Abstract:
An internal unloader brace includes an elongate bending member having an intermediate portion configured to bend under resistance such that joint forces are unloaded.

Description:
[0001]    This application claims priority under 35 U.S.C. §119 to U.S. Provisional App. No. 61/779,281, filed 13 Mar. 2013, the entirety of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed towards apparatus and methods for treating tissue of a body and more particularly, towards approaches designed to reduce mechanical energy transferred between members forming a natural joint. 
       BACKGROUND OF THE INVENTION 
       [0003]    A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally. Structural classification is determined by how the bones connect to each other, while functional classification is determined by the degree of movement between the articulating bones. In practice, there is significant overlap between the two types of classifications. 
         [0004]    There are three structural classifications of joints, namely fibrous or immovable joints, cartilaginous joints and synovial joints. Fibrous/Immovable bones are connected by dense connective tissue, consisting mainly of collagen. The fibrous joints are further divided into three types:
       sutures which are found between bones of the skull;       
 
         [0006]    syndesmosis which are found between long bones of the body; and
       gomphosis which is a joint between the root of a tooth and the sockets in the maxilla or mandible.       
 
         [0008]    Cartilaginous bones are connected entirely by cartilage (also known as “synchondroses”). Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. An example of a cartilaginous joint is an intervertebral disc. Synovial joints have a space between the articulating bones for synovial fluid. This classification contains joints that are the most mobile of the three, and includes the knee and shoulder. These are further classified into ball and socket joints, condyloid joints, saddle joints, hinge joints, pivot joints, and gliding joints. 
         [0009]    Joints can also be classified functionally, by the degree of mobility they allow. Synarthrosis joints permit little or no mobility. They can be categorized by how the two bones are joined together. That is, synchrondoses are joints where the two bones are connected by a piece of cartilage. Synostoses are where two bones that are initially separated eventually fuse together as a child approaches adulthood. By contrast, amphiarthrosis joints permit slight mobility. The two bone surfaces at the joint are both covered in hyaline cartilage and joined by strands of fibrocartilage. Most amphiarthrosis joints are cartilaginous. 
         [0010]    Finally, diarthrosis joints permit a variety of movements (e.g. flexion, adduction, pronation). Only synovial joints are diarthrodial and they can be divided into six classes: 1. ball and socket—such as the shoulder or the hip and femur; 2. hinge—such as the elbow; 3. pivot—such as the radius and ulna; 4. condyloidal (or ellipsoidal)—such as the wrist between radius and carps, or knee; 5. saddle—such as the joint between carpal thumbs and metacarpals; and 6. gliding—such as between the carpals. 
         [0011]    Synovial joints (or diarthroses, or diarthroidal joints) are the most common and most moveable type of joints in the body. As with all other joints in the body, synovial joints achieve movement at the point of contact of the articulating bones. Structural and functional differences distinguish the synovial joints from the two other types of joints in the body, with the main structural difference being the existence of a cavity between the articulating bones and the occupation of a fluid in that cavity which aids movement. The whole of a diarthrosis is contained by a ligamentous sac, the joint capsule or articular capsule. The surfaces of the two bones at the joint are covered in cartilage. The thickness of the cartilage varies with each joint, and sometimes may be of uneven thickness. Articular cartilage is multi-layered. A thin superficial layer provides a smooth surface for the two bones to slide against each other. Of all the layers, it has the highest concentration of collagen and the lowest concentration of proteoglycans, making it very resistant to shear stresses. Deeper than that is an intermediate layer, which is mechanically designed to absorb shocks and distribute the load efficiently. The deepest layer is highly calcified, and anchors the articular cartilage to the bone. In joints where the two surfaces do not fit snugly together, a meniscus or multiple folds of fibro-cartilage within the joint correct the fit, ensuring stability and the optimal distribution of load forces. The synovium is a membrane that covers all the non-cartilaginous surfaces within the joint capsule. It secretes synovial fluid into the joint, which nourishes and lubricates the articular cartilage. The synovium is separated from the capsule by a layer of cellular tissue that contains blood vessels and nerves. 
         [0012]    Cartilage is a type of dense connective tissue and as noted above, it forms a critical part of the functionality of a body joint. It is composed of collagenous fibers and/or elastin fibers, and cells called chondrocytes, all of which are embedded in a firm gel-like ground substance called the matrix. Articular cartilage is avascular (contains no blood vessels) and nutrients are diffused through the matrix. Cartilage serves several functions, including providing a framework upon which bone deposition can begin and supplying smooth surfaces for the movement of articulating bones. Cartilage is found in many places in the body including the joints, the rib cage, the ear, the nose, the bronchial tubes and between intervertebral discs. There are three main types of cartilage: hyaline, elastic and fibrocartilage. 
         [0013]    Chondrocytes are the only cells found in cartilage. They produce and maintain the cartilaginous matrix. Experimental evidence indicates that cells are sensitive to their mechanical (stress-strain) state, and react directly to mechanical stimuli. The biosynthetic response of chondrocytes was found to be sensitive to the frequency and amplitude of loading (Wong et al., 1999 and Kurz et al., 2001). Recent experimental studies further indicate that excessive, repetitive loading may induce cell death, and cause morphological and cellular damage, as seen in degenerative joint disease (Lucchinetti et al., 2002 and Sauerland et al., 2003). Islam et al. (2002) found that continuous cyclic hydrostatic pressure (5 MPa, 1 Hz for 4 hours) induced apoptosis in human chondrocytes derived from osteoarthritic cartilage in vitro. In contrast, cyclic, physiological-like loading was found to trigger a partial recovery of morphological and ultra-structural aspects in osteoarthritic human articular chondrocytes (Nerucci et al., 1999). 
         [0014]    Cancellous bone (also known as trabecular, or spongy) is a type of osseous tissue which also forms an important aspect of a body joint. Cancellous bone has a low density and strength but very high surface area, that fills the inner cavity of long bones. The external layer of cancellous bone contains red bone marrow where the production of blood cellular components (known as hematopoiesis) takes place. Cancellous bone is also where most of the arteries and veins of bone organs are found. The second type of osseous tissue is known as cortical bone, forming the hard outer layer of bone organs. 
         [0015]    Various maladies can affect the joints, one of which is arthritis. Arthritis is a group of conditions where there is damage caused to the joints of the body. Arthritis is the leading cause of disability in people over the age of 65. 
         [0016]    There are many forms of arthritis, each of which has a different cause. Rheumatoid arthritis and psoriatic arthritis are autoimmune diseases in which the body is attacking itself. Septic arthritis is caused by joint infection. Gouty arthritis is caused by deposition of uric acid crystals in the joint that results in subsequent inflammation. The most common form of arthritis, osteoarthritis is also known as degenerative joint disease and occurs following trauma to the joint, following an infection of the joint or simply as a result of aging. 
         [0017]    Unfortunately, all arthritides feature pain. Patterns of pain differ among the arthritides and the location. Rheumatoid arthritis is generally worse in the morning; in the early stages, patients often do not have symptoms following their morning shower. 
         [0018]    Osteoarthritis (OA, also known as degenerative arthritis or degenerative joint disease, and sometimes referred to as “arthrosis” or “osteoarthrosis” or in more colloquial terms “wear and tear”), is a condition in which low-grade inflammation results in pain in the joints, caused by wearing of the cartilage that covers and acts as a cushion inside joints. As the bone surfaces become less well protected by cartilage, the patient experiences pain upon weight bearing, including walking and standing. Due to decreased movement because of the pain, regional muscles may atrophy, and ligaments may become more lax. OA is the most common form of arthritis. 
         [0019]    The main symptoms of osteoarthritis is chronic pain, causing loss of mobility and often stiffness. “Pain” is generally described as a sharp ache, or a burning sensation in the associated muscles and tendons. OA can cause a crackling noise (called “crepitus”) when the affected joint is moved or touched, and patients may experience muscle spasm and contractions in the tendons. Occasionally, the joints may also be filled with fluid. Humid weather increases the pain in many patients. 
         [0020]    OA commonly affects the hand, feet, spine, and the large weight-bearing joints, such as the hips and knees, although in theory, any joint in the body can be affected. As OA progresses, the affected joints appear larger, are stiff and painful, and usually feel worse, the more they are used and loaded throughout the day, thus distinguishing it from rheumatoid arthritis. With progression in OA, cartilage loses its viscoelastic properties and its ability to absorb load. 
