For some people with foot issues, over-the-counter insoles at the pharmacy aren’t enough.

But custom orthotics can cost hundreds of dollars, and sometimes still don’t fit correctly.

That’s why Zac Cartun founded StrideSoles, a podiatry app, in his Newton Centre apartment two years ago. Patients scan their feet, and their data are sent to a podiatry clinic that will 3D print orthotics.

The current primary method for custom orthotics involves a person being sent a foam impression kit, stepping into the foam, and sending it back to the company, where they manufacture the orthotic. But the foam impressions don’t always create the most accurate model of a person’s foot, and the numerous steps involved in the process adds to the cost, which can be, in some cases, over a thousand dollars.

Podiatrists were initially skeptical of Cartun’s idea.

“It’s not easy to take a 3D foot scan, and it’s hard to get people to do that consistently without the help of a medical professional,” he acknowledged. But he has an AI model that will take the patient’s at-home scan and rework it to be in the standard pose that someone would have done at a medical clinic.

The clinic he works with has been open for 40 years, and consequently, has a lot of examples to use as modeling data. The ability to 3D print also helps cut down on costs.

“We don’t need anyone holding a piece of plastic to a milling machine,” he said.

Cartun is a physician, with a degree from UMass Medical School in Worcester. For complicated historical reasons, podiatry, the medical care of feet, is considered a separate field, like dentistry.

“We learned surprisingly little about foot health in medical school,” Cartun said. He did learn, however, the desirability of telehealth, due to the COVID-19 pandemic. “We could provide healthcare to people all over,”

After finishing his degree, he worked for a startup that created a digital ultrasound method for expectant mothers, and he saw the way smartphone scanning abilities can be used for telehealth. While doing an MBA in France, one of Cartun’s classmate asked if anyone knew where to get custom orthotics, because his hadn’t arrived in time.

This made him wonder about the potentials for improving the market.

“One of the reasons it’s stagnant is because it’s not very exciting,” Cartun said.

One of the things Cartun hopes to change is the view that orthotics are only about treating medical conditions.

“They can also be a preventative tool, and they can be useful for athletes to improve their performance, too,” he said. He hopes that in the current environment where people are interested in health and wellness, this will make people more interested in custom orthotics. “We want to position ourselves as a lifestyle optimization item.”

Athletes can benefit from shock absorption and by having additional stability and control. But they are also medical devices that treat conditions like plantar fasciitis and Morton’s neuroma.

Cartun started out by reaching out to physical therapists and other clinicians and asking them to use the app in their office. Once he felt confident in his product, he began offering direct-to-consumer sales in September 2024. So far, 95% of orthotics have been a success, and if it isn’t, he will have the item remade.

“Nobody is just casually trying out custom orthotics. I know it’s important for it to fit correctly,” he said.