Wrist splint

A wrist splint with an initially generally planar malleable metal core covered by a layer of synthetic foam padding material on each of its opposite sides and protected by an outer cover of fabric. Depending on the orientation of the splint relative to the patient, the splint provides greater or lesser firmness of support when the core is bent to conform the splint to the patient's hand, wrist, and forearm.

BACKGROUND OF THE INVENTION

The present invention relates to splints for immobilizing injured body members, and particularly to an improved splint that can be shaped to support a patient's hand, wrist, and forearm in comfort.

Splints for use in emergency and post-operative situations are known, for example, from Scheinberg, U.S. Pat. No. 4,676,233 and U.S. Pat. No. 3,943,923, both of which teach the use of a soft metal sheet formed into a configuration that provides needed support for an injured limb. Bentele U.S. Pat. No. 4,161,175 discloses surgical splints incorporating formed sheet metal or molded plastic bases. Ender U.S. Pat. No. 4,549,537 discloses another splint based on the use of sheet aluminum material. Bolla et al. U.S. Pat. No. 6,039,706 discloses a splint using a sheet of corrugated metal as its principal supporting structure.

Health care professionals have long used splints and casts fashioned out of plaster, fiberglass, preformed metal, or molded thermoplastic materials. These splints are designed to rigidly prevent motion and once formed into position cannot be reformed, for example to accommodate swelling, without considerable difficulty. A plastic or fiberglass splint once cured cannot be reformed. If swelling is excessive, a new fiberglass or plaster splint must be applied or an instrument resembling a large pliers (often referred to as a cast bender) is used to break the plaster or fiberglass material in order to relieve the pressure caused by the swelling. A thermoplastic splint is usually rigid and requires heat in order to be reformed. Preformed metal splints are also quite rigid and difficult to bend or mold. None of the above mentioned splints once formed allow a patient to perform any significant active movement or provide variably controlled active movement.

Active movement in a joint is movement performed by the patient as opposed to passive movement, i.e., movement performed by a physical therapist. Controlled variable active movement is active movement that can be increased or decreased according to the desire of the treating health professional. For example, it is desirable for orthopedic surgeons to vary a patient's allowable active movement during a post-operative convalescent period—i.e., the surgeon might desire less active movement during the first post-operative week and greater movement during the second post-operative week. Today, active movement is thought to be of significant value in the rehabilitation and treatment of fractures and soft tissue conditions. For example, following an open reduction and internal fixation of a distal radial (wrist) fracture orthopedic surgeons frequently direct their patients to remove their splints several times a day for active range of motion exercises. When these splints are removed patients are at increased risk of sustaining an injury. Therefore, it is desirable, to have not only an easily formable splint to accommodate post injury swelling, but a splint capable of allowing variable degrees of active movement while remaining in place.

SUMMARY OF THE INVENTION

The present invention provides an answer to some of the shortcomings of the previously available splints, by providing an easily usable splint that is conveniently storable in a planar configuration prior to preparation for use with a particular patient, and which can be formed to provide comfortable support for a patient's hand, wrist, and forearm with a chosen amount of firmness.

In a first preferred embodiment of the invention, such a splint has a body that includes an elongate flat supportive member, or core, of malleable metal that is more supportive at one end of the splint than at the other end. The same splint then can be used depending on its orientation, to provide either a greater or lesser amount of firmness of support for a patient's wrist, varying the patient's ability to perform active movements.

A layer of padding material is attached to each side of the core, and in one preferred embodiment of the invention an outer cover provides additional comfort and carries indicia to identify the amount of support provided by each end of the splint.

In one preferred embodiment of the invention, the padding material on a skin contact surface, or the splint surface directly adjacent to the skin, referred to herein as the closer face of the splint may preferably be of open-cell synthetic polymeric foam material, and the outer cover on that closer face of the splint is preferably of absorbent fabric that is open to passage of moisture and vapors, so as to maintain the patient's comfort with the splint in contact with the patient's skin.

In one preferred embodiment of the invention, a portion of the outer cover located on the opposite the splint surface not in contact with the skin, or farther face of the splint, is of material adapted to be engaged by the hook-carrying fastener portion of a hook-and-loop fastener system in order to facilitate the attachment of straps used to encircle the patient's hand, wrist, and arm to hold the splint in place.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings which form a part of the disclosure herein, inFIGS. 1 and 2a splint12which is a first preferred embodiment of the present invention is shown in a generally planar configuration in which the splint is manufactured and is usually packaged for shipment and for storage prior to its use. A body of the splint12has a first end14and an opposite second end16defining a length18that is greater than the width20. For example, the length18may be twelve or fifteen inches and the width20may be in the range of four to six inches, and preferably about 4½ inches for a splint12intended for use to support the wrist of an adult.

