Abstract:
A dynamic hip stabilizer utilized to prevent postoperative and recurrent traumatic hip dislocations. The stabilizer includes a pelvic girdle defining an upper opening for the wearer&#39;s waist and a lower opening for the wearer&#39;s hips, at least one thigh cuff defining an upper opening for a thigh of the wearer and a lower opening for a lower region of the wearer&#39;s thigh, and elastic cables attached to the pelvic girdle and the thigh cuff and extending therebetween in a longitudinal direction of the stabilizer. The stabilizer further includes channeling features associated with the pelvic girdle for guiding and controlling movement of the cables in directions transverse to the longitudinal direction of the stabilizer. The stabilizer may optionally include lateral extensions that connect the girdle to each thigh cuff.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/319,519, filed Sep. 4, 2002. 
    
    
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to devices utilized to prevent postoperative hip dislocations and recurrent traumatic hip dislocations. More particularly, this invention relates to a dynamic hip stabilizer with a combination of components that generate tensile forces capable of holding a patient&#39;s thigh with enough tension to control excessive adduction, flexion or extension, control excessive internal or external rotation, provide hip stability by controlling and modifying certain hip motions through increasing tension as the extremes of a particular motion are approached, and provide hip stability by constantly maintaining elevated abductor tension across the hip joint. 
     2. Description of the Related Art 
     There are a variety of techniques currently in use to prevent postoperative hip dislocations, recurrent traumatic hip dislocations, etc., some of which make use of specialized devices. A basic technique is to place a pillow between the thighs of the patient to cause abduction of the hips. A slightly more advanced technique is to secure a foam abduction pillow between the thighs with hook and loop straps to hold the hips in wide abduction. More advanced techniques include the use of single hip spica abduction braces, which generally comprise a thermoplastic waist brace attached to a thermoplastic thigh component by a hinged metal bar. The metal hinge portion allows flexion of the hip within a variable fixed range which can be set by the treatment provider. Single and bilateral hip spica casts, which serve to prevent all hip motions, also have long been used. Another type of device is the hip abduction brace, which generally comprises two curved semicircular plastic plates connected by hinges to a central threaded expansion-contraction device. By turning a central control threaded screw, the semicircular plastic plates spread out. When held between the proximal thighs by hook and loop straps, the device pushes the thighs apart, attempting to maintain abduction of the hips. 
     Various shortcomings are associated with the use of the above techniques and devices. Conventional pillows are too moveable and not wide enough to give consistent abduction, and undesirably allow the patient to move about. As a result, a pillow is rarely capable of preventing postoperative dislocation because it does not move with the patient who rolls over, or when the patient sits at the side of the bed or is being transferred to a wheel chair. Foam abduction pillows are clumsy and require considerable nursing effort to roll a patient from side to side. Furthermore, foam abduction pillows must be removed when the patient sits up and when bed-to-chair transfers are required. 
     A significant shortcoming of hip spica casts is the risk of prolonged stiffness because of the lack of all motion at the hip for many weeks. While single hip spica abduction braces avoid this concern, they require measurement and fitting by an orthotist and are formed from prefabricated parts of thermoplastic material and metal struts. Though single hip spica abduction braces can be worn in bed and while the patient sits and is being transferred, form-fit plastic abdominal and thigh portions of the brace often do not fit well, and allow many patients to rotate, putting the hip at risk. These braces also often allow some adduction and internal rotation, which is a significant risk to hip stability. Furthermore, this type of brace offers no compression of the femur against the pelvic acetabulum. 
     Hip abduction braces work reasonably well for the first days after surgery when the patient is fairly inactive. However, if not maintained in its fully abducted position, this type of brace allows for adduction to neutral and flexion is uncontrolled. The brace is removed for perineal care and when sitting the patient up at bedside. In addition, this type of brace cannot be worn during patient bed-to-wheelchair transfers or during gait training. 
