Knee brace and method for securing the same

BACKGROUND

A. Background Information on Knee Braces

0001Knee braces are widely used to treat a variety of knee infirmities. Such braces may be configured to impart forces or leverage on the limbs surrounding the knee joint in order to relieve compressive forces within a portion of the knee joint, or to reduce the load on that portion of the knee. Moreover, in the event that knee ligaments are weak and infirm, a knee brace may stabilize, protect, support, or rehabilitate the knee. A knee brace according to the preamble of claim 1 is known from <patcit id="pcit0001" dnum="US5316547A"><text>US-A-5 316 547</text></patcit>.

0002The knee is acknowledged as one of the weakest joints in the body, and serves as the articulating joint between the thigh and calf muscle groups. The knee is held together primarily by small but powerful ligaments. Knee instability arising out of cartilage damage, ligament strain and other causes is relatively commonplace since the knee joint is subjected to significant loads during the course of almost any kind of physical activity requiring the use of the legs.

0003A healthy knee has an even distribution of pressure in both the medial and lateral compartments of the knee. It is normal for a person with a healthy knee to place a varus moment on the knee when standing so that the pressure between the medial and lateral compartments is uneven but still natural.

0004One type of knee infirmity that many individuals are prone to having is compartmental osteoarthritis. Compartmental osteoarthritis may arise when there is a persistent uneven distribution of pressure in one of the medial and lateral compartments of the knee. Compartmental osteoarthritis can be caused by injury, obesity, misalignment of the knee, or simply due to aging of the knee.

0005A major problem resulting from osteoarthritis of the knee is that the smooth cartilage lining the inside of the knee wears away. This leads to a narrowing of the joint space with the development of cysts and erosions in the bone ends. Because of the narrowing of the joint, bone comes directly in contact with bone, and an uneven distribution of pressure develops across the knee which may result in the formation off bone spurs around the joint. All of these changes ultimately lead to increasing pain and stiffness of the joint.

0006While there are no cures to osteoarthritis, there are many treatments. Individuals who have a diagnosis of isolated medial compartmental osteoarthritis of the knee are confronted with a variety of treatment options such as medications, surgery, and nonsurgical interventions. Nonsurgical interventions include the use of canes, lateral shoe wedges, and knee bracing.

0007Knee bracing is useful to provide compartment pain relief by reducing the load on the compartment through the application of an opposing external valgus or varus moment about the knee joint. Unloading knee braces have been shown to significantly reduce osteoarthritic knee pain while improving knee function.

B. Prior Art Knee Braces

0008There are many known unloading knee braces. An example of a known brace is described in <patcit id="pcit0002" dnum="US5277698A"><text>U.S. Patent 5,277,698</text></patcit> assigned to Generation II Orthotics, Inc. of British Columbia, which is incorporated herein by reference. Typically, braces of this type are designed to apply a moment about the knee through two mechanisms. The first mechanism is through the angulations of hinge components which induce a bending moment at a hinge. The second mechanism is provided by a three-point bending system via a force strap that spirals around the knee and applies a force to a prescribed aspect of the knee.

0009<figref idref="f0001">Figs. 1 and 2</figref> exemplify the application of forces by the brace on a leg and over a knee joint according to <patcit id="pcit0003" dnum="US5277698A"><text>U.S. Patent 5,277,698</text></patcit>. The arrows B₁ and B₂ show lateral and force strap forces. The resulting moments in the leg due to lateral forces are shown by arrows Y₁ and Y₂. The principal force A is that applied immediately adjacent that compartment of the knee baving osteoarthritis. <figref idref="f0001">Fig. 2</figref> shows R as the normal axis of rotation of the knee. The resultant moment Y_R is a single rotational moment.

0010It has been found that as the force strap is increased in tension, the hinge valgus producing moment decreases. Therefore, the force strap and the hinge are found not to be adequately working in harmony. More specifically, it was discovered that the hinge produces about 20% of the total valgus moment in this brace. It is believed that since the hinge is aligned close to the knee, the strap urges the knee against the hinge. Moreover, the rigidity of this type of hinge limits the displacement of the hinge relative to the knee.

0011In a conventional brace having a hinge, a clearance is provided between the hinge and the knee to allow for movement of the knee towards the hinge. This results in a bulky brace since a large hinge is required which may extend at least an inch away from the knee.

0012It has been determined that if more unloading of the knee is required by the brace than is obtained from normal strap tension, and if the force strap is further tightened, the knee is drawn towards the hinge and might strike the hinge. This results in the hinge applying forces to the knee that counteract the force applied by the force strap. In turn, the additional tightening of the force strap is mitigated or negated by the force exerted onto the knee from the hinge.

0013For example, a study was conducted on a patient wearing a conventional knee brace having a force strap. In normal strap tension, the force strap component unloaded 5.8 Nm of the knee and the hinge unloaded about 2.2 Nm. By increasing the force strap tension, the unloading of the force strap resulted in 11.6 Nm, but the hinge resulted in unloading -2.4 Nm since the hinge was pressed against the knee.

0014As will be more fully evident in the ensuing discussion, the embodiments described herein are provided to overcome the deficiencies of prior art unloading braces by including arrangements that provide maximum unloading of the knee brace, while removing the mitigating effects of the hinges in known knee braces. Moreover, the embodiments of the invention are arranged for treating compartmental osteoarthritis, and have improved mechanical properties that remove undesirable rotational forces incurred by the brace and provide a more effective mechanism for generating a valgus or varus moment at the knee.

0015While known knee braces are successful at reducing pain at or stabilizing a knee joint, many users find these braces to be bulky, difficult to don, complicated to configure, and uncomfortable to wear. For these reasons, the embodiments described herein have streamlined features capable of providing relief for medial or lateral compartmental osteoarthritis, or functional stability of the knee without the attendant drawbacks of known unloading knee braces.

SUMMARY

0016The present invention is directed to an improved knee brace that serves to reduce the effects of either medial compartmental or lateral compartmental osteoarthritis. This problem is solved by a knee brace according to claim 1. Advantageous embodiments are defined in the subclaims 2 to 9. The knee brace according to the invention reduces the effects of compartmental osteoarthritis by applying multiple forces to the knee on the side remote from the compartment having osteoarthritis while providing forces on the side of the compartment to maintain the brace securely on a leg while minimizing rotational forces.

0017According to one embodiment of the knee brace, proximal and distal breathable shells are inserted into pockets defined by a sleeve and spacer elements corresponding to the shells. First and second force straps are connected to the shells and intersect at an intersection point located between the first and second shells, and posterior the normal axis of the knee brace. A tightening device is provided for each force strap to tension or release tension of the force straps against a leg of a user of the knee brace.

0018In a preferred embodiment, the knee brace is provided with at least one breathable spacer element having an inner surface connected to an inner facing surface of at least one of the proximal and distal members. The at least one spacer element defines an outer surface opposing the inner surface and includes a frictional feature.

0019In a preferred embodiment of the spacer element, both the spacer element and the frictional feature are perforated. According to this variation the spacer element is a textile having a surface with a plurality of apertures upon which a silicone is coated along the non-apertured portions thereof. This yields a highly breathable spacer element that provides resistance to rotational forces caused by the force straps. Moreover, a spacer element on both proximal and distal portions of the knee brace prevents the proximal and distal portions of the knee brace from drawing closer to one another due to the forces applied by the force straps.

0020In combination with the force straps and spacer elements, one can achieve more unloading forces than with one force strap without increasing the pressure applied to the knee. This is due to the total unloading moment that is doubled with two force straps; the same amount of pressure is applied to the knee since there are two pressure points.

0021Second proximal and distal principal points of force are generated by the spacer elements secured to the frame members on a second side of the leg at locations above and below, respectively, the first proximal and distal principal points of force. The spacer elements maintain the knee brace on a leg and the frame members apart. The spacer elements may remove the need for a hinge as is used in the prior art braces.

0022Multiple other embodiments of a knee brace and variations of components thereof are discussed more fully in the discussion that follows. The features of the various embodiments of the knee brace result in a knee brace that provides not only greater unloading of the knee, but also result in a knee brace that is simpler to use and has a slimmer profile than conventional knee braces.

0023Of course, other methods, embodiments, and variations thereof are described in greater detail in the following discussion.

BRIEF DESCRIPTION OF THE DRAWINGS

0024These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: <ul id="ul0001" list-style="none"><li><figref idref="f0001">Fig. 1</figref> is a schematic view of forces applied on a leg usmg a pnor art Knee brace;</li><li><figref idref="f0001">Fig. 2</figref> illustrates the rotational force applied on a leg by the prior art knee brace of <figref idref="f0001">Fig. 1</figref>;</li><li><figref idref="f0002">Fig. 3</figref> is a perspective view of an embodiment of a knee brace divided along anterior-posterior, proximal-distal, and lateral-medial planes;</li><li><figref idref="f0003">Fig. 4</figref> is a front elevation view of the embodiment of <figref idref="f0002">Fig. 3</figref> divided along the lateral-medial and proximal-distal planes;</li><li><figref idref="f0003">Fig. 5</figref> is a side elevation view of the embodiment of <figref idref="f0002">Fig. 3</figref> divided along the anterior-posterior and proximal-distal planes;</li><li><figref idref="f0003">Fig. 6</figref> is a top plan view of the embodiment of <figref idref="f0002">Fig. 3</figref>, divided along the anterior-posterior and lateral-medial planes;</li><li><figref idref="f0004">Fig. 7</figref> is a perspective view of an embodiment of a knee brace:</li><li><figref idref="f0004">Fig. 8</figref> is a front elevation view of the embodiment of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0005">Fig. 9</figref> is a medial side elevation view of the embodiment of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0005">Fig. 10</figref> is a lateral side elevation view of the embodiment of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0006">Fig. 11</figref> is an exploded view of the embodiment of <figref idref="f0004">Fig. 7</figref> without a sleeve;</li><li><figref idref="f0007">Fig. 12</figref> is a schematic view of forces applied on a leg using the brace shown in <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0007">Fig. 13</figref> illustrates the rotational force applied on a leg by the brace of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0008">Fig. 14</figref> generally illustrates where the force is applied externally of the knee m the brace of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0008">Fig. 15</figref> is a sectional view taken along line XV-XV of <figref idref="f0008">Fig. 14</figref>;</li><li><figref idref="f0009">Figs. 16 and 17</figref> are perspective views of a variation of the force strap and the stability strap, respectively;</li><li><figref idref="f0010">Fig. 18</figref> is a detailed perspective view of the proximal shell of <figref idref="f0006">Fig. 11</figref>;</li><li><figref idref="f0010">Fig. 19</figref> is a detailed perspective view of the distal shell of <figref idref="f0006">Fig. 11</figref>;</li><li><figref idref="f0010">Fig. 20</figref> is a detailed sectional view of cut-away XX-XX in <figref idref="f0006">Fig. 11</figref>;</li><li><figref idref="f0010">Fig. 21</figref> is a detailed section view of <figref idref="f0010">Fig. 20</figref> generally rotated about 180°;</li><li><figref idref="f0011">Fig. 22</figref> is a front elevational view of another variation of a proximal shell;</li><li><figref idref="f0011">Fig. 23</figref> is a front elevational view of another variation of a distal shell;</li><li><figref idref="f0012">Figs. 24-27</figref> are force diagrams showing pressure distribution across prior art frame members and the proximal shell of the brace in <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0013">Fig. 28</figref> is a frontal perspective view of the sleeve of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0013">Fig. 29</figref> is a rear perspective view of the sleeve of <figref idref="f0004">Fig. 7</figref>;</li><li><figref idref="f0013">Fig. 30</figref> is a front elevational view of a sleeve embodiment for the knee brace;</li><li><figref idref="f0013">Fig. 31</figref> is a perspective view of a feature of the sleeve of <figref idref="f0013">Fig. 30</figref>;</li><li><figref idref="f0013">Fig. 32</figref> is a sectional view taken along line XXXII-XXXII of <figref idref="f0007">Fig. 13</figref>;</li><li><figref idref="f0014">Fig. 33</figref> is a perspective view of another embodiment of the knee brace.</li></ul>

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

A. Overview

0025A better understanding of different embodiments of the invention may be bad from the following description read in conjunction with the accompanying drawings in which like reference characters refer to like elements.

B. Environment and Context of Embodiments

0026Numerous embodiments of the invention are provided to reduce the effect of osteoarthritis in a knee joint, or stabilize a knee joint that has been weakened by injury or other infirmities. Embodiments of the invention may be configured to reduce or cure both medial or lateral knee joint infirmities.

0027Embodiments of the invention are particularly adapted for a human knee joint, and may be dimensioned to accommodate different types, shapes and sizes of human joints and appendages. In addition, embodiments may be modified to orient principal forces exerted by strap systems of the embodiments at any desirable location to treat knee infirmities.

0028For explanatory purposes, each knee brace embodiment described herein is divided into sections which are denoted by general anatomical terms for the human body. Each of these terms is used in reference to a human leg which is divided in similar sections with a proximal-distal plane generally extending along the meniscus of the knee between the femur and tibia.

0029In reference to <figref idref="f0002">Fig. 3</figref>, an embodiment of the knee brace is divided into anterior and posterior sections by an anterior-posterior plane. The anterior-posterior plane generally corresponds to the coronal or frontal plane of a human leg. Each of the anterior and posterior sections is further divided about the center of the knee by a proximal-distal plane and a lateral-medial plane.