         [0021]    Generally speaking, the process of clinically detectable osteoarthritis is irreversible, and typical treatment consists of medication or other interventions that can reduce the pain of OA and thereby improve the function of the joint. According to an article entitled “Surgical approaches for osteoarthritis” by Klaus-Peter Günther, MD, over recent decades, a variety of surgical procedures have been developed with the aim of decreasing or eliminating pain and improving function in patients with advanced osteoarthritis (OA). The different approaches include preservation or restoration of articular surfaces, total joint replacement with artificial implants, and arthrodeses. 
         [0022]    Arthrodeses are described as being reasonable alternatives for treating OA of small hand and foot joints as well as degenerative disorders of the spine, but were deemed to be rarely indicated in large weight-bearing joints such as the knee due to functional impairment of gait, cosmetic problems and further side-effects. Total joint replacement was characterized as an extremely effective treatment for severe joint disease. Moreover, recently developed joint-preserving treatment modalities were identified as having a potential to stimulate the formation of a new articular surface in the future. However, it was concluded that such techniques do not presently predictably restore a durable articular surface to an osteoarthritic joint. Thus, the correction of mechanical abnormalities by osteotomy and joint debridement are still considered as treatment options in many patients. Moreover, patients with limb malalignment, instability and intra-articular causes of mechanical dysfunction can benefit from an osteotomy to provide pain relief, with the goal being the transfer of weight-bearing forces from arthritic portions to healthier locations of a joint. 
         [0023]    Joint replacement is one of the most common and successful operations in modern orthopedic surgery. It consists of replacing painful, arthritic, worn or diseased parts of the joint with artificial surfaces shaped in such a way as to allow joint movement. Such procedures are a last resort treatment as they are highly invasive and require substantial periods of recovery. Some forms of joint replacement are referred to as total joint replacement indicating that all joint surfaces are replaced. This contrasts with hemiarthroplasty (half arthroplasty) in which only one bone&#39;s joint surface is replaced and unicompartmental arthroplasty in which both surfaces of the knee, for example, are replaced but only on the inner or outer sides, not both. Thus, arthroplasty, as a general term, is an operative procedure of orthopedic surgery performed, in which the arthritic or dysfunctional joint surface is replaced with something better or by remodeling or realigning the joint by osteotomy or some other procedure. These procedures are also characterized by relatively long recovery times and are highly invasive procedures. The currently available therapies are not condro-protective. Previously, a popular form of arthroplasty was interpositional arthroplasty with interposition of some other tissue like skin, muscle or tendon to keep inflammatory surfaces apart or excisional arthroplasty in which the joint surface and bone was removed leaving scar tissue to fill in the gap. Other forms of arthroplasty include resection(al) arthroplasty, resurfacing arthroplasty, mold arthroplasty, cup arthroplasty, silicone replacement arthroplasty, etc. Osteotomy to restore or modify joint congruity is also an arthroplasty. 
         [0024]    Osteotomy is a related surgical procedure involving cutting of bone to improve alignment. The goal of osteotomy is to relieve pain by equalizing forces across the joint as well as increase the lifespan of the joint. This procedure is often used in younger, more active or heavier patients. High tibial osteotomy (HTO) is associated with a decrease in pain and improved function. However, HTO does not address ligamentous instability—only mechanical alignment. HTO is associated with good early results, but results typically deteriorate over time. 
         [0025]    Other approaches to treating osteoarthritis involve an analysis of loads that exist at a joint. Both cartilage and bone are living tissues that respond and adapt to the loads they experience. If a joint surface remains unloaded for appreciable periods of time the cartilage tends to soften and weaken. Further, as with most materials that experience structural loads, particularly cyclic structural loads, both bone and cartilage begin to show signs of failure at loads that are below their ultimate strength. However, cartilage and bone have some ability to repair themselves. There is also a level of load at which the skeleton will fail catastrophically. Bone healing research has shown that some mechanical stimulation can enhance the healing response and it is likely that the optimum regime for a cartilage/bone graft or construct will include partial/reduced from normal loading of the healing tissues. 
         [0026]    Thus, there has been identified a need for devices which facilitate the control of load on a joint undergoing treatment or therapy, to thereby enable use of the joint within a healthy loading zone. 
         [0027]    The present invention can satisfy these and other needs. 
       SUMMARY 
       [0028]    According to one aspect of the invention, an internal unloader brace comprises: an elongate bending member having a first end portion, a second end portion and an intermediate portion; said first end portion configured to be attached to a first anatomical member of an articulating, anatomical joint; said second end portion configured to be attached to a second anatomical member of the anatomical joint; and said intermediate portion configured to bend, under resistance, when said first end portion is attached to the first anatomical member and said second end portion is attached to the second anatomical member. When said elongate bending member is attached to a first side of the anatomical joint, said resistance to bending applies forces to the first and second anatomical members to unload a second side portion of the anatomical joint, wherein the second side is opposite the first side. 
