WO2011154779A1

WO2011154779A1 - Articulated joint for knee brace to correct varus or valgus knee

Info

Publication number: WO2011154779A1
Application number: PCT/IB2010/052616
Authority: WO
Inventors: Moreno Ferrigolo; Alberto Turrini
Original assignee: F.G.P. Srl
Priority date: 2010-06-11
Filing date: 2010-06-11
Publication date: 2011-12-15

Abstract

A knee brace consisting of a device designed to correct varus or valgus knee, this knee brace substantially consisting of a joint (10) formed by two bars (11, 12) which are united in correspondence with an articulated joint (13), the joint (13) of the knee brace being equipped with a cap (14) which, due to the action of the mechanism, moves away from or closer to the joint at right angles with respect to the plane on which the joint moves angularly, like a sort of pantograph.

Description

"ARTICULATED JOINT FOR KNEE BRACE TO CORRECT VARUS OR VALGUS KNEE"

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TECHNICAL FIELD

This invention concerns an articulated joint inserted in a brace for the knee joint and which is designed to correct the varism or valgism of this joint.

In particular, the joint according to the invention was designed for minor disorders, not serious ones which would require the use of more specific devices.

The mechanics of the knee brace in which the articulated joint according to the invention is inserted consist of the application of the three thrust point principle: one at the condylar area opposite to the one affected by the disorder and two "counter-thrusts" on the femoral and tibial sectors, respectively. This load configuration makes it possible to realign the joint, thus taking the load off the contact are at condylar level .

This joint was also designed to provide dynamic action: that is to say it intervenes during walking so as to increase the pressure on the condyle opposite the one affected by the osteoarthritis when the loading phase starts and the joint has to support the patient's weight.

This invention can be applied in the medical ad orthopedics sector with particular reference to manufacturers of prostheses, braces or ortheses.

BACKGROUND ART

It is known that subjects with varus or valgus knee can, especially when older, present with thinning of the knee joint cartilage.

This thinning can lead to acute or chronic inflammation of the joints or to more or less severe forms of osteoarthritis, all of which are accompanied by pain and limitations in walking.

Traditional braces, designed for subjects with varus or valgus knee with the aim of achieving realignment of the knee joint, are proposed in forms that, through the use of particular hinges fitted on the uprights of the joints, allow application of pressure on the condyle opposite to the one affected by the disorder, thus making it possible to alter the contact between the opposite condyles of the knee joint, reducing the pressure on them and limiting the pain. In these applications the joints are not "active" for the purpose of load application, but the load is only transmitted through them.

Other solutions have, however, been proposed in which the articulated joint is the active element for the transmission of the load; for example the document US- 5807294 presents a brace that consists of a structure with a hinge working at an angle and mobile plates positioned in correspondence with the articulation in order to apply a lateral force on this articulation.

This structure uses screws to adjust the angle of each adjustable plate and consequently of the force applied on the knee joint. Appropriate positioning of the arm of the structure and application of the correct pressure to be exercised on the adjustable plates are not particularly practical operations and cannot be carried out independently and immediately by the person wearing this brace.

In any case, in this solution the thrust on the hinges of the plates is static and can only be activated by the operator, with a bar/joint articulation that is independent of the "thrust" plate, thus obliging the wearer to make continuous adjustments according to personal requirements.

The document US 7500957 B2 proposes a brace equipped with a joint for each arm that allows the joint to be angled towards the knee. A cam mechanism actively angles each arm of the joint, creating a moment which opposes the moment of the disorder.

This brace is designed for the joint to be positioned in the same condylar area as the pathological contact between the tibia and femur, so that the moment which develops is transposed and not direct, with all the consequent problems.

DESCRIPTION OF THE INVENTION

This invention proposes to provide a knee brace designed to correct a varus or valgus knee, and which is able to eliminate or at least reduce the problems described above.

The invention also proposes to provide a knee brace for varus or valgus knee which is relatively simple to produce and which above all uses a dynamic model, that is to say which is able to move the thrust plate according to the angle of the bar/joint without any external intervention .

This is achieved by means of a knee brace for varus or valgus knee, whose features are described in the main claim.

The dependent claims of the solution in question describe advantageous embodiments of the invention.

The main advantage of this solution is that it is a knee brace equipped with an active thrust system integrated in the joint of the knee brace and which therefore does not constrain the structure of the brace which can thus assume various configurations.

The mechanics of the knee brace consist of the application of the three thrust point principle which makes it possible to achieve an unloading effect for the condyle affected by osteoarthritis.

The three thrust points are: one at the condyle opposite to the one affected by the disorder and two "counter-thrusts" on the femoral and tibia sectors respectively.

This device is designed to provide a dynamic action: that is to say it intervenes during walking so as to increase the pressure on the opposite condyle to the one affected by osteoarthritis when the joint loading phase starts and has to support the patient's weight, and this corresponds to a position of around 120° in relative extension between the femur and the tibia.

DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become clear on reading the description below of one embodiment of the invention, given as a non-binding example, with the help of the accompanying drawings in which :

figures 1 to 3 represent schematic views of the knee brace according to the invention, in an opening position at 40°;

figures 4 to 6 represent schematic views of the knee brace according to the invention, at an angle of 120°;

figures 7 to 9 show schematic views of the knee brace according to the invention, according to an open angle of 180°;

figures 10 to 13 show schematic views of the knee brace according to the invention, positioned at 40°, in which the joint is fitted with a cap;

figures 14 to 17 show schematic views of the knee brace according to the invention, positioned at 120°, in which the joint is fitted with a cap;

figures 18 to 21 show schematic views of the knee brace according to the invention, positioned at 180°, in which the joint is fitted with a cap;

figure 22 is an exploded view of the knee brace according to the invention,

figures 23 to 25 show details of the joint on which the cap is fitted.

DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

With reference to the accompanying drawings, the joint according to the invention substantially consists of an articulation 10 formed by two half-sections or bars 11 and 12 which are united at the level of the knee joint: the half-section 11 being applied to the femoral sector and the half-section 12 to the tibial sector.

At the central point, the two femoral 11 and tibial sectors 12 are united in correspondence with the joint 13, constructed as will be seen below, this joint being the particular part of the invention.

In order to exercise the thrust, the joint 13 is equipped with a cap 14 (fig. 12) which, due to the action of a particular mechanism according to the invention, moves away from or closer to the joint at right angles with respect to the development of the plates.

As can be seen in the exploded view in figure 22, starting from the outer area of the device, the joint 13 comprises a plate 15 on which the two bars 11 and 12, whose inner ends consist of toothed sectors 16 and 17, are hinged.

These bars 11 and 12 are provided with housings 18 and 19, in the proposed configuration, for the insertion of straps and zones for positioning the Velcro strips for fixing the joint to the body of the knee brace. A hollow rack 20 is positioned between the toothed sectors of the bars .

Inside the rack 20 is a sliding block 21 which slides along the entire length of the rack when the joint is operational.

The sliding block 21 is provided with an indent which acts as a hinge constraint on a connecting arm 21' whose opposite end is hinged to a frame 22 whose outer ends are equipped with two pins 23 and 24 on which two arms 25 and 26, one at each end of the frame 22, are fitted.

The frame 22 and the two arms 25 and 26 are inserted in specific housings in the cap 14 which represents the mobile part, and which moves at right angles with respect to the plane on which the joint moves angularly, like a sort of pantograph.

The brace is designed to be integral with leg, so the bars 11 and 12 of the joint 10 follow its entire range of movement .

If we imagine assessing this movement starting from the condition of maximum flexion (40° relative angle - Figs. 1 and 10) until the bars form an angle of 120° (Figs. 4 and 14), the mechanism is inactive because the rack 20 which is pushed by the bars 11 and 12 of the joint does not intervene on the sliding block 21.

From 120° to 180° (Figs. 7 and 27), on the other hand, the rack 20 pushes the sliding block 21 causing it to follow the rack, with the consequence that the arm 21' hinged on the sliding block 21 receives a thrust that it transmits to the frame 22. The effects of the geometrical configuration of the connections between the elements generates a "pantograph" movement which causes the cap 14 to move away from the inner plate 15 and thus the thrust action on the knee.

The invention is described above with reference to a preferred embodiment. It is nevertheless clear that the invention is susceptible to numerous variations which lie within the s cope of its disclosure, in the framework of technical equivalents.

Claims

A knee brace consisting of a device designed to correct varus or valgus knee, this knee brace substantially consisting of a joint (10) formed by two bars (11, 12) which are united in correspondence with an articulated joint (13) , said knee brace being characterised in that the joint (13) is equipped with a cap (14) which, due to the action of the mechanism, moves away from or closer to the joint at right angles with respect to the development of the plates, said mechanism comprising a plate (15) on which two bars (11, 12) are hinged and whose inner ends consist of toothed sectors (16, 17) between which a hollow rack (20) is positioned, inside which, during operation of the joint, a sliding block (21) slides the entire length of the rack, this sliding block (21) being provided with an indent which acts as a hinge constraint on a connecting arm whose opposite end is hinged to a frame (22) whose outer ends are equipped with two pins (23, 24) on which in turn two arms (25, 26), one at each end of the frame (22), are fitted, these arms (25, 26) being inserted in specific housings in the cap (14) which represents the mobile part, and which moves at right angles with respect to the plane on which the joint moves angularly, like a sort of pantograph.

A knee brace for varus or valgus knee according to the foregoing claim, characterised in that, in order to exercise the thrust, the joint (13) is equipped with a cap (14) which, due to the action of a particular mechanism according to the invention, moves away from or closer to the joint at right angles with respect to the development of the plates. A knee brace for varus or valgus knee according to either of the foregoing claims, characterised in that the joint (13) comprises a plate (15) on which two bars (11, 12) are hinged and whose inner ends consist of toothed sectors (16, 17) .

A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that these bars (11, 12) are equipped with housings (18, 19) for the insertion of straps and zones for positioning the Velcro strips for fixing the joint to the body of the knee brace and in that a rack (20) is positioned between the toothed sectors of the bars. A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that inside the rack (20) is a sliding block (21) which slides along the entire length of the rack when the joint is operational.

A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that the sliding block (21) is provided with an indent which acts as a hinge constraint on a connecting arm (21') whose opposite end is hinged to a frame (22) whose outer ends are equipped with two pins (23, 24) on which two arms (25, 26) , one at each end of the frame (22) , are inserted.

A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that the frame (22) and the two arms (25, 26) are inserted in specific housings in the cap (14) which represents the mobile part, and which moves at right angles with respect to the plane on which the joint moves angularly, like a sort of pantograph.

A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that starting from the condition of maximum flexion (40° relative angle) until the bars form an angle of 120°, the mechanism is inactive because the rack (20), which is pushed by the bars (11, 12) of the joint, does not intervene on the sliding block (21) .

9. A knee brace for varus or valgus knee according to any of the foregoing claims, characterised in that from 120° to 180° the rack (20) pushes the sliding block (21) causing it to follow the rack, and the arm (21' ) hinged on the sliding block (21) receives a thrust that it transmits to the frame (22) generating a "pantograph" movement which causes the cap (14) to move away from the inner plate (15) and thus the thrust action on the knee.