Facilitating Locking Pin Alignment in Transtibial Amputees via Auto-Retracting Tethered Pin

Abstract

Transtibial amputees have a variety of suspension systems available to them. One of the more common systems uses a locking pin to create a mechanical connection to their prosthesis. For those using a locking pin, it is common for the user to partially doff while seated in order to release pressures created by the socket on the residual limb. When attempting to re-don, there can be difficulty aligning and inserting the pin into the lock, requiring multiple attempts or for the user to stand with a not yet connected prosthesis. This can be an issue and possibly a fall risk for a new user or someone who has poor proprioception. By introducing an auto-retracting tether between the socket and pin, a constant connection is created. The retraction guides the pin into the lock without fail and allows for ease of donning while seated. In this investigation, a prototype design is modelled and built. Transtibial amputee participants are fitted with the system and provide feedback to further develop the system. Feedback was overall positive with a majority saying they would personally use the system. This improved functionality is designed to promote the frequency of partial doffing which may positively impact limb health.