         [0029]    According to another aspect of the invention, an internal unloader brace comprises an elongate bending member having a first end portion, a second end portion and an intermediate portion; said first end portion being angled with respect to a longitudinal axis by a first predefined angle when said elongate bending member is in an unbiased configuration; said second end portion being angled with respect to the longitudinal axis by a second predefined angle when said elongate bending member is in an unbiased configuration. In a biased configuration, said first end portion is configured to be attached to a first anatomical member of an articulating, anatomical joint and said first end portion is closer to alignment with the longitudinal axis than when in said unbiased configuration. In said biased configuration, said second end portion is configured to be attached to a second anatomical member of an articulating, anatomical joint and said second end portion is closer to alignment with the longitudinal axis than when in said unbiased configuration. Said intermediate portion is configured to bend, under resistance, in said biased configuration and said first end portion is attached to the first anatomical member and said second end portion is attached to the second anatomical member, said bending member applies rotational forces to the first and second anatomical members through said first and second end portions, respectively. 
         [0030]    In accordance with a further aspect of the invention, an internal unloader brace comprises an elongate bending member having a first end portion, a second end portion and an intermediate portion; said elongate member configured to be attached across an articulating, anatomical joint by attachment of said first end portion to a first anatomical member of the articulating, anatomical joint and attachment of said second end portion to a second anatomical member of the anatomical joint. Said intermediate portion applies rotational forces to locations of attachment of said first and second end portions to the first and second anatomical members, respectively. The rotational forces are applied transversely to a main plane in which articulation of the anatomical joint occurs. 
         [0031]    In accordance with another aspect of the invention, a method for treating an articulating anatomical joint comprises attaching a first end portion of a biasing member to a first anatomical member of the anatomical joint; attaching a second end portion of the biasing member to a second anatomical member of the anatomical joint; and applying rotational forces from said biasing member to the first and second anatomical members to bias a portion of the anatomical joint by biasing portions of the first and second anatomical members away from one another. 
         [0032]    These and other features of the invention will become apparent to those persons skilled in the art upon reading the details of the assemblies and methods as more fully described below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  is a front view, demonstrating normal forces existing on a side of a joint. 
           [0034]      FIG. 2  is a front view, depicting the effect an internal unloading device of the present invention has on the opposite side of the joint. 
           [0035]      FIG. 3A  illustrates an embodiment of the present invention in which a biasing member of a device is mounted to a side of the joint that is opposite of the side of the joint to be unloaded or distracted. 
           [0036]      FIG. 3B  illustrates a biasing member in a loaded configuration according to an embodiment of the present invention. 
           [0037]      FIG. 3C  illustrates the biasing member of  FIG. 3B  in an unloaded configuration. 
           [0038]      FIG. 3D  illustrates an end portion of a biasing member having a circular through hole according to an embodiment of the present invention. 
           [0039]      FIG. 3E  is a partial view of an embodiment of the present invention in which a biasing member of a device is mounted to a side of the joint that is opposite of the side of the joint to be unloaded or distracted. 
           [0040]      FIG. 4  illustrates an end portion of a biasing member having an elongated or oblong through hole or slot according to an embodiment of the present invention. 
           [0041]      FIG. 5A  shows the end portion of  FIG. 4  with a washer against the outer surface thereof and covering a portion of the through hole or slot according to an embodiment of the present invention. 
           [0042]      FIG. 5B  shows the end portion of  FIG. 4  with a washer against the inner surface thereof and covering a portion of the through hole or slot according to an embodiment of the present invention. 
           [0043]      FIG. 6  shows an alternative embodiment of an attachment member according to an embodiment of the present invention. 
           [0044]      FIG. 7A  is a side view and  FIG. 7B  is an outside surface view of an end portion of a biasing member having an alternative embodiment of an elongated through hole or slot. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0045]    Before the present devices and methods are described, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. 
         [0046]    Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. 
         [0047]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. 
         [0048]    It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a screw” includes a plurality of such screws and reference to “the device” includes reference to one or more devices and equivalents thereof known to those skilled in the art, and so forth. 
