AJ: The Auto-adjusting Socket System
Shelby Ingram


Introducing AJ: The Auto-adjusting Socket System

AJ is an auto-adjusting socket system for lower limb amputees that changes size according to variation of the residual limb’s volume throughout the day.


Why is it needed?

The residual limb of an amputee can fluctuate in size throughout the day from 2-10%. These fluctuations can be caused by diabetes, exercise, eating, daily activities and more. An ill-fitting socket can lead to many daily challenges for an amputee.

In order to make their socket fit, an amputee uses prosthetic socks. These socks are put on and taken off throughout the day, and amputees can use anywhere from 3 to 15 ply socks, with multiple layers of each ply. However these socks can be time consuming, uncomfortable, and unhygienic.

How does it work?

AJ uses a system of air bladders and pressure sensors to help detect an ill-fitting socket. Fluid changes within the residual limb happen due to edema. These changes are specific to the anatomy of the residual limb, which calls for independent bladders.

Other Important Features

It’s important to me that amputees have options to make them feel comfortable mentally in their prosthetic as well. Due to the choice of materials, AJ is offered in a range of colors in order to match the amputee’s skin tone.


The Road to AJ

Research and Model Making

In order to gain insight on the lives of amputees, I shadowed a prosthetist once a week. These sessions allowed me to see what an amputee has to go through when getting a new prosthetic, getting their socket checked, or coming in for any other issues. I was able to sit in with patients as well. This allowed me to hear direct complaints, see common problems in current prosthetics, and see what the prosthetist does on site to fix these problems.

Most of my modeling consisted in creating CAD Models to ideate different forms for the inner socket. I then modeled each part of the socket system in SolidWorks, created the assembly, and rendered each part in Keyshot. All of my work throughout the year was presented each week on research boards, where I showed my development in research, ideation, and validation.

Synthesis of Research


Shelby Ingram

I am a designer from Cleveland, Ohio who is driven by empathy and human factors. My ultimate goal in life is to design prosthetics for amputees! Through my designs, I strive to find the perfect balance between functionality and aesthetics. I would like to send a special thank you to my professors, Hanger Clinic, Globus Medical, and friends and family for all of your help with my senior thesis.

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