Cross-Reference to Related Applications

This patent application claims priority of Italian Patent Application No. 102021000014345 filed on June 1, 2021, the entire disclosure of which is incorporated herein by reference.

Technical Field of the Invention

The present invention relates to an external fixing system for an orthopaedic exoskeleton.

Background of the Invention

Usually external exoskeletons for orthopaedic use comprise support elements (such as bars and/or screws and/or threads) and serve to stabilise a limb following a major trauma. More specifically, exoskeletons are used to reduce the risk of secondary trauma and achieve primary stabilisation by giving the patient's body time to recover from the acute phase before subsequent surgery.

One of the most important components of external exoskeletons of the type described above is the fixing system, which is an orthopaedic device capable of rigidly connecting two transverse support elements (screws and/or bars and/or threads).

Figure 1 shows a first example of a fixing system A of the prior art. Such fixing system A comprises a clamp B, which has a first clamping seat C designed to house a first bar (or screw); a clamp D, which is adjacent and connected to the clamp B in a rotary manner and has a clamping seat E designed to house a further bar. A spring is arranged about a rod (partially illustrated) connecting the clamps B and D to allow a relative rotation of such clamps. In use, it is possible to rotate a knob F to screw the rod into the clamp D and then bring clamps B and D closer so as to block the relative rotation of such clamps B and D and tighten the seats C and E to clamp the bars arranged there.

The fixing systems of this type have several problems among which the following may be mentioned:

• difficulty in closing the clamps; as it is necessary to apply a large rotational force on the knob F in order to have a secure lock;

• when a high force is applied to the knob F, a leverage effect is caused on the bars connected to the fixing system, which may, therefore, be easily damaged;

• need to use torque wrenches to understand whether the correct force is being applied (applying too much force would risk breakage);

• the correct relative orientation of the two clamps B and D is difficult to achieve, since, thanks to the interposed spring, the clamps are freely rotatable with respect to each other; • the system is little flexible, as it is only possible to use bars and/or screws with specific defined diameters (in particular, very thin bars or screws are difficult, if not impossible, to be clamped). Figures 2 and 3 show a second example of a fixing system

A' of the prior art. Such fixing system A' is essentially identical to the fixing system A, from which it differs only in that an Allen key G is screwed in instead of turning the knob F to lock the relative movement of the clamps B and D. The fixing system A' has fewer problems related to the leverage effect exerted on the bars/screws. However, it has the drawback of making stable locking difficult, as the force required to tighten the Allen key G is very high.

US2012150181A1 discloses a fixing clamp for use in an external fixing system to retain bone fragments adjacent to each other with the aid of fixing elements. A first jaw and a second jaw are in contact with each other via respective contact surfaces. Two orientation devices extend from the contact surfaces and serve to orientate the first jaw with respect to the second jaw.

US2015308478A1 discloses a locking device for positioning longitudinal fixing elements and includes a first clamp having a substantially S-shape defining a first and second locking opening to receive longitudinal fixing elements therebetween; and a second clamp comprising a first and a second locking arm defining a third locking opening to receive a longitudinal fixing element therebetween.

WO2020239815A1 discloses an external fixator clamp comprising: a first coupling provided with at least one bar housing seat; a second coupling provided with at least one bar housing seat; a connector which, in a clamped configuration, passes through the first coupling and the second coupling locking the bars and/or bone screws within the bar housing seats. Aim of the present invention is to provide an external fixing system for an orthopaedic exoskeleton, which system allows to overcome, at least partially, the drawbacks of the prior art and is, at the same time, easy and cheap to manufacture . Subject and Summary of the Invention

According to the present invention, there is provided an external fixing system as claimed in the hereinafter independent claim, and preferably in any one of the claims dependent directly or indirectly on the independent claim. Brief Description of the Drawings

The invention will be hereinafter described with reference to the accompanying drawings, which show some non limiting embodiments thereof, wherein:

- Figure 1 is a side view of a fixing system of the prior art; - Figure 2 is a perspective view of an additional fixing system of the prior art;

- Figure 3 is a side view of the system of Figure 2;

- Figure 4 is an exploded perspective view of a fixing system according to the present invention;

- Figure 5 is a side view of the fixing system of Figure

4;

- Figure 6 is a front view of the fixing system of Figure 4;

- Figure 7 is a sectional side view along the line VII- VII of Figure 6; and

- Figure 8 is a perspective view of the fixing system of Figure 4.

