Abstract:
A knee orthosis gait swing assist mechanism is provided having an adjustable portion and upper and lower fulcrum points, each of the upper and lower fulcrum points attaching opposing ends of an elastic band, the elastic band stretching over the adjustable portion.

Description:
PRIOR APPLICATIONS 
       [0001]    This application is a continuation-in-part application of U.S. Ser. No. 12/366,925, filed on Feb. 6, 2009, now pending, which is a divisional application of U.S. Ser. No. 11/556,557, filed Nov. 3, 2006, now patented as U.S. Pat. No. 7,608,051. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to knee braces. More particularly, it refers to structural parts used with knee braces. And with more particularity, it refers to a knee brace swing assist mechanism used to assist in flexion and extension and improve gait. 
       BACKGROUND OF THE INVENTION 
       [0003]    Orthotic devices and appliances commonly referred to as “orthotics,” have been utilized for many years by orthotists, physical therapists, and occupational therapists to assist in the rehabilitation of patient&#39;s joints and associated limbs or adjacent skeletal parts of the patient&#39;s body. 
         [0004]    Webster&#39;s New College Dictionary defines “orthotics” as a branch of mechanical and medical science that deals with the support and bracing of weak or ineffective joints or muscles. 
         [0005]    Orthotics or limb braces have been designed to support and protect the joint, alleviate pain associated with joint movement, and to rehabilitate the joint over time with orthotic use. 
         [0006]    Primary osteoarthritis is usually related to aging. With aging, the water content of the cartilage increases and the protein makeup of the cartilage degenerates. Repetitive use of the joints over the years can irritate and inflame the cartilage, causing joint pain and swelling. Eventually, cartilage begins to degenerate by flaking or forming tiny crevasses. In advanced cases, there is a total loss of cartilage cushion between the femur and tibia bones at the knee joint, leading to diminished joint space on the affected side of the knee resulting in pain and limitation of joint mobility. Inflammation of the cartilage also can stimulate new bone outgrowths (spurs) to form around the joints causing increased pain and joint inflammation. 
         [0007]    Osteoarthritis is often described as “wear and tear” arthritis, as it is highly correlated to age. Osteoarthritis is one of the most frequent causes of physical disability among adults. More than 20 million people in the US have the disease. By 2030, 20 percent of Americans, about 70 million people, will have passed their 65 th  birthday and will be at risk for osteoarthritis. 
         [0008]    Osteoarthrosis is a condition where the joint is affected by degeneration. Osteoarthritis implies the same meaning, but the “itis” adds the meaning that the joint is inflamed. The two terms are often used interchangeably. 
         [0009]    Joint replacement surgery of the knee is the surgical treatment for osteoarthrosis or osteoarthritis. It is best to delay knee joint replacement surgery as long as possible, as a total knee replacement may need to be replaced in ten to twenty years. It is a major surgery which requires considerable rehabilitation therapy to restore full function. 
         [0010]    Exercise, weight loss if needed, and the use of anti-inflammatory medications and analgesics are often prescribed to assist the patient in managing the pain associated with osteoarthritis. Minimizing the progression of the damage to the cartilage of the knee joint and preventing the formation of bone spurs from “bone on bone” during knee joint bending is an important part of patient care. 
         [0011]    The actual pain of osteoarthritis or osteoarthrosis comes from wearing away of the soft cartilage that pads the junction of the femur (upper leg bone of the knee) and the tibia (lower leg bone of the knee). With irritation of the joint, bone spurs can form causing bits of bone and cartilage to break off which float inside the joint space further irritating the knee. The most common form of osteoarthritis or osteoarthrosis is unicompartmental, meaning that only one of the three compartments of the knee joint are significantly affected by the loss of cartilage padding. The medial compartment of the knee is on the inside of the center line of the body. The lateral compartment of the knee is on the outside plane of the body, and the patellar compartment is in the center top of the knee behind the patella or knee cap. The majority of cases of osteoarthritis are medial compartment degeneration where the cartilage or cushioning of the knee joint has significantly deteriorated. The knee then becomes imbalanced, with the knee bowing outwards. This is often called a “bowleg” condition. A “bowleg” (genu varum), commonly referred to as a varus deformity of the knee joint, places significant force on the medial compartment of the knee, which aggravates the pain associated with osteoarthritis when the patient walks, bends the knee, or stands up. 
         [0012]    As the cartilage or padding of the knee joint on the lateral compartment cartilage is worn away, the knee will deform abnormally bending inwards at the knee joint giving the patient a knock kneed appearance. This is referred to as a valgus deformity of the knee joint. 
