Evaluating Leg Length Discrepancy during Total Hip Arthroplasty

Abstract

The human body, although seemingly symmetrical, can in fact be highly asymmetrical. Our bodies are predetermined by our DNA and co-shaped by our environment. This leads to most of the world's population having a discrepancy in leg length either from birth or developed during their life time. It is completely natural and goes unnoticed, as changes are incremental and people get used to it. On the contrary, when undergoing total hip replacement surgery and waking up with one leg longer than the other, the change is almost instantaneous and immediately noticeable. Current surgical solutions do not address this issue in a practical manner within the operating theatre, leading to surgical teams developing their own methods and procedures to evaluate the change in patient's leg length.
 
Introducing new workflows to medical professionals often entails neglecting the protocols they spent years practicing. This thesis identified this bottleneck and instead of introducing new methods and procedures, it was decided to build on existing ones. This was done by exploring common surgical workflows in respect to total hip replacement and determining an approach to enhance surgical team's capabilities in evaluating leg length discrepancy.. Important in achieving this goal it to make any given design solution effortless, reliable and undisruptive to various workflows

In order to do so, user research was performed by joining multiple surgical teams within the OR, thereby observing and evaluating their methods. One method in particular stood out, which is best described as the 'loaded assessment'. During this assessment the surgeon or circulating nurse will centre the patient's feet, apply pressure to the heels and try to evaluate the discrepancy. Although this method being seemingly simple, its execution is difficult to perform by a single person and varying pressure differences may confuse the assessment.

Following the initial research phase, co-creation sessions with technical experts were organised, after which various concepts were developed and tested on the basis of feasibility, desirability and viability. Finally, a functional prototype based on the loaded assessment principle was developed and tested for its functionality and conceptual expectation.