FR2982167A1 - DEVICE FOR PROTECTING THE ARTICULATION OF THE KNEE SUITABLE TO COOPERATE WITH A SKI SHOE - Google Patents

Abstract

The invention relates to a device for protecting the knee joint of a skier (S) intended to be installed on a ski boot (2) comprising a footwear portion surmounted by a collar (21), the device comprising first connecting means (22a, 22b, 23) for attachment to the collar (21) of the shoe (2) and a shell (10) for at least partially covering the front of the skier's tibia (T) ( S), this shell (10) extending between an upper portion (11) intended to be located at the knee of the skier and a lower end (12) covering a portion of the collar (21) of the shoe (2), the shell (10) supporting, on its upper part (11), lateral cheeks (11a, 11b) adapted to be brought into contact with the knee on either side of the knee being, at least, in contact with the femoral condyles (CF) of the skier (S), the lower part (12) of the hull (10) being intended to partially cover the collar (21) of the boot ( 2) and comprising second complementary connection means (12a, 12b) of the first connection means (22a, 22b) of the collar (21) of the shoe (2) to be secured to the collar (21) of the shoe (2). ).

Description

Title of the invention "Device for protecting the knee joint capable of cooperating with a ski boot".

BACKGROUND OF THE INVENTION The present invention relates to the general field of devices for protecting the knee joint adapted to cooperate with a ski boot comprising, conventionally, a footwear portion surmounted by a collar. Such a device is intended for competitive and / or recreational skiers. Today, the number of knee sprains with or without ligament rupture following a ski fall per year in France is estimated at 17,000. This results in long treatments and often significant sequelae. The direct and indirect costs for the company are very important, evaluated at 300ME per year. It is known that the knee can tolerate a relatively strong stress if it is of very short duration. On the other hand, ligamentous lesions can appear for low stress levels if the stress is maintained for a sufficiently long duration. Knee protection devices are designed to reduce the risk of ligament rupture in a skier's knee. The proper functioning of these devices implies that the joint is protected when it is very stressed while leaving it free of its movements in normal skiing situation. In general, the only safety element that exists to protect the skier's knee is the ski binding. The principle is to release the shoe when the jaws of the binding record a torque greater than a certain trigger threshold. This situation poses two main problems in practice: a competitive skier or an experienced skier will tend to set the trigger threshold of these bindings very high. It will thus avoid nuisance tripping when taking abrupt edges. On the other hand, a fall will be much more risky since the bindings will release more difficult the shoe. A beginner skier can, in turn, be brought to make a very slow fall. The triggering threshold will never be reached even if it is set low enough.

A number of documents among which US 4 136 404, GB 2 436 799 or US 6 524 110 describe systems intended to be hung on the shoe. These systems follow the lower limb, generally on both sides of it, and allow to laterally stiffen the knee joint. For this, in all these documents, it is a question of articulating a rigid upper part on a lower part also rigid, the articulation being located at the level of the knee. These devices have generally not given rise to very limited exploitation or exploitation towards very specific audiences, particularly among people suffering from certain forms of mild disabilities. They are indeed complex to manufacture and not easy to install on the lower limb. Since these devices include a hinge intended to be aligned with the knee joint of the skier, they must also be made to measure.

Thus, we note that these products are not commercially available and are not used by competitors. It should also be noted that tibia fractures may occur instead of or simultaneously with a sprained knee. An excessive bending or twisting of the leg while the foot and ankle are almost locked in the ski boot contributes to the conditions leading to fracture of the tibia. OBJECT AND SUMMARY OF THE INVENTION The main object of the present invention is therefore to limit the risk of ligament and / or bone injury in a ski situation with a device that is simple to manufacture and install on the lower limb and that can be used by a skier. whatever ski pair he uses. For this, the invention proposes a device for protecting the knee joint of a skier intended to be installed on a ski boot comprising a footwear portion surmounted by a collar, the device comprising first connecting means for to be fixed on the collar of the boot and a shell for at least partially covering the front of the tibia, the shell extending between an upper portion intended to be located at the knee and a low end covering a portion of the collar of the boot, the hull supporting on its upper part, lateral cheeks adapted to be placed in contact with the knee on either side of the knee being, at least, in contact with the condyles of the femur, the lower part of the shell being intended to partially cover the collar of the shoe and comprising second connecting means complementary to the first binding means of the collar of the shoe to be solidar with the collar of the shoe. The invention takes account of the fact that the protective device must not interfere with the skier in normal ski conditions and that the natural mobility of the knee depends on its bending angle. Indeed, in full extension, the knee does not allow axial rotation of the tibia relative to the femur. The amplitude of the axial rotation, external or internal, allowed by the knee increases with its bending angle. Thus, at a bending angle of 90 °, the internal rotation, bearing the tip of the foot inwards, combined with the movement of adduction or abduction of the foot is about 30 °. It is about 40 ° in external rotation. The locking of the ankle by the ski boot greatly limits this amplitude of rotation, which is then considered to be less than 20 ° in internal rotation and 25 ° in external rotation, ie a total amplitude of less than 45 °. The object of the invention makes it possible, with a particularly simple manufacture, to limit the risk of injury.