     Other techniques and braces that pertain to the prevention of hip dislocations, or more generally to supporting or bracing the hip region, include U.S. Pat. No. 976,564 to Goodson, U.S. Pat. No. 1,722,192 to Brokaw, U.S. Pat. No. 2,332,119 Springer, U.S. Pat. No. 4,531,515 to Rolfes, U.S. Pat. No. 4,709,692 to Kirschenberg et al., U.S. Pat. No. 4,901,710 to Meyer, U.S. Pat. No. 4,905,678 to Cumins et al., U.S. Pat. No. 4,926,845 to Harris, U.S. Pat. No. 5,267,928 to Barile et al., U.S. Pat. No. 5,286,251 to Thompson et al., U.S. Pat. No. 5,465,428 to Earl, U.S. Pat. No. 5,840,050 to Lerman, U.S. Pat. No. 5,893,367 to Dubats et al., U.S. Pat. No. 5,928,175 to Tanaka, and U.S. Pat. No. 6,039,707 to Crawford et al. Each of Goodson, Brokaw, Barile et al. and Earl entail device with a waist portion, thigh portions, and elastic straps that interconnect the waist and thigh portions. Goodson&#39;s straps are limited to the posterior to provide posture support. Brokaw discloses a brace with inelastic anterior straps and elastic posterior straps. Barile et al. disclose a one-piece support garment with elastic anterior and posterior straps and elastic lateral straps, the latter of which may be wrapped in various ways around the thighs or hips of the wearer. Finally, Earl discloses an exercise device whose elastic straps are limited to the posterior side of the device. 
     It would be desirable if an improved device was available that was specifically configured to prevent hip dislocations by controlling excessive adduction, flexion and/or extension, controlling excessive internal or external rotation, increasing hip stability. 
     SUMMARY OF INVENTION 
     The present invention provides a dynamic hip stabilizer utilized to prevent hip dislocations, including postoperative and recurrent traumatic hip dislocations. The stabilizer generally comprises a pelvic girdle defining an upper opening for the wearer&#39;s waist, at least one thigh cuff defining a lower opening for a lower region of the wearer&#39;s thigh, and elastic cables attached to the pelvic girdle and the thigh cuff and extending therebetween in a longitudinal direction of the dynamic hip stabilizer. The stabilizer further includes channeling means associated with the pelvic girdle for guiding and controlling movement of the elastic cables in the longitudinal direction of the stabilizer and for inhibiting movement of the elastic cables in directions transverse to the longitudinal direction of the stabilizer. The channeling means preferably operate to control the paths of the cables in a manner that promotes their effect while preventing them from causing discomfort to the wearer. Additional and preferred features of the invention include lateral extensions that connect the girdle to each thigh cuff, and configuring the girdle and thigh cuffs to have opposing frustroconical shapes to inhibit movement of the girdle and thigh cuffs toward each other. 
     According to a preferred aspect of the invention, the tensile forces generated by the multiple elastic cables are capable of holding the wearer&#39;s thigh with enough tension to control excessive adduction, flexion or extension, provide hip stability by controlling and modifying certain hip motions through increasing tension as the extremes of a particular motion are approached, and provide hip stability by constantly maintaining elevated abductor tension. The girdle and thigh cuff are configured to permit attachment and positioning elastic cables of potentially different lengths in multiple directions to generate different tensions, thereby enabling the stabilizer to provide a range of stabilizing forces. The girdle and thigh cuff are also preferably configured to permit attachment of one or more cables from the posterior of the girdle to the anterior of the thigh cuff, enabling control of excessive internal or external rotation. The channeling means make such configurations possible without discomfort to the wearer. 
     Other objects and advantages of this invention will be better appreciated from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1 ,  2  and  3  represent anterior, lateral and posterior views, respectively, of a patient wearing a dynamic hip stabilizer in accordance with a preferred embodiment of the invention. 
         FIGS. 4 and 5  are plan views of the exterior and interior surfaces, respectively, of the dynamic hip stabilizer shown in  FIGS. 1 ,  2  and  3 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 5  show a dynamic hip stabilizer  10  in accordance with the present invention as comprising three primary components: a pelvic girdle  12 , thigh cuffs  14  (at least one, preferably two), and elastic cables  16 . The cables  16  are shown connected to the girdle  12  and the thigh cuffs  14  so as to be under elastic tension, such that the cuffs  14  prevent rotation of the girdle  12  as a result of the force generated by the cables  16 . In some patients, only the operative thigh cuff  14  may be necessary. 
     The girdle  12  and thigh cuffs  14  preferably comprise a flexible but firm outer layer  18  of fabric material sewn or adhered to an inner lining material  20  that is preferably soft and nonirritating to the skin. The outer layer  18  is preferably relatively stiffer than the inner lining material  20  to provide support to the lining material  20 . The inner lining material  20  preferably has a high skin friction equivalent, i.e., resists slippage against the skin, a particularly suitable example of which is commonly referred to as polar fleece. A suitable material for the outer layer  18  is plastic-molded polyester mesh. 
