GB2038638A - Fracture appliance - Google Patents

Abstract

An outer monolateral fixator with overlapping bars for the adjustment and stabilization of bone fractures comprises two parallelelepipedal plates (1, 2) adapted for guiding together a plurality of nails (3), engaging specially provided holes (10a, 10b, 10c) formed in the cortices adjacently the fracture line (5). The two plates (1, 2) are inter-connected by adjusting and stiffening bars (17, 18), there being further provided means for further orienting said nails. <IMAGE>

Description

SPECIFICATION Outer monolateral overlapping bar fixator This invention relates to an outer monolateral overlapping barfixatorforthe reduction and stabilization of bone fractures.

Several techniques and pieces of equipment are known and currently employed in the bone surgery field, and it is considered unnecessary to review herein each individual application, the discussion being limited to some instances which more than others happen to be basic ones in this specific field.

Such techniques currently used in particular for the reduction of fractured bones can be divided in two main classes: a first class concerning methods which involve the use of external equipment, i.e.

away from the affected region and better known as external fasteners, and a second class wherein such equipment directly contacts the affected region or focus, the equipment being identified in this case as endomedullary plates and nails.

The first technical solution comprises essentially a preventative preparation of the fractured region of the bone, better known as "adjustment", and subsequent execution of a plurality of transosseous holes through the bone, from one cortex to the other, both ahead and behind of the fracture region, and spaced apart from the rima.

These holes accommodate nails, which will obviously penetrate through the two cortices, thereafter such nails are interconnected by a series of substantially specular kinematic links, thereby a bilateral fixator is obtained.

The devices summarized hereinabove are not devoid of drawbacks, which are mainly centred about an intricate application technique in actual practice, and the difficulty of achieving accurate dynamic stability of the fracture line.

Another drawback is to be found in the considerable bulkiness and operative surface area presented by said fixators, which obviously requires a long period of immobility for the patient.

Lastly, the drawback should be noted that there are several elements arranged in different planes, but in opposition to the focus origin, which in addition to limiting and hindering the adjustment capabilities, may obviously cause damages to muscles, as well as vases and nerves, owing to the presence of through-bone nails adapted for supporting the multiple links.

The second method provides for the use of metal plates and comprises essentially a preventative reduction i.e. adjustment of the fracture and fastening thereof by means of bicortical through-bone screws on to said plate.

This approach also has many disadvantages, which are envisayed particularly in the irrational nature thereof, which is further aggravated by the negative consequences induced thereby in the tissues of the periosteum.

This system involves indeed a blocking of the biological cycle of the bone re-activation, causing in the portion contacting the plate necrosis with attendant perishment of the periosteum tissues and connective osteo-tissues.

A further drawback, not to be overlooked, is that no dynamic characteristic and static balance condition of the fracture line, are provided owing to a single cortex being subjected to a compressive action, whilst the opposite one, which is left unretained, tends to open.

A third method which finds widespread application, in cases of transversal and mid-diaphysis fractures, is that providing an endomedullar nail, which consists of inserting a nail through the medullar channel. This approach, while solving or overcoming some of the problems, has also drawbacks of not negligible import. In fact, even with this endomedullar nail, ideal stability conditions cannot be achieved, while also difficult is to reduce i.e. adjust any possible axial rotations of the fractured limb.

From the above review of the state of the art, it will be appreciated that the shortcomings thereof are significant ones and substantially ingenerated by the irrationality of the systems and the multiple equipments used in treating individual fractures.

In view of that particular situation, the Applicants have deemed it convenient to arrange for this invention to provide a monolateral outer fixator which affords rationality, functionality, versatility and lowcost production capabilities.

Within that general aim, it is possible to arrange that the monolateral outer fixator of this invention has extremely rational structural components, which are formed and obtained through simple but remarkably effective mechanical principles.

It is further possible to arrange that the monolateral outer fixator according to this invention affords extremely functional performance characteristics, through the operation on bone adjustment control and activation devices which, at the same time, enable continuous and accurate adjustment during the entire re-activation cycle of the offended parts.

It is further possible to arrange thatthe monolateral outer fixator of this invention is versatile, i.e.

serves the dual function of reductor compressor and distractor in the event of a fragmentary bone fracture or necessity for stretching a limb.

It is further possible to arrange that the monolateral outer fixator of this invention includes mechanical components and features, such as to allow the correction, and possibly the dissipation, of any unbalancing forces which may adversely affect the re-composition of the offended parts.

It is further possible to arrange that the monolateral outer fixator according to this invention presents a single working or operative surface, thereby it only spans one side of the limb, thus eliminating the risk of hurting the vascular and muscular tissues, thus limiting the affected region centering and adjusting operations, and reducing the number of the paths to infection.

