Development of a Prosthetic Biofeedback Method and Device to Measure Quality of Fit for Trans-Tibial Amputees
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As the primary interface between the prosthetic and the residual limb, the socket is a crucial component affecting fit and function of the device. While prostheses have been used for centuries, prosthetic socket design concepts have remained stagnant. With the increase in prevalence of obesity and diabetes, amputations associated with secondary complications have risen as a consequence. In particular, neuropathy complicates transition of a new amputee to using a prosthetic socket crucial for their quality of life by reducing -or in some cases completely hindering- tactile sensation and healing in the residual limb. The objectives of this thesis are to: 1) create a protocol to evaluate innovative technology within the socket in vitro while maintaining a true sense of the users limb geometry and material characteristics that interface with the socket, and 2) develop and validate a method of providing biofeedback to prosthesis users, particularly those with neuropathy.The focus of this thesis will be on trans-tibial amputees and prosthesis to reduce the complexity of including a knee joint and to address the largest population of amputees. In this thesis, a method of testing innovations through the use of artificial biofidelic limbs by systematically varying dimensions was first developed and validated against in vivo measurement of amputees reported by Silver-Thorn . Materials characterization yielded closely matching relaxation at 5s to published values - achieving a range of 22.43-31.94% to that of Silver-Thorn with a range of 25.35-49.25%. However, full relaxation and size control during fabrication needs improvement to create a more consistent limb. The max relaxation being measured as 39.06% against the in vivo measurements reaching 68.03%. Additionally the size of the limbs varied from the model by a maximum of 13mm. Following development of the test methods, a method of measuring fit changes within the socket using a single pneumatic (PicoPress) sensor on the distal end to measure distal end (or end-pad) contact pressures. Tests using the biofidelic limbs indicates the use of a single picopress sensor in the distal end is a viable option to detect fit changes over time. However, settling times need to be further investigated to identify barriers to dynamic use (e.g. gait during walking). Feedback from practicing orthotists indicate the PicoPress approach is a viable option to include in existing fabrication processes used to generate custom sockets without altering supply lead times and fabrication times.
Cite this version of the work
Robin Murdock (2021). Development of a Prosthetic Biofeedback Method and Device to Measure Quality of Fit for Trans-Tibial Amputees. UWSpace. http://hdl.handle.net/10012/17029