Charcot-Marie-Tooth feet were more cavovarus inside their AFOs on weightbearing CT

A prospective imaging study published in Clinical Orthopaedics and Related Research on 12 October 2026, from the University of Utah and the University of Iowa.

Twenty adults with Charcot-Marie-Tooth disease (CMT) who already wore bilateral ankle-foot orthoses (AFOs) were scanned in a standing weightbearing CT, once barefoot and once in their usual AFOs and shoes. Two feet were excluded, leaving 38. The researchers measured standard 2D angles and also built a 3D statistical shape model of 14 foot bones. The main outcome was a "cavovarus score": how far each foot's overall shape sat towards cavovarus on that model.

Participants wore their own AFOs, a mix of custom and off-the-shelf. The researchers had no prescriptions, manufacturers or wear-time data, and classified each device from the CT images.

Meary's angle in the sagittal plane was 3.8° higher in the AFO (16.9° barefoot against 20.7°; 95% CI 0.3 to 7.2), meaning a higher arch. The calcaneal–first metatarsal angle also changed, by 3.3°.

Hindfoot alignment, talar tilt, axial Meary's angle and calcaneal pitch didn't change meaningfully.

The overall cavovarus shape score was 27% higher in the AFO on average. The range reported around it ran from −57% to +110%, so some feet were less cavovarus in their AFO and others much more. A plantarflexion shape score rose 54% and a midfoot elevation score 42% on average, with similarly wide ranges. Hindfoot varus shape didn't change significantly.

Custom footplates did better on two measures and no better overall. Feet in custom footplates changed less on the calcaneal–first metatarsal angle (−2.7° against −3.9° for flat and −5.0° for flat plus insole) and on midfoot elevation (8% against 78% and 113%). On the overall cavovarus score, custom footplates were no different (27% against 26% for flat and 15% for flat plus insole). Most custom footplates were on posterior-spring AFOs, so footplate and AFO design can't be separated, and the groups were small.

The study was funded by NIH grants, and the authors declared no commercial associations. Bone segmentation used Paragon 28's Bonelogic software, with no relationship declared.

On static weightbearing CT, AFOs didn't reduce cavovarus deformity in these CMT feet. On average they made a few measures more cavus, and the hindfoot measures didn't move.

Some feet improved in their AFO. With a range from −57% to +110%, the response varied a lot between feet, and the study can't say why.

Without device details, the result can't be tied to a design. Self-selected devices of unknown make and prescription, mixed across materials, functions and footplates, mean the 27% is an average across very different AFOs. That's the same problem we've raised with shockwave research: without the protocol, it's hard to draw conclusions about any one treatment.

The comparison was barefoot against brace plus shoe, standing still. The study didn't measure walking, pain, falls or deformity progression over time, and the shoe itself may have changed foot position.

A static scan can't show what happens to loading during walking. The authors suggest AFOs don't change the foot's mechanical loading pattern, which is more than standing CT can measure.

In 20 adults with CMT, feet were on average more cavovarus standing in their usual AFOs than barefoot, with large variation between feet and no record of the devices. It seems like whatever AFOs do for these patients happens through stability, at least while standing. It'd be worth repeating with documented devices and walking measures.