New socket design could improve prosthesis fit, comfort

BOSTON — A novel design could improve the fit of prosthetic sockets, according to study results presented at the American Orthotic and Prosthetic Association National Assembly, here.

Stefania Fatone, PhD, BPO(Hons), associate professor at the Northwestern University-Prosthetics Orthotics Center, presented the university’s Flexible Sub-Ischial Vacuum Socket (NU-FlexSIV) for patients with transfemoral amputation.

Stefania Fatone

“The current standard of ischial containment sockets restricts function by limiting hip range of motion,” Fantone said. “We wanted to design something that could improve upon that aspects.”

According to Fatone, the NU-FlexSIV comes with flexibility, lower trim lines to avoid gapping and vacuum-assisted suspension, which could increase range of motion and comfort. The socket uses plaster, no special alignment is needed and is casted while the patient is seated, which Fatone says makes the process faster. She said the socket also is designed with a narrow base and no compensation is need to the trunk.

According to the study, “this is the first attempt to create a sub-ischial socket technique that results in improved comfort and comparable function to ischial containment sockets. Socket stability during walking was confirmed by lack of lateral trunk flexion and lateral socket gapping at mid stance. Clinical experience fitting the socket to nearly 100 patients confirms the research findings. Initial evaluation of the socket with military amputees is promising.”

Fatone said future work includes a Department of Defense-funded assessor-blinded, randomized crossover trial, which will compare comfort and functional performance with the NU-FlexSIV Socket to the ischial containment socket in persons with unilateral transfemoral amputation. That study is currently in progress. – by Shawn M. Carter


Fatone S. Development of the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket for persons with transfemoral amputation. Presented at: American Orthotic and Prosthetic Association National Assembly; Sept. 8-11, 2016; Boston.

Disclosure: Fatone reports supplemental funding was awarded through the Joint Warfighter Medical Research Program.

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