Indeed, the use of simple cheeks bearing on the femoral condyles in combination with a shell shin limited in its movements relative to the ski boot allows to secure the thigh relative to the shoe. This limitation greatly reduces the risk of pathogenic movements of rotation and / or shearing of the knee.

According to an advantageous characteristic, the fastening of the lower part of the shell with the collar of the shoe provided by the combination of the first and second connecting means makes a connection to at least one degree of freedom in rotation of the shell relative to the shoe about an axis substantially parallel to the axis of the collar of the shoe, the connecting means being such that this rotation of the shell relative to the shoe is limited to a predetermined angular sector. With this feature, the connecting means allow a connection to at least one degree of freedom in rotation about an axis parallel to the axis of the tibia. The skier thus retains a satisfactory amplitude of movement in a ski situation. On the other hand, the axial rotation between the tibia and the femur is limited by the presence of the hull. According to a preferred characteristic, the device comprises means for adjusting the predetermined angular sector for limiting this rotation.

This feature allows the skier to adapt the limitation of rotation of the device to his way of skiing. Indeed, it adjusts the threshold beyond which the axial rotation is blocked or at least braked by the device. According to a particular characteristic of the invention, the device is such that the predetermined angular sector is less than 45 °, advantageously less than 30 ° and preferentially less than 14 °. An angular sector located between 45 and 30 ° makes it possible to limit the risks of knee sprains for certain positions of sag while preserving an optimal skiability. Indeed, it is the axial rotation between the tibia and the femur is thus limited. An angular sector of between 30 ° and 14 ° gives a wider protection spectrum of the knee with a minor detriment to the skiability. Such an angular limitation makes it possible in particular not to reach the limit of rupture of the tibia. This provides increased protection for the tibia and knee joint while allowing considerable movement latitude in certain ski situations.

An angular sector less than 14 ° angularly secures the femur with the shoe for a very small angle which ensures the protection of the knee. An angular limitation of 14 ° corresponds on average to the admissible angular amplitude between the tibia and the femur. The protection is optimal because it is guaranteed not to reach it regardless of the other behavior of the tibia. It should be noted here that, generally, the whole foot / ankle / tibia is constrained in such a way in the ski boots that the adduction and abduction are very limited. The movement of the foot relative to the tibia is very limited. During a shock, the skier can not benefit from this angular margin.

Moreover, the limits of rupture of the femur being, in the general case, well beyond those of the sprain of the knee, this risk is low. In the case where the femoral rupture limit is approached during an impact, the device according to the invention may include a mechanical fuse in order to postpone the load on the knee at the risk of seeing a sprain.

In each of the embodiments, the device according to the invention stops or, in the worst case, slows the movement of the thigh in rotation relative to the shoe. The risks of ligament and / or bone damage are thus significantly limited by the presence of the lateral cheeks in contact with the condyles and the limited hinge of the shell on the shoe, this limitation being adapted according to the angular amplitude. maximum allowed by the knee and the user's skiability preferences. In an advantageous implementation of the invention, the first connecting means comprise at least one guide piece intended to be installed in a fixed manner on the collar of the boot, this guide piece being able to cooperate with the second means of connection. connecting the complementary shell of this guide piece to limit the rotation on the predetermined angular sector.