0030Referring specifically to <figref idref="f0003">Figs. 4-6</figref>, the anterior section of the knee brace of <figref idref="f0002">Fig. 3</figref> has the following quadrants: (I) proximal-medial, (II) distal-medial, (III) distal-lateral, and (IV) proximal-lateral. The posterior section of the knee brace of <figref idref="f0002">Fig. 3</figref> has the following quadrants: (V) proximal-medial, (VI) distal-medial, (VII) distal-lateral, and (VIII) proximal-lateral.

0031The anatomical terms described herein are not intended to detract from the normal understanding of such terms as readily understood by one of ordinary skill in the art of orthotics.

C. Various Embodiments of the Knee Brace

i. Overview of Knee Embodiments

0032Referring to <figref idref="f0004 f0005">Figs. 7-10</figref>, a knee brace embodiment 10 is shown. While this knee brace is particularly shown and configured for treating lateral osteoarthritis of the knee, it is understood that the knee brace may be configured by reversing the features in order to treat medial osteoarthritis of the knee.

0033According to this embodiment, the brace 10 includes a sleeve 12 covering or upon which various components and assemblies are secured. As will be described below in reference to proximal and distal frame elements or shells 40, 42, these shells are connected to, inserted into, or secured against the sleeve to provide sufficient rigidity to the brace.

0034According to this embodiment, the sleeve 12 includes a breathable central strip portion 14 generally extending along the proximal-distal plane of the brace 10, and a center ring 16 located approximately about the center of the sleeve 12. The center ring 16 is preferably constructed from an elastic material so as to provide sufficient flexure of the brace 10 about the center portion thereof, and is located so as to assist a user of the device in placing the center portion over the anterior knee. Moreover, the portion of the sleeve 12 corresponding to the proximal portion of the knee is left exposed in order prevent interference of extension and flexion of the knee.

0035First and second force straps 18, 20 are each secured at a first end to a corresponding tightening device 22, 23 that protrudes out of an opening 24, 25 of the sleeve 12. The second end of each of the force straps 18, 20 is secured to a corresponding bracket assembly 26, 27 also secured to the sleeve 12. The first and second force straps 18, 20 intersect at intersection point 21 that is located near or along the proximal-distal plane on the posterior, medial side of the brace 10.

0036Each of the force straps 18, 20 may include a cushion feature that may be located near or at locations anterior or posterior of the intersection point 21. Moreover, the force straps 18, 20 preferably each have a length adjustment feature 29, such as a hook and loop fastener system, to enable adjustment of the length of such straps 18, 20.

0037In this embodiment, the force straps 18, 20 are substantially inelastic in order to apply a greater amount of pressure against the knee as opposed to what may occur if elastic straps are used. It has been found that force straps having substantially elastic properties do not effectively unload a knee. Instead, elastic force straps put the knee into flexion such that when the leg is straightened, the force straps resist flexure of the knee. As a result, while tightening the force straps may indeed unload the knee, the knee is unable to undergo full extension due to the tendency of the knee to go into flexion. Unlike the elastic straps, substantially inelastic straps do not possess these drawbacks since they draw the knee towards a hinge and unload the knee while permitting both flexure and extension of the knee.

0038It should be understood, however, that embodiments of the knee brace are not limited to usage of substantially inelastic straps. To the contrary, straps of various degrees of elasticity may be employed with the various components in different the embodiments of the knee braces to suit various needs of an individual wearing the brace.

0039The first force strap 18 is secured to a lateral-proximal bracket assembly 26 and spirals along the posterior of the brace 10 towards the medial-distal side of the sleeve 12. The first force strap 18 then enters in the sleeve 12 and secures to a distal tightening device 23 generally located on the anterior-lateral, distal side of the sleeve 12.

0040The second force strap 20 is secured to a lateral-distal bracket assembly 27 and spirals around the posterior of the brace 10 towards the medial proximal side of the sleeve. The strap 20 then enters the sleeve 12 and secures to a proximal tightening device 22 generally located on the anterior-lateral proximal side of the sleeve 10. As will be described in the ensuing discussion, the proximal and distal tightening assemblies 22, 23 are provided to incrementally tension the first and second force straps 18, 20, and selectively allow release of tension in the force straps 18,20.

0041A proximal stability strap 28 is secured to the medial side ot the brace 10 and extends to the lateral side whereat it is connected to a proximal buckle assembly 32 that is connected to the sleeve 12, A distal stability strap 30 is secured to the medial side of the sleeve 12 and extends to the lateral side whereat it is connected to a distal buckle assembly 33 which is also connected to the sleeve 12.

0042According to this embodiment, each of the stability straps 28, 30 includes a cushion feature 34, such as foam or a textile pad, that is secured thereon for enhanced rotational prevention and additional comfort. The stability straps 28, 30 each have an adjustment feature 35, such as a hook and loop fastener system, to enable adjustment of the length of such straps 28, 30. Moreover, the cushion feature may include a frictional feature (not shown), such as a pattern of deposited silicone, rubber, or a mildly abrasive material. In addition, the cushion feature may be breathable, and have a construction similar to the spacer elements described below.

0043In one variation, the stability straps may be releasably secured to the knee brace. For example, the stability straps may include a snap fastener element that corresponds to a snap fastener element supported by shells of the knee brace. In another variation, other suitable releasable fasteners may be used to permit installation and removal of the stability straps from the knee brace.

0044An embodiment of the knee brace may be provided alternatively with one force strap connected to a tightening device and another strap that is adjustable with a fastener system such as hook and loop fasteners. For example, in the event that it is desired to provide a low profile brace, one could use a force strap system that is connected to and adjustable at the proximal portion (corresponding to the femur of the wearer) of the brace that includes a tightening device, whereas the force strap system connected to the distal portion (corresponding to the tibia of the wearer) may simply use a hook and loop fastener system. Variations of this embodiment are also useful in order to mitigate issues of a tightening device extending over pressure points that may be present over the tibia.

0045The embodiment of the brace of <figref idref="f0004 f0005">Figs. 7-10</figref> is generally oriented to relieve lateral compartmental osteoarthritis of a left knee. This brace may be configured to treat medial compartmental osteoarthritis of the left leg or, in the alternative, medial or lateral compartmental osteoarthritis of a right knee. The reconfiguration for treating medial compartmental osteoarthritis comprises arranging the force straps in a reverse configuration so the force-straps have an intersection point on the proximal distal plane on the posterior-medial side of the device.

0046Turning to <figref idref="f0006">Fig. 11</figref>, the internal features of the embodiment of the brace 10 are shown in greater detail without the sleeve 12. Of interest are the proximal and distal shells 40, 43 which provide the structure for brace, and connect to the force straps 18, 20 and the stability straps 28, 30. Of additional interest are the proximal and distal spacer elements 46, 48 which provide anti-rotational means, such as a frictional feature, and cushioning for the brace 10 when worn on a leg.

