and11′.

The movement of the temporarily slightly released bone portion is controlled rotationally by the nails3, which are not to be removed until the device1later on is finally fixed in situ, and in relation to the device1via the screw2′ in the hole13a.

After establishing such a bone end contact, a hole of a dimension suitable for fixing the screw12therein is drilled with the cavity or hole12aas a template. The screw12is thereafter fitted to keep the bone ends11and11′ together. As seen inFIG. 8the screw2′ in the cavity13ais retightened and another screw2″ is in a fashion as described above fitted to a drilled hole, using the cavity13bas a template.

Finally as shown inFIG. 9a screw2″ is fitted to a hole drilled through the cavity13bat the distal end of the device1.

As an option an extra screw2′″ may be attached to the elongated cavity13ain order to achieve an enhanced compression of the osteotomy.