We Change, They Adjust: A Guide to Adjustable Socket Technology

Written by Bryan Potok, CPO on June 26, 2018
Last updated on December 7, 2018

Revised and updated December 6, 2018.

Naturally your residual limb will change size during the course of the day. The game changer for prosthetic users is wearing a prosthesis that can change in sync with these volume fluctuations.

Over the last 5 years, creative and prosthetic minds developed innovative ways to improve the bond between a person and their prosthesis. The development of the Socket-Less Socket™ and adjustable sockets has made self-adjusting prostheses possible. In mere seconds, you can self-adjust your socket fit, doing away with midday breaks to add sock plies or gel pads.

Even more exciting, these technological advancements ultimately lead to a more intimate bond with your residual limb, through micro-adjustments that you can facilitate in minutes.

Adjustable sockets are ultimately trying to close the technology gap and innovation speed between sophisticated microprocessor components below the socket and the socket interface. Often times, the socket interface is the weak link between a prosthetic user and their limb. But with these innovations in adjustable socket technology, prosthetic users are empowered with more options that can maximize comfort and daily usability.

To better understand how these technologies work and what they can do for you, I put together this guide on some of the latest offerings from some innovative companies.

Adjustable Sockets by Click Medical

Ottobock and Click Medical are working together to offer adjustable sockets that are accessible through your Prosthetist and Ottobock's Central Fabrication Service in Salt Lake City, Utah. Designed and patented by Click Medical, RevoFit micro-adjustable sockets are designed to accommodate fluctuations in limb size by allowing prosthetic users to self-adjust their socket fit during the day with the turn of a dial. Some of its key features are:

Adjustability. Rather than removing your prosthesis and adding prosthetic socks to your residual limb, a RevoFit socket features movable panels that allow you to quickly and single-handedly adjust your socket fit by turning a dial. You can even make adjustments through your clothing.
Strategically placed movable panels.These panels allow you to fine-tune compression along predetermined areas within the socket to either tighten or loosen your socket fit. The adjusting dial operates all movable panels in unison for the desired volume change.

One-hand release. Removing your prosthesis is made easy by simply pulling the adjusting dial with one hand to release.

The Infinite Socket TT-S and TF by LIM Innovations

San Francisco based company LIM Innovations created the Infinite Socket, which leverages digital technologies to offer a custom, self-adjusting socket. Their system uses LIM Capture™, which takes measurements and images of a physical mold of your limb and then creates a 3D digital version used to fabricate your unique Infinite Socket. LIM Innovations claims their system will say "goodbye to test sockets" and multiple prosthetic visits.

TT-S Infinite socket has an adjustable posterior pad for bending comfort.

A feature that I find really interesting and one that becomes apparent for Infinite Socket users is how the thermoplastic carbon frame of both the TT-S and TF Infinite Socket drowns out harsh forces when walking. Built-in flex allows absorption of jarring ground reaction forces. The structural frames are designed to flex and diminish these jarring forces exerted by the ground. This “dynamic flex” or bending permits the socket shape to change along with user in an anatomical fashion, dampening ground forces felt through the Infinite Socket. The Infinite Socket benefits:

Adaptability. The multi-durometer socket provides select areas of flex and rigidity, relieving areas of bony prominences and reducing chances of skin ulcerations.
Self-Adjustability. Allows prosthetic users to gain full control of their socket fit. A user can self-adjust their socket anytime through their clothing.
Full Range of Motion. Above-knee and below-knee socket designs permit unrestricted range of motion.
Modular setup. The TT-S for below-knee amputees features a modular back pad to improve knee flexion comfort and range. A height adjustable ischial seat and inner brim on the Infinite Socket™ TF improves sitting and weight-bearing comfort for above-knee amputees.

Socket-less Socket™ by Martin Bionics

Martin Bionics has reinvented the prosthetic socket with an innovative design that removes many of the pain points of the traditional socket. The Socket-less Socket™ eliminates the hard static brim of traditional sockets and instead uses soft conforming materials and an open frame design allowing your residual limb to flex and breathe. The need for prosthetic socks to help manage volume changes has been replaced with self-adjustable ratchets, allowing you to fine-tune your socket fit. The inherent conformability of Martin Bionics’ technology provides that comfortable morning fit all day. Some key features of the Socket-less Socket™ are:

Above knee amputee running with a Socket-less socket by Martin Bionics on the track.

All limb types and sizes. Their technology can be fit on all limb types from pediatric to obese (even over 400 pounds), any length residual limb, geriatric to athletic, and all amputation levels.
Sitting comfort. My favorite feature is their SwingBrim™ technology that conforms to the above-knee prosthetic user just like a hammock, providing a soft floating cushioned seat on every step. Sitting comfort is improved by eliminating the lump you feel along the brim in traditional above-knee sockets.
Full Range of Motion. The Socket-less Socket’s™ conforming materials allow you to bend and sit comfortably with unrestricted range of motion.
Micro-adjustable. Incrementally adjust your Socket-less Socket™ over your clothing to maximize comfort throughout the day.

Some final thoughts

Traditional prosthetic sockets are for the most part fixed and rigid in shape; aside from managing sock ply, they're limited in how much self-adjusting is available to the wearer. In contrast, all three technologies mentioned above offer socket innovations that are very adjustable and forgiving.

Depending on your amputation level, lifestyle, and your overall medical condition, each technology mentioned above is different. However, all share a common theme as they are focused on providing maximum comfort, empowerment, adjustability, and innovation. The differences lie in user preference and input from your Prosthetist.

Comparison Chart

The chart below is intended to help you during the early stages of determining which socket technology best suites your needs.

Function	LIM Innovations	Martin Bionics	Click Medical
Custom to Mold	X	X	X
Custom to measurement	X	X	X
Covered by insurance	X	X	X
Open Design	X	X
Above Knee	X	X	X
Below Knee	X	X	X
Below Elbow		X	X
Above Elbow		X	X
Hip Disarticulation		X	X
Symes		X	X
Liner with pin or lanyard	X	X	X
Use with any liner type	X	X	X
Vacuum Assisted	X	X	X
Real-time Micro-Adjustability	X	X	X
Adjust through clothing	X	X	X
Weight Limit	~320lbs	>400lbs	TBD