     As evident from the Figures, the girdle  12  is narrower at an upper opening defined by its upper extent  22  (corresponding to the waist level of the wearer) and wider at a lower opening defined by its lower extent  24  (corresponding to the pelvic-hip level of the wearer), so as to have a frustroconical shape. As shown, the inner lining material  20  may project beyond the upper extent  22  of the girdle  12  for added comfort to the wearer. In addition, extensions  26  of the inner lining material  20  project below the outer layer  18  at the lateral portions of the girdle  12  to extend distally along the midlateral of each thigh, preferably for about three to about five inches (about eight to about thirteen cm) below the outer layer  18 ,and are releasably connected with zippers  28  (or other suitable releasable fastener) to the thigh cuffs  14 . The extensions  26  serve to inhibit slippage and motion between the wearer and the stabilizer  10 , inhibit hip flexion, limit rotation of the thigh cuffs  14  when under elastic rotational tension, and help maintain the distance relationship between the girdle  12  and cuffs  14 . Similar to the girdle  12 , each of the thigh cuffs  14  is frustroconical-shaped, though inverted relative to the girdle  12  so as to be wider at an upper opening defined by its proximal-top extent  32  and narrower at a lower opening defined by its inferior-bottom extent  34  in accordance with the shape of the human thigh. With this arrangement, the girdle  12  and thigh cuffs  14  are inhibited from moving toward each other under the tension generated by the cables  16 . The girdle  12  and the thigh cuffs  14  are preferably closable with hook-and loop-closures  30  (or another suitable releasable fasteners), so that the upper and lower openings of the girdle  12  and thigh cuffs  14  can be appropriately sized for the wearer. The closures  30  of the thigh cuffs  14  are preferably located over the inside of the wearer&#39;s thighs when the stabilizer  10  is worn. 
     As evident from  FIGS. 1 through 4 , the girdle  12  and thigh cuffs  14  are equipped with series of loops  36 . A single transverse row of loops  36  is shown as located near the upper extent  22  of the girdle  12 , extending around nearly the full circumference of the girdle  12  while avoiding the hook-and-loop closure  30  ( FIG. 1 ). The transverse loops  36  of the girdle  12  are preferably spaced apart about every two and one-half inches (about six cm).  FIGS. 1 through 4  show each thigh cuff  14  as being provided with three rows of the transverse loops  36  vertically spaced apart in the longitudinal direction of the stabilizer  10 , with each row extending about three quarters of the circumference of each thigh cuff  14  to avoid the hook-and-loop closures  30  located at the inner thigh. While the girdle  12  is shown with a single transverse row of loops  36  and the thigh cuffs  14  are shown with three transverse rows of loops  36 , any number of rows and loops  36  could be used. In particular, the lower row of loops  36  on the cuffs  14  are believed to be optional, as under certain conditions a cable  16  attached to a loop  36  near the lower extent  34  of a cuff  14  may cause the cuff  14  to curl toward the girdle  12 . Finally, the loops  36  of the girdle  12  and cuffs  14  need not be aligned in rows. 
     As also evident from  FIGS. 1 through 4 , the girdle  12  is further equipped with a series of channel loops  38  arranged in longitudinal rows that are aligned with the transverse loops  36  and extend toward the lower extent  24  of the girdle  12  and thigh cuffs  14 . The channel loops  38  can be formed of fabric to be of any suitable size, e.g., one and one-eighth inches (about 2.8 cm) wide and one and one-quarter inches (about 3.2 cm) long. While shown as raised loops, other channel-type configurations could be used, including more rigid tubes attached to the girdle  12  or channels recessed into or beneath the surface of the girdle  12 . Each of the elastic cables  16  is attached to one of the transverse loops  36  of the girdle  12  and to one of the transverse loops  36  of the thigh cuffs  14 , passing therebetween through one of the longitudinal rows of channel loops  38  on the girdle  12  so as to be guided and controlled by the channel loops  38 . Simple “C” rings  40  or other appropriate connectors can be used to connect the proximal ends of the elastic cables  16  to the transverse loops  36  of the girdle  12 , whereas quick links  42  or other releasable connectors preferably connect the cables  16  to the transverse loops  36  on the thigh cuffs  14 . The quick links  42 , well known and commercially available from a variety of sources, are covered with neoprene tubes that act as metal covers. It is foreseeable that quick links could be used in place of the “C” rings  40  at attach proximal ends of the cables  16 . 
