WO2019220284A1

WO2019220284A1 - Fracture reduction device

Info

Publication number: WO2019220284A1
Application number: PCT/IB2019/053863
Authority: WO
Inventors: Carmelo Francesco PASCALI
Original assignee: Ferrari, Francesco
Priority date: 2018-05-16
Filing date: 2019-05-10
Publication date: 2019-11-21
Also published as: IT201800005439A1

Abstract

Fracture reduction device (100), configured to contact a human or animal bone, having an elongated planar flexible body, made of biocompatible material, extending along a longitudinal axis (L) and having a first surface (102) configured to contact a bone and a second surface (104) opposite to the first surface (102), wherein the elongated planar flexible body comprises: - a central section (110) provided on the second surface (104) with a plurality of teeth (112) arranged transversely to the longitudinal axis (L) of the elongated planar flexible body and forming a rack, - a first end section (120), and - a second end section (130) provided with a head (136) that protrudes from the second surface (104) and is provided with a pass-through slot (137) having at least one pawl (138) operating as ratchet configured to elastically interact with said rack formed by the plurality of teeth (112) and to allow the first end section (120) and the rack to be exclusively inserted into the pass-through slot (137) to make a loop an inner surface of which coincides with the first surface (102), wherein the head (136) has shape of a spherical cap protruding from the second surface (104).

Description

FRACTURE REDUCTION DEVICE

* * *

The present invention relates to a fracture reduction device, in particular both simple and multi-fragmented diaphyseal fractures of long bones, that allows in a simple, rapid, reliable, efficient and inexpensive way to realign the stumps of a bone that has suffered a displaced fracture, permitting a subsequent osteosynthesis by applying fixation devices, such as screws, plates and nails, to stabilise the fracture.

As is known, a displaced fracture is the interruption of the continuity of a bone in two or more stumps (in the first case the fracture is defined as "simple", in the second case it is defined as "multi-fragmented") wherein the arrangement of these stumps loses the mutual alignment thereof; in particular, this occurs more frequently in case of diaphyseal fractures of long bones. In the case of a displaced fracture, it is necessary for the orthopedist to proceed with the reduction thereof, i.e. with the realignment of the bone stumps that allows to restore the anatomical configuration that the bone had before the fracture. When such reduction is bloody (i.e. surgical), the realignment of the bone stumps can only be performed manually or, more often, with proper tools, such as forceps. Optionally, the reduction is followed by osteosynthesis with fracture stabilisation devices, which allow the bone realignment to be maintained steadily during the formation of the bone callus, permitting to reduce both the time required for functional recovery and the risks of residual disability; examples of fracture stabilisation devices are disclosed in documents US 4905679 A and WO 2015/138995 Al. In this regard, a widely used reduction and osteosynthesis technique is the so-called surgical technique of open reduction and internal fixation, called ORIF.

A problem encountered in surgical reduction techniques, especially if preliminary to osteosynthesis with fixation devices, e.g. the ORIF technique, is due to the difficulty of maintaining the stability of the fracture reduction. This difficulty increases with the increase of the inclination angle of the (at least one) fracture line with respect to the longitudinal axis of the fractured bone. In case of osteosynthesis with plate following the fracture reduction, an insufficient stability of the fracture reduction in the operative phase that elapses between the correct realignment of the fracture stumps and the fixation of the osteosynthesis devices (e.g., screws, plates or nails) hinders a correct positioning of these devices and, consequently, the result of the osteosynthesis.

A partial solution to this problem has been proposed through adjustable and/or elastic osteosynthesis devices, which allow the reduction and osteosynthesis steps to be performed at the same time.

However, also this partial solution suffers from some significant drawbacks, due to the complexity of manufacture of such adjustable and/or elastic devices, that causes them to be expensive, and to the complexity of application of such devices, that reduces reliability and efficiency thereof.

Thus, it is an object of the present invention to allow in a simple, rapid, reliable, efficient and inexpensive way to realign the stumps of a bone that has suffered a displaced fracture, possibly permitting a subsequent osteosynthesis by applying fixation devices, such as screws, plates and nails, to stabilise the fracture.

It is a specific subject matter of the present invention a fracture reduction device, configured to contact a human or animal bone, having an elongated planar flexible body, made of biocompatible material, extending along a longitudinal axis and having a first surface configured to contact a bone and a second surface opposite to the first surface, wherein the elongated planar flexible body comprises:

a central section provided on the second surface with a plurality of teeth arranged transversely to the longitudinal axis of the elongated planar flexible body and forming a rack,

a first end section, and

a second end section provided with a head that protrudes from the second surface and is provided with a pass-through slot having at least one pawl operating as ratchet configured to elastically interact with said rack formed by the plurality of teeth and to allow the first end section and the rack to be exclusively inserted into the pass-through slot to make a loop an inner surface of which coincides with the first surface, wherein the head may have shape of a spherical cap protruding from the second surface.

According to a further aspect of the invention, a height of the head (136) is lower than the radius of the spherical cap.

According to an additional aspect of the invention, the second end section may comprise a joining portion that joins the head to the central section.

According to another aspect of the invention, the joining portion may be shaped so as to form three discs aligned to each other along the longitudinal axis, optionally partially overlapping each other. According to a further aspect of the invention, the three discs may be equal to each other and a base of the spherical cap may have a diameter equal to a diameter of the three discs.

According to an additional aspect of the invention, the pass-through slot may extend along an axis that is orthogonal to the longitudinal axis of the elongated planar flexible body.

According to another aspect of the invention, the first end section may form a tab ending with a tip having a width lower than a width of the central section.

According to a further aspect of the invention, the biocompatible material may be resorbable by a human or animal body.

It is also a specific subject matter of the present invention a fracture reduction and stabilisation assembly comprising:

a fracture reduction device as previously described, and

a fixation plate, having a surface configured to contact and be fixed on a human or animal bone, that is provided with one or more grooves each one of which has a thickness configured to house a portion of the fracture reduction device, optionally a portion of the central section thereof, when the fixation plate is fixed to the bone.

The fracture reduction device according to the invention allows, in a simple, rapid and reliable way, to maintain stable the reduction that has been obtained exclusively manually or with proper tools, such as forceps, in a surgical reduction technique, e.g. the ORIF technique.

Also, the fracture reduction device according to the invention permits the application of (at least) one fixation device, such as a screw, a plate or a nail, without interfering with it and ensuring the correctness of positioning thereof and the reliability and efficiency of osteosynthesis. In particular, in the case where the fixation device is a plate, this can be easily superimposed on the fracture reduction device according to the invention.

In some embodiments, the fracture reduction device according to the invention is made of a resorbable material.

Finally, the fracture reduction device according to the invention is simple and consequently inexpensive to manufacture.

The present invention will be now described, by way of illustration and not by way of limitation, according to its preferred embodiments, by particularly referring to the Figures of the annexed drawings, wherein:

Figure 1 shows a plan view of a preferred embodiment of the fracture reduction device according to the invention; Figure 2 shows a side view of the fracture reduction device of Figure 1;

Figure 3 shows a partial front perspective view of a long bone that has suffered a displaced simple diaphyseal fracture;

Figure 4 shows a plan view of a fixation plate to apply on the fractured bone of Figure 3;

Figure 5 shows a rear perspective view of the fractured bone during the operation of fracture reduction through the fracture reduction device of Figure 1; and

Figure 6 shows a front perspective view of the reduced fractured bone of Figure 5 to which the fixation plate of Figure 4 has been applied.

In the Figures the same reference numerals will be used for similar elements.

Making reference to Figures 1 and 2, it may be observed that a preferred embodiment of the fracture reduction device according to the invention, generally indicated with the reference numeral 100, has an elongated planar flexible body extending along the longitudinal axis L of the fracture reduction device 100 (and coinciding with the longitudinal axis of the elongated planar flexible body) and having a rear surface 102, configured to contact a bone, and a front surface 104 (opposite to the rear surface 102 and shown in Figure 2). The elongated planar flexible body comprises a central section 110 and a first end section forming a tab 120 and a second end section 130 (opposite to the first end section); the central section and the two end sections are integral to each other in the elongated planar flexible body.

The central section 110 is provided, on the front surface 104, with a plurality of teeth 112 arranged transversely to the longitudinal axis of the fracture reduction device 100 so as to form a rack.

The tab 120 of the first end section ends with a tip 122, advantageously rounded, having a width TW (i.e. a dimension along the direction orthogonal to the longitudinal axis L in the device plane) lower than the width CW of the central section 110 (even if this is not an essential feature for the invention, and the width TW could be also equal to the width CW); in the preferred embodiment of the fracture reduction device according to the invention, shown in the Figures, the end portion of the tab 120 has a substantially triangular shape (even if this is not an essential feature for the invention, and the shape of the end portion of the tab 120 could be also different, e.g. trapezoidal). The tab is preferably devoid of teeth (differently from the central section 110).

The second end section 130, that (differently from the central section 110) is devoid of teeth, comprises a portion 132 for joining to the central section 110 and a head 136. The joining portion 132 is shaped so as to form three discs 133, 134 and 135 equal to each other and aligned to each other along the longitudinal axis L and partially overlapping each other, so that the side edge 131 of the joining portion 132 are curvilinear; the maximum width of the joining portion 132 is equal to the diameter DW of the three discs 133, 134 and 135, and is larger than the width CW of the central section 110 (even if this is not an essential feature for the invention, and the diameter DW could be also equal to or lower than the width CW). The head 136 has the shape of a spherical cap (i.e. of a spherical segment with one base) that protrudes from the front surface 104 of the elongated planar flexible body of the fracture reduction device 100, and it is provided with a pass-through slot 137 extending along an axis S and having rectangular cross section corresponding to the cross section of the central section 110 of the elongated planar flexible body of the fracture reduction device 100. The height of the head 136 is lower than the radius of the spherical cap (even if this is not an essential feature for the invention, and the height of the head 136 could be also equal or slightly larger than the radius of the spherical cap), and the base of the spherical cap has a diameter HW equal to the diameter DW of the three discs 133, 134 and 135 (even if this is not an essential feature for the invention, and the diameter DW could be also larger or lower than the diameter DW); the diameter HW of the base of the spherical cap of the head 136 is larger than the width CW of the central section 110.

The pass-through slot 137 is provided with a pawl 138, configured to interact with the teeth 112 of the central section 110 of the elongated planar flexible body of the fracture reduction device 100 so that the pawl 138 acts as ratchet configured to elastically interact (in particular, the pawl 138 is flexible) with the rack formed by the plurality of teeth 112: the pawl 138 and the teeth 112 are configured to allow the rack exclusively to be inserted into the pass through slot 137 for making a loop the inner surface of which coincides with the rear surface 102 of the elongated planar flexible body of the fracture reduction device 100 (and the outer surface of the loop coincides with the front surface 104), preventing, once that it is inserted into the pass-through slot 137, the rack from being moved backwards to exit from the pass-through slot 137 (even if a limited backward movement, equal to the distance between two contiguous teeth 112, is possible). To this end, the teeth 112 may have a conventional shape, such as for instance a cross section (along a plane passing through the longitudinal axis L) having the shape of a right- angled triangle projecting from the front surface 104 in which the hypotenuse is directed towards the tab 120 and a cathetus is directed towards the head 136 (the other cathetus lies on the front surface 104), whereby the pawl 138 is capable to slide over the hypotenuse (during insertion of the rack into the pass-through slot 137), but it is not capable to go over the wall corresponding to the cathetus directed towards the head 136 (during an attempt of extraction of the rack from the pass-through slot 137).

In other words, once that the tab 120 has been inserted into the pass-through slot 137 until it makes the pawl 138 elastically interact with the tooth 112 closest to the tip 122 of the tab 120, the pawl 138 exclusively allows an additional insertion of the rack into the pass-through slot 137, tightening the loop thus made by the fracture reduction device 100, and prevent the release of the rack from the pass-through slot 137 that would open such loop again.

Other embodiments of the fracture reduction device according to the invention may comprise two or more pawls into the pass-through slot 137.

In the preferred embodiment of the fracture reduction device 100, the axis S along which the pass-through slot 137 extends is orthogonal to the longitudinal axis L. It must be noted that this is not an essential feature for the invention and that other embodiments of the fracture reduction device may have the axis S that forms an angle different from 90° with the longitudinal axis L (or with the front surface 104), and the axis S could be also parallel to the longitudinal axis L (and to the front surface 104); in particular, the angle formed by the axis S with the longitudinal axis L (or with the front surface 104) may depend from the specific type of bone and/or from the specific type of fracture that the fracture reduction device according to the invention is intended to reduce.

Further embodiments of the fracture reduction device according to the invention may have the portion 132 joining the second end section 130 to the central section 110 that, instead of being shaped so as to form three discs, may be shaped differently, e.g. so as to form a number of discs different from three (i.e., only one disc or two or four or more discs), or so as to form an ellipse, or so as to form a rhombus or a rectangle, advantageously with rounded edges, having a width (along the direction orthogonal to the longitudinal axis L in the device plane) larger than, equal to or lower than the width CW of the central section 110.

Moreover, other embodiments of the fracture reduction device according to the invention may be devoid of the joining portion 132, whereby the second end section 130 comprises only the head 136.

Also, further embodiments of the fracture reduction device according to the invention may have the head 136 having a shape that protrudes from the front surface 104 of the elongated planar flexible body of the fracture reduction device different from a spherical cap, such as for instance an ellipsoidal cap, or a cylinder with smooth edges or a parallelepiped with smooth edges.

The fracture reduction device according to the invention is made of a biocompatible material, optionally resorbable by the human or animal body, for instance polylactic acid (PLA), poly-L-lactic acid (PLLA), polyglycolic acid (PGA), polycaprolactone (PCL), polycarbonate (PC) based materials, polyether (PE) based materials, and copolymers of two or more of these.

In the preferred embodiment, the elongated planar flexible body extends for a total length of 20 centimetres and has a thickness (apart from the head 136) ranging from 1 millimetre and 2 millimetres, whereas the head 136 has a thickness of 5 millimetres; the width CW of the central section 110 is equal to 3 millimetres and the diameter DW of the three discs 133, 134 and 135 is equal to the diameter HW of the base of the spherical cap of the head 136 and are equal to 7 millimetres; the portion 132 for joining to the central section 110 has a length equal to 18 millimetres. However, it must be noted that the sizes are not an essential feature for the invention and they can change also in function of the specific type of bone and/o of the specific type of fracture that the fracture reduction device according to the invention is intended to reduce.

In order to better understand the invention, modes of use of the preferred embodiment del fracture reduction device according to the invention are illustrated in the following, similar modes being valid for other embodiments.

In particular, the fracture reduction device according to the invention allows to obtain a stable fracture reduction in thein the operative phase that elapses between the correct positioning of the fracture stumps and the fixation of osteosynthesis devices, also osteosynthesis devices currently already in use.

Figure 3 shows a partial front perspective view of a long bone that has suffered a displaced simple diaphyseal fracture, whereby the bone has been fragmented into two stumps, indicated with the reference numerals 200 and 250, which are not aligned according to the anatomical configuration of the bone.

Figure 4 shows a plan view of a fixation plate 300 to apply, according to surgical technique, e.g. ORIF technique, on the two stumps 200 and 250 of the fractured bone of Figure 3 in correspondence with the fracture line to stabilise the fracture, after that the latter has been reduced by realigning the two stumps 200 and 250 according to the anatomical configuration of the bone before the fracture. In particular, the fixation plate 300 extends along its own longitudinal axis P and comprises ten sections 310 (having substantially rectangular shape with rounded edges) which are aligned along the longitudinal axis P and integral to each other.

Figure 5 shows a rear perspective view of the fractured bone, after that the fracture has been reduced by the orthopedist (e.g. through forceps) during the application of the fracture reduction device 100 to maintain stable the reduction. To this end, the orthopedist juxtaposes the fracture reduction device 100 to the reduced fracture with the rear surface 102 directed towards the bone in correspondence of the fracture line. The orthopedist inserts the tab 120 into the pass-through slot 137 until interaction with the rack formed by the teeth 112 and continues with such insertion, tightening the loop thus formed by the fracture reduction device 100 until the rear surface 102 enters into contact with the two stumps 200 and 250 of the bone in correspondence of the fracture line, thus making fracture reduction stable. In other words, tightening of the fracture reduction device 100, carried out in a simple manner by pulling the tab 120 after that it has been inserted into the pass-through slot 137 of the head 136, maintains the tension reached thanks to the system of rack-ratchet interaction, i.e. by maintaining the radial compression on the two due stumps 200 and 250 even when no pulling force is exerted anymore on the tab 120. In particular, the shape of a spherical cap (or in any case with smooth edges) of the head 136 allows to avoid damages on the tissues with which it enters into contact. Figure 5 shows a configuration of the fracture reduction device 100 wherein the tab 120 is inserted into the pass-through slot 137 but the loop thus formed is not yet completely tightened, whereby not the whole rear surface 102 is yet entered into contact with the two stumps 200 and 250 of the bone in correspondence of the fracture line. Advantageously, as shown in Figures 3, 5 and 6, the fracture reduction device 100 is tightened on the fractured bone so that the second end section 130 is positioned at a position diametrically opposite to the zone of the fractured bone where the fixation plate 300 will be applied.

In particular, the three discs 133, 134 and 135 facilitate the orthopedist to grip and to control handling of the fracture reduction device 100 in the phase of perimetral application to the fractured bone. Also, the three discs 133, 134 and 135 facilitate, through twisting and pushing, movements of the fracture reduction device 100 between fractured bone and soft tissues adhering thereto. Furthermore, the larger surface of the fracture reduction device 100 in correspondence of the joining portion 132 (having the three discs 133, 134 and 135) with respect to the width CW of the central section 110 allows a better tightening of the reduced fracture.