         [0049]    The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed. 
         [0050]    Referring now to the drawings, which are provided by way of example and not limitation, the present invention is directed towards devices and methods for treating body tissues. In applications relating to the treatment of body joints, the present invention seeks to alleviate pain associated with the function of diseased or malaligned members forming a body joint. Whereas the present invention is particularly suited to address issues associated with osteoarthritis, the energy manipulation accomplished by the present invention lends itself well to broader applications. Moreover, the present invention is particularly suited to treating synovial joints such as the knee and shoulder. However, it is also contemplated that the apparatus and method of the present invention can be employed to treat the spine facet joints and spine vertebral joints as well as other synovial and various other joints of the body such as those of the hand and feet, including those of the fingers and toes. 
         [0051]    In one particular aspect, the present invention seeks to permit and complement the unique articulating motion of the members defining a body joint of a patient while simultaneously manipulating energy being experienced by both cartilage and osseous tissue (cancellous and cortical bone). It has been postulated that to minimize pain, off-loading/unloading or absorption of 1-40% of forces, in varying degrees, may be necessary. Variable off-loading/unloading or absorption in the range of 5-20% can be a target for certain applications. In certain specific applications, distraction is employed in the energy manipulation approach. 
         [0052]    Conventional or surgical or minimally invasive approaches are taken to gain access to a body joint or other anatomy requiring attention. Arthroscopic approaches are thus contemplated when reasonable to both implant the energy manipulation assembly as well as to accomplish adjusting an implanted assembly. Moreover, biologically inert materials of various kinds can be employed in constructing the energy manipulation assemblies of the present invention. 
         [0053]    In one particular approach, a biasing member is contemplated to manipulate or absorb forces between body parts on an opposite side of a joint to which the device is mounted by providing an rotational force to the body parts. Thus, a device utilizing an element or elements that can apply rotational forces to the bones that are joined by the joint may be desirable to treat afflictions such as osteoarthritis, trauma, or other pain-causing conditions in a joint. 
         [0054]    Referring to  FIGS. 1-2 , forces occurring between members forming a body joint (anatomical joint) are described. The arrows  50  shown in  FIG. 1  represent forces/load occurring between adjacent members  6 ,  7  on one side of a body joint lacking an internal unloading brace device  10  of the present invention. However, as shown in  FIG. 2 , in body anatomy incorporating the present invention, less forces/load are transferred to the bones and cartilage of the members defining the joint on the side that is opposite to the side that the biasing member of the device  10  is attached to. Where the body joint is treated with the described unloading devices of the present invention, a portion of the forces/load between body members is unloaded from the opposite side and taken up by the biasing member  14 . Accordingly, with the internal unloading device  10  in place, less force is placed on the joint than when the assembly  10  is not present. Particularly, the opposite side of the joint is unloaded, as already noted, and as indicated by the smaller force line  56  in  FIG. 2 . 
         [0055]    Although the device  10  is schematically represented as being installed on the medial side of the joint shown in  FIG. 2 , the present invention is not limited to such an arrangement, as device  10  can alternatively be installed on the lateral side of the joint. 
         [0056]      FIG. 3A  illustrates an embodiment of the present invention in which a biasing member  12  of device  10  is mounted to a side of the joint (i.e., to the femur  6  and tibia  7  bones) in a loaded configuration. In the loaded configuration shown in  FIG. 3A , the biasing member is curved. When implanted the biasing member  12  moves from the curved configuration toward a straight configuration illustrated in  FIG. 3C . This motion from the loaded (curved configuration) toward the unloaded (straight) configuration results in both motion of the bones  6 ,  7  away from one another and rotation of the bones  6 ,  7 . The motion of the bones away from one another causes unloading or distraction on the same side of the joint that the device  10  is mounted to, while rotation of the ends of the device  10  cause unloading or distraction on the side of the joint that is opposite of the side of the joint where the device is implanted. The amount of unloading on each side of the joint will depend on the particular biasing member  12  and the amount of loading provided in the biasing member. 
         [0057]    In one example, to unload or distract the medial side of a knee joint, biasing member  12  is mounted to the lateral side of that knee joint and is designed for primarily rotating and minimal bending. Conversely, to unload or distract the lateral side of a knee joint, the same biasing member  12  is mounted to the medial side of that knee joint. Alternatively, to unload the medial side of the knee joint with a medial implant, the biasing member  12  is designed for primarily elongation and minimal rotation. 
         [0058]      FIGS. 3B and 3C  illustrate biasing member  12  in a loaded configuration and an unloaded configuration, respectively. In the unloaded configuration, a first end portion  16  is angled with respect to a longitudinal axis L-L of the biasing member  12  by a predetermined acute angle  17 . Angle  17  may be in the range of about twenty to about fifty degrees, typically about thirty degrees to achieve rotation of the joint and unloading of an opposite side. Likewise, the second end portion  18  is angled relative to the longitudinal axis L-L when biasing member is in an unloaded configuration as illustrated in  FIG. 3C . Angle  19  typically, but not necessarily is equal to the angle  17  of the first end portion, relative to the longitudinal axis L-L, but may be different from angle  17  In either case, angle  19  may be in the range of about twenty to fifty degrees. When the biasing member  12  is designed primarily for elongation the angle  19  can be less than 20 degrees. The main body portion  14  (i.e., intermediate portion, portion that is intermediate of first and second portions  16 ,  18 ), in the unloaded configuration is substantially straight and is typically substantially aligned with the longitudinal axis L-L as shown in  FIG. 3C . 
         [0059]    In a loaded configuration, the first and second end portions are rotated to positions forming smaller angles than angles  17  and  19 , respectively, relative to the longitudinal axis L-L. Typically, first and second end portions  16 ,  18  are substantially aligned with the longitudinal axis L-L when in a loaded configuration, as illustrated in  FIG. 3B . This loading causes bending of the intermediate (main body) portion  14 , as shown in  FIG. 3B , such that main body portion  14  bows outwardly from longitudinal axis L-L in a direction opposite of the direction in which the end portions  16 ,  18  have been rotated. 
         [0060]    Main body member is resilient, and resists bending. Accordingly, upon bending, as in  FIG. 3B , the bent main body portion stores potential energy and applies forces to end portions  16 ,  18  in directions toward the unbiased locations of the end portions  16 ,  18 . Main body member  14  may be made of resilient metal or metal alloy, such as, but not limited to: titanium, titanium alloys, nickel-titanium alloys, various alloys of stainless steel 
         [0061]    In a preferred embodiment, all portions of biasing member  12  are integrally formed from metal or a metal alloy. Alternatively, one or both of first and second end components may include an elastomeric connector 
         [0062]    When biasing member  12  is mounted to a joint, such as in a manner illustrated in  FIG. 3A , main body portion  14  bends about the longitudinal axis of biasing member  12 . This can be seen by comparing the loaded and unloaded illustrations of  FIGS. 3B and 3C , where main body portion  14  is bent or bowed in the loaded configuration of  FIG. 3B  and main body portion is substantially straight, or at least significantly less bent or bowed in  FIG. 3C . The elastic deformation of main body  14  that occurs in the loaded configuration shown in  FIGS. 3A-3B  causes biasing member  12  to apply torque in the opposite rotational directions (see arrows in  FIG. 3A ) to the rotational direction that effected the bending. As a result, biasing member  12 , transfers force from the intermediate main body member  14  through the end portions  16  and  18  to the locations of attachment to the anatomical members  6  and  7 , respectively. As applied in  FIG. 3A , the forces applied are rotational forces in the clockwise direction to the femur  6  and in the counterclockwise direction to the tibia  7 . This results in forces that urge medial side of the knee joint apart, when the biasing member  12  is attached to the lateral side of the knee joint as shown in the anterior view of  FIG. 3A . Thus, the knee joint is partially unloaded on the medial side in this instance, reducing the amount of load that is transferred from the medial condyle of the femur to the medial condyle of the tibia during the gait cycle, relative to that which would otherwise be transferred when device  12  is not installed. In at least one embodiment, the knee joint is partially unloaded by about forty pounds on the side opposite to the side that the biasing member  12  is attached. 
         [0063]    In general, the intermediate, bending portion  14  applies rotational forces to locations of attachment of the first and second end portions  16 ,  18  to the first and second anatomical members, respectively, wherein the rotational forces are applied transversely to a main plane in which articulation of the anatomical joint occurs. The biasing member  12  can thus be attached to apply rotational forces to bias first and second anatomical members away from each other on a side of the joint that is opposite a side of the joint that the biasing member  12  is attached across. 
