3D-printed ankle braces may help with balance, foot pain: Study
Design could be further customized to boost acceptance, tolerance in patients
The use of 3D-printed, customized ankle braces may improve balance and reduce foot pain in people with Charcot-Marie-Tooth (CMT) disease, according to a recent pilot study in New Zealand.
Although patients reported variable levels of comfort and satisfaction, they generally said the braces were moderately comfortable, and were moderately satisfied with their use.
“However, larger scale studies are warranted to further explore the impact of the brace on function and balance outcomes along with the long‐term effects of the brace in people with CMT,” researchers wrote in the study “3D-printed custom ankle braces for people with Charcot-Marie-Tooth disease: A pilot study,” which was published in the Journal of Foot and Ankle Research.
CMT is a neurological condition caused by mutations in genes that affect the function of the peripheral nervous system, or the network of nerves that control movement and sensation in the limbs. As a consequence, the nerves progressively lose the ability to transmit nerve signals, leading to muscle weakness and wasting.
Common CMT symptoms include impaired balance, ankle instability, foot drop
Common disease symptoms include impaired balance and gait, ankle instability, and foot drop, which is when the toes drop forward as patients lift their feet while walking. This may lead patients to use ankle foot orthoses, or biomechanical devices to stabilize joints and improve gait, which may cause discomfort and pain.
In the study, researchers in New Zealand tested whether a fully customized and lightweight 3D-printed ankle brace could improve function and balance in people with CMT.
For that, 10 patients with a mean age of 48.2 years were fitted with 3D-printed ankle braces. The EXO-L UP ankle braces consist of a thermoplastic nylon piece enclosing the lower leg, a fabric attachment to footwear, and a nylon cord connecting the shell and footwear. They are an adaptation of the EXO-L brace marketed by Brace for Innovation to help athletes avoid ankle sprains.
Participants had a mean disease duration of 22.8 years, and all except one had foot drop in both feet. Eight had sensory loss. The mean number of falls in the previous month was 12.1. Eight participants reported previous foot surgery.
A 3D scan of the feet and ankles was performed to determine the measurements needed to manufacture the braces. The devices were then produced by a 3D printer, and fabric patches were added to the shoes to allow attachment of the brace. Participants received one or two devices depending on whether one or both feet were affected.
After four weeks of use, participants underwent walking and balance tests under two conditions: using their usual athletic style footwear alone, or together with the ankle braces.
Using ankle brace was associated with significant improvement in balance
Results showed that using the ankle brace was associated with a significant improvement in balance while standing on one foot with eyes open, measured as the time that participants maintained the position, compared to the use of the shoes alone (9.3 vs. 7.5 seconds).
Moreover, the use of braces was associated with reduced foot pain, assessed by a visual analogue scale (VAS). This scale uses a 100-mm ruler, wherein a higher score indicates greater pain intensity.
Using a 100-mm VAS for comfort, ranging from “not comfortable at all” to “extremely comfortable,” patients reported a mean score of 62.7 mm. With a VAS scale ranging from “not satisfied at all” to “extremely satisfied,” patients reported a mean score of 73.9 mm. These results suggest that comfort and satisfaction were moderate.
One patient found the brace too firm around the ankle due to their loss of soft tissue, while two found it challenging to handle the braces due to the loss of hand dexterity that results from CMT-related nerve damage.
“These findings suggest that the design of the brace could potentially be refined and customised further to improve acceptance and tolerance in people with CMT, including considering hand dexterity and soft tissue wasting around the ankles,” the researchers wrote.
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