         [0013]    Osteoarthritis knee braces are designed to do two things: first, correct the abnormal bending of the knee joint inwards or outwards (varus or valgus correction). Secondly, many osteoarthritis knee orthotics or braces are designed to prevent the “bone on bone” contact of the femur and tibia bones in the medial or lateral compartment of the knee joint as the patient bears weight during ambulation. This action of lifting femur, pulling down the tibia or keeping the femur and tibia bones from coming in contact during the straightening of the knee during heel strike is often called “unloading” the knee joint. By “unloading” the knee joint, the constant irritation of the degenerated cartilage in the affected compartment of the knee (medial or lateral) can lead to a significant reduction in pain and further injury to the knee joint. Osteoarthritis knee braces also provide improved alignment of the upper and lower aspects of the knee joint by preventing the bending inwards or outwards of the knee joint during gait. These two features, unloading and alignment are provided by most of the osteoarthritis knee orthotics available in today&#39;s market. 
         [0014]    The majority of knee orthotics available to treat osteoarthritis of the knee utilizes a single upright attached to an upper thigh cuff and lower shin cuff. The upright is located on the side of the collapsed compartment of the knee; i.e. medial side for medial compartment osteoarthritis. The attached cuffs “offload” the biomechanical force on the affected compartment of the knee by increasing the joint space on the affected side as the knee goes from flexion to extension. Many osteoarthritis braces use an angled strap from the upper part of the brace that goes across the opposite side of the knee joint from the side bar or upright to improve the alignment of the knee during ambulation to better balance the forces on the knee during gait more evenly. The strap provides a three point leverage that pulls the knee joint into proper alignment during gait. A combination of the single sided upright with cuff attachments and the valgus producing strap have shown to provide improved performance in severe genu varum osteoarthritis. However, it is difficult to set the desired degrees of flexion and extension. 
         [0015]    Although many of the existing knee braces containing locking hinge assemblies serve their intended purpose, difficulty in ease of setting the desired degrees of flexion and extension continues to be a problem. Improvement is needed whereby a swing assist mechanism is provided for any type of knee brace, either having flexion and extension degree setting points or without such setting points, but which assists the knee brace to swing outward and then return for improving knee performance and correcting abnormal gait in a patient using such knee brace. 
       SUMMARY OF THE INVENTION 
       [0016]    The present invention is dynamic swing assist mechanism used with or in any type of knee brace having at least one upright. The mechanism can have desired degree of flexion and extension or not. Further, the mechanism can be attached to an outside portion of a hinge of the knee brace along the at least one upright, made integral as part of the hinge or made integral has part of the at least one upright. Still further, two dynamic swing assist mechanisms, configured as mentioned directly above, can be employed in a knee brace having a pair of uprights. 
         [0017]    In knee braces that unload the pressure on an affected side of a knee joint, balance the joint space on both sides of the knee during ambulation and improve knee joint alignment, the swing assist can then be adjusted as the condition of the knee improves or deteriorates to maintain joint space balance, change the unloading effect on the affected side of the knee joint, improve knee joint alignment during gait and correct improper gait. 
         [0018]    As alignment of the knee changes (joint space balance), the swing assist mechanism of the knee brace is adjusted so that joint space balance is continually maintained with joint rehabilitation. The current invention in one embodiment achieves this significant improvement with an adjustable dynamic fulcrum to allow the clinician to quickly and easily adjust the brace to maintain joint space balance as needed during the knee rehabilitation process. 
         [0019]    As an example, the present invention can accomplish the desired result of joint space balance by providing a lateral polycentric hinge and a medial unicentric hinge component positionable respectively laterally and medially adjacent the knee joint. A shin cuff is circumscribable about on one front or back side of the lower leg. The lower member of each hinge is attached to a lateral and medial upright element respectively integral with the shin cuff. A thigh cuff is aligned with one of the front or back sides of patient&#39;s thigh, above the knee joint. The thigh cuff has a lateral and medial element extending downwardly to engage a top hinge arm of the lateral and medial hinge respectively. An adjustable swing assist mechanism, such as a dynamic fulcrum hinge component, is then used to assist during leg extension and flexion (i.e., during walking), squatting and sitting. By moving setting blocks different degrees of tension is introduced into the polycentric lateral hinge. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    This invention can be best understood by those having ordinary skill in the art by reference to the following detailed description, when considered in conjunction with the accompanying drawings in which: 
           [0021]      FIG. 1  is a lateral side perspective view of a knee brace employing a first embodiment of the swing assist mechanism of this invention. 
           [0022]      FIG. 2  is a medial side perspective view of the mechanism of  FIG. 1 . 
           [0023]      FIG. 3  is a front view of a knee with a hidden view of the patella out of alignment. 
           [0024]      FIG. 4  is a front view of a knee with a hidden view of the patella with a knee brace utilizing the swing assist mechanism of this invention in place. 
           [0025]      FIG. 5A  is a lateral side view of a knee brace hinge assembly and the novel swing assist mechanism of  FIG. 1  on an extended leg of a patient. 
           [0026]      FIG. 5B  is a lateral side view of a knee brace hinge assembly and the novel swing assist mechanism of  FIG. 5A  with the patient&#39;s knee in a bent position. 
           [0027]      FIG. 6A  is a lateral side view of a knee brace hinge assembly and the novel swing assist mechanism of  FIG. 1  on an extended leg of a patient with only two setting blocks in place. 
           [0028]      FIG. 6B  is a lateral side elevational view according to  FIG. 6A  with the patient&#39;s knee bent. 
           [0029]      FIG. 7A  is a lateral side view of a knee brace hinge assembly and the novel swing assist mechanism of  FIG. 1  on an extended leg of a patient with only one setting block in place. 
           [0030]      FIG. 7B  is a lateral side according to  FIG. 7A  with the patient&#39;s knee bent. 
           [0031]      FIG. 8A  is a lateral side view according to  FIG. 1  on an extended leg of a patient with the setting blocks moved to an extreme position. 
           [0032]      FIG. 8B  is a lateral side view according to  FIG. 8A  with the patient&#39;s knee bent. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Throughout the following detailed description the same reference numerals refer to the same elements in all figures. 
         [0034]    Referring to  FIGS. 1 and 2 , the osteoarthritis knee orthosis  10  (hereafter identified as OA), has a medial unicentric hinge  12  with flexion stop  14  and extension stop  16  at any setting. The medial unicentric hinge  12  is substantially parallel to a lateral polycentric adjustable tension offloading hinge  18 . The bottom end  20  of medial hinge  12  is attached to a first upright member  22  integral with a knee ring  24 . A lower gear plate  26  of lateral hinge  18  is attached to a second upright member  28  integral with knee ring  24 . 
         [0035]    An upper arm  30  of the lateral hinge  18  connects at an upper end to a flexible upper thigh cuff  32 . A lower portion of the lateral hinge broadens out to a slotted hinge connector plate  34 . A slot  36 , in connector plate  34  contains a transverse shaft on rivet  40 . The rivet  40  attaches a first star gear  42  to an inside surface of the slotted connector plate  34 . A second star gear  43  is integral with a gear plate  44  attached to an inner surface of upper arm  30 . 
         [0036]    An upper arm  48  of the medial hinge  12  is attached at its top end  50  to the flexible upper thigh cuff  32 . Medial hinge  12  is a KWIK-SET design set forth in U.S. Pat. No. 6,039,709, incorporated herein by reference. The upper arm  48  of medial hinge  12  is significantly longer than the upper arm  30  of the lateral hinge set  18 ; about 1½ inches in the medium size. The longer length of medial upper arm  48  compared to the upper arm  30  of the lateral hinge  18  encourages unloading of force from the medial compartment of the knee by lifting the medial side  52  of the femur  54  off of the tibia  56  with weight bearing during full leg extension. See the gap  58  shown in  FIG. 4 . 
         [0037]    The lower medial side upright  22  and lower lateral side upright  28  are equivalent in length. The medial upper arm  48  is set back at an angle of approximately 15° to 20° with the leg straight whereas upper lateral arm  30  and lower lateral upright  28  are in a relatively straight alignment with the hinge when the leg is straight. The offset portion of arm  48  improves knee alignment from 20° of flexion to full extension of the knee joint and prevents “reverse Screw Home Mechanism” rotation of the knee. 
         [0038]    As shown, the various elements are held together by rivets such as rivet  40 . Other equivalent means of attachment could be substituted for the rivets. 
         [0039]    On polycentric hinge  18 , an elastic band  60  attaches at a lower end on the outside of the second upright member  28  at fulcrum point  70  and travels adjacent adjustable dynamic fulcrum setting blocks  62 ,  64  and  66  to terminate at fulcrum  68 . The dynamic tension of the fulcrum  68  can be set by the fitter by using fulcrum blocks  62 ,  64  and  66 . In addition, various elastic bands  60  with varying elastic properties can be substituted to allow the fitter to adjust the dynamic fulcrum with multiple tension forces. The dynamic adjustable fulcrum is derived from the band  60  positioned from the lower fulcrum point  70  and stretched over blocks  62 ,  64  and  66  at the lateral hinge as the knee bends. See  FIG. 5B . The adjustable dynamic fulcrum is used to provide a dynamic tension force at the knee joint that can be used to balance the joint space  58  between the medial and lateral compartments and to provide optimal alignment of the knee with the OA  10  brace. 
