WO1990009157A1

WO1990009157A1 - Rehabilitory knee brace

Info

Publication number: WO1990009157A1
Application number: PCT/US1989/000557
Authority: WO
Inventors: Edwin R. Scott
Original assignee: Scott Edwin R
Priority date: 1989-02-10
Filing date: 1989-02-10
Publication date: 1990-08-23
Also published as: EP0414801A1; EP0414801A4

Abstract

A knee support useful in knee and leg braces for functional devices by restricting ligamentous instabilities of the knee having a rigid lower cuff (20) including a shell (21) molded to the leg beneath the knee and a strap (25) to encircle the leg; an upper cuff (22) including crossed, non-resistent straps (41, 42) to position anteriorly of the thigh and a strap (44) to encircle the thigh and the crossed straps and a pair of hinges (10, 11) to extend along opposite sides of the knee and rigidly connected to the shells and having crossed straps attached thereto with the improvements including condylar pads (60, 61), semi rigid moldable lower cuff (20) and range and motion limiting means over the hinges.

Description

REHABILITORY KNEE BRACE

BRIEF DESCRIPTION OF THE INVENTION

1. Field of the Invention.

This invention relates to a knee brace and particularly t knee and leg braces which provide for hinged movement of the knee while at the same time providing for lateral and rotational stability to the knee joint. More particularly, this invention relates to an improved functional knee brace which restricts the ligamentous instabilities of the knee and

~ _* ^• at the same time provides for adjustable restraints.

2. Prior Art.

The human knee is subjected to a great deal of stress and strain, and in particular during running and jumping movements Athletes, in particular, are very prone to incur a knee injury as a result of a blow to the side of the knee or to a twisting of the knee joint. Such injuries are especially likely to occur during participation in contact sports.

The knee joint is made up of two condyloid joints and a third joint, partly arthrodial, but not completely, since the articular surfaces are not mutually adapted to each other, so that the movement is not a simple gliding motion. The principal movements that take place at the knee-joint_*are flexion and extension. The movements of flexion and extension at this joint differ from the axis around which motion takes ^■place is not fixed, but shifts forward during extension, as a gliding movement is superposed on the rolling, and shifts backward during flexion.

Persons who have sustained knee injuries, who have had operations to remove cartilage, or who have weak knee joints from causes, such as arthritis or athletes who have sustained an injury to the medial collateral ligament or lateral collateral ligament of the knee, require protection, principally against lateral motion of the knee, that is, such motion may be the result of a blow to the side of the knee. At the same time, a suitable knee support should not interfere with the normal flexion and extension of the leg. The support should protect the knee joint against sidewise motions during both flexion and extension; this means that the supporting structure should continue to lie parallel to the upper and lower parts of the leg in all positions of the leg and support structure, while the support structure remains substantially at the knee joint center and provide protection to the knee.

It is very important that the knee support provide functional stability without pistoning, migrating or shifting on the leg at the knee joint. Without the elimination of pistoning and shifting it was found that a dramatic shift in soft tissue of the thigh (quadriceps and hamstrings) takes place during knee flexion. It has also been found that the wide variety of polycentric joints used in other braces do not approximate the external axis shift any better than a single axis hinge. The external axis shift, includes the movement of soft tissue, and its effect on the pistoning phenomenon. The external shift is nearly 4 times the shift measured internally. This shift has caused a problem to manufacturers who have attempted to mimic this internal axis shift with a variety of innovative polycentric joints. These devices would probably b effective if the braces could be attached to the femur and tibia. However, braces and supports are attached to soft tissue and therefore support design must take into account the effect of soft tissue movement.

-*.

The knee braces proposed in the past have employed rigid upper and lower cuffs to accommodate the hinge of the brace. In such braces, there is a tendency for the brace to angularly shift away from and then back against the wearer's leg as the knee flexes and extends. This shifting or "pistoning" action results in eventual slipping or migration of the brace towards the ankle.

OBJECTS OF THE INVENTION An object of the present invention is to provide for an improved functional knee support which permits and provides freedom of movement of the knee during flexion and extension without restriction or physical discomfort during wearing and movement of the knee.

Another object of the present invention is to provide an improved functional knee support assembly which permits and provides for use on an already injured knee and provides prevention of further injury or strain.

Another object of the present invention is to provide a rigid functional knee support in the form of a knee brace which restricts the ligamentous instabilities of the knee.