     As evident from  FIGS. 1 through 3 , the channel loops  38  control the paths of the cables  16 , directing the tension generated by the cables  16  along paths beneficial to the wearer. Simultaneously, the loops  38  prevent the cables  16  from moving in directions transverse to the longitudinal direction of the stabilizer  10 , which would likely cause discomfort to the wearer. For example, the loops  38  are able to prevent the cables  18  rolling and snapping over the wearer&#39;s buttocks or catching in the gluteal cleft. In practice, a single transverse row of channel loops  38  near the lower extent  24  of the girdle  12  has been shown to be adequate, such that the row of channel loops  38  nearest the loops  36  can be considered as optional. 
     As evident from  FIGS. 1 and 3 , respectively, cables  16  can be routed between the anterior sides of the girdle  12  and cuffs  14  and between the posterior sides of the girdle  12  and cuffs  14 . As represented in  FIG. 2 , cables  16  can also be routed from the posterior of the girdle  12  to the anterior or sides of the thigh cuffs  14 . Beneficial effects associated with the ability to selectively establish different routes for the cables  16  include the capability of applying internal or external rotational forces. Anterior hip dislocations require an internal rotation and flexion force, while posterior dislocations require external rotation and an extension force. Lateral abductor deficiencies require an abduction force, which can also be generated by appropriately routing one or more cables  16 . By varying the tensions and lengths of the cables  16 , greater and lesser flexion or extension forces can be created. 
     The dynamic hip stabilizer  10  described above is able to solve various problems, shortcomings and disadvantages of the prior art. The stabilizer  10  eliminates motion between the wearer&#39;s skin and the stabilizer  10  by using custom-fitting girdle  12  and thigh cuffs  14  equipped with a soft, high-friction inner lining material  20 . With the closures  30 , the sizes/circumferences of the girdle  12  and thigh cuffs  14  can be individually tailored to allow for individual abdominal-thigh size variations. The cuffs  14  can then be individually attached to the girdle  12  with the zippers  28 , thereby inhibiting slippage and motion between the wearer and the stabilizer  10 . Multiple elastic cables  16  can be provided in multiple lengths and generate any number of different tension loads in multiple directions to provide the stabilizing forces required by the wearer&#39;s condition. In particular, the cables  16  can be routed between the girdle  12  and the thigh cuffs  14  so that the wearer&#39;s thigh is held to the pelvis with enough tension to control excessive adduction, flexion, and/or extension, control excessive internal or external rotation (by passing one or more cables  16  from back to front), provide hip stability by controlling and modifying certain hip motions through increasing tension as the extremes of a particular motion are approached, and provide hip stability by constantly maintaining elevated abductor tension and hip joint compression. 
     With the dynamic hip stabilizer  10  of this invention, the wearer can be allowed a full range of motion against an increasing tension, which increase strength and institutes proprioceptive feedback to create a muscle contraction throughout the range, thereby aiding the abductor muscles in keeping the hip in place. The constant tension and full range of motion should allow the wearer to move about in bed, sit safely at the side of the bed, and transfer safely to a wheelchair or commode. Unlike various other devices that are commercially available, the stabilizer  10  does not need to be removed for motion or activities. Furthermore, the open groin and buttock areas allow for urination and defecation without having to remove or adjust the stabilizer  10 . Finally, the constant and adjustable tension generated by the cables  16  acts as a progressive resistive strengthening device to aid in postoperative rehabilitation. 
     While the invention has been described in terms of a preferred embodiment, it is apparent that other forms could be adopted by one skilled in the art. For example, the pelvic girdle  12  could be modified to use different materials, the cables  16  can be in the form of flat straps, round tubing, etc., the construction of the girdle  12  and thigh cuffs  14  could be simplified to use a single material, the  12  girdle could be in the form of a compression or plain pair of shorts with some form of elastic cables (straps) attached, and a stabilizer device having a similar function could be devised but with the connection between the pelvic girdle  12  and the thigh cuffs  14  eliminated. Therefore, the scope of the invention is to be limited only by the following claims.