         [0040]      FIGS. 6A and 6B  show alignment using only two blocks,  62  and  64 , on the polycentric hinge  18 . 
         [0041]      FIGS. 7A and 7B  show minimal alignment using only one block  62  on the polycentric hinge  18 . 
         [0042]      FIGS. 8A and 8B  show an extreme alignment using blocks  64 ,  66  and  67 . In this condition there is no block  62  in lower aperture  98  on the polycentric hinge  18 . 
         [0043]    A strap  72  tightens thigh cuff  32  in place. 
         [0044]    A second mid-thigh cuff securing strap  78  is a soft elastic material with a soft adjustable pad  74  placed at the inner midpoint area of strap  78 . Strap  72  is placed through a D-ring fastener  76  on the side of the thigh cuff  72 . Hook and loop material is used to engage strap  72  to itself. Soft padded mid-thigh securing strap  78  travels from the lateral side of OA  10  through a second D-ring fastener  80  on the medial side of OA  10 . The strap  78  fastens to itself by hook and loop material. 
         [0045]    A shin cuff soft elastic material securing strap  82  travels across the back of the patient&#39;s calf through a third D-ring fastener  84  on the lower end of the lateral upright  28  and fastens onto itself with hook and loop material. A padded calf strap  86  travels around the back of the calf with an adjustable pad  88  located at mid strap  86 . Strap  86  passes through a D-ring fastener  93  on the lower upright  28  and is attached to itself by hook and loop material. 
         [0046]    The knee brace bends with free moving axial hinges, each with six equivalently sized axial teeth on the upper and lower aspects of the inner hinge assembly of the medial and lateral hinges  12  and  18 . As the knee bends, the bend movement is tracked or guided by the rigid brace uprights at the hinge center axle through groove  36  on the lateral hinge. The hinge alignment forces the bend line of the brace through grooves  36  that is pre-cut into the lateral hinge  18 . The specific bend movement of the knee is controlled by the hinge axle traveling through the grooves  36  in the lateral hinge  18 . The adjustable dynamic fulcrum on the lateral hinge  18  can be set to provide a dynamic assist mechanism  62 ,  64  and  66  with spring band  60  to assist in controlling the alignment and movement of the knee from 20° of flexion to full extension of the knee. The adjustable properties of the dynamic fulcrum offer the fitter or wearer multiple settings to maintain knee joint space balance, improved knee joint alignment, and prevention of “reverse Screw Home Mechanism” or controlled rotation of the knee as the knee goes from 20° flexion to extension. 
         [0047]    The adjustable dynamic fulcrum band mechanism  60  is on the lateral upright of the OA Knee Brace  10  for medial compartment osteoarthritis. Four threaded holes  92 ,  94 ,  96  and  98  are arranged along the hinge of the outer lateral connector plate  34 . Blocks  62 ,  64 ,  66  and  67  are screwed into the holes as needed. Block  64  can be inserted in hole  96  providing the center point of the elastic band fulcrum as the knee bends if the optimal dynamic setting of the adjustable pull mechanism is needed. A second block  62  with elastic band  60  tracking material can be inserted into threaded hole  98  if another optimal dynamic setting of the adjustable pull mechanism is needed. A third adjustable dynamic fulcrum mechanism is available by inserting block  66  with the elastic band  60  tracking material into threaded hole  94 . By providing three or more incrementally stronger or more elastic bands, the fitter will have multiple settings to adjust the dynamic fulcrum to maintain the correct amount of dynamic force to maintain optimal joint space on both the medial and lateral compartments of the knee as well as to maintain optimal knee alignment during the motion of the knee during ambulation. 
         [0048]    It is understood that an OA knee brace having two uprights has been used above to describe a first embodiment of the swing assist mechanism of the present invention. Other knee braces can be used with the present invention having one or two uprights and if two uprights are employed, then the uprights are not offset. Further, swing assist mechanism can be attached to the outer side of a brace hinge, made integral with a brace hinge or made integral with one or more brace uprights. 
         [0049]    Other equivalent elements can be substituted for the elements disclosed herein to produce the same results in the same way by the same manner.