Method for injection-molding an orthopedic device and...

Surgery: splint – brace – or bandage – Orthopedic bandage – Splint or brace

Reissue Patent

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Details

C602S023000, C024S452000, C428S100000, C264S328100

Reissue Patent

active

RE037338

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an injection-molded thermoplastic orthopedic device and a method of making same. In particular, the invention relates to a method of injection-molding a thermoplastic orthopedic device wherein at least one wall of the device has an integrally-formed field of hooks formed during the injection-molding of the orthopedic device to receive a strap loop in releasably attaching engagement in order to secure the orthopedic device generally to the circumferential contour of the lower part of the leg and ankle.
BACKGROUND OF THE INVENTION
In the management of certain injuries to the lower extremities, such as fractures of the tibia and fibula, malleolar fractures, or severe ankle sprains, it is common to completely immobilize the lower extremity (following open or closed reduction in the case of fractures) by use of the well-known molded plaster or resin cast.
After the injured extremity has become stable, however, it has been found that recovery may be effected more rapidly by gradually and progressively permitting the extremity to bear weight and undergo other permitted exercises. Thus, for example, during a second stage of management, a walking heel may be attached to a long plaster cast, or the latter replaced by a shorter unit, or by a walking cast specifically adapted to facilitate such maneuvers.
One form of walking cast commercially available under the trademark AIRCAST is described in U.S. Pat. No. 3,955,565. Additional types of orthopedic devices which permit substantially normal plantoflexion and dorsoflexion movements of the ankle but limit inversion and eversion, thus stabilizing the ankle, are also commercially available such as those described in U.S. Pat. No. 4,280,489.
In order to maintain such orthopedic devices in proper fitting engagement about the lower extremity, a pair of longitudinally-spaced, circumferentially extending fastener straps with loops, generally available under the trademark VELCRO, are usually adapted to cooperate with first and second surfaces having circumferentially-spaced fastener hooks.
The fastening material sold under the trademark VELCRO generally comprises two components. Each component has a flexible backing material having a surface thereon. One surface is comprised of the resilient hooks, while the other is comprised of a short-pile, looped fabric. As the two fastening surfaces are pressed together, the hooks releasably engage the loops, thus releasably holding the fastening materials together. The fastening surfaces are separated by pulling them apart with sufficient force to cause the resilient hooks to straighten sufficiently to come out of engagement with the loops.
Previously, VELCRO-fastener hooks were secured by conventional methods to the exterior surface of orthopedic devices. The strap loops were then adapted to matingly engage the corresponding hooks so that the strap loops could be drawn and tensioned snugly against the exterior of the orthopedic device for placement next to the lower leg or ankle. Various other methods for attaching the hooks to the orthopedic device have been utilized in the past as well. All such prior conventional methods, however, provided for the hooks to be attached to the orthopedic device after the orthopedic device was molded and formed. The present invention, however, allows the hooks to be injection-molded as an integrally-formed part of the orthopedic device.
Typically, the prior fastening hooks were manufactured attached to the surface of orthopedic devices and other devices by the use of adhesives, ultrasonic welding, stitching or through the use of continuous extrusion molding. Such former methods of manufacturing and attaching the hooks and loop fastening materials have been described in U.S. Pat. Nos. 4,814,036, 4,470,857, and 4,726,975. Improvements to the traditional, adhesive, ultrasonic welding or stitching methods have occurred through advancements in the overall process of molding the fastener material strips by extrusion molding techniques, such as those disclosed in U.S. Pat. Nos. 4,814,036, 4,563,380, 4,872,243 and 4,794,028.
All of the prior methods of attaching the hooks to various devices, including orthopedic devices, have required the use of extensive labor in the process of either cutting and applying the hooks to the previously formed orthopedic device or through the use of extrusion molding.
As the use of VELCRO-type hooks and loop fasteners has increased, however, the industry has sought less labor intensive and costly methods of manufacturing and attaching these hooks.
The present invention eliminates many of the disadvantages inherent with such prior labor-intensive and material-expensive processes of extrusion molding, adhesive and stitching by integrally forming the hooks with the orthopedic device during the injection-molding process. The present invention thereby eliminates the separate step of attaching the hooks during production.
SUMMARY OF THE INVENTION
The present invention relates to an injection-molded thermoplastic orthopedic device and method of making same. In particular, the orthopedic device includes at least one wall having an arcuate transverse cross-sectional shape sufficient to conform generally to the circumferential contour of the inner or outer side of the lower leg and ankle. The orthopedic device normally has at least one strap of material having loops therein attached to at least one wall of the orthopedic device for holding the wall against the lower leg and ankle and has a field of injection-molded hooks integrally formed on a predetermined area of at least one wall of the orthopedic device during the injection-molding process for receiving the strap loops in a releasably attached engagement.
The hooks of the present invention have a reduced radius from that of prior hooks and a changed geometry for promoting ejection during the injection-molding process, yet still maintain the desired fastening function. In the preferred embodiment of the invention, the hooks comprise spaced rows of hooks with adjacent rows of hooks facing in the opposite directions.
The thermoplastic material, preferably polypropylene, used for injection-molding the integrally-formed hooks has a memory sufficient to cause the hooks to return substantially to their original position after being removed from the mold, and yet has sufficient flexibility to allow the hooks to bend during removal from the mold and during engagement and release with the attached strap loops.
The present invention also relates to a method of forming an orthopedic device conforming generally to the lower leg and ankle and held in place by at least one strip of material having loops thereon. The method preferably comprises the steps of (1) injection-molding the orthopedic device and (2) simultaneously integrally forming a field of hooks in at least one predetermined area on the device during the injection-molding process for receiving the strap loops in releasably attaching engagement.


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