As shown in Figure 6, once that the fracture reduction has been made stable by the application and tightening of the fracture reduction device 100, the orthopedist may apply the fixation plate BOO on the two stumps 200 and 250 in correspondence of the fracture line to stabilise the fracture. Advantageously, the fixation plate 300 is applied on the fractured bone with its own longitudinal axis P substantially parallel to the longitudinal axis of the fractured bone, and so that it is arranged in a substantially symmetrical manner around the fracture line, whereby the ten sections 310 are distributes between the two stumps 200 and 250.

When it has been tightened, the portion of the fracture reduction device 100 going from the tip 122 of the tab 120 up to the head 136 (that is still partially visible in Figure 6) may be cut and removed by the orthopedist before or after the application of the fixation plate 300. In this regard, the projecting spherical shape of the head 136 further allows to control and carry out in a simple and reliable way the removal of such portion of the fracture reduction device 100.

Also, after the application of the fixation plate 300, it is possible to remove the loop formed by the fracture reduction device 100 apart from the portion underneath the fixation plate 300. In any case, such remaining portion does not involve any problem since the fracture reduction device 100 is made of biocompatible material, optionally resorbable. In this regard, it is also possible to leave in situ, inside the human or animal body, the entire loop formed by the fracture reduction device 100, thanks to the fact that the material is biocompatible, optionally resorbable, and also thanks to its shape devoid of sharp edges.

A particular embodiment of the invention comprises, in association with the fracture reduction device, also a fixation plate, having a surface configured to enter into contact and to be fixed on a bone that is provided with one or more grooves each one of which has a thickness configured to house a portion of the fracture reduction device (optionally a portion of the central section 110) when the fixation plate is fixed to the bone. Advantageously, such one or more grooves are symmetrically distributed with respect to the centroid of the fracture reduction device.

The preferred embodiments of this invention have been described and a number of variations have been suggested hereinbefore, but it should be understood that those skilled in the art can make other variations and changes without so departing from the scope of protection thereof, as defined by the attached claims.

Claims

1. Fracture reduction device (100), configured to contact a human or animal bone, having an elongated planar flexible body, made of biocompatible material, extending along a longitudinal axis (L) and having a first surface (102) configured to contact a bone and a second surface (104) opposite to the first surface (102), wherein the elongated planar flexible body comprises:

a central section (110) provided on the second surface (104) with a plurality of teeth (112) arranged transversely to the longitudinal axis (L) of the elongated planar flexible body and forming a rack,

a first end section (120), and

a second end section (ISO) provided with a head (136) that protrudes from the second surface (104) and is provided with a pass-through slot (137) having at least one pawl (138) operating as ratchet configured to elastically interact with said rack formed by the plurality of teeth (112) and to allow the first end section (120) and the rack to be exclusively inserted into the pass-through slot (137) to make a loop an inner surface of which coincides with the first surface (102),

wherein the head (136) has shape of a spherical cap protruding from the second surface (104).

2. Fracture reduction device (100) according to claim 1, wherein a height of the head (136) is lower than the radius of the spherical cap.

3. Fracture reduction device (100) according to claim 1 o 2, wherein the second end section (130) comprises a joining portion (132) joining the head (136) to the central section (110).

4. Fracture reduction device (100) according to claim 3, wherein the joining portion (132) is shaped so as to form three discs (133, 134, 135) aligned to each other along the longitudinal axis (L), optionally partially overlapping each other.

5. Fracture reduction device (100) according to claim 4, wherein the three discs (133, 134, 135) are equal to each other and a base of the spherical cap has a diameter (HW) equal to a diameter (DW) of the three discs (133, 134, 135).

6. Fracture reduction device (100) according to any one of the preceding claims, wherein the pass-through slot (137) extends along an axis (S) that is orthogonal to the longitudinal axis (L) of the elongated planar flexible body.

7. Fracture reduction device (100) according to any one of the preceding claims, wherein the first end section forms a tab (120) ending with a tip (122) having a width (TW) lower than a width (CW) of the central section (110).

8. Fracture reduction device (100) according to any one of the preceding claims, wherein the biocompatible material is resorbable by a human or animal body.

9. Fracture reduction and stabilisation assembly comprising:

- a fracture reduction device (100) according to any one claims 1 to 8, and

a fixation plate, having a surface configured to contact and be fixed on a human or animal bone, that is provided with one or more grooves each one of which has a thickness configured to house a portion of the fracture reduction device (100), optionally a portion of the central section (110) thereof, when the fixation plate is fixed to the bone.