0047The proximal and distal shells 40, 42 are configured for placement between the lateral and medial sides of an anterior portion of the brace 10. Similarly, the proximal and distal spacer elements 46, 48 are configured with a shape generally corresponding to the proximal and distal shells 40, 42, and are arranged for connection to a rear portion of the sleeve 12 in register with the shells 40, 42. It is desirable that the proximal and distal shells 40, 42 be in register with the proximal and distal spacer elements 46, 48 so that as the force straps and stability straps are tensioned about a leg. The spacer elements 46, 48 are urged against a leg so as to prevent rotation of the brace 10 due to the forces applied to the leg from the force straps.

0048According to variations of the shells, they may be configured for placement on the posterior side of the brace, or at least have sections that extend over a portion of the posterior section of the brace. In addition, variations of the shells may involve one shell such as the proximal shell extending about the anterior side of the brace between the lateral and medial sections, whereas the distal shell extends over the posterior side of the brace and further includes a segment wrapping over at least one of the lateral and medial sides to cover a portion of the distal-anterior section of the brace.

0049A benefit of the spacer elements in a hingeless knee brace is that these spacer elements prevent migration of the shells towards one another. The spacer elements, also maintain the knee brace on the user's leg due to anti-rotation means. Moreover, the spacer elements can also resist any rotational forces that may be applied by the force straps.

ii. Method of Applying the Knee Brace

0050In operation, the embodiment of the brace according to <figref idref="f0004 f0005 f0006">Figs. 7-11</figref> is attached to the user, for whom it may be custom made or pre-fabricated, by positioning the device on the leg with the center portion of the sleeve placed over the anterior knee. The proximal and distal force straps 18, 20 are positioned above and below a side of the knee, and tightened accordingly. This arrangement of the force straps ensures that the force straps tighten above and below the knee as the leg moves into extension and loosens as the leg moves into flexion. The tightening of the force straps 18, 20 during extension of the knee prevents movement of the bone upon extension ot the leg, ana thus treats the adverse affect of compartmental osteoarthritis.

0051<figref idref="f0007">Figs. 12 and 13</figref> illustrate the brace on a left leg 11 that defines proximal and distal portions corresponding to the femur and tibia, respectively. The tightening of the force straps 18, 20 tends to depressurize the compartment of the knee by increasing the space between the bones on the affected side of the knee. The configuration of the force straps along the frame elements 40, 42 provides reaction points for the force straps 18, 20. Thus, tightening of the force straps 18, 20 causes the frame elements 40, 42 in combination with the spacer elements to stabilize the - knee on the side opposite the intersection area 21.

0052From <figref idref="f0007">Fig. 12</figref>, the forces A₁ and A₂ are shown applied to the medial side of the knee at a greater degree than the single force A generated by the prior art braces, as exemplified in <figref idref="f0001">Figs. 1 and 2</figref>, due to the greater distribution of pressure on the leg. Additional forces B are applied on the lateral side of the leg approximately where the force straps are attached to the proximal and distal members. By applying two forces, these forces counteract to mitigate the rotational moment that is present in the prior art braces wherein rotational forces Y_R1 and Y_R2 are generally equal to and cancel one another.

0053It has been found that if only one force strap is used without any intersecting points, as in the prior art braces, the skin and soft muscle tissue move with the shells. As a result, the unloading effect of the straps decreases significantly. By using the two force straps to form forces A₁ and A₂, rotation of the device on the leg is reduced and effectively prevented. This provides a sufficient unloading effect by the brace on the knee.

0054The force straps are substantially inelastic since, as mentioned previously, n has been found that in prior art braces that employ elastic force straps, the knee and leg counteract the suppleness of the elastic straps thereby reducing the unloading effect on the knee. By using substantially inelastic force straps, the knee is unable to resist the straps and, consequently, a greater unloading effect is obtained of the knee.

0055Referring to <figref idref="f0008">Figs. 14 and 15</figref>, the resultant forces A₁ and A₂ are applied as the knee goes into extension. The force straps preferably cross at intersection point 21 at angle α ranging about 5° to 20° posterior of the normal axis of rotation of the knee with the knee cap 51 being in front of rotational axis R and tibia 53. The intersection point is preferably not the point of unloading; instead, the unloading point is directly on the lateral side for the medial brace, and directly on the medial side for the lateral brace.

0056The knee brace may be tailored to optimize the forces generated by the force straps. When the brace includes two force straps or has a single force strap with two intersecting portions, a greater moment is applied to a leg providing that the same force is now applied by two force straps. This results in a lower angle that may be used to configure the force strap(s), and consequently proximal and distal frame members or shells may be positioned closer together as opposed to in prior art braces having only a single cross-strap which spirally extends once between proximal and distal members.

0057In following discussion, descriptions and variations of the specific components pertaining to the inventive knee brace are described.

iii. Straps

0058The force straps and stability straps may be constructed from a variety of different textiles and other suitable materials. According to one variation exemplified in <figref idref="f0009">Figs. 16 and 17</figref>, the force strap 400 and stability strap 412 are shown as comprising a two layer system; an inner core 404, 416 surrounded by an outer layer 402, 414. Suitable stitching 406, 420 is provided to secure the inner core 404, 416 and outer layer 402, 414 together. When viewed from a rear end, the two layer system combines to form a C-folded strap wherein the outer layer 402, 414 wraps around the inner core 404, 416 to generally define an elongated C-shape about the corners of the strap.

0059The inner core 404, 416 is preferably constructed from a soft loop material. This material is generally soft to the touch so that for a knee brace having the strap extend about the popliteal (back of the knee), the worn strap is comfortable to the wearer of the brace. This is evidenced when the wearer flexes his leg as well as when the leg is fully extended. The compliance and softness of inner core mitigates the need for a cushion feature of the very type shown in <figref idref="f0004 f0005">Figs. 7-10</figref>.

0060The outer layer 402, 414 may be constructed from any suitable textile since the compliance of the strap is essentially provided by the inner core 404, 416. This enables the use of a cosmetically pleasing or a substantially inelastic material.

0061Both of the straps 400, 412 may include a tab 410, 418 located at the front end of the straps to provide adequate reinforcement to this area. The tab 410, 418 may comprise a plastic or metal piece that is secured to the front end of the straps by a press fit, stitching, adhesive or other suitable means. In addition, as will be discussed in further detail below, the force strap 400 may include indicia 408 representative or incremental settings of the strap.

