December 18, 2017

Advances in Ankle Foot Orthotics (AFO’s)

By Matt Zydron, CPO

Ankle Foot Orthosis, also called AFO’s, have been around for decades. These braces work to restore function to the lower extremity. This helps patients with drop foot due to stroke, spinal cord injuries, multiple sclerosis, neurological conditions or other ankle instabilities (to name a few) decrease pain, increase or decrease range of motion, and ambulate more closely to normal gait.

In the past, AFO’s have primarily been fabricated from polypropylene-based plastic and other thermoplastics. While these materials have proven to be durable, lightweight, while allowing for customization, the profiles may be thick, uncomfortable, and limit a patient’s footwear choices.

The next generation AFO’s | Pre-preg carbon
A new process of pre-impregnating a carbon composite with a thermosetting resin is bringing improved applications for orthotic devices. Pre-preg AFO’s have several advantages over traditional, thermoplastic orthoses. Improvements include:

• Pre-preg carbon AFO’s are stronger than traditional, thermoplastic braces

• They have a thin, light profile which improves patient comfort and does not require accommodative shoes

• Pre-preg AFO’s provide a dynamic response, facilitating ambulation

• Carbon pre-preg has a high strength- to-weight ratio

• They provide completely customizable forefoot and spring flexibility configurations to tune the device to the exact specifications needed for the patient

The process of fabricating the carbon AFO’s can be done relatively quickly, getting patients up and walking more safely in a short amount of time.

First, a cast or 3D scan is made of the patient’s calf, ankle, and foot. Once the cast is modified, the pre-impregnated carbon composite fabric is cut into strips to create the calf band, strut, and foot plate of the AFO. After the carbon is fit into place, it is placed under vacuum and heated to cure the resin.  Finally, the edges of the AFO are smoothed on a grinding machine, and straps and padding are added.

Carbon pre-preg AFO’s are just one way that new materials are making their way into orthotic and prosthetic technology. Lighter, stronger materials are improving patient comfort and performance, which in turn improves patient outcomes.

Matt Zydron, CPO, is a graduate of Northwestern University’s Prosthetic and Orthotic Program, and received his undergraduate degree from Hampden-Sydney College. He is certified by the American Orthotic and Prosthetic Association and has been a practicing O&P clinician since 2002.