The ISNY Socket System
SIDNEY FISHMAN, PHD AND NORMAN BERGER, MA*New York, New York
A new Icelandic-Swedish-New York University socket system consists of two separate structures, each with its own function, a) a thin, pliable, vacuum formed, translucent socket for tissue containment and b) a supporting carbon fiber-reinforced laminated frame for weight transmission. The socket nests in a quadrilateral-brim-type frame supported on a medial strut. The separation result in a socket which differs from the conventional design in that it is soft and flexible rather than hard and rigid, translucent rather than opaque and formed from sheet thermoplastics rather than thermosetting resins. The system provides enhanced comfort, inasmuch as the flexible socket changes its shape to correspond with amputation limb changes caused by muscular contraction during walking and by contact with a chair seat during sitting. It also affords much better sensory input and improved heat dissipation for the amputee. It can be used as a "check" or "permanent" socket and offers the prosthetist improved ability to assess, obtain and maintain socket fit. Longitudinal and circumferential adjustments to accommodate amputation limb growth are easily accomplished.
The frame provides such extraordinary strength that it need cover only a small portion of the socket, leaving approximately three-fourths of the amputation limb encased only in flexible polyethylene. The frame can be attached to any commercially available knee unit, shank and foot, while suspension of the prosthesis is accomplished by any of the current techniques.
*New York University Medical Center, Prosthetics and Orthotics, 317 East 34th Street, New York, NY 10016