Dr. Lucy Armitage

Associate lecturer

UNSW Sydney

Dr. Lucy Armitage submitted her Ph.D. at the Graduate School of Biomedical Engineering at UNSW Sydney in August 219. She is currently working as an Associate Lecturer at the School of Biomedical Engineering at The University of Sydney. She graduated as a Physiotherapist in 2007 and worked for several years in the hospital system. She then undertook a combined Bachelor of Mechanical Engineering/Master of Biomedical Engineering degree at UNSW and graduated in 2015. Her Ph.D. research focuses on prosthetic development for people with lower limb amputation. She has published four journal articles in this area to date and has presented her research at national and international conferences. She aims to combine her clinical and engineering skills to provide improved outcomes for people with lower limb loss. She is also a strong advocate for women in engineering. She is a postgraduate member of the Faculty of Engineering Equity and Diversity Committee at UNSW. She has presented at different Women in Engineering events including outreach events for school students and scholarship awards functions.

Many people with transtibial amputation rate the fit between their residual limb and prosthetic socket as the most important factor in the use of their prosthesis. Current research suggests that poor fit between the residual limb and the prosthetic socket can cause pain, skin breakdown or alteration of gait. This thesis focused on measurement methods to assess residual limb – prosthetic socket fit in people with transtibial amputation. Three aspects of fit were examined and new measurement methods for each aspect were explored.

Fit affects the amount of relative movement that occurs between the residual limb and prosthetic socket. A method to measure this movement was proposed using motion capture analysis. The development and attempted validation of the method were outlined. Results were unpredictable and subject to confounding factors such as marker movement artefact. Therefore, the method was deemed not to be appropriate as a fit measurement tool in its current form. Based on these findings it was deemed necessary to investigate other measures of fit.

Fluctuation in residual limb volume can also affect fit. The reliability and validity of current residual limb volume measurement techniques were examined in a systematic review. Results demonstrated that circumferential measurements are the most reliable and valid tool currently available. The results from this review informed a study investigating the use of a low-cost optical scanner as a clinical volume measurement tool. Results found that the scanner was reliable when used by the same assessor but was not valid.

The loading state at the prosthetic socket-residual limb interface is also an important factor in assessment of fit. The effect of pressure feedback on the design of prosthetic sockets was assessed. It found that feedback resulted in reduction in pressure over anatomical regions of concern, and improved consistency between prosthetists. A new sensor to measure pressure and shear at the socket-limb interface was developed and benchtop testing was performed.

These methods have the potential to aid in an improved understanding of the mechanisms that affect fit at the socket-limb interface of people with transtibial amputation.