title: Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket.
abstract: BACKGROUND
  The fit and function of a prosthetic socket depend on the prosthetist's ability to design the socket's shape to distribute load comfortably over the residual limb. We recently developed a sub-ischial socket for persons with transfemoral amputation: the Northwestern University Flexible Sub-Ischial Vacuum Socket.
  
  
  OBJECTIVE
  This study aimed to quantify the rectifications required to fit the Northwestern University Flexible Sub-Ischial Vacuum Socket to teach the technique to prosthetists as well as provide a computer-aided design-computer-aided manufacturing option.
  
  
  METHODS
  Development project.
  
  
  METHODS
  A program was used to align scans of unrectified and rectified negative molds and calculate shape change as a result of rectification. Averaged rectifications were used to create a socket template, which was shared with a central fabrication facility engaged in provision of Northwestern University Flexible Sub-Ischial Vacuum Sockets to early clinical adopters. Feedback regarding quality of fitting was obtained.
  
  
  RESULTS
  Rectification maps created from 30 cast pairs of successfully fit Northwestern University Flexible Sub-Ischial Vacuum Sockets confirmed that material was primarily removed from the positive mold in the proximal-lateral and posterior regions. The template was used to fabricate check sockets for 15 persons with transfemoral amputation. Feedback suggested that the template provided a reasonable initial fit with only minor adjustments.
  
  
  CONCLUSIONS
  Rectification maps and template were used to facilitate teaching and central fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket. Minor issues with quality of initial fit achieved with the template may be due to inability to adjust the template to patient characteristics (e.g. tissue type, limb shape) and/or the degree to which it represented a fully mature version of the technique. Clinical relevance Rectification maps help communicate an important step in the fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket facilitating dissemination of the technique, while the average template provides an alternative fabrication option via computer-aided design-computer-aided manufacturing and central fabrication.
authors.affiliation: 1 Northwestern University Prosthetics-Orthotics Center, Northwestern University, Chicago, IL, USA.
authors.forename: Stefania
authors.initials: S
authors.lastname: Fatone
authors.affiliation: 1 Northwestern University Prosthetics-Orthotics Center, Northwestern University, Chicago, IL, USA.
authors.forename: William Brett
authors.initials: WB
authors.lastname: Johnson
authors.affiliation: 1 Northwestern University Prosthetics-Orthotics Center, Northwestern University, Chicago, IL, USA.
authors.forename: Lilly
authors.initials: L
authors.lastname: Tran
authors.affiliation: 1 Northwestern University Prosthetics-Orthotics Center, Northwestern University, Chicago, IL, USA.
authors.forename: Kerice
authors.initials: K
authors.lastname: Tucker
authors.affiliation: 2 Scheck & Siress Prosthetics, Orthotics, and Pedorthics, Oakbrook Terrace, IL, USA.|3 Advanced Orthotic and Prosthetic Solutions, Hickory Hills, IL.
authors.forename: Christofer
authors.initials: C
authors.lastname: Mowrer
authors.affiliation: 1 Northwestern University Prosthetics-Orthotics Center, Northwestern University, Chicago, IL, USA.|2 Scheck & Siress Prosthetics, Orthotics, and Pedorthics, Oakbrook Terrace, IL, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Caldwell
mesh_terms: D000671:Amputation, Surgical; D000672:Amputation Stumps; D001186:Artificial Limbs; D005269:Femur; D006801:Humans; D007512:Ischium; D007595:Joint Prosthesis; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D014618:Vacuum; D016474:Weight-Bearing
keywords: Prosthetic design; computer-aided design–computer-aided manufacturing; fabrication techniques; prosthetics