It is further possible to arrange that the monolateral outer fixator according to this invention is constructed of simple and easily manufactured elements, such as to reduce the production costs.

According to one aspect of the present invention, there is provided an outer monolateral fixator with overlapping bars for the adjustment and stabilisa tion of bone fractures, characterized in that it com prises two parallelepipedal plates adapted for rigidly guiding together a plurality of nails arranged to engage respective holes formed in the cortices adjacently the fracture line, said two plates being interconnected by adjusting and stiffening bars, there being further provided means for further orienting said nails.

Further features and advantages of the invention will be more clearly apparent from the detailed description of a preferred embodiment thereof, illustrated by way of example in the accompanying drawings, where: Figure 1 is a front view of this device as applied to a fractured bone; Figure 2 is a perspective exploded view of this monolateral outer fixator device; Figure 3 is a side view of the device as applied to a bone; Figure 4 is a front view of that same device, as employed to stretch a bone, thus performing as a distractor; Figures is an exploded perspective view of all the parts which constitutes a first embodiment; Figure 6 is a perspective partial view of the device shown in Figure 5 according to a first embodiment; and Figures 7 and 8 illustrate a second embodiment of this monolateral outer fixator device.

With reference to the cited figures, the numerals 1 and 2 designate two substantially parallelepipedal plates constituting rigid engagement means for a plurality of nails 3 affixed to a bone 4 having a fractured region 5.

The devices thus far indicated are arranged in mirror-like relationship with respect to an ideal centerline extending through the origin of the affected region; thus, for convenience of discussion and for a clearer illustration of the innovative value of the invention, one part only will be described, the same explanation applying to the other part as well.

Said parallelepipedal plates 1 and 2 are penetrated along a vertical axis by a plurality of holes, in this specific example indicated at 6a-b-c, which have a slight slope, substantially converging toward the fracture location.

Along a perpendicular axis to the one just mentioned, and substantially parallel to the fractured bone 4, there are provided two further holes 7a and 7b penetrating the full extension of the plate.

Said holes 6a-b-c accommodate said bone fastening nails 3.

Such nails 3 comprise a first shank 8 engaging the plate 1 and 2 directly, while the terminating portion 9 of smaller diameter is received in corresponding holes 1 Oa-b-c formed in the cortices of the fractured bone 4.

Furthermore, and if required, the ends of said nails may be formed with a faceted top surface 11 for handling it with ordinary pliers or a drill, and with a sharp bottom end ortip 12 for easier insertion through the holes formed in the cortices.

If necessary, at least one of said bone fastening nails is partially threaded over the terminating portion 13 in order to prevent it from coming loose in the event of incidental shocks during the limb reactivation stage.

Said nails 3 are suitably secured to the plate 1-2, after the correct position has been attained through the setscrews 14.

At 15 and 1 so, there are indicated two or more through holes, extending approximately parallel to the holes 6a-b-c and obviously having a smaller diameter and being adapted for receiving a series of wires 16, known per Se, for the first centering step of the plates 1 and 2.

As mentioned, the holes 7a and 7b, which are arranged parallel to the ideal axis of the fractured limb, constitute seats for the engagement with two longitudinal bars 17 and 18 interconnecting and strengthening the two plates 1-2.

Obviously, for the definitive blocking and securing after all the parts have been suitably set up, a plurality of locking nuts 19 are provided.

To complete the above-described construction, on the rear of said plates 1 and 2, there is provided a longitudinal stringer 20 which is formed with two longitudinal slots 21a and 21b, which are engaged by connective means 22, in this specific example screws, which penetrate specially provided holes in said plates for engagement therewith.

From the above presentation of this first embodiment of the monolateral outerfixator of this invention, it will be appreciated that its actual application is extremely simple.

In fact, the operator will initiate the bone adjustment or reduction cycle by carring out a preliminary reduction of the fractured limb and a recomposition of the fracture rima, thereafter the operator will carry out an accurate reduction by means of a reducercompressor device, disclosed in Italian patent application No 41671 A/78 filed by the same Applicant.

The application cycle comprises the steps of placing both plates 1-2, as interconnected by the two threaded bars 17 and 18, against the fractured limb.

Then, the operator will pass through the hole indicated at 1 5a and 1 5b the pre-centering wire, of the "Kirchener" type for preliminary centering; obviously, the cross-section of said wire being extremely small, the wire will penetrate the cortex tissues by application of a slight pressure to result in a good securing point for said plate.

At this stage, with the aid of a drill, a first hole 1 Oa will be drilled through the cortex, using said hole 6a as a guide, and a first bone fastening nail inserted therethrough.

