BACKGROUND OF THE INVENTION

The present invention relates to the field of orthotic or orthopedic device liners, that is, cushioning devices for orthopedic casts, and more specifically a device and method for using a supplemental cushion to prevent chaffing and injury to the webbing that connects the thumb and index finger (sometimes called the thenar space, and referred to herein as such), when the wrist or hand is encased in a cast but the thumb is not.

Casts are typically used to immobilize limbs and joints to permit healing of broken bones, or of surgically repaired muscles and tendons. Typically, the limb is first wrapped or encased in a material that cushions the limb from chaffing during the lengthy time that the cast is worn. The cushion or pad is then encased in a sheath or shell (the terms being used interchangeably herein), which provides rigidity and stability, in order to form the finished cast. Historically, the cushioning material was fabric or cotton padding, while the sheaths were made from plaster bandages, such as cotton impregnated with plaster of Paris which hardens after wetting. More recently, synthetic materials are used for both cushioning and sheaths. Examples include knitted fiberglass bandages impregnated with polyurethane, or bandages of thermoplastic. See, for example, U.S. Pat. No. 5,916,184, the entire contents of which are incorporated herein by reference.

When the wrist and hand are encased in part of the cast, the thumb and fingers are often not encased in the circumstance where they do not have to be immobilized, even if the cast itself must encase the palm of the hand in order to anchor the cast to the limb. Allowing freedom of movement of thumb and/or fingers allows the patient to more easily accomplish tasks of daily living during the long recuperation period.

However, the sheath material takes some time to set and harden, and the limb, along with encased bones, muscles and tendons, must not move during that time. Thus, even if a thumb is not encased, the thumb may be held at rest (and not moving) during the application of the sheath.

However, after the sheath has set, when a thumb is raised, the thenar space (i.e., the skin webbing between the thumb and forefinger) expands and extends beyond the plane of the palm. In contrast, when the thumb is at rest, it does not. This movement of the thenar space will rub against the cushion and sheath, producing chaffing and irritation, possibly even laceration, abrasion or maceration. This movement may also cause pain and discomfort.

Examples of previous attempts to reduce this type of abrasion are disclosed in U.S. Pat. Nos. 4,530,351 and 5,180,359. U.S. Pat. No. 4,530,351 eliminates the part of the sheath which encases the palm and the back of the hand, and instead keeps the sheath from sliding up the patient's arm with a smooth metal or plastic rod that is attached to the sheath. The rod crosses the palm, loops over the thenar space and the thumb and then continues over the back of the hand, connecting back to the sheath. The rod maintains contact with the thenar space via its smooth surface (rather than an abrasive one), and also keeps the contact to a minimum. However, similar to replacing the back-strap of a sandal with a metal rod that curves around the heel, such a metal rod would still allow for the risk of significant abrasion. In addition, the rod of U.S. Pat. No. 4,530,351 does not alleviate abrasions that may occur when medical personnel elect to anchor the sheath by encasing the palm and thenar space within the sheath material, as is frequently done.

U.S. Pat. No. 5,180,359 teaches how a padding with a raised edge can be placed on top of a stockinette/bandage casing before applying the sheath material, in order to ensure that the edges of the sheath material are not rough or inherently abrasive to skin that comes in contact with it. As such, the hole in the cast left for the thumb can have a smooth edge, as depicted in FIG. 28 and FIG. 29 of U.S. Pat. No. 5,180,359. However, this padding addresses only one cause of the abrasion, the rough edge of the sheath. This prior art padding does not alleviate abrasion from movement of the skin continually moving back and forth under tension at an edge (i.e., as the thumb moves up and down, expanding the web of the thenar space), because the hardened sheath material is still tight to the palm and thenar space.

Accordingly, there is a need for a cushion or padding that will allow for a sheath to be applied in customary manner, as known to medical professionals and practitioners of the art, while the thumb is at rest, and yet still provide room for the thenar space to expand when the thumb is extended, thereby alleviating pain and suffering of the patient during the healing period.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a small supplemental cushion constructed of synthetic materials, with enough structural integrity to retain its general shape, but still configured to be squeezed for additional cushioning effect. The synthetic materials are preferably moisture and air impermeable, and more preferably water and air impermeable. The construction makes them non-absorbent and they may incorporate anti-microbial materials. The cushion is shaped and sized to provide a space between the palm and the central part of the cushion, into which the webbing between the thumb and forefinger can expand when the thumb is extended or raised.

In use, the supplemental cushion is placed over the thenar space with the thumb extended. Typical cushioning or padding is applied to the limb (e.g., hand, wrist, and arm), such as by wrapping the cushioning/padding around the palm of the hand, including wrapping it around the supplemental cushion so that the supplemental cushion is held in place next to the thenar space. After the typical cushioning is applied to the limb, the thumb can be relaxed. This supplemental cushion has sufficient structural integrity that when held in place by typical cushioning, the space for the thumb-forefinger webbing is not crushed. The sheath is then applied, and allowed to harden and set, in order to form the cast. After the sheath is hardened, the supplemental cushion will reduce chaffing of thenar space while the cast is worn.

These and other objectives and features of the present invention will be better understood and appreciated from the following detailed description of the main embodiment thereof, selected for purposes of illustration and depicted in the accompany drawings.

