New prosthetic fabrication technique offers improved efficiency

LAS VEGAS — Braiding is a more efficient technique for prosthetic socket design than current fabrication methods, according to a speaker at the American Orthotic & Prosthetic Association National Assembly, here.

Dennis Clark

Dennis Clark, CPO, founder and president of Clark & Associates and president of the Orthotic and Prosthetic Group of America, presented research suggesting that current prosthetic socket manufacturing methods are not standardized.

He said that many of the current methods vary among fabrication facilities, are not repeatable and are susceptible to operator variability. Since current prosthetic sockets are not subject to any formal standards, strength and variability are relatively unknown, he added.

Current methods create a mold from the residual limb and stretch a pre-fabricated carbon sock over that mold. Since limb diameter varies widely among amputees, stretching the carbon sock causes inconsistency from socket to socket, resin pooling and non-uniformity of fiber orientation, Clark noted.

Spyder Technologies, a prosthetic socket manufacturer and department of defense contractor, assisted Clark and his team in developing engineered braided sockets that compensate for some of the drawbacks in current fabrication methods.

‘The braiding system allows consistency… so it is repeatable,” Clark said. “The sockets are lighter and stronger [as a result of using carbon fibers], and consistent in thickness from the very distal end to the very proximal end.”

By braiding the sock directly over the socket mold, the fabrication process conforms to the exact size and shape of the residual limb. This ensures consistency from socket to socket and eliminates resin pooling, Clark said.

The braided sockets have high stiffness, tensile strength, chemical resistance, temperature tolerance and low thermal expansion. Socket layups are based on patient weight and K-levels, and can be tailored to specific conditions.

The fabrication process for these sockets is standardized and meets ISO criteria.

Clark said that understanding the performance of prosthetic sockets is key in ensuring quality for lower limb amputees. This research is a foundation for additional investigation and comparison of prosthetic sockets, he added. by Shawn M. Carter


For more information:

Clark. Symposium: Modern Technologies. Presented at: American Orthotic & Prosthetic Association National Assembly. Sept. 4-7, 2014. Las Vegas.

Disclosure: Clark has no relevant financial disclosures.


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