It is another object to provide such a functional knee support that does not interfere with normal extension and

flexion of the wearer's leg, while preventing sideways motion of the knee joint whether the leg is flexed or extended.

Yet another object of the present invention is to provide a knee support having a rigid, moldable lower leg engaging member or cuff that will engage the anterior of the leg and cooperate with the tibia to provide an immobilized reaction member for the brace while also having a moldable upper cuff that will accommodate customary knee bending.

Another object of the present invention is to provide a rehabilitory knee support with adjustable condylar pads, moldable upper and lower cuffs, and having a range or motion limiting device cooperating with the hinge.

Other objects and features of the invention will become apparent from the following detailed description and drawings, disclosing what is presently contemplated as being the best mode of the invention. FEATURES OF THE INVENTION Principle features of the functional knee support of this invention include a non-rigid, formable moldable lower leg cuf to engage the soft tissue about the tibia and a wide elasticized rubberized strap that will provide a%ι interior cushion for the non-rigid member and wraps fully around the non-rigid member to immobilize the member with respect to the tibia.

Crossing straps are provided to fit across the front to the user's thigh, above the knee, and the crossing straps are connected to upper, extension arms, of hinge assemblies, the lower portions of which are rigidly affixed to the lower semi¬ rigid formable member. A flexible pad, connected to one of th upper extensions is adapted to extend around the rear of the user's leg, above the knee and a wide, elasticized rubber strap, is connected to the other of the upper links, and is adapted to be attached to the flap and to extend fully around the crisscross straps and the flap, to properly position the crisscross straps above the knee. Another strap extends from one of the rigid hinge members around the leg, above the calf to be adjustably secured to the other rigid hinge member.

The knee support of the present invention includes a support structure comprising a pair of rigid linking support bars positioned in proximate position beside the knee joint on on each side of the knee. Whereas prior devices have a substantially concave off-set through the proximate position over the side of the knee, the present knee support has provided adjustable condylar pads placed along side the knee joint opposite the injured ligament for better fit and comfort.

In the preferred embodiment, the present invention encompasses a knee support for functional use in activities after ligament injury. With the formable semi-rigid cuffs especially the non-rigid thigh design allows for hypertrophy or atrophy of the thigh musculature without compromising the fit of the brace. The brace can therefore be used as a post- injury, post-operative support as well as a functional knee orthosis.

Other objects, features and advantages will appear from the following description of a preferred embodiment of the invention, taken together with the attached drawings, in which:

FIG. 1 shows an example of an adjustable hinge pivot joint as incorporated in the present invention;

FIG. 2 shows the knee support in position on the knee prior to fastening the wraps and straps;

FIG. 3 is a side view showing the knee support partially in place on the knee with the knee in 45 degree of flexion;

FIG. 4 is a frontal view showing the knee support in place and secured on the knee joint according to the present invention.

DETAILED DESCRIPTION Referring to the drawings:

In the illustrated preferred embodiment, the knee support of the present invention, shown generally at FIG.1-4, includes a lower semi-rigid moldable cuff 20 and an upper cuff 22 inter¬ connected by pivoting links 30 and 31.

The lower cuff 20 comprises a semi-rigid moldable shell 21, made of, for example, aluminum, or other suitable moldable materials, and hand moldable to fit around the anterior portion of the lower leg, beneath the knee, of the user. The shell is made to extend from approximately two inches below the knee cap for a distance of between four and five inches. It has been found that if the width of the shell is less than about three inches it does not provide sufficient gripping action to accomplish the stabilization required for the knee brace. Also, it has been found that if the shell is over about six inches in width it becomes too uncomfortable for the user and adds additional undesirable weight to the brace. A lower wide strap 25 fully covers the inside of the moldable shell 21 extending slightly beyond one end of the shell and above and beyond the top and bottom edges thereof with sufficient length to allow the strap to be passed around the posterior of the lower leg and fully around the outside the shell before being secured upon itself by means of eye and hook fasteners 45 which may be "Velcro" fasteners of the well known type. The hook fasteners engage with a napped back surface of the straps, the front surfaces of which are exposed rubberized material. The lower wide strap 25 is made stretchable so that it can be _tfirmly wrapped around the user's leg and the rubberized material will hold the cuff against slippage up and down the leg.