This implementation which involves the installation on each shoe of at least one particular element allowing the operation of the connecting means of the shell allows to control exactly the behavior of the shell relative to the shoe. It is envisaged that these first binding means installed on the shoe are elements present by default on the shoe as a fastener or other element with respect to which the shell will be positioned to be limited in rotation. It is noted here that with this characteristic, only ski boots must be provided beforehand with connecting means to implement the complementary connecting means of the shell without the need to change anything at the level of the pair of skis. In addition, one and the same hull can be perfectly used by the same skier with any one of a plurality of pairs of shoes, all equipped with at least one guide piece according to this implementation. In a particular embodiment, the guide piece comprises at least one rail intended to be fixed on the collar of the boot substantially parallel to the axis of the collar, the second connecting means constituting a groove complementary to the rail, the groove having a spacing wider than the rail width, this spacing allowing the limited rotation around the axis substantially parallel to the collar of the shoe.

The use of such a guide piece forming a rail along the axis of the collar of the shoe in cooperation with a groove carried by the connecting means of the shell allows that, when the groove has a wider spacing. that the width of the rail, it can be mobilized in rotation on a limited angular portion and, in this case, on an angular sector less than 45 ° or preferably less than 30 ° or preferably less than 14 °. The spacing of the groove and the width of the rail will then be determined according to the desired rotation limitation of the shell on the collar of the shoe.

In another embodiment, the guide piece comprises at least one groove intended to be fixed on a lateral side of the collar of the boot substantially parallel to the axis of the collar, the second connecting means constituting a complementary rail of the groove , the groove having a spacing wider than the width of the rail, this spacing allowing the limited rotation about the axis substantially parallel to the collar of the shoe. In this embodiment, the collar of the shoe bears, this time, a groove and the shell which carries a rail capable of being mobilized in the groove through a spacing of the groove greater than the width of the rail. In a preferred feature, the difference between the spacing of the groove and the width of the rail is variable along these structures, this difference in variable width providing a front / rear bending angle between the shell and the shoe. A variable difference in widths between the two structures, grooves and rails, ensures a forward / backward bending angle between the shell and the boot. Indeed, in the case where the top of the groove is wider than the bottom of the groove with a rail of constant width, the shell can have a tilting movement on the front freely. In another embodiment, the spacing of the groove and the width of the rail being constant, the length of the rail is sized to provide a forward / backward bending angle between the shell and the shoe. This embodiment allows pivoting of the groove around the rail. The rail then acts as a pivot within the groove that pivots around the rail. According to a second implementation of the invention, the first or second fastening means comprise at least one strap fastened, on the one hand, to the collar of the boot and, on the other hand, to the shell for securing the shell with the collar of the shoe. This implementation uses either the elasticity of the strap adapted according to the desired rotation limitation, or a particular adjustment of the tightening of the strap then inextensible to allow a limited rotation of the shell relative to the shoe. Such a particular adjustment of the tightening of the strap allowing limited rotational movement on a predetermined angular sector is achieved by means of a mechanical element to lengthen or shorten or maintain a predetermined length of the strap.

This type of device facilitates the establishment of the connection between the shell and the collar. Advantageously, the strap will have a particular length or a particular marking for its adjustment. In the case of the guide piece, the limitation is obtained by adjusting the width of the rail, in the case where a strap is used, the limitation is obtained by the extensibility of the strap, either by initial laxity, or by elasticity. Either the strap is able to limit the rotational movement in both directions, or the strap will be completed by a stop, or two straps are used. Thus, in a particular embodiment, the first or second fixing means comprise two straps, each of which has one end attached to the collar and the other end to the shell, the extension of the straps limiting the rotation in each of the two directions. of rotation. The use of the two straps makes it possible to adjust the rotational movement of the shell in both directions of rotation and to limit this movement in both directions of rotation. In a particular embodiment, the device further comprises at least one abutment piece intended to be fixed on the collar of the boot, the shell further comprising a stop element of the collar complementary to the abutment piece of the collar and able to cooperate with this one to ensure the vertical positioning of the hull along the tibia. The stop piece makes it possible to control the correct vertical positioning of the shell with respect to the tibia and therefore with respect to the lower limb, in a general manner.

In one embodiment, the device being positioned at rest on a lower limb, the cheeks apply a force on the condyles substantially normal to the sides of the thigh intensity in the range] 0.100N]. It is indeed advantageous that the cheeks exert a non-zero force on the condyles of the femur, so that the movement thereof relative to the cheeks of the shell is minimal. In such a case, the only degree of freedom in rotation is offered by the hull connecting means on the collar of the boot and the deformability of the shell material. In an advantageous embodiment, the cheeks are of contour in elliptical portion of principal radius greater than 6 cm, the ellipse being inclined at an angle of between 45 and 135 ° with respect to the main axis of the shell when the device is placed relative to the ski boot. According to the invention in its first definition, the cheek is of any shape and of sufficient size to cover the surface of the condyles of the femur. The preferential use of elliptical contoured cheeks is particularly suitable for lateral support at the lateral flanks of the thigh. The main axis of the hull belonging to the frontal plane of the skier when it is straightened, the orientation of the cheeks allows a correct maintenance of the femur of the skier in ski position without discomfort for it.

Advantageously, the ellipse is inclined at an angle of between 70 ° and 90 ° with respect to the main axis of the shell. Such a particular inclination keeps the relationship between the cheeks and the end of the femur despite the movements of the condyles during flexion / extension of the knee. This inclination also corresponds to an intermediate inclination of the positions of the thigh in motion or at rest. Advantageously, the main radius of the cheeks is between 8 and 11 centimeters. Such a size makes it possible to ensure good coverage of the femoral epiphysis while preventing the skier from being obstructed by the device according to the invention. Advantageously, the shell supports at least one strap provided with a self-gripping tape for its maintenance around the tibia. Such a feature is the simplest way to maintain the shell relative to the shin of the skier in addition to its attachment to the shoe. It has the advantage of being easy to implement and simple handling for the skier. In a preferred embodiment, the contact of the lateral cheeks on the condyles of the femur is ensured by means of ergonomic wedges inserted on the inner face of the cheeks. This characteristic makes it possible to adapt the same shell to various dimensions of condyles by interposing spacers. The same molded shell can thus be used for different sizes of devices but also to achieve personalized devices. In this case, only the shims must be modified to obtain various sizes or a personalized device. The inner surface of the wedges can actually be made to measure to fit the shape of the lower limb of the skier without hindering the flexion / extension of the knee. Advantageously, the ergonomic wedges have a surface resulting from the melting of the surfaces observed at the level of the condyles of the skier for at least two privileged angular positions of the lower limbs of the skier. This personalization feature allows the device to be particularly pleasant to use in all ski positions. In addition, this customization of the protective device according to the invention is very interesting insofar as it ensures a very good connection of the lateral cheeks with the knee. This prevents a penalizing game is present at this level of the device, such a game involving an angle of rotation of the femur relative to the shoe greater than the maximum angle provided by the device according to the invention. Advantageously, the device further comprises linings intended to be in contact with the knee of the skier. This feature makes it possible not to impair the effectiveness of the invention in terms of lateral rotation but allows, on the other hand, to increase the comfort of the skier who does not undergo the direct support of a hull or a hold on the lateral flanks of the thigh. The trimmings are arranged on the inner faces of the cheeks or, preferably, wedges when they are present. The fittings may be made of flexible material of the cellular material type (foam, etc.), or of the gel type (silicone, etc.). Thus, the liner is advantageously made from at least one elastomeric or plastic material of the EVA (ethylene-vinyl acetate) or other type and thermoformable or not and of sufficient thickness and density to allow comfort during the movements. of the lower limb when skiing. More particularly, the material may be a silicone gel in the form of a plate of 1 to 10 mm and preferably 2 to 5 mm.

The shell and shims are advantageously made from an inorganic or organic material, in monolithic or composite form, chosen from the following materials: magnesium, aluminum, titanium, metal alloys, filled or uncharged polymers, reinforced or not, composite resins or not, loaded or not, reinforced or not.

Advantageously, the composite consists of a matrix based on epoxy, polyester or other thermosetting resin, or a thermoplastic resin of the polyamide (PA) or polycarbonate (PC) type, or the like, and at least one reinforcing material. The reinforcement may be based on carbon fiber, and / or fiberglass, and / or aramid, for example Kevlar * brand from the company Dupont de Nemours and or Poly p-phenylene-2,6-bezobisoxazole (PBO) * trademark of the company Toyobo Japan and / or the PIPD M5 from the company Dupont de Nemours, and / or the Ultra High Molecular Weight PolyEthylene (UHMWPE) DYNEEMA brand of the company DSM Holland. The degree of reinforcement in the composite is between 0% and 70%. The reinforcement may be woven or knitted or braided, of the 2D or 3D or unidirectional type, or of cut fiber. Organic or inorganic fillers can be added to the matrix according to the desired specifications. Incidentally, the polymer materials of the matrix as well as the reinforcing fibers may contain carbon nanotubes in order to improve the mechanical characteristics. These materials in general make it possible to ensure good rigidity of the hull and shims while ensuring a good lightness and a certain comfort. On at least one side of the liner in contact with the lower limb, an elastane or elastic-type film or fabric having a thickness of at least 10 μm may be affixed by gluing to said surface to conform to the shape of the liner. the hold. The material of the film or fabric may have a low coefficient of friction. By way of example, the material may be manufactured from polytetrafluoroethylene, PTFE (former Teflon brand DUPONT from Nemours USA).