0062In yet another variation, the stability straps may be substantially stretchable and secured to the sleeve or shells. The straps according to this variation may be configured so that they are dimensioned so as to permit the brace to be donned and doffed by being slidable on a leg of an individual wearing the brace, but sufficiently tensioned so as to wear tightly on the individual's leg.

iv. Shells

0063<figref idref="f0010">Figs. 18 and 19</figref> illustrate one variation of the proximal and distal shells 40, 42 of the brace of <figref idref="f0004">Fig. 7</figref>. Each of these shells 40, 42 has a perforated structure 52 which ventilates the brace and therefore mitigates heat build-up when the brace 10 is worn on a leg. Moreover, each shell has a clearance 50 which extends between the lateral and medial sides thereof as a further ventilation feature. While the shells 40, 42 are of sufficient rigidity and strength to withstand forces exerted by the force straps 18, 20 and the stability straps 28, 30, the shells 40, 42 may be flexible to conform to corresponding portions of a leg.

0064Because the shells 40, 42 have a perforated structure 52 and the clearance 50, the shells may be sized larger than other known structural features or frame members know in the knee bracing art. For example, the proximal shell 40 has an enlarged first side portion 54 that provides sufficient support against a leg and can accommodate the tightening device 22 and buckle assembly 26. The shell 40 also defines a protruding section 56 extending from the first side portion 54 in a direction generally tracing the path of the second force strap 20 so as to distribute the pressure of the strap against the leg.

0065The shell 40 defines a second portion 58 that is sufficiently large to secure to a leg, yet is of minimal size to prevent excessive intrusion on a corresponding side of a leg. Similarly, the distal shell 42 defines features corresponding to the proximal shell 40, such as an enlarged first side portion 68, a protruding section 70, and a second side portion 72.

0066As exemplified in <figref idref="f0010">Figs. 20 and 21</figref>, each of the shells 40, 42 preferably has provisions for mounting the tightening devices 22, 23, the bracket assemblies 26, 27, and the buckle assemblies 32, 33. The shells 40, 42 may each include an opening 66 for receiving a mounting feature 82 of a tightening assembly, and an eyelet 62 located on the lateral portions 54, 68 which is arranged to receive corresponding pins or similar features 82 of the bracket assemblies 26, 27 and buckle assemblies 32, 33. The eyelet 62 defines a seat portion 64 in which the mounting feature 82 of the bracket and buckle assemblies, such as a pin, button, flange, hook, or similar element, are urged and retained thereagainst The seat portion 64 is defined as a reduced portion of the eyelet 62 having a radius just larger than the mounting feature.

0067The construction of the eyelet of this embodiment is particularly advantageous in that it facilitates detachment of the buckle assemblies and bracket assemblies from the device when not worn on a leg. For example, when the force straps and stability straps are de tensioned, or the brace 10 is not worn, the mounting feature 82 may be urged from the seat 64, and subsequently removed from the shells 40, 42. However, when the straps are in tension, the mounting feature is urged and locked in register with the eyelet seat 64.

0068In a variation of this embodiment, individual eyelets of the type described above may be defined on the shells for individually accommodating both a buckle assembly, and a bracket element having a mounting feature. According to another variation of this embodiment, either of the buckle assembly or bracket element may have a hook which is securable against a corresponding eyelet defined in the shells. In yet another variation of this embodiment, the bracket element and buckle assembly may be permanently secured onto the shells using means such as rivets or other known fasteners.

0069In accordance with another variation of the shells, <figref idref="f0011">Figs. 22 and 23</figref> show proximal and distal shells 422, 448 having a different perforated structure 424 from the embodiments of <figref idref="f0010">Figs. 18 and 19</figref>. Specifically, the perforated structure 424 comprises a plurality of generally horizontal- slots 426 extending along segments across the width direction of the shells 422, 448. These slots 426 are interspersed with a plurality of slats 428. Frame portions 430 of each of the shells 422, 448 surround the slots 426 and slats 428.

0070The shape of the proximal shell 422 generally resembles the shape of the proximal shell shown in <figref idref="f0010">Fig. 18</figref>. Particularly, the proximal shell 422 defines a second side portion 432 that expends downwardly from a transverse portion 434 corresponding to the anterior-proximal portion of the shell and spanning to a first side portion 436. The transverse portion 434 includes an arcuate profile that is preferably pronounced on the distal side thereof and conforms to the anatomy of a thigh. The first side portion 436 extends downwardly beyond the distance expended by the second side portion 432, and is generally wider in size than the second side portion 432 to provide additional support on the leg.

0071The proximal shell 422 includes an eyelet 440 located on the second side portion 430. The eyelet 440 is configured for receiving a pin or locking device of a buckle assembly. A seat 442 is located on a side of the eyelet that is preferably distant from the second side portion 432 of the shell. The seat 442 may form a slot extending from the eyelet 440 and has a smaller diameter than the eyelet 440.

0072The proximal shell 422 also includes a slot 444 that is separate and larger than the slots 426, and is located near the transition between the first side portion 436 and the transverse portion 434. Preferably, the slot 444 is directed at an angle relative to the slots 426. The slot 444 includes a compliant edge 445 that is located at a side thereof closest to the transverse portion 435. The complaint edge 445 imparts a smaller effective height for the slot 444 and is arranged for receiving a pin, knob or other securing means -carried by the ratchet assembly, as described more fully connection with Fig. 43.

0073The compliant edge 445 is formed of a material that is preferably more flexible than the material used to form the proximal and distal shells, 422, 448. For the example, the rim 445 may be a silicone rubber or a suitable polymeric material.

0074The proximal shell 422 also includes a slot 446 that is located at the second side portion 432 of the shell. Similarly, the slot 446 is located at an angle relative to the slots 426 and likewise includes a compliant edge 447 that is located at an end portion remote from the transverse portion 434.

0075The shape of the distal shell 448 differs from the shape of the distal shell 42 shown in <figref idref="f0010">Fig. 19</figref>. Specifically, the distal shell 448 includes a second side portion 450 that connects to a transverse portion 452 corresponding to the anterior-proximal portion of the shell. The transverse portion 452 has a proximal arcuate profile 453 that is generally contoured to the shape of a shin of a human leg, From the transverse portion 452, a proximal side of the distal shell rises to apex 455 which provides additional support to the wearer at a first side portion 454 ot the shell 448. The shell 448 also includes a calf extension member 456 that protrudes from the second side portion 454 of the shell 448.

0076The calf extension member 456 extends to the posterior section of the brace when worn on a leg. The calf extension member 456 has the benefit of preventing the shell 448 from rotating when the knee brace is worn on a leg, and also serves as an additional suspension feature since it is preferably configured to extend over the thickest point of a human calf. Another benefit of the calf extension member 456 is that it removes the necessity of two stability straps for connection to the distal shell since the calf extension member effectively provides substantial support about the calf.