Preferred Embodiments of the Invention

In Figure 4, numeral 1 indicates as a whole an external fixing system for an orthopaedic exoskeleton (known per se and not depicted), which comprises two support elements (e.g. bars and/or screws and/or threads).

The fixing system 1 comprises a clamp 2, which has two jaws 3 and 4 and a clamping seat 5 designed to (configured to) house a first support element ES (schematically shown in Figure 5), and a clamp 6 which is adjacent to and connected to clamp 2 (in an orientable manner, more specifically rotatable about a rod 17 - described in more detail below) and has two clamping jaws 7 and 8 and a clamping seat 9 designed to (configured to) house a second support element ESS.

According to some non-limiting embodiments, the jaw 4 is arranged between the jaw 3 and the jaw 7 and the jaw 7 is arranged between the jaw 4 and the jaw 8.

According to some non-limiting embodiments, the system

1 further comprises a locking assembly 10 for limiting, in particular locking, the relative orientation (in particular, rotation; more specifically, about a rod 17 - described in more detail below) of the clamps 2 and 6 with respect to each other. The locking assembly 10 comprises a backing element 11, which is arranged on the opposite side of the clamp 2 relative to the clamp 6 (in other words, the clamp

2 is arranged between the backing element 11 and the clamp 6), in particular to exert a force on the clamp 2 towards the clamp 6.

Advantageously, but not necessarily, the system 1 (more precisely, the locking assembly 10) also comprises an elastic element 12 (e.g. a spring - see, in particular, Figure 4), in particular arranged between the clamp 2 and the clamp 6.

Note that the particular position of the elastic element 12 allows, in a rest condition (i.e. when external forces are not applied to the system 1), to keep the clamps 2 and 6 spaced apart, making it possible to easily (at least partially) change their relative orientation. According to some non-limiting embodiments, the locking assembly 10 comprises at least one locking element 13 (shown in hatching) arranged on the clamp 2, and a locking element 14, which is arranged on the clamp 6 and designed to (configured to) couple with the locking element 13 to limit (more precisely, to lock) the relative rotation of the clamps 2 and 6 with respect to each other.

More precisely, but not necessarily, the locking element 13 is arranged on the jaw 4 and the locking element 14 is arranged on the jaw 7. The jaws 4 and 7 face each other and are arranged between the jaws 3 and 8.

According to some non-limiting embodiments, the locking elements 13 and 14 have respective shapes that are substantially complementary to each other. In particular, at least one of the locking elements 13 and 14 has at least one protrusion 15. At least the other one of the locking elements 13 and 14 has at least one seat (a recess) 16 designed to (configured to) be engaged by the protrusion 15 to limit, in particular lock, the relative rotation of the clamps 2 and 6 with respect to each other.

Advantageously but not necessarily, the locking elements 13 and 14 each have a plurality of protrusions 15 and a plurality of seats 16, which are (designed to be) engaged by the protrusions 15. According to the embodiment shown, each protrusion 15 extends radially with respect to a circumference defined by a succession of the protrusions 15 themselves.

In particular, the locking elements 13 and 14 are knurled.

According to some non-limiting embodiments, the system

I (in particular, the locking assembly 10) also comprises a connecting rod 17 (cylindrical with circular cross-section), which is connected to the clamp 6 (in particular, it is mounted integral with the jaw 8) and to the backing element

II and is passed through the clamp 2. In particular, the first clamp 2 is (at least partially) sliding along the rod 17.

Advantageously, but not necessarily, the spring (of the elastic element 12) is arranged around the rod 17.

More precisely, the connecting rod 17 extends through holes 18 (pass-through holes) of the jaws 3, 4, 7 and is connected to the jaw 8. In particular, the holes 18 are substantially circular in shape.

According to some non-limiting embodiments, the backing element 11 is mounted (in particular, in a substantially integral manner) on one end of the rod 17 (opposite to another end, on which the jaw 8 is mounted).