Hinges 10 and 11 each have a lower extension arm 15 riveted at 16 and 17 to the shell 21 and projecting upwardly therefrom to be pivotally connected at 51 to upper extension arm 18 that project further upwardly to serve as components of the upper cuff 22.

Another narrow strap 54 of flexible resilient material ha one end 55 fixed to one lower extension arm 15 above shell 21 and another end 56 adapted to be turned through a D-ring 57 fixed to a free end 58 of a short strap 54, the other end of which is fixed to the other lower extension 15 above shell 22. The strap 54 is adapted to be passed posteriorly around the to of the calf muscle, just below the popileteal space of the use and is tightened up and secured by attached hook connectors 36 on the end of strip 37 to the strap itself.

Upper cuff 22, in addition to the upper arm extension 18, includes a pair of centrally crossing flexible straps 41 and 4 of non-resilient material. Each of the straps 41 and 42 has one end connected to an upper arm extension 18 adjacent to the top thereof and another end connected to the other upper arm extension intermediate the lengths of the arm extensions. The flexible straps 41 and 42 are attached to the upper arm extensions by appropriate attaching means, such as screws. A protective flap 43 preferably made from the same material as strap 44, has a pair of pads 45 and 46 of hooked material and with pad 45 intermediate the length of the strap and pad 46 at a free end of the strap. The other end of strap 43 is attached to the other movable extension arm 18 as by sewing it around the link and by attaching it with appropriate means for attaching. The strap 46 is long enough to extend posteriorly around the upper thigh of the user when t^he crosse straps 41 and 42 are positioned anteriorly on the upper leg. Pad 49 engages and is locked to the napped back side of the protective flap 43 and strap 46 then stretches fully around th leg and over straps 41 and 42 so that the pad 49 will lock on the napped surface of strap 46. The width of the upper cuff, i.e. the distance between ends of straps 41 and 42 on an upper arm extension 18 and the width of the protective flap 43 and strap 46 must be at least four inches to insure proper anchor¬ ing of the cuff to the user's leg.

In using the knee support of the invention the moldable lower cuff is positioned to have the padded shell 25 fit the lower leg and is strapped thereto with strap 54 so that the shell becomes locked to the leg over the tibia. Strap 54 is secured around the leg and the straps 41 and 42 are placed on the upper leg, with the knee-cap between the upper and lower cuffs. The hinges are then on opposite sides of the leg as shown in FIG. 2. The hinges 10 and 11 are angled from the lower cuff 20 to fit closely alongside the leg of the user. While wearing the knee support a user can bend the knee. During such bending action the crossed straps 41 and 42 permit sufficient movement of the upper portion of the support with the thigh to accommodate the bending of the knee about plural pivot points as the knee bends in the usual fashion. Pistoning of the upper and lower cuffs does not occur during use.

The hinges 10 and 11 are preferably covered above the lower cuff by a resilient cushion material for the comfort of the user. The improvement of the present invention includes the positioning of adjustable condylar pads 60 and 61 on the interior of the hinges placed in close proximity to the knee joint.

Although a preferred form of this improved invention has been disclosed and described herein, it is to be understood that the present disclosure is by way of example and explanation and that variations are possible without departing from the subject matter and that in accordance with the doctrine of equivalents, various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

What is claimed is:

1. In a knee support comprising a lower cuff snugly fitted on the anterior lower leg and strap means extending fully around the shell and rigidly connecting the shell to the lower leg; an upper cuff including a pair of crossing, flexible fabric non-resilient straps and spaced upper extension arms comprising components of hinges and a second strap means attached to one of the upper extension arms and adapted to extend around the upper leg and over the crossed straps and hinges including the upper extension arms, interconnecting the lower and upper cuffs, said hinges include lower extension arms rigidly connected to opposite sides of the shell; the improvement which includes (1) adjustable condylar pads positioned interior each hinge area proximate the knee joint, (2) a moldable lower cuff, and (3) continuously adjustable flexion setting means on the hinge.

2. A knee support as in claim 1, wherein the adjustable condylar pads are various sizes to accommodate the fit to the wearer's knee and leg.

3. A knee support as in claim 1, wherein the moldable lower cuff is made of aluminum.

4. A knee support as in claim 1, wherein the adjustable flexion setting is continuous with means to lock or allow limited movement m the leg and knee joint.