0077The distal shell 448 includes an eyelet 458 that has a seat portion 460 which is similarly constructed as the eyelet 440 and seat portion 442 of <figref idref="f0010">Fig. 20</figref>. The distal shell also includes a slot 462 and a corresponding compliant edge 463 that generally corresponds to the same location with the exception of their orientation as the slot 444 and respective rim 445 in <figref idref="f0010">Fig. 20</figref>. Also, the distal shell has a slot 464 and a respective compliant edge 465 that corresponds in location with the exception of orientation to the slot 446 and respective rim 447 in <figref idref="f0010">Fig. 20</figref>.

0078The shells 422 and 448 may include a compliant feature 470 disposed about the entirety or at least portions about their periphery. The compliant feature is constructed of a material that is more flexible than the material comprising the shell bodies. The compliant feature 470 extends beyond the outer perimeter of the shells. The compliant feature is preferably a flexible resilient material that is secured to the shells by bonding, mechanical interlocking or any other suitable arrangement. An example of a method tor providing the compliant feature is described m <patcit id="pcit0004" dnum="US5445602A"><text>U.S. patent 5,445,602</text></patcit>.

0079The shells may be custom sized and contoured to accommodate the leg of a wearer of the brace. Also, the shells may be preformed to curve to the contour of a leg, or curved as a result of the straps and sleeves causing the shells to curve about the leg of a wearer of the brace. While the embodiments described herein assume the shells to be sufficiently flexible to accommodate a wearer's leg in both extension and flexion of the knee, the shells can also be configured to be substantially rigid as in prior art braces.

0080The proximal and distal shells of these variations may be constructed of variety of materials such as TRIAX (abs/nylon blend), polypropylene, polyethylene, nylon, carbon or glass fiber prepeg with thermosetting or thermoplastic resins, and rigid foam from EVA, platezote or polyurethane. In another variation, the proximal and distal shells may be constructed similarly to the orthotic sleeve described in <patcit id="pcit0005" dnum="US6592539B"><text>U.S. Patent 6,592,539</text></patcit>.

0081The perforated structure of the shells enables the shells to be sized larger than most frame members used in knee braces. As a result, the pressure exerted against the leg by the force straps can be more evenly distributed about the leg.

0082<figref idref="f0012">Figs. 24-27</figref> schematically show how the shells of the aforementioned embodiment of the knee brace are advantageous over those in known knee braces. <figref idref="f0012">Fig. 24</figref> schematically shows a hypothetical horizontal force F_a, corresponding to the direction of a force strap, extending from a midpoint of a prior art shell 39. In this arrangement, pressure from the force F_a is evenly distributed across the shell 39 and across leg 13. <figref idref="f0012">Fig. 25</figref> shows hypothetical horizontal force F_b extending trom a distal portion of shell 39. In this arrangement, the force F_b exerts greater pressure across the leg 13 at the bottom of the shell than at the top of the shell.

0083<figref idref="f0012">Figs. 26 and 27</figref> more aptly exemplify the actual force exerted by a force strap on a proximal shell. <figref idref="f0012">Fig. 26</figref> shows a shell 39 in the prior art having a small size in order to minimize weight of the brace and the generation of heat due to the shell being worn against a leg. Because the shell is small, the force strap is secured to a center portion of the shell and diagonal force F_c creates greater pressure on a lower portion of the shell across the leg 13 than at the upper portion.

0084<figref idref="f0012">Fig. 27</figref> shows shell 40, wherein due to the ability to provide a larger shell, the force strap can be mounted at the upper portion of the shell. This results in diagonal force F_d which corresponds to a greater portion of the shell than the force F_o, and thereby more evenly distributes pressure from the force F_d over the shell and across the leg 13. By placing the force strap above the middle portion of the shell, one can obtain better distribution of pressure over the shell.

0085It has been found with known prior art knee braces that when force straps are not located at the same positions at both proximal and distal frame members, rotation of the frame members may occur. Since these frame members have a tendency to be significantly smaller than the shells according to the aforementioned knee brace embodiment, they are often located closer together, and proximate to the knee.

0086Particular benefits of the shells of the aforementioned embodiment are discussed in the following examples. In these examples, it is assumed that a force strap is provided which is pulled with a 10 N force, and the width of the knee or distance x is the same. In the first instance, the distance Y, which is defined as the distance between the shells, is 6 units. By moving the distance Y to 8 units, a greater moment due to the leverage arm is formed by the distance of the shells. Because of the increase in distance Y, the vertical force caused by the force strap is increased as a result of the change in angle of the force strap. Consequently, the shells are more strongly urged towards one another. On the other hand, the horizontal force is reduced so that the pressure on the knee in the horizontal direction is reduced, even though there is a greater moment applied to the knee.

0087It follows that if the shells are moved closer together, for example back to 6 units in distance, the moment is reduced yet there is more horizontal pressure on the knee. Moreover, the force exerted by the force strap must be increased in order to achieve the same amount of moment as created when the shells are separated by 8 units which results in yet more horizontal force about the knee. By providing the dual force strap arrangement, it is readily evident that the dual force strap provides two points of pressure and two straps creating a load on the knee. Therefore, the knee brace is more comfortable when unloading a knee since there is greater pressure distribution.

0088In addition to the advantages of the shells regarding pressure distribution, the shells can be arranged to extend over a greater portion of the leg than in known frame members. For example, prior art braces have small frame members that extend minimally about the leg, and the frame members have a tendency to rotate about the knee when the force straps are unloading the knee. This results in minimal tibia hyperextension and ligament control.

v. Sleeve

0089<figref idref="f0013">Figs. 28 and 29</figref> illustrate an embodiment of a sleeve 12 and the spacer elements 46, 48 that form proximal and distal pockets 84, 86 therebetween. The pockets 84, 86 include proximal and distal openings 74, 76. The openings 74, 76 may be closeable with closing means such as hook and loop fasteners, zippers, buttons, and other suitable means. The openings 74, 76 are configured for permitting insertion of the shells 40, 42 into the pockets 84, 86 which are shaped to closely conform to the shape of the respective shells 40, 42. The sleeve 12 further defines proximal and distal eyelets 78, 79, which correspond to the proximal and distal eyelets 62, 63 of the shells 40,42.

0090In a variation of the embodiment of <figref idref="f0013">Figs. 28 and 29</figref>, the sleeve includes pockets within the sleeve itself, wherein the shells are insertable into the pockets, and the pockets are closeable with a suitable fastener feature, such as with hook and loop fasteners, stitching, rivets, and other known means readily available to a skilled artisan. The spacer elements are secured against a rear portion of the sleeve corresponding in shape and location to the shells.

