ISNY Applications for Children

SIDNEY FISHMAN, PHD, AND DAVID KREBS, MA*New York, New York


The ISNY growth-adjustable above-knee prosthesis for children consists of a proximal socket section similar to that utilized for adult amputees, but which can adapt to circumferential and longitudinal growth. Circumferential growth is accommodated by heating or replacing the thermoplastic socket as amputation limb girth increases. In anticipation of such socket changes, an extra layer of Dacron felt is applied to the proximal wings of the rigid frame during initial fabrication. The wings can then be ground away to receive a replacement socket having a larger anteroposterior dimension. Length adjustability is provided by fabricating the frame with approximately 1 in. of removable prosthetic foam in the distal cup. The lightweight foam is subsequently removed to accommodate a longer socket as the amputation limb's length increases. Initially the knee bolt is set approximately 1/4 in. lower than in conventional placement; the bolt will rise to the appropriate height as shims are applied at the ankle block to accommodate the child's height increases. This system has been used successfully for 10 children, with a current total of five growth-related socket replacements.

*Prosthetics and Orthotics, New York University Post-Graduate Medical School, 317 East 34th Street, New York, NY 10016