The body of the splint has a skin contact, or closer face24, intended to be placed in contact with a patient's skin or wound dressing, and shown inFIG. 2, but facing downward inFIG. 1. An opposite or farther face22of the splint facing upward, inFIG. 1, and normally faces outward, away from a patient's skin when the splint12is in use. The designations as closer and farther faces24and22thus refer to the proper orientation of the splint12with respect to a person's arm, wrist, and hand when the splint12is in use.

Identifying indicia are provided on the face22of the splint12, in the form of, for example, a single diamond26displayed on the farther face22adjacent the first end14of the splint12and a pair of diamonds28or other distinguishable marking provided on the farther face22adjacent the second end16of the splint12. The indicia26and28distinguish the first end14from the second end16, because the construction of the splint, as will be explained presently, provides support for a patient's hand and wrist with a first amount of firmness provided by the structure at the first end14of the splint12and with a second, greater, amount of firmness provided by the structure of the second end16of the splint12.

The splint12as shown inFIGS. 1–3has a core30of malleable metal in the form of a flat sheet whose dimensions are slightly smaller than the length18and width20of the splint12.

At the second end16of the splint12, the core30includes a thicker portion34having a length36preferably in the range of about 3 to 6 inches, and preferably of about 4.5 inches, for a splint whose length20is in the range of about 9–15 inches, in which the core30has a greater thickness, in order for the splint to provide greater firmness. The greater thickness may be provided by folding the aluminum sheet material back upon itself adjacent the second end16. The length36of the thicker portion34is thus long enough to provide support for the wrist76of an adult. As a result of the greater thickness, the thicker portion34of the core30adjacent the second end16of the splint12is stiffer than the portion of the core30adjacent the first end14of the splint12. Preferably the core30is of nearly pure aluminum such as Aluminum Association Type 1XXX aluminum, and preferably Type 1145 aluminum sheet material (99.45% pure) having a thickness32in the range of 0.008 inch–0.025 inch, and preferably having a thickness of about 0.016 inch. Preferably the metal is annealed to a dead soft or “O” temper. Bending the aluminum core30during the process of adjusting the splint12to conform to a patient creates a curved cross-section that increases the rigidity of the splint, i.e., makes it more resistant to bending.

A layer of pressure-sensitive adhesive material, which may be acrylic based, is provided on the surface of each of the layers of polymeric foam material of the farther side layer42and the closer side layer44, protected by a peel-off liner which is removed when the layers42and44of padding material are attached to the core. This adhesive material becomes the layer50mentioned above, in the manufacture of the splint12.

Enclosing the core30and the layers42and44of padding material is an outer cover52of textile fabric. Preferably, the outer cover52is made of two different types of fabric, with a first, or closer face part54of the outer cover52being located on and defining the closer face24of the splint12, and preferably extending around the lateral margins46and48and onto the farther face22a short distance, as seen best inFIGS. 1 and 3. A farther face part56of the outer cover52is preferably of a different fabric.

The farther side layer42of padding material has a thickness43preferably in the range of 1/16 inch to ¼ inch, and the thickness43is most preferably ⅛ inch. The farther side layer42of padding material should be of a somewhat resiliently compressible or elastomeric material, and may be of a polymeric foam such as a closed cell microcellular low density expanded polyethylene available from Voltek Division of Sakisui American Corporation as its Volara Type A foam, with a layer of a flexible pressure-sensitive adhesive material already applied to one side of the foam to serve as the layer of adhesive50.

Such foam material used as the farther side layer42preferably has a density of at least about 1.5 lbs. per cubic foot and preferably at least 2.0 lbs. per cubic foot. Greater densities, up to at least about 4 lbs. per cubic foot are desirable, but are considerably more expensive.

The closer side layer44of padding material in a preferred embodiment of the splint12has a thickness45of about ¼ inch, although a thickness45in the range of ⅛ inch to ⅜ inch is acceptable. The closer side layer44of padding material should also be somewhat resiliently compressible, and is preferably porous. Therefore, the layer44is preferably of open-cell polymeric foam, such as a polyurethane foam, with an applied layer of flexible pressure sensitive adhesive. An acceptable density for such foam material is 1.0–4.0 lbs. per cubic foot, with 1.5 lbs.–3.0 lbs. per cubic foot being preferred. An indentation load deflection of about 75 is preferred, but any value in the range of 25 to 150 is acceptable, to provide sufficient firmness yet be comfortable. The open-cell construction of the closer side layer44of padding material allows sufficient circulation of air, to cool and to dissipate evaporation from the skin of a patient using the splint12, in order to provide ample comfort for a patient using the splint12. One acceptable material for the closer side layer44is available from Foamex, of Compton, Calif., as its Foam Grade F 145 44 F.6 FA 44145-304.