0091In another variation, the sleeve and spacer elements may be secured to one another so that the pockets form at the lower side of the proximal section and the upper side of the distal section. According to this variation, the shells may be inserted into the pockets so that the spacers and sleeve effectively cover the shells, yet so that the shells are easily removed from the sleeve and spacers. This also enables the shells to slide into the pockets while the shells are still connected to one another.

0092In yet another variation, the shells may be secured, either permanently or removable, to the posterior side of the sleeve with a suitable fastener feature. In yet another variation, the brace may be provided without the sleeve, and simply possess the structure shown in <figref idref="f0006">Fig. 11</figref>, wherein the spacer elements are secured to the shells by a suitable fastener feature. A hinge may be used to connect the shells, or other suitable connecting elements may be used to prevent the shells from being drawn towards one another when the brace is provided without the sleeve.

0093In yet another variation of the sleeve, the sleeve comprises proximal and distal portions that are separate from one another. According to this variation, the proximal and distal portions may include the aforementioned pockets for retaining the shells, or in the alternative, the shells may be secured to a surface of the sleeve portions. According to this variation, the sleeve portions may be connected by a hinge located on one of the lateral or medial side of the brace, or with one of the other connecting element described herein.

0094Another variation of the sleeve is shown in <figref idref="f0013">Fig. 30</figref> wherein the sleeve 242 is configured for enveloping frame elements and is removable therefrom. According to this variation, the sleeve 242 generally conforms to the outer surfaces of the proximal and distal members, and preferably envelopes the outer surfaces of the aforementioned features of the knee brace. The sleeve 242 includes an opening 246 that generally corresponds to an anterior knee. This provides access to the knee cap and is located at a portion of the sleeve that is subjected to bending of the knee.

0095Encircling the opening 244 is a first beveled portion 246 that eases the flexion of the sleeve 242 during gait. In addition, the sleeve 242 is provided with a second beveled portion 248 disposed along the proximal and distal edges. The first and second beveled portions 246, 248 relieve the brace of any sharp or blunted edges that may catch on clothing, and are thus provided to facilitate the donning of clothing over brace.

0096The sleeve 242 may be applied over the underlying features of the knee brace in a variety of manners. According to the variant shown herein, the sleeve 242 takes the form of a socket that surrounds the underlying features. Also, the sleeve 242 may include pockets wherein proximal and distal shells may be inserted therein, and means on the exterior of the sleeve for securing spacer elements. The sleeve may be unrolled from a rolled up condition for donning over the underlying features, and is secured thereon due to elasticity of the sleeve or, in the alternative, by hook and loop fasteners or other suitable means.

0097The sleeve 242 may include a zipper 290 located along one side of the proximal section thereof. As shown in <figref idref="f0013">Fig. 31</figref>, the zipper 290 provides an access 292 to a tightening mechanism 295 secured to a proximal shell 293 and a force strap 294. This particular variation allows for concealment of the tightening mechanism 295 under the sleeve 242, yet still permits facile access for adjusting the tightening mechanism. Moreover, this variation prevents the tightening mechanism from catching on clothing or any other objects that the leg may come into contact with, and further provides for a more cosmetically pleasing brace. The proximal portion of the sleeve can have a similar zipper and access to the distal shell.

0098The sleeve may be constructed of a fabric including spandex, lycra, nylon, polyester, OUTLAST, COOLMAX, AEROSPACER, microfiber, three-dimensional fabrics, and other suitable fabrics. The sleeve may have various treatments incorporated therein such as antibacterial, scenting, and moisture wicking agents.

0099In yet another variation of the sleeve, the sleeve may be constructed as me orthotic sleeve in <patcit id="pcit0006" dnum="US6592539B"><text>U.S. Patent 6,592,539</text></patcit> wherein elasticized fabric is used to form the sleeve and is arranged in different sections that exhibit different elastic stiffness in lengthwise and widthwise directions of the fabric. That is, the fabric is essentially stiffer in one direction than in a direction perpendicular to the one direction.

vi. Spacers

0100As shown in <figref idref="f0006">Figs. 11</figref> and <figref idref="f0013">29</figref>, the brace 10 includes proximal and distal spacer elements 46, 48 that are contoured in a similar configuration as the shells 40, 42. These spacer elements 46, 48 are arranged so as to be breathable by permitting a free flow of air therethrough. The spacer elements also preferably include a friction feature on at least one side thereof.

0101The spacer elements may be connected to the sleeve via removable means, such as with a hook and loop fastener system, or may alternatively be secured to the sleeve via stitching, adhesive, or other similar fastener features. While the spacer elements are intended not to interfere with the motion of the knee, they are intended to provide sufficient frictional force to maintain the shells against the knee due to the vertical forces created by the force straps.

0102According to this embodiment, the spacer elements 46, 48 are secured to the posterior side of the sleeve 12. The spacer elements 46, 48 have a breathability feature 88. According to a variation, the breathability feature comprises a pattern of openings defined across the spacer elements 46, 48. Alternatively, the breathability feature may comprise a breathable fabric, and may be combined with a pattern of perforations to further enhance the breathability of the spacers. Moreover, the spacer elements may be constructed from a material that provides cushioning and further compresses, at least in part, when the brace is worn.

0103As shown in <figref idref="f0013">Fig. 32</figref>, the spacer elements 46, 48 preferably have a friction feature 92 that is coated on at least a posterior surface of a substrate material 90 that forms the body of the spacer elements 46, 48. This friction feature 92 has a high frictional coefficient against the skin or clothing. Moreover, the friction feature 92 does not occlude the breathability feature 88 of each spacer element 46, 48, and permits a transfer of air through the spacer elements.

0104According to this embodiment, the spacer elements have a mesh or core portion 94 that permits the passage of air therethrough, and yet is compressible to provide adequate cushioning and securing to a leg when placed in tension. In addition, the spacer elements have a reinforced edging 96 provided to protect the core portion, and enhance the durability of the spacer elements.

0105In another variation, as shown in Fig. 60, the spacer elements may be directly connected to the shells. Of course, such spacer elements may be configured so that they may be removed from the shells and reapplied without harming their structure. Fasteners such as hook and loop systems may be used to attach the spacer elements to the shells.

0106Preferred substrate materials that may be used to form the spacer elements include foams, neoprene, and textiles. While numerous materials may be used as the spacer elements, it is desirable that these materials have a three-dimensional knit structure covered by a mesh that provides sufficient breathability, insulation, compression, durability, and recovery. An exemplary material is produced by Gehring Textiles under product numbers SHR 701, SHR 714 or SHR 754F.

0107According to this embodiment, the posterior surfaces ot the spacer elements are coated with the friction feature which comprises a continuous, discrete layer of cured silicone elastomer material 92. The silicone elastomer material is preferably sufficiently thick and soft to be comfortable to the user, and yet provides a seal between the proximal and distal members, and the skin or clothing of a user of the brace 10. The silicone coating preferably has apertures which correspond to apertures of the mesh surface of the three-dimensional fabric when such a fabric is used to form the substrate of the spacers. In a variation, the silicone coating may comprise a plurality of dots which are deposited to the surface of the substrate of the spacers.