         [0064]    The rotational forces are applied to locations of attachment of the first and second end portions  16 ,  18 , to the anatomy. First and second end portions  16 ,  18  are each provided with an opening  22  or  22 ′ configured and dimensioned to receive an attachment member therethrough, which is used to attach and anchor the biasing member to anatomical members forming a joint. Examples of attachment members  24  that may be used include bolts  24   b  and screws  24   s . Opening  22  may be a round through hole  22 , as shown in  FIG. 3D , which is dimensioned to form a close fit with the attachment member  22  passing therethrough. In this way, the forces from the bending member  14  are efficiently transferred through the end portions  16  and  18  and attachment members  24  by maintaining the inside surfaces  16   i  and  18   i  of end portions  16  and  18  substantially normal to the longitudinal axes of the respective attachment members  24  passing through the openings  22 ,  22 ′ thereof. 
         [0065]    The attachment locations  16   a  and  18   a  (and particularly  16   a  in the example of the knee) are selected to be as near to centers of rotation as possible so as to minimize any variation in length between the attachment locations over the full cycle of joint articulation (gait cycle, in the case of the knee). Further, at least one of the openings  22  may be provided as an oblong or slotted opening  22 ′ as illustrated in  FIG. 4 . Typically, only one of the end portions  16 ,  18  is provided with an elongated, oblong or slotted opening  22 ′ and the other end portion  16 ,  18  is provided with a round opening  22  configured and dimensioned as described above. However, both end portions  16 ,  18  may be provided with openings  22 ′. Further alternatively, one or both end portions may be provided with elastomeric connections 
         [0066]    In  FIG. 3A , the attachment members used are bolts  24 , pins or bi-cortical bone screws. Nuts  24   n  are threaded over the distal free ends of the bolts  24  and torqued down so as to force the heads of the bolts  24  against the biasing member  12  to attach the biasing member to the anatomical members as shown in  FIG. 3A . Thus, openings are established to pass completely through the anatomical members  6  and  7 , from one side to the other, when using bolts  24   b  as attachment members  24 . 
         [0067]      FIG. 3E  is a partial view of an alternative embodiment wherein screws  24   s  are used as the attachment members. In this case, screws  24   s  are provided to tap into the cortical bone  25   c  of the anatomical member on the opposite side of the anatomical member from the side against which the biasing member  12  is attached. Thus, attachment member  24   s  is passed through an opening in an end portion of the biasing member, through cortical bone  25   c  on the side of the anatomical member against which the biasing member  12  is to be fixed, through cancellous bone  25   n , and is threaded into cortical bone  25   c  on the opposite side of the anatomical member, as illustrated in  FIG. 3E . Upon threading/tapping the distal, threaded end of screw  24   s  into the cortical bone  25   c  on the opposite side, this forces the end portion of biasing member  12  against the anatomical member and fixes it there 
         [0068]    Contoured spacers  28  may be provided between the inner surfaces  16   i ,  18   i  of the end portions and the outer surfaces of the anatomical members  6 , 7  to which the biasing member is attached. The contoured spacers  28  each have a first side generally contoured to the surface contours of the anatomical member that it is to interface with at a location where the interface will take place. The opposite side of each contoured spacer  28  is substantially perpendicular to a through hole  28   h  (see  FIG. 3E ) passing through the contoured spacer. In this way, opposite side of each contoured spacer  28  is configured to be substantially parallel with a main plane in which the anatomical joint articulates, when the first side is mounted against the first or second anatomical member. This therefore aligns the inside surfaces  16   i  and  18   i  substantially with the main plane in which the anatomical joint articulates, as can be seen in  FIGS. 3A and 3E . Also, the forces applied to the anatomical member by the end portion  16 ,  18  are distributed by the contoured spacer  28 . Likewise, contoured spacers  30  may be provided against the opposite sides of the anatomical members, between the outer surfaces of the anatomical members and mating attachment members  24   n  as shown in  FIG. 3A . to maintain the inner surfaces of the mating attachment members  24   n  substantially parallel with the main plane of anatomical joint articulation and to facilitate a substantially equal application of force to the surface of the anatomical member along all radial directions from the through hole  30   h.    
         [0069]    As noted above at least one of the first and second end portions  16 ,  18  may be provided with an elongated or oblong opening or slot  22 ′ to permit the attachment member  24  to translate relative to the first or second end portion  16 ,  18  when the biasing member  12  is attached to the first and second anatomical members.  FIG. 4  illustrates end portion  16  provided with an elongated or oblong opening or slot  22 ′. 