The thickness of the film or fabric is selected according to the desired mechanical characteristics. In general, the ability to adjust and adapt the device by the use of wedges can adapt the device to the variability of skiers: age, sex, fitness, muscle tone and contraction levels etc ... predicted loading conditions are also so many parameters of adjustment of the device: shearing, lateral bending, speeds, position of the skier, vertical acceleration, prestressing between the device and the knee etc.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will emerge from the description given below, with reference to the accompanying drawings which illustrate an embodiment having no limiting character. In the figures: - Figure 1 shows the principle of the invention; FIGS. 2A to 2E show a first embodiment of the invention; FIGS. 3A to 3E show a second embodiment of the invention; FIGS. 4A to 4E show a third embodiment of the invention; FIGS. 5A to 5C show schematically the principle of a fourth embodiment according to the invention; FIGS. 6A and 6B show a preferred embodiment of the invention; FIGS. 7A to 7C show shims as used in the preferred embodiment of the invention; - Figure 8 shows a device according to the invention, provided with shims according to the preferred embodiment of the invention; Fig. 9 shows a perspective view of a preferred embodiment; - Figure 10 illustrates the effectiveness of the invention.

Detailed Description of an Embodiment 2 982 16 7 12 Figure 1 shows a block diagram of the invention. In this figure, the lower body of a skier S is shown. The skier S wears a ski boot 2, itself attached to a ski 1, via a fastener 1a. The boot 2 has a footwear part and a collar 21. In FIG. 1, the foot P, the tibia T and the femur F of the skier S are represented. The femur F has CF condyles at its distal end. These condyles CF take a plurality of intermediate positions between two extreme positions shown in FIG. 1 as a function of the flexion position of the skier S. In FIG. 1, the skier S carries a device 10 according to the invention. This device 10 comprises an upper part 11 and a lower part 12. The lower part 12 comprises connecting means for securing the shell 10 with the collar 21 of the boot 2. The upper part of the shell 10 has two lateral flanges which come cover the condyles CF of the femur F on either side of the leg of the skier S, this overlap being ensured by the lateral cheeks irrespective of the bending position of the skier S. The lateral cheeks are of contour in portions of ellipse, their major axis being oriented around 50 °. This orientation included between 45 ° and 135 ° makes it possible to obtain a satisfactory support of the femoral condyles and thus a good retention of the femur in rotation relative to the tibia. The following embodiments show preferential orientations of the lateral cheeks between 70 and 90 °. Thus, the lateral cheeks completely cover the distal femoral epiphysis by coming to bear each on either side of the end of the femur, namely on the condyles of the femur CF on each side of the knee. They make it possible to limit the lateral rotation of the femur F relative to the foot P of the skier S. Advantageously, the force with which the cheeks come to press on the condyles will be adjustable. The cheeks apply a force on the condyles substantially normal to the sides of the thigh of intensity in the range 0.100 N]. FIGS. 2A to 2E show a first embodiment of the invention. These figures respectively show a front view of the device 10, a side view, a top view and, after installation on a skier's boot, a side view and a perspective view. The device 10 comprises two lateral cheeks 11a and 11b, intended to be placed on either side of the knee of the skier to come and grip it at the level of the condyles of the femur CF. The lateral cheeks 11a and 11b can themselves be in contact with the garment covering the condyles CF or come into contact with these same condyles CF by means of shims, as will be described later.

The lower part 12 of the device 11 comprises second connecting means 12a and 12b. The second connecting means of the shell 12a and 12b are complementary first connecting means, denoted 22a and 22b, making guide pieces on the collar 21 of the shoe 2. Such first connecting means 22a and 22b are shown on the Figures 2D and 2E.

In the embodiment shown in FIG. 2, the first connecting means 22a and 22b consist of a guide piece formed of two elements denoted M1 and M2 jaw. The second connecting means 12a and 12b are constituted by two tabs denoted La and Lb each slipping between the two pairs of jaws M1 and M2 placed on either side of the collar 21 of the shoe 2. It is noted here that it may be envisaged to use only a single pair of jaws M1, M2 placed on one side of the collar 21 of the shoe 2, preferably the outer side. Indeed, this pair of jaws associated with a tongue of the type shown in Figure 2, is sufficient, strictly speaking, to limit the rotation of the shell relative to the shoe when the shell is also secured to the skier's tibia using a simple Velcro tape. Nevertheless, the use of two pairs makes it possible to make the behavior of the shell more robust and in particular to avoid its global pivoting around the tongue La.

The width of the open space between the two jaws M1 and M2 being greater than the width of the tongue La, the latter can move slightly, this movement causes a movement in rotation on a limited angular sector of the device 10. Thus, the fixing of the device 10 on the collar 21 of the boot 2 offers a degree of freedom in rotation with respect to the boot 2 on a predetermined and limited angular sector. It is noted here that the jaws M1 and M2 may also be positioned so that the tongue is immobilized in rotation. In this case, the attachment of the shell with the shoe is maximum and the protection of the knee is optimal. Indeed, during a movement of the femur in rotation relative to the axis of the ski, it then abuts on the side cheeks 11A and 11b and prevents twisting of the knee. This can, however, affect skiability. Here is therefore understood the advantage of the implementations of the invention for which a freedom of rotation limited in its magnitude is obtained.

The use of a slight angular sector on which the hull 10 has a freedom of movement in rotation is interesting from a skiability point of view. Such freedom of rotation over a limited angular sector does not substantially impair the protection conferred by the invention since the joints concerned have a certain margin of tolerance before deterioration.

In Figure 2, the elements Mi and M2 jaw are fixed relative to the shoe 2. It is noted here that at least one of these elements Mi and M2 may be slidably mounted in order to adjust the lateral space in which the second connecting means 12A and 12b of the hull can move. This thus makes it possible to adjust the angular sector on which the tongues La and Lb of the second connecting means 12a and 12b of the shell 10 can move in the first connecting means 22a and 22b fixed to the collar 21 of the shoe 2. The Figure 3 shows a second embodiment of the invention. In this embodiment, the shell 10 comprises two lateral cheeks 11a and 11b on its upper part 11 which is comparable to the upper part of the previous embodiment. The shell 10 comprises second connecting means 12a and 12b different from those of the previous embodiment. These connecting means 12a and 12b have holes for hanging a strap 13 visible in Figures 3D and 3E. The strap 13 is typically riveted into the orifices 12a and 12b.

The strap 13 is also attached to a support noted 23 mounted on the shoes 2, the support 23 constituting the first connecting means attached to the collar 21 of the shoe. The laxity of adjustment of the strap 13 or its pre-calibrated elasticity makes it possible to limit the rotation of the shell 10 with respect to the axis of the ski 1 and therefore, with respect to the axis of the boot 2 in which is located the skier's foot S. Figure 3 shows a single side strap for reasons of simplicity of representation. It is understood that the implementation of two straps on each side of the shoe 2 is necessary to limit the rotation in both directions. It will be noted here, however, that a single strap fastened at the second connection means 12a and 12b of the shell shown in FIG. 3 may be used with first connection means adapted to the boot 2 to completely adjust. the rotation of the shell 10 relative to the shoe 2. It is also noted that it is possible to use a strap for one of the directions of rotation of the shell relative to the boot 2 and another means of the type of the guide piece shown in the previous embodiment to limit the rotation in the other direction of rotation. In this case, a single guide piece comprising for example two jaws M1 and M2 will be necessary for the implementation of the invention. Figure 4 shows a third embodiment slightly different from the second embodiment. This embodiment uses a strap 13 to secure the lower part 12 of the shell 10 with the shoe. Here the strap is fixed in a lumen 12a but its function is substantially identical to that performed by the strap 13 of Figure 3. It is nevertheless understood that the strap 13 can not really prevent a movement of the shell 10 upwards. This movement would interfere with the operation of the invention and could be giant for the skier. Also, an abutment piece 24 is placed on the shoe 2. This abutment piece 24 is complementary to an abutment element 14, here an orifice of the shell 10. This abutment piece 24 allows the hull 10 to be positioned by compared to the collar 21 of the shoe 2 in its vertical position and to prevent the vertical movements thereof along the skier's tibia. Such a stop piece 24 is also used in the embodiment of FIG. 5. This figure shows a guide piece 22a, which can be directly attached to a lateral side of the collar 21 of the shoe 2. The piece of 22a guide comprises a rail R noted, terminated by a second abutment piece 25, complementary to the stop piece 24. It is understood that the stop piece 25 prevents any downward movement of the hull 10, a portion of which the lower part 12 is shown in Figures 5B and 5C. This lower part 12 of the shell 10 comprises a slideway or groove G which is positioned relative to the rail R by sliding along it. In the perspective view of FIG. 5C, it can be seen that the rail R has a width such that the slideway or groove G can move backwards and forwards at a greater or lesser angle of flexion. This bending angle depends on the play present between the rail R and the slide G. This makes it possible to maintain a satisfactory skia. The spacing between the rail R and the slide G is therefore advantageously adjustable to allow control of the few degrees of rotation of the system about the axis of the shoe 2. Figure 6A shows a shell 10 completed with a shim 30 useful for the positioning of the hull 10 with respect to the skier's leg S. FIG. 6B shows the device of FIG. 6A installed on the skier's leg shown for two extremal bending positions. FIGS. 7A to 7C show different perspective views of the functional lateral parts of shim 30, denoted 30a and 30b. Note that the surfaces of these functional parts of the shim 30 are molded into very specific shapes. These forms correspond to the fusion of the surfaces observed at the level of the CF femoral condyles F between the two preferred positions, which may for example be the extreme bending positions of the thigh of the skier S 20 shown in FIG. 6B. These forms correspond to the fusion of the surfaces observed at the CF condyles of the femur F between the two extreme flexion positions of the thigh of the skier S shown in FIG. 6B. Thus, maximum comfort of the skier is ensured which, between the two most extreme positions, retains a lateral pressure adapted to its morphology, or even personalized, on the condyles of the femur. The functional parts 30a and 30b of the spacer 30 are thus unsymmetrical because the sides of the knee have distinct shapes and deformations during the articulatory movement thereof. On the other hand, a symmetry may exist between the corresponding functional parts of the two knees. Figure 8 shows a preferred embodiment where the shell 10 is provided with two functional parts 30a and 30b. This is the hull adapted for the right knee. The hull of the left knee will advantageously be symmetrical with the hull shown in FIG.

In this figure, the shell 10 has a central stop hole 14 and grooves G, here oblong holes. These grooves G cooperate with a stop or a rail as shown in Figure 5 to provide an angularly limited rotation.

The shell 10 of Figure 8 also includes loops or holes O to allow the placement of a mechanical element which ensures the attachment of a strap. This strap is a strap of the type shown in Figures 3 and 4. In this case the two types of limitation in rotation of the shell according to the invention coexist within the same object.

Nevertheless, a particularly simple and preferential version uses only a strap permanently attached to the shell or the shoe as shown in FIG. 9. In this case, it is the adjustment of the strap fixed in the orifices. O which completely determines the angular sector on which the hull can rotate.

FIG. 10 shows a modeling of the internal rotation, in degrees in the horizontal plane, between the femur and the foot with respect to time for a skier equipped with a device according to the invention on the AKG curve and for a skier devoid of device according to the invention on the SKG curve. It can be seen here that the internal rotation is drastically reduced when the device according to the invention is worn by the skier. It can therefore be expected that the invention, although particularly simple manufacturing and installation on the leg of the skier, provides some improvements in terms of accidents causing a sprained knee. Thanks to its simplicity and its low cost of production, the invention makes it possible to reach a wide audience. Indeed, models carrying standardized lateral cheeks and, preferably, a wedge of functional surfaces calculated from an average of the surfaces of the femoral condyles observed on the population between the two extreme flexion positions in ski conditions.

However, for smaller audiences, typically in the field of competition, the invention also makes it very easy to customize the protection device according to the invention. It suffices to use a hull used for consumer products in combination with functional wedge portions specifically designed and shaped to match the particular morphology, for example of a ski champion. Finally, it should be noted that various implementations can be made according to the principles of the invention defined in the following claims. In particular, the limitation of the rotation of the shell relative to the shoe on a limited angular sector may be implemented by various connecting means having the necessary functions of the invention.