0108The silicone material may be mixed with scenting, anti-inflammatory, antibacterial, and coloring agents. Moreover, the silicone material may include skin friendly agents such as aloe vera or Vaseline. A more complete description of additives to the silicone may be found in <patcit id="pcit0007" dnum="US6485776B"><text>U.S. Patent 6,485,776</text></patcit>.

0109The silicone elastomer preferably has a Shore hardness of 25-70; a minimum tensile strength of 11.4 kg/m; a 100% modulus of 55.12 kPa; a 500% modulus of 420.29 kPa; a minimum tear strength of 2.76 kg/m ; a maximum strength of 28.2 kg/m and an elongation of about 1000%.

0110The silicone elastomer coating may be disposed in a uniform thickness in both circumferential and longitudinal directions, or may have a varying thickness to accommodate varying shapes of a leg, protrusions, contours, etc. The coating may also be configured to have a specific relief from localized pressure that may result from installation of the proximal and distal members on a human leg.

0111While the spacer elements are preferably coated only on their posterior surfaces, the anterior surfaces of the spacer elements may likewise be coated so as to frictionally couple with the sleeve. In the alternative, the friction elements may be constructed of sections of elasticized fabric and coated with silicone of the type described in <patcit id="pcit0008" dnum="US6592539B"><text>U.S. Patent 6,592,539</text></patcit>.

0112In a variation of the brace, the brace does not include the spacer elements and instead relies on the proximal and distal member straps for attachment to a user. In another variation, the spacer elements that are not coated with silicone. These spacer elements provide a compressive buffer between the proximal and distal members and a leg of a user of the brace. In yet another variation, the substrate may comprises a textile having superior frictional properties, and as a result, merely the compression of the textile is sufficient to prevent rotation of the brace when worn on a leg.

0113In yet another variation, the spacer elements may comprise a silicone mesh comprising a textile that is impregnated with silicone. This silicone mesh defines a pattern of apertures that permit the transport of air therethrough. In yet another variation, the spacer elements consist a silicone sheet having a pattern of apertures, and sufficient thickness to serve as a buffer between the sleeve, frame members, and a leg.

Vii Alternate Knee Brace Embodiment

0114<figref idref="f0014">Fig. 33</figref> illustrates another embodiment of a knee brace 210. This brace 210 includes a proximal frame member 212 and a distal frame member 214 both located on the anterior side of the device 210, and extending between lateral and medial portions thereof. Both the frame members 212, 214 have anterior and posterior facing surfaces. A connecting element 216 connects the frame members 212, 214. A force strap 218 is connected to the frame members 212, 214, and defines first and second strap portions 220, 222 that cross at an intersection area 224 located between the frame members 212, 214.

0115The intersection area 224 is generally defined in the same region as in the intersection area in the embodiment of <figref idref="f0004 f0005">Figs. 7-10</figref>. Moreover, the location of the force strap 218 relative to the frame members 212, 214 is similar to that also described in connection with the embodiment of <figref idref="f0004 f0005">Figs. 7-10</figref>.

0116A first end of the first strap portion 220 is anchored to the proximal frame member 212 and spirals towards the distal frame member 214. A plurality of strap guides 226 guide the force strap 218 along an outer surface of the distal member 214 and redirect the force strap 218 towards the proximal member 212. The second strap portion 222 emerges from the distal member 214 and intersects with the first strap portion 220 while extending towards the proximal member 212.

0117A second end of the second strap portion 222 is secured to a bracket 228 connected to a cord 230. The cord 230 is received by a tightening device 232, of any of the types described herein that are secured to the proximal member 212. The tightening device 232, as described in connection with the aforementioned embodiments, is provided to incrementally tension the force strap 218 and selectively allow release of tension in the force strap 318. The connection between the second strap portion 222 and the tightening device 232 is oriented in a predetermined direction to obtain a preferred orientation at the intersection area 224 between the first and second strap portions 220, 222.

0118Proximal and distal spacers 234, 23 6 are connected to the frame members 212, 214, respectively, along the inner surfaces thereof. As with the aforementioned spacers, the spacers 234, 236 have a coating that has a high frictional coefficient against skin or clothing. When applied against skin or clothing, the friction spacers 234, 236 resist movement of the knee brace 10 relative to the skin or clothing.

0119The proximal member 212 includes a stability strap 238 secured and extending between opposed lateral and medial sides of the proximal member 212. The distal member 214 includes a stability strap 240 likewise secured and extending between opposed lateral and medial sides of the distal member 214. The proximal and distal straps 238, 240 preferably have hook and loop fastener systems to connect to the medial and lateral sides of the respective frame members 212, 214.

0120According to the embodiment of <figref idref="f0014">Fig. 33</figref>, the frame members 212, 214 may be rigid or flexible members. Moreover, they may be perforated or rendered breathable in the manner described in reference to the shells of <figref idref="f0010">Figs. 18 and 19</figref>. In variations of the knee brace, however, the frame members may be constructed of soft members that are sufficiently strong to withstand forces on a knee produced by the force strap 218 but sufficiently compliant to provide comfort to a user of the knee brace.

0121The connecting element 216 is a ring that connects to both the proximal and distal members 212, 214. The connecting element 216 is not limited to a ring-like structure, and instead may be provided in any shape having suitable structure and strength that is sufficient to maintain the frame members 213, 214 apart while providing sufficient bending over the knee cap during gait

0122The connecting element is preferably constructed of a medial grade silicone having a sufficient durometer (i.e., 10) and sufficient stiffuess to maintain the frame members 212, 214 apart Alternatively, the connecting element 216 may be constructed of a stiff foam from EVA, plastezote or polyurethane.

0123In a variation at least one hinge provided on one of the medial or lateral sides of the brace may take the place of the connecting element, or be provided in combination with the connecting element

0124The tightening device 232 may include any one of the aforementioned systems used for tightening the force strap 218. Moreover, the force strap 218 and the stability straps 232 may be mounted onto the shells in any of the aforementioned manners described in connection with the embodiment of <figref idref="f0004 f0005">Figs. 7-10</figref>.

0125The various embodiments of knee braces described above thus provide a product that reduces pain, speeds a healing process, and imparts improved stability to the knee. The knee brace is lightweight and has a streamlined profile that is simple to use for wearers of the brace of various age groups. Moreover, the knee brace permits more precise adjustment of the brace and enables efficient coordination between a medical professional and the wearer as to the degree the knee brace should be configured. Patient comfort is also enhanced, and donning and doffing of the brace is eased with the novel features of the present knee brace.