         [0070]      FIGS. 5A and 5B  illustrate inside and outside views of the end portion  16 , respectively, and a washer  32  placed against the outer surface  16   t  or inner surface  16   i , respectively, of end portion  16 . Each washer  32  has a through hole  32   h  having an inside diameter closely fitting to an outside diameter of the attachment member  24  that passes through the washers  32  to attach end portion  16  to an anatomical member. This close fit is designed to maintain the attachment member  24  extending perpendicular to the washers  32 . Thus, when washers  32  are forced against the inner and outer surfaces  16   i ,  16   t  as end portion  16  is attached to the anatomical member as described, this arrangement prevents skewing of the portion  16  out of substantial alignment with the main plane of articulation of the anatomical joint, even as attachment member  24  translates relative to elongated opening  22 ′, since washers  32  on both sides of slot  22 ′ prevent the attachment member  24  from straying from its perpendicular relationship with washers  32 , and washers  32  are maintained parallel to the portion  16  by virtue of being held in contact therewith. The arrangement just described thus uses an attachment member  24 , such as  24   b  or  24   s , with a first washer  32  being slid over the attachment member  24  and against the head of the attachment member, between the head of the attachment member and the outer surface of the portion  16  or  18 . A second washer  32  is slid over the attachment member  24  after sliding the portion  16  or  18  over the attachment member  24 . Spacer  28  may occupy the position between the second washer  32  and the outer surface of the anatomical member, the same way as illustrated in  FIG. 3A . 
         [0071]      FIG. 6  illustrates an alternative embodiment of an attachment member  24 ′ that may be used in accordance with an embodiment of the present invention. Attachment member  24  may have a distal end that makes it function as a bolt  24   b ′ or a screw  24   s ′ in the same manner that the distal ends of bolts  24   b  and screws  24   s  are provided as described above. However, the proximal end of attachment member  24 ′ includes a washer  2432  formed integrally with (or welded to, or otherwise fixed relative to) the shaft of attachment member  24 ′ and extending perpendicularly to the longitudinal axis of the attachment member  24 ′. A predetermined length of the shaft of attachment member  24 ′ extends proximally of the fixed washer  2432 . This predetermined length is about equal to the width of the first or second portion  16 ,  18 . A second washer  32 ′ is provided to be mounted against the outside surface of the first or second portion  16 ,  18 . This second washer has a through hole  32   h ′ that forms a close fit with a second attachment member  224  while allowing the shaft of the second attachment member  224  to slide therethrough. The proximal end of attachment member  24 ′ has an axial bore  24   b ′ extending therein that is internally threaded to mate with threads provided on the distal end of second attachment member  224 . Thus, when first or second end portion  16 ,  18  is mounted over the proximal end portion  24   p ′ and second attachment member  224  is passed through second washer  32 ′ and torqued into axial threaded bore  24   b ′, the washers  2432  and  32 ′ contact opposite sides of the end portion  16  or  18  and maintain attachment member  24 ′ substantially perpendicular to the inside surface of end portion  16  or  18  and thus substantially perpendicular to the main plane of articulation of the anatomical joint, while allowing attachment member  24 ′ to translate in elongated opening  22 ′. 
         [0072]      FIGS. 7A-7B  illustrate another alternative arrangement that permits an attachment member  24  to translate relative to a first or second end portion  16 ,  18  when biasing member  12  is attached to an anatomical joint. In this embodiment, an elongated opening  22 ′ is provided through the first or second portion as in the previous embodiments. However, opening  22 ′ also extends into the first or second end portion  16 ,  18  to form a groove  22 ″ in which washer  32 ″ can translate along. Thus, washer  32 ″ is provided within the groove  22 ″ and can translate relative to elongated opening  22 ′. Attachment member  24  is maintained substantially perpendicular to the washer  32 ″ by the close fitting tolerances in the same manner as described above. Likewise, the groove  22 ″ formed in end portion  16  or  18  is only slightly thicker than the thickness of washer  32 ″ so as to allow washer  32 ″ to slide relative thereto, while at the same time maintaining washer  32 ″ substantially parallel to the surfaces of the groove  22 ″ and therefore substantially parallel to the main plane of articulation of the anatomical joint. 
         [0073]    Further alternatively, at least one of the first and second end portions may include an elastomeric connector 
         [0074]    While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto.