Computational Design, Fabrication, and Evaluation of Optimized Patient-Specific Transtibial Prosthetic Sockets
Condition: Amputation Stump
Study type: Interventional

Summary: 
      The overall goal of this study is to further develop and clinically assess a computational
      and data-driven design and manufacturing framework for mechanical interfaces that
      quantitatively produces transtibial prosthetic sockets in a faster and more cost-effective
      way than conventional processes. The main hypothesis of this proposal is that the novel
      quantitative interface is equivalent to, or better than, a conventional interface in terms
      of: 1) gait symmetry, 2) skin contact pressures, 3) skin surface temperature, and 4) comfort
      as evaluated from a questionnaire.
    

Detailed description: 
      Title: Computational Design, Fabrication, and Evaluation of Optimized Patient-Specific
      Transtibial Prosthetic Sockets

      Principle Investigator: Dr. Hugh Herr

      Background: The overall goal of this application is to further develop and clinically assess
      a computational and data-driven design and manufacturing framework for mechanical interfaces
      that quantitatively produces transtibial prosthetic sockets in a faster and more
      cost-effective way than conventional processes. Traditionally, prosthetic socket production
      has been a craft activity, based primarily on the experience of the prosthetist. Even with
      advances in computer-aided design and computer-aided manufacturing (CAD/CAM), the design
      process remains manual. The manual nature of the process means it is non-repeatable and
      currently largely non-data-driven, and quantitative data is either not obtained or
      insufficiently employed. Furthermore, discomfort, skin problems and pressure ulcer formation
      remain prevalent. Through the proposed computational modeling framework, a repeatable,
      data-driven and patient-specific design process is made available which is based on
      scientific rationale.

      Objective/hypothesis: The main hypothesis of this proposal is that a socket, designed using
      the novel computational design framework, is equivalent to, or better than, a conventional
      socket (designed by a prosthetist) in terms of: 1) gait symmetry, 2) skin contact pressures,
      3) skin surface temperature, and 4) comfort as evaluated from a questionnaire. Our hypothesis
      is supported by the presented pilot data which shows reduced or equivalent skin contact
      pressures and subject reported comfort levels for several critical anatomical regions.

      Specific Aims: 1) Subject-specific biomechanical modeling for N=18 subjects, 2) Computational
      design and fabrication of sockets for N=18 subjects, and 3) Clinical evaluation of novel
      sockets for N=18 subjects.

      Study Design: A cohort of 18 subjects will be recruited for this study. MRI or CT data will
      be recorded for all subjects. Through image segmentation geometrically accurate 3D finite
      element analysis (FEA) models will be constructed. The resulting predictive FEA models will
      then be used in a novel, data-driven, and automated computational design framework for
      prosthetic sockets, to design prosthetic sockets for all subjects. The framework optimizes
      the socket designs, as assessed by skin contact pressures and internal tissue strain, through
      iterative adjustment of the virtual tests sockets. Final designs are subsequently 3D printed.
      To evaluate the prosthetic sockets with each of the subjects each subject will do a standing
      and walking exercise using their conventional sockets or the novel sockets. Meanwhile skin
      contact pressures and temperatures are recorded, gait symmetry data is collecetd, and socket
      comfort is assessed using a questionnaire. Together this data provides a quantitative and
      qualitative evaluation and comparison of the novel and conventional sockets.
    

Intervention name(s): Prosthetic socket for transtibial amputee
Intervention type(s): Device
Intervention description(s): To wear a prosthetic socket for evaluation of comfort and biomechanical metrics such as skin loading conditions.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Prosthetic socket; Biomechanics