Claims (15)

REVENDICATIONS1. Device for protecting the knee joint of a skier (S) intended to be installed on a ski boot (2) comprising a footwear portion surmounted by a collar (21), the device comprising first connecting means ( 22a, 22b, 23) intended to be fixed on the collar (21) of the shoe (2) and a shell (10) intended to cover at least partially the front of the tibia (T) of the skier (S), this hull (10) extending between an upper portion (11) intended to be located at the knee of the skier and a lower end (12) covering a portion of the collar (21) of the shoe (2), the shell (10) supporting, on its upper part (11), side cheeks (11a, 11b) adapted to be brought into contact with the knee on either side of the knee while being, at least, in contact with the condyles of the femur (CF ) of the skier (S), the lower part (12) of the shell (10) being intended to partially cover the collar (21) of the shoe (2) and comprising sec complementary connecting means (12a, 12b) of the first connecting means (22a, 22b) of the collar (21) of the boot (2) to be secured to the collar (21) of the shoe (2). 2. Device according to claim 1, characterized in that the fastening of the lower part (12) of the shell (10) with the collar (21) of the shoe (2) provided by the combination of the first and second means of link (22a, 22b, 12a, 12b) provides a connection to at least one degree of freedom in rotation of the shell (10) relative to the shoe (2) about an axis substantially parallel to the axis of the collar ( 21) of the shoe (2), the connecting means (22a, 22b, 12a, 12b) being such that this rotation of the shell (10) relative to the shoe (2) is limited to a predetermined angular sector. 3. Device according to claim 2, characterized in that it comprises means for adjusting the predetermined angular sector of limitation of the rotation. 4. Device according to one of the preceding claims, characterized in that the first connecting means (22a, 22b) comprise at least one guide piece (M1, M2, R) intended to be installed in a fixed manner on the collar ( 21) 2 982 16 7 20 of the shoe (2), this guide piece being able to cooperate with the second connecting means (12a, 12b, G) of the shell (10) complementary to this guide piece (M1, M2, R) to limit the rotation on the predetermined angular sector. 5 5. Device according to one of claims 1 to 3, characterized in that the first or second fixing means comprise at least one strap (13) fixed on the one hand to the collar (21) of the shoe (2). and, on the other hand, the shell (10) for securing the shell (10) with the collar (21) of the shoe (2). 10 6. Device according to one of the preceding claims, characterized in that it further comprises at least one stop piece (24) intended to be fixed on the collar (21) of the shoe (2), the hull (10). ) further comprising an abutment element (14) complementary to the abutment piece (24) of the collar (21) and able to cooperate therewith to ensure the vertical positioning of the shell (10) along the tibia ( T). 7. Device according to one of the preceding claims, characterized in that, the device being positioned at rest on a lower limb, the cheeks 20 (11a, 11b) apply a force on the condyles (CF) substantially normal to the flanks of the leg of intensity in the range] 0.100N]. 8. Device according to one of the preceding claims, characterized in that the cheeks (11a, 11b) are of ellipsoid contour principal radius greater than 6 cm, the ellipse being inclined at an angle between 45 and 135 ° relative to the main axis of the hull (10). 9. Device according to claim 8, characterized in that the ellipse is inclined at an angle between 70 and 90 ° relative to the main axis of the shell (10). 10. Device according to one of claims 8 and 9, characterized in that the main radius of the cheeks (11a, 11b) is between 8 and 11 centimeters. 11. Device according to one of the preceding claims, characterized in that the shell (10) supports at least one strap provided with a self-gripping tape for its maintenance around the tibia (T). 12. Device according to one of the preceding claims, characterized in that the contact of the side flanges (11a, 11b) on the condyles of the femur (CF) is provided by means of ergonomic wedges (30) inserted on the inner face cheeks (11a, 11b). 13. Device according to claim 12, characterized in that the ergonomic wedges (30) have a surface resulting from the melting of the surfaces observed at the condyles (CF) of the skier (S) for at least two preferred angular positions of the lower limbs. of the skier (S). 14. Device according to one of the preceding claims, characterized in that it further comprises linings intended to be in contact with the knee of the skier (S). 15. Device according to one of the preceding claims, characterized in that the shell (10) is made from an inorganic or organic material, in monolithic or composite form, selected from the following materials: magnesium, aluminum, titanium, metal alloys, whether or not loaded or unhardened, whether or not reinforced resins, whether or not composite resins, filled or not, reinforced or not.