In a similar manner, the same step is carried out at the corresponding hole before the focus line 5, where a similar nail 3 will be received.

The same step is repeated sequentially at all of the remaining holes.

As mentioned already, at least one of said nails for both plates is threaded at its bottom portion to create and ensure a rigid anchoring point for the whole fixator device.

Subsequently thereto, the operator will conveniently space said plates, as associated with the threaded bars, away from the fractured limb, and lock the same to said bone fastening nails by means of the setscrews. After performing this preliminary locking operation, by acting on the nuts 19 provided on the threaded bars, a careful and perfect reduction of the fractured part is accomplished, in general by application of a compressive force through the lower bar, and a distraction force through the upper bar.

More specifically, as may be observed, the arrangement of the nails to slope toward the affected region, generates a thrust force which is evenly distributed across the entire front of the affected region, which will obviously encourage the formation of connective bone tissue (i.e. the growing of a bone callus).

After this calibration and reduction of the fracture has been completed, the entire outer fixator device is stiffened by means of said small bar 20 formed with the slots 21a-b.

The latter have in fact the function of adjusting as required the distances, which obviously vary from one plate to the other.

Figure 4 illustrates a similar outer fixator with overlapping bars which is normally used where the fracture has such features that it requires no compression, or where it is necessary to stretch a limb.

In this case, that same equipment is applied to the fractured ends with a dynamic schedule, identical to the former, excepting, of course, for the slope or inclination of the bone fastening nails, which lay at an angle diverging from the affected region to thus generate a distraction action of the fractured ends.

From the foregoing description of this novel monolateral outer fixator, it will be apparent that the invention's objects have been achieved.

Indeed, a fixator has been provided having functionality-reliability characteristics and a limited overall size.

The first characteristic and advantage has been achieved by providing a fixator which is suitable for a wide range of applications, both with bone fractures having a normal rima and a fragmentary one, as well as to distract or stretch limbs.

In addition thereto, a further resultant advantage is that of involving the bone at its outermost portions or portions less concerned with delicate neuromuscular and vascular structures.

Another advantage thus achieved is that of introducing extremely simple but highly effective bone reduction and biomechanical concepts, to achieve minute adjustment and distribution of the compressive forces across the entire fractured region.

A further advantage afforded by this invention is that of reducing the overall size of the fixator to a minimum, thus allowing the patent free movement possibilities.

A not unimportant advantage is the faculty of acting with the adjustment devices equipping it even during the days following the intervention, to adapt and further reduce the fracture.

Afinal advantage resides in the capability of controlling the pressures by differentiating the amounts of compression or stretch applied through manipulation of the two overlapping bars, thus achieving, where necessary, a correction of the periosteum tissues.

As a first embodiment of the invention, related substantially to outer fixators for bone fractures, the Applicant has considered it suitable to provide other similar devices including mechanical features such that a variation of the planes of lay of the bone fastening nails of one plate with respect to the other can be obtained where starting from an already aligned fracture.

To this regard, Figure 5 shows a perspective exploded view of its component parts, where the numeral 23 generally designates an assembly including a plate and bone fastening nails and made up of two identical half-plates 24 and 25 facing each other and joined together by two screws 26a and 26b.

More specifically, the half-plate 25 is provided with three vertical and sloping holes 20a-b-c, similar to the previously mentioned holes 6a-b-c, which accommodate said bone fastening nails 28a-b-c, as described hereinabove.

On the front exposed face of said half-plate 25, there are provided respectively a threaded horizontal hole 29 for the insertion of the screw 26a therethrough and a semicircular slot 30 for the insertion of the lock-screw 26b.

The rear half-plate 24 has instead two longitudinal through holes 31a and 31b arranged in the same horizontal plane and spaced apart in parallel relationship with each other, wherein the stiffening threaded bars 32a and 32b engage between the first set of plates 23 and the following one 33.

It will be noted that the two half-plates 24 and 25 are enabled to vary their planes of lay.

In fact, the half-plate 25, carrying bone fastening nails, can be conveniently applied to the fractured bone before the affected region, thereafter the plane of lay can be varied with respect to the rear half-plate 24 carrying the threaded bars 32a and 32b.

The second set of plates 33, arranged after the affected region, also comprises two half-plates 34a and 35b, the half-plate 34a being similar to the previous one, 24, attached to the overlapping bars 32a and 32b, whilst the half-plate 35b is provided with multiple linkage systems to ensure a correct placement of the bone fastening nails arranged thereon, thus enabling the planes of lay of the two half-plates 34a and 35b to be varied.

Said multiple adjustment elements comprise four adjustment screws 3Se-b-c-d substantially located at the four corners of the half-plate 35b and two further semicircular slots 37 and 38 wherein two locking screws 39 are engaged.