Preferably, the closer face part54of the outer cover52is made of a soft, absorbent fabric with a significant amount of elasticity in at least the transverse direction, indicated by the arrow55inFIG. 3. For example, a brushed terrycloth or boucle fleece of 65 percent polyester and 35 percent rayon fiber of 100 denier yarn, available from Eclat Textile Co. Ltd. of Industry, Calif. as its product number 1206D performs well for absorbing moisture and exudate from a patient's skin. Preferably, such a cloth is a low loop, tightly knitted material, brushed to provide a soft and slightly matted surface which is absorbent and not abrasive, so that the splint12can be used comfortably in direct contact with the patient's skin.

The elasticity of the fabric of the closer face part54of the outer cover52allows the closer side layer44of padding material to conform easily to a patient's hand, wrist, and arm without the fabric of the closer face part56being pulled free from the closer side layer44of padding material when it is compressed irregularly by conforming to the shape of the patient's hand, wrist, and forearm.

The farther face part56of the outer cover52, located on and defining a part of the farther face22, is preferably of a material which is receptive to the hooked material portion of a hook-and-loop fastening material such as that commonly known under the trademark Velcro® or an equivalent “thistle-cloth” fastener material. Preferably the fabric of the farther face part56is significantly less elastic than the fabric of the closer face part54, in order better to resist separating from the foam material of the farther side layer42of padding material when such a hooked fastener material is disconnected from the farther face part56of the outer cover52. The farther face part56of the outer cover52extends from the first end14of the splint toward the second end16, and extends over most of the width20of the splint12, from one to the other of the margins of the closer face part54of the outer cover52, as shown inFIGS. 1 and 3. Adjacent the second end16of the splint, a small piece58of the material of the farther face part56may be attached to the material of the closer face part54at the second end16, to extend toward the first end14of the splint, slightly overlapping a portion of the main piece of the farther face part56to leave a slot at the second end16through which the core30and layers42and44of padding material may be inserted into the outer cover52. Thereafter, a label60including indicia such as the previously mentioned pair of diamonds28is fastened in place, preferably by a heat-activated adhesive, to secure the outer cover52. A label including the indicia26may also be attached in the same manner. A suitable material for the farther face part56of the outer cover52is a brushed nylon tricot such as is available from the Fabrite Laminating Corporation of Wood-Ridge, N.J. as its style 5437 material, which is a warp knit fabric of 32 gauge, using 40 denier yarn to produce cloth having a weight of 2.04 ounces per square yard and a finished thickness of 0.035 inch. This cloth provides ample protection for the farther side layer42of padding material and is strong enough to receive and be engaged by the hook portion of a hook-and-loop fastener material appropriate for fastening straps to attach the splint12to a patient's arm78. The material is stable enough in size not to stretch excessively when the hooked fastener material is removed. As a result, removal of the fastener materials to disconnect straps from the splint does not unduly tend to separate the material from the farther side layer42of padding material. The outer cover52is attached to the adjacent surfaces of the layers42and44of padding material by the use of a layer of fusible heat-activated fabric adhesive, activated after the core30and layers of padding material42and44have been placed within the outer cover52. Preferred fusible fabric adhesives are available from Freudenberg Nonwovens, of Durham, N.C., under the trademark Pellon®, as its product number 807 Wonder-Web™ fusible web and its product number 725 heavy-duty Wonder-Under® fusible web. The web of fusible adhesive is porous and once activated continues to permit free movement of moisture and vapor through the outer cover and the open-cell material of the closer side layer44of padding material.

Referring toFIGS. 4A and 4B, instead of the core30of sheet aluminum of which a portion34is folded back as shown inFIG. 2, a core30′ may be of aluminum formed, possibly by extrusion, to include a first portion62corresponding to the single thickness portion of the core30shown inFIG. 2for the first end14of the splint12, a thicker second portion64, with a thickness generally corresponding with the doubled portion34of the core30for the second end16of the splint12, and a tapered transitional portion66. The thicker part64thus provides the desired greater firmness for the second end16of a splint12including the core30′.

Alternatively, as shown inFIG. 4B, a core30″ may be uniformly and gradually tapered from a thinner end68to a thicker end70, to provide greater firmness at the second end16of a splint12including the core30″ with its thicker end70located at the second end16.

The splint12is prepared and used as depicted inFIGS. 5,6,7, and8in order to provide a desired level of support for an injured patient's hand74, wrist76, or forearm78. If a moderate degree of immobilization and support is desired, the first end14of the splint12, identifiable by the single diamond26or other indicium, is placed alongside the patient's hand, with the second end16extending toward the patient's elbow. Alternatively, if a greater degree of support and immobilization of the wrist and hand is desired, the second end16is placed adjacent to the hand74, as shown inFIG. 5, while the first end14is placed alongside the patient's forearm78. In either case the closer face24of the splint12should be directed toward the volar side of the patient's arm, usually in direct contact therewith.

In order to provide the required amount of support, the splint12must be shaped to conform to the patient's hand74, wrist76, and forearm78. This is accomplished manually by the attending medical personnel, by first bending the splint12to conform generally to his or her own wrist and hand. The splint12is placed with the chosen end14or16nearer the patient's hand, and with the distal farther face22directed away from the hand74and forearm78, as shown inFIG. 5, and the attending medical professional pushes on the splint12, shaping it to conform roughly to his or her arm, as illustrated inFIG. 6. This results in the core30bending to assume and retain the required shape. The end portion14or16of the splint12adjacent the ulnar side79of the hand74is also bent upward around the hand74as indicated by the arrow inFIG. 7, to provide additional support and fit smoothly.

The attending person can then adjust the shape of the splint12to fit the patient more precisely by pushing with the thumbs against the closer face24while the fingers press on the farther face22of the splint12. The end14or76of the splint12is that located within the patient's hand74may also be bent downward in the form of a small roll, if desired, to support the patient's fingers in a comfortable attitude, preferably using a splint12whose length18is ample. The relatively thin and firm padding material of the farther side layer42enables the attending person to feel the shape to which the core30is being bent and allows him or her to manipulate the core30precisely to conform as desired to the patient's hand74, wrist76, and arm78. Since the core30is preferably annealed to be deadsoft for initial manufacture of the splint, it is initially easy to bend the core into the desired form. The required form of the splint12has a bending curved cross-section that provides improved rigidity by acting structurally as a “C”-shaped channel.

Once the shape of the splint12has been properly adjusted to fit the patient, the splint is put into place as shown inFIG. 8, with the closer face24of the splint facing toward the volar aspect of the patient. The splint12is secured in place by wrapping the patient's hand74, wrist76, and arm78, and the splint12with an elastic bandage80as shown inFIG. 8.

Alternatively, as shown inFIG. 9, the splint12may be held in place by wrapping it with flexible straps82provided with hook-and-loop fasteners. Patches84of the hook portion of such hook-and-loop fastener material may be engaged in the material of the farther face part56of the outer cover52as shown inFIG. 9. Because of the nature of the fabric preferably used as the farther face part56of the outer cover52removal of the fastener material, as for adjusting the shape82, does not significantly degrade the material of the farther face part56or pull it apart from the underlying farther side layer42of padding material.

Alternatively, as shown inFIG. 10flexible separate straps86equipped with D-rings88and hook-and-loop fastener materials90and92may be placed around the patient's hand74, wrist76, and arm78and the splint12, and if desired the hooked portion92of the fastener material may be engaged with the fabric of the farther face part56of the outer cover52.

As mentioned above, use of the splint12with the second end16adjacent the patient's hand74and wrist78gives greater support than use of the splint12with the first end14adjacent the hand74and wrist76. In a situation where maximum immobilization of a patient's hand74and wrist76is required, a pair of splints12may be applied simultaneously to both the volar and dorsal sides of the patient's arm78, as shown inFIG. 11. The two splints12are both shaped separately to conform to their respective intended positions and then both are secured to the patient in generally the same manner described above with respect to a single splint12.

In some cases, it may be desired to provide additional stiffness in the portion of the splint12along the patient's arm78by bending the splint outward to form side flanges94along the side margins46and48as shown in cross-section view inFIG. 12. The degree of stiffness in either end14or16of the splint can be varied most easily by folding such a portion of the splint. It is desirable in particular to bend a portion along the lateral margin46or48which is to be located on the ulnar, or little finger side of the patient's wrist76and forearm78into the form of a flange95along the ulnar side79, as shown inFIGS. 7 and 13, to provide added stiffness to the splint12and thus provide additional firmness of support, in direct proportion to the length and depth of the portion thus formed into a flange95.

As shown inFIG. 14, the core30,30′, or30″ may be perforated, providing ventilation through an array of holes96. The holes96cooperate with the absorbent material of the closer face part54of the outer cover52, and with the closer side layer44of padding material, to provide comfort by promoting ventilation and facilitating cooling and evaporation of perspiration from the patient's skin. When a perforated core is used, an open-cell foam similar to that described for use as the closer side layer44may also be used for the farther side layer42.

Referring toFIG. 15, a splint100is similar to the splint12, except that it is perforated by holes102, arranged in a regular pattern. The holes102may be circular, with diameters104in the range of 1/32 inch to ⅛ inch, for example, and spaced apart by a distance106, of ½ inch to 1 inch, to provide comforting ventilation without significantly weakening the splint.