A potential way to relieve arthritic knees without drugs or surgery

New study led by U engineering professor shows gait retraining could significantly ease pain and slow cartilage damage.

Even Lerner, University of Utah, August 13, 2025

Nearly a quarter of people over the age of 40 experience painful osteoarthritis, making it a leading cause of disability in adults. Osteoarthritis degrades joint-cushioning cartilage, and there is currently no way of reversing this damage: the only option is to manage pain with medication, and eventually, joint replacement.

Researchers from the University of Utah, New York University and Stanford University are now demonstrating the potential for another option: gait retraining.

By making a small adjustment to the angle of their foot while walking, participants in a year-long randomized control trial experienced pain relief equivalent to medication. Critically, those participants also showed less knee cartilage degradation over that period as compared to a group that received a placebo treatment.

Published in The Lancet Rheumatology and co-led by Scott Uhlrich of Utah’s John and Marcia Price College of Engineering, these findings come from the first placebo-controlled study to demonstrate the effectiveness of a biomechanical intervention for osteoarthritis.

“We’ve known that for people with osteoarthritis, higher loads in their knee accelerate progression, and that changing the foot angle can reduce knee load,” said Uhlrich, an assistant professor of mechanical engineering. “So the idea of a biomechanical intervention is not new, but there have not been randomized, placebo-controlled studies to show that they’re effective.”

A personalized approach to gait retraining

With support from the National Institutes of Health and other federal agencies, the researchers were specifically looking at patients with mild-to-moderate osteoarthritis in the medial compartment of the knee—on the inside of the leg—which tends to bear more weight than the lateral, outside, compartment. This form of osteoarthritis is the most common, but the ideal foot angle for reducing load in the medial side of the knee differs from person to person, depending on their natural gait and how it changes when they adopt the new walking pattern.

“Previous trials prescribed the same intervention to all individuals, resulting in some individuals not reducing, or even increasing, their joint loading,” Uhlrich said. “We used a personalized approach to selecting each individual’s new walking pattern, which improved how much individuals could offload their knee and likely contributed to the positive effect on pain and cartilage that we saw.”

In their first two visits, participants received a baseline MRI and practiced walking on a pressure-sensitive treadmill while motion-capture cameras recorded the mechanics of their gait. This allowed the researchers to determine whether turning the patient’s toe inward or outward would reduce load more, and whether a 5-degree or 10-degree adjustment would be ideal.

This personalized analysis also screened out potential participants who could not benefit from the intervention in instances where none of the foot-angle changes could decrease loading in their knees. These participants were included in previous studies, which may have contributed to those studies’ inconclusive pain results.

Promising results, but more clinical trials are needed to refine the process

Moreover, after their initial intake sessions, half of the 68 participants were assigned to a sham treatment group to control for the placebo effect. These participants were prescribed foot angles that were actually identical to their natural gait. Conversely, participants in the intervention group were prescribed the change in foot angle that maximally reduced their knee loading.

Participants from both groups returned to the lab for six weekly training sessions, where they received biofeedback—vibrations from a device worn on the shin—that helped them maintain the prescribed foot angle while walking on the lab’s treadmill. After the six-week training period, participants were encouraged to practice their new gait for at least 20 minutes a day, to the point where it became natural. Periodic check-in visits showed that participants were adhering to their prescribed foot angle within a degree on average.

After a year, all participants self-reported their experience of knee pain and had a second MRI to quantitatively assess the damage to their knee cartilage.

“The reported decrease in pain over the placebo group was somewhere between what you’d expect from an over-the-counter medication, like ibuprofen, and a narcotic, like oxycontin,” Uhlrich said. “With the MRIs, we also saw slower degradation of a marker of cartilage health in the intervