Patent Application
20050076940
1. Field of the Invention
The present inventions are directed to medical devices for ambulatory care and more particularly ergonomic crutches.
2. Relevant Technology
A crutch is generally thought of as a medical device that is used to support all or part of a patient's body weight. A crutch has traditionally been made of wood or metal, and is ordinarily long enough to reach from a patient's underarm to the walking surface. There is typically a concave surface fitting underneath the arm, and a cross bar for the hand, both used for supporting the body weight. Crutches may be used by a patient for only a few days or, in some instances, a lifetime. Crutches have caused or led indirectly to multiple injuries and disorders despite their ability to transfer weight. In addition, each repetition of an injurious action can produce micro-trauma to the tissues and joints of the body. Although the human body has enormous self-repair abilities, continued exposure to such activities can outweigh these abilities, which then results in injury.
The injuries resulting from crutch use are in part due to the fact that patients overly rely upon the underarm portion to support the body weight. Most crutch designs have not taken into consideration the appropriate contour of the axilla. This has resulted in nerve injuries varying from neuropraxia to complete paralysis of the arm. In addition, the hand grip is rarely contoured to fit a patient's palm. The general construction and design of crutch hand grips does not provide the correct ergonomic orientation between the wrist and forearm even though padding may be present. Failure to achieve correct alignment and padding in the palmar area can result in disorders of wear and tear, including overuse syndromes, repetitive strain injuries, musculoskeletal injuries, and compressive neuropathies. Common injuries resulting in such usage include: carpal tunnel syndrome, wrist tendonitis, medial or lateral elbow epicondylitis, and rotator cuff muscle strains and tears. These disorders appear to be more common in the chronic crutch user, and are the result of repeated stresses on a particular musculoskeletal area.
Crutches have traditionally imported a fixed-length frame having a concave cushioned upper end for placement under the arm, a horizontally-directed rigid handle that extends between two bows that act primarily to carry the weight of a patient, and a lower end configured to contact the ground. Shock absorbing devices have been placed on crutches to lessen the impact to a patient as the body weight is transferred to the walking surface. An added benefit of a shock absorbing device is to assist a patient on uneven ground, as well. Different crutch ends have been designed to provide contact between the crutch and the walking surface. However, an appropriate gripping surface to decrease friction is necessary to prevent the crutch from sliding or slipping. A distal end that not only grips the surface but angulates with the movement of the crutch is necessary to assure full contact.
While various modifications have been attempted, there presently does not exist a crutch that incorporates the appropriate ergonomic structure in a light-weight, sure gripping, user friendly, shock absorbing, and collapsible format.
The present inventions meet the above-described needs and others. Specifically the present inventions provide an ergonomically designed shock absorbing collapsible crutch to facilitate walking and minimize injurious impact to a patient.
The present inventions present an improved crutch. The crutch has one supporting member in place of two for easier usage and transport. The underarm support surface located toward the proximal end of the supporting member may have interchangeable cushioning pads and is contoured to fit underneath the axilla comfortably. The hand grip located toward the distal end of the supporting member has the appropriate contours for the palm of the hand and ergonomic angulation between the wrist and forearm. An alignment rib connects the supporting member to an adjustable portion to provide support, lengthening and collapsibility. Both the proximal and distal ends of the alignment rib have a snap button to connect to the supporting member and adjustable portion, respectively. A shock absorbing device may be connected to the distal end of the adjustable portion to assist in ambulating over uneven surfaces and to provide a cushioning effect. The distal end of the crutch has a gripping pad that provides appropriate friction between the crutch and the walking environment. It also angulates to provide full contact with the ground throughout the stance phase of the gait cycle. The crutch is collapsible to approximately half of its length allowing for ease in storage and transportation.
The accompanying drawings incorporated in and forming a part of the specification illustrate preferred embodiments of the present inventions. Some, although not all, alternative embodiments are described in the following description and therefore the drawings are not intended to limit the scope of the inventions. The inventions will be described and explained with additional specificity and detail through the use of the accompanying drawings where:
Embodiments of the present inventions can be better understood with reference to the drawings where like parts are designated with like numerals throughout.
The underarm support 101 located toward the proximal end of the supporting member has interchangeable cushioning pads. The underarm support 101 may be padded with an elastomeric material such as EVA, urethane foam, neoprene foam, PVC, natural rubber, cork or any other possible materials. The hand grip 103 is located toward the distal end of the supporting member 102 and has the appropriate contours and ergonomic angulation to fit the palm and align the wrist. The hand grip 103 may be fabricated of elastomeric material such as EVA, urethane foam, neoprene foam, PVC, natural rubber, cork or any other possible materials. An alignment rib 115 connects the supporting member 102 to an adjustable portion 116 to provide support, height adjustment and collapsibility.
The supporting member 102, alignment rib 115 and adjustable portion 116 may be fabricated of metal such as aluminum, steel, or titanium, and are formed in a generally hollow cylindrical shape. The internal and external diameter of the supporting member 102, alignment rib 115 and adjustable portion 116 can be of varying dimensions to accommodate a patient's needs and to provide for the pieces of the crutch to fit together. For example, a pediatric patient may utilize a crutch with a smaller external diameter than an adult patient. A shock absorbing portion 106 may be used at the distal end of the adjustable portion 116 to assist in ambulating over uneven surfaces and to provide a cushioning effect. The distal end of the crutch has a gripping pad 107 that provides appropriate friction between the crutch and the walking environment. The gripping pad 107 may be formed of an elastomeric material such as EVA, urethane foam, neoprene foam, PVC, natural rubber, cork or any other possible materials.
The underarm support 101 is generally parallel to the x-axis 121 and it is contoured to fit the underarm of a patient. The length of the underarm support 101 extends considerably beyond either side of a patient's arm. The underarm support 101 has a concave curvature along the top edge and a convex curvature along its underside. The concave curve along the top edge is designed to prevent slippage and provide comfort and stability to a patient.
The stabilizing portion 117 is generally parallel to the y-axis 120. The stabilizing portion 117 is configured to be at an angular orientation α with respect to the underarm support 101 in the range of 45° to 135°. The crutch embodiment of
The middle bend portion 118 projects from the stabilizing portion 117 in a downward direction toward the y-axis 120 such that the x-coordinate of the distal end of the middle bend portion 118 is close to the x-coordinate of the proximal end of the hand grip portion 119 in
The hand grip portion 119 projects from the distal end of the middle bend portion 118 in a generally vertical direction. In one embodiment of the ergonomic collapsible crutch the hand grip portion 119 directly follows the y-axis 120 such that the x-coordinate of the proximal end of the hand grip portion 119 is close to the x-coordinate of the distal end of the hand grip portion 119. In one embodiment as depicted in
The alignment rib 115 provides the connection between the supporting member 102 via the hand grip portion 119 and the adjustable portion 116. The hand grip portion 119 of the supporting member 102 includes dual snap buttons 105 to accommodate patients of varying heights. Alternative devices may be used as a latching mechanism instead of the illustrated dual snap buttons 105. For example, a single pin radially biased outward would be sufficient. In one embodiment of the ergonomic collapsible crutch the adjustable portion 116 is connected to a shock absorbing portion 106 to lessen impact on a patient. Additionally, a gripping pad 107 is at the end of the crutch to provide stability and grip on uneven or slick surfaces.
The underarm pad 217 may be generally cylindrical in shape and may be fabricated with an elastomeric material such as EVA, urethane foam, neoprene foam, PVC, natural rubber, cork or any other possible materials. The exterior diameter of the underarm pad 217 may be custom designed to fit a patient's desired thickness and density. The interior diameter of the underarm pad 217 may also be custom designed to fit the diameter of the underarm support 101. In addition, the underarm pad 217 is removable/replaceable in the event an alternative material, thickness, diameter and/or density is desired. The underarm support 101 is a portion of the supporting member 102 and is connected to the hand grip portion 119, via the stabilizing portion 117 and the middle bend portion 118.
The hand grip portion 119 has a series of diametrically opposed hand grip adjustment apertures 203 to allow the hand grip 103 to be placed in a variety of positions to accommodate height adjustment and a patient's desired orientation of the crutch. The hand grip portion 119 is further described and illustrated in
The hand grip 103 is connected to the hand grip portion 119 of the supporting member 102 via a hand grip shaft 202. In one embodiment of the ergonomic collapsible crutch the hand grip 103 is secured to the supporting member 102 via a machine screw 301 that extends through a set of hand grip adjustment apertures 203.
The hand grip may be of varying diameters to accommodate the palm of a patient. In one embodiment of the ergonomic collapsible crutch, the hand grip 103 is about 1 cm smaller than a patient's inside grip diameter. The pressure of the hand grip 103 on the hand should be distributed over the fat pads of the hands. The contour of the hand grip 103 corresponds with the curve of the transverse palmar arch and the natural palmar curve of the fingers as they flex toward the palm.
The length of the hand grip 103 should be long enough to evenly distribute the grasping forces over the palm of the hand. A grip with a length in the range of about 4 to about 5 inches or from about 10 to about 12 centimeters provides sufficient area to spread the grasping force over the palm of an average adult patient. However, the length of the hand grip 103 may be customized to the palm of any patient.
The hand grip 103 is oriented to maintain the wrist in a neutral position throughout a patient's walking motion. The neutral position is generally maintained by keeping a patient's third metacarpal generally aligned with his radius. Therefore, the hand grip 103 is angled outwardly from the y-axis 304 at an angle λ from the x-axis 303 allowing for a patient's third metacarpal to be more generally aligned with his radius. The edge of the hand grip shaft 302 that contacts the supporting member 102 may be manufactured to provide complete contact such that when the hand grip 103 is at an angle λ there is little to no gap between the edge of the hand grip shaft 302 and the supporting member 102. The angle λ is determined by a variety of factors including the orientation of the crutch. The crutch may be used in the forward orientation as illustrated in
A crutch placed in the reverse orientation with respect to a patient, as illustrated in
In one embodiment, the height of the crutch may be adjusted by providing an adjustable portion 116 as shown in
A shock absorbing portion 106 may be included in an ergonomic collapsible crutch. In one embodiment a spring 214 is used to provide a shock absorbing mechanism, as illustrated in
While the present crutch has been described and illustrated in conjunction with a number of specific examples, those skilled in the art will appreciate that variations and modifications may be made without departing from the principles herein illustrated, described, and claimed. The present inventions, as defined by the appended claims, may be embodied in other specific forms without departing from its spirit or essential characteristics. The configurations of articles described herein are to be considered in all respects as only illustrative, and not restrictive. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