According to some non-limiting embodiments, the locking assembly 13 comprises a hooking system (not shown) between the rod 17 and the clamp 6 (in particular, the jaw 8), which coupling system is designed to (configured to) normally keep the distance between the backing element 11 and the clamp 6 fixed (in other words, the coupling system secures the rod 17 to the clamp 6). In particular, the hooking system comprises two threads, which are designed to (configured to) cooperate to allow the backing element 11 to move closer to or further away from the clamp 6. More precisely, one of the threads is arranged in the clamp 6 (in particular, in the jaw 8) and the second thread is arranged on the rod 17 (in particular, at the end of the rod 17 opposite the backing element 11).

According to some non-limiting embodiments (such as the one shown), the backing element 11 also acts as a knob and may be used by the operator as a grip to rotate the rod 17. Each jaw 3, 4, 7 and 8 has a respective locking surface

20. The locking surfaces 20 of the jaws 3 and 4 at least partially enclose the clamping seat 5; the locking surfaces 20 of the jaws 7 and 8 at least partially enclose the clamping seat 9. Each jaw 3, 4, 7 and 8 has one end 21 opposite the respective locking surface 20.

Advantageously, but not necessarily, the clamp 2 comprises two additional clamping seats 23 and 24, which are configured to house the first support element ES and are arranged at the end 21 of the jaw 3.

Referring in particular to Figure 5, advantageously but not necessarily, the seat 23 is configured to house the first support element ES with a cross section smaller than a cross section of the first support element ES which the seat 5 is configured to house. Additionally or alternatively, the seat 24 is configured to house the first support element ES with a cross section smaller than the cross section of the first support element ES that the seat 23 is configured to house.

In this way, it is possible to lock support elements of different sizes and types with a single fixing system 1.

In this regard, for example, the seat 5 is designed to (configured to) house the first support element ES with a cross section ranging from about 10 mm to about 14 mm (in particular, around 12 mm). Additionally or alternatively, the seat 23 is designed to (configured to) house the first support element ES with a cross section ranging from about 4 mm to about 8 mm (in particular, to about 6 mm). Additionally or alternatively, the seat 24 is designed to (configured to) house the first support element ES with a cross section ranging from about 1 mm (in particular, from about 1.5 mm; more specifically, from about 1.8 mm) to about 4 mm (in particular, to about 3.5 mm).

More precisely, the clamping seat 23 has a cross section with a size (area) smaller than a cross section of the clamping seat 5. Additionally or alternatively, the clamping seat 24 has a cross section smaller than the cross section area of the clamping seat 23.

In this regard, for example, the seat 5 has a cross section ranging from about 10 mm to about 14 mm (in particular, about 12 mm). In addition or alternatively, the seat 23 has a cross section ranging from about 4 mm to about 8 mm (in particular, to about 6 mm). Additionally or alternatively, the seat 24 has a cross section from about 1 mm (in particular, ranging from about 1.5 mm; more specifically, from about 1.8 mm) to about 4 mm (in particular, to about 3.5 mm).

It should be noted that typically, but not necessarily, the seats 5, 23 and 24 (and also 9) have an elongated shape with open ends.

Advantageously, but not necessarily, the clamping seat 24 is arranged between the clamping seat 5 and the clamping seat 23. In particular, the clamping seat 24 is arranged between the connecting rod 17 and the clamping seat 23.

It has been experimentally surprisingly observed that these mutual seat positions make the system 1 usable quickly and easily. For example, by reversing the position of the seats 23 and 24, the seat 23 becomes difficult to reach.

According to some non-limiting embodiments, it should be noted that the clamping seats 23 and 24 are each delimited by respective locking surfaces of the jaws 3 and 4.

Advantageously, but not necessarily, the system 1 also comprises an adjustment block 26, which is arranged so that the jaw 3 is between the adjustment block 26 and the jaw 4. The adjustment block 26 has a coupling surface 26a, which faces the jaw 3 and is concave (towards the jaw 3) so as to allow the jaw 3 to swing with respect to the jaw 26 itself.

Advantageously, but not necessarily, the jaw 3 has a coupling surface 3b, which faces the adjustment block 26 and is convex to allow the jaw 3 to swing with respect to the adjustment block 26. In particular, the coupling surface 3b is configured to slide on the coupling surface 26a.

According to some preferred but not limiting embodiments, the adjustment block 26 comprises a recess 27 arranged on one edge of the adjustment block 26 and delimited by two overhangs 28. The jaw 3 comprises an overhang 29 which is arranged (at least partially) in the recess 27 (so as to partially limit the relative oscillation between the adjustment block 26 and the jaw 3). In particular, the overhang 29 and the recess 27 cooperate to prevent the adjustment block 26 and the jaw 3 from rotating relative to each other (around the rod 17).

In particular, the (lower) ends of the overhangs 28 define parts of the locking surface 20 of the seat 5.

Advantageously, but not necessarily, the adjustment block 26 has an opposing surface 26b, which is arranged opposite the coupling surface 26a and is essentially plane. In this way (thanks to the interaction between the backing element 11 and the surface 26b), it is possible to limit the oscillation (in other words, the change in inclination) of the adjustment block 26 with respect to the rod 17.

According to some non-limiting embodiments, the backing element 11 has a pushing face 31 facing the adapter adjustment block 26 at least with a portion substantially perpendicular to the rod 17. In particular, such at least one portion is parallel to the opposing surface 26b.

Advantageously, but not necessarily, the system 1 also comprises an intermediate element 32 (specifically, a washer), which comprises a pushing surface 32a substantially parallel to the opposing surface 26b. It was experimentally observed that the element 32 improves load distribution, aids smoothness and prevents the backing element 11 from damaging the surface 26b.

According to some non-limiting embodiments, the intermediate element 32 is arranged between the backing element 11 and the clamp 2, in particular, between the backing element 11 and the adjustment block 26.

Advantageously, but not necessarily, the adjustment block 26 is arranged between the backing element 11 and the first clamp 2 and has a through-hole 30 through which the connecting rod 17 extends with such a play as to allow the inclination of the adjustment block 26 itself to be modified with respect to the connecting rod 17.

Advantageously, but not necessarily, the through-hole 30 of the adjustment block 26 and the through-hole 18 of the jaw 3 are configured in such a way that the adjustment block 26 may change its inclination with respect to the rod 17 less than the jaw 3 can change its inclination with respect to the rod 17. In particular, the through-hole 18 of the jaw 3 is wider than the through-hole 30 of the adjustment block 26.

According to some non-limiting embodiments, the jaw 3 has a coupling surface 3a. The jaw 4 has a coupling surface 4a, which is facing (in particular, in contact with) the coupling surface 3a, and a coupling surface 4b (in particular, opposite the surface 4a).

More precisely, but not necessarily, the jaw 4 (in particular, the surface 4a) has at least one seat 33 and the jaw 3 (in particular, the surface 3a) has an overhang 34, which engages the seat 33 so that the jaws 3 and 4 keep their relative positions (and, in particular, do not rotate about the (longitudinal) axis of the rod 17 and/or do not move transversely to the axis with respect to each other).

Advantageously, but not necessarily, the seat 33 has some play for the overhang 34 so that the jaw 3 can change its inclination with respect to the jaw 4 (and with respect to the rod 17).

According to some non-limiting embodiments, the jaw 4 (in particular, the surface 4a) has two seats 33 arranged on opposite sides of the rod 17. In these cases, similarly, the jaw 3 (in particular, the surface 3a) has two overhangs 34, each of which engages one of the respective seats 33.

In addition or alternatively, the third jaw 7 has a coupling surface 7a, which is facing (in particular, in contact with) the coupling surface 4b, and a coupling surface 7b (in particular, opposite the surface 7a). The jaw 8 has a coupling surface 8a, which is facing (in particular in contact with) the coupling surface 7b.

In particular, the connecting rod 17 extends through the holes 18 with such a play as to allow the angle of the jaws 3, 4, 7 (and 8) to be modified in relation to the connecting rod.

Advantageously, the area (more precisely, the diameter) of the hole 18 of the jaw 3 is larger than the area of the holes 18 of the jaws 4 and 7.

According to some embodiments, the hole 18 of the jaw 3 has an area ranging from 200 mm ² (in particular, from 225 mm ² ) to 300 mm ² (in particular, to 275 mm ² ). Alternatively or additionally, the holes 18 of the jaws 4 and 7 have, each independently of the other, an area ranging from 100 mm ² (in particular, from 125 mm ² ) to 200 mm ² (in particular, to 175 mm ² ). Alternatively or additionally, the rod 17 has the cross section with an area ranging from 80 mm ² (in particular, from 100 mm ² ) to 140 mm ² (in particular, to 120 mm ² ). It should be noted that the rod 17 (having to pass through the holes 18) still has a cross section smaller than the holes 18 (at least at the holes 18 themselves).