Thus, it will be apparent that by operating said screw devices, adjustment capabilities are achieved in both the vertical and horizontal planes, as well as a limited rotation in either directions of the entire fixator device, after the latter has been associated with the fractured bone.

This novel approach widens the field of application and usefulness of the newfixatorto achieve the fundamental advantage that the half-plates carrying the bone fastening nails can be positioned and the fracture rima aligned.

This latter biomechanical operation is obviously carried out with the aid of the adjustment screws, whereas the entire fixator is locked in place by means of the overlapping threaded bars such as to resultin a rigid whole.

Figures 7 and 8 show instead a further solution and possible embodiment for adjusting the planes of lay between the two half-plates 40 and 41.

In this instance, use is made of a ball joint substantially comprising a cylindrical socket 42 formed in the half-plate 40 and substantially intervening bet weenthetwoattaching bars 43a and 43b .

Said socket has an annular curved surface intended for providing free travel ability for a substantially spherical element 44 associated with the half-plate 41.

Obviously, and as already mentioned, with the half-plate 41 there are associated said bone fastening nails, thereby by acting on said ball joint, the desired adjustment can be achieved.

Said ball joint can be locked by means of a setscrew 45 which locks the spherical element 44 in position on its socket 42.

With the latter solutions, it will be noted again that the invention's objects are achieved, thus providingadjustment devices which allow the planes of lay and alignment of the individual plates to be varied, which results in an improved reduction of bone fractures, whether these are normal or comminute.

Obviously, other variations and mechanical arrangements can be introduced and applied to the device described in the foregoing without departing from the scope of this invention, while the materials and dimensions may be any ones to suit individual requirements.

Claims (13)

1. An outer monolateral fixatorwith overlapping bars for the reduction and stabilization of bone fractures, characterized in that it comprises two parallelepipedal plates adapted for guiding together a plurality of nails arranged to engage respective holes formed in the cortices adjacently the fracture line, said two plates being interconnected by adjusting and stiffening bars, there being further provided means for further orienting said nails.

2. A fixator according to Claim 1, characterized in that said parallelepipedal metal plates are provided with a plurality of holes, said holes being arranged both in the vertical and horizontal planes.

3. A fixator according to Claims 1 and 2, characterized in that said vertically arranged plurality of holes may be suitably inclined or not, and in any case parallel to one another, said holes being adapted to form guiding means for as many bone fastening nails.

4. A fixator according to Claims 1 and 2, characterized in that said bone fastening nails, being sup ported by said metal plate and engaging holes dril led in the cortices adjacently the fracture, have a pointed end and a faceted one for receiving a control wrench, said nail being further provided with a threaded lower portion.

5. A fixator according to Claim 4, characterized in that said bone fastening nails are associated with said plate by means of a plurality of setscrews.

6. A fixator according to Claims 1 and 2, charac terized in that said horizontal through holes are arranged in the same plane and spaced apart from one another in parallel relationship, and adapted for accommodating two threaded bars intended for interconnecting a pair of parallelepipedal plates.

7. A fixator according to Claims 2-6, characterized in that said threaded bars are provided with a plurality of nuts, said nuts, when suitably operated, being effective to produce a reduction of the bone fracture.

8. A fixator according to Claims 2, 6 and 7, characterized in that through said lowerthreaded bar a preliminary reduction is performed by approaching the two parallelepipedal plates to each other under tension, through said upper bar there being instead performed an approaching movement and uniform distribution of the pressure across said fracture rima.

9. A fixator according to Claim 1, characterized in that said assembly of elements comprising the plates and multiple means for fastening to the bone and adjusting are held united and steadily balanced by a longitudinal stiffening stringer, said stringer being associated with said plates by means of conventional screw fasteners.

10. A fixator according to Claim 1, characterized in that.said means effective to vary the orientation of the nails comprise two parallelepipedal half-plates one whereof supports said bone fastening nails and the other supports the longitudinal stiffening and adjusting bars, the variation of the planes of lay between said two half-plates being accomplished through a plurality of screws substantially located at the corners of the plate supporting the nails.

11. A fixator according to Claims 1-10, characterized in that, as an alternative to the first solution, said variation of the planes of lay of the two half-plates is accomplished by means of a ball joint, said ball joint being such as to allow a different and variable arrangement of said bone fastening nails, there being further provided means for fixing and securely locking said ball joint.

12. An outer monolateral fixator with overlapping bars for the reduction and stabilization of bone fractures, substantially as herein described with reference to the accompanying drawings.

13. Any novel element, or combination of elements, herein described and/or shown in the accompanying drawings, irrespective of whether the present claim is within the scope of, or relates to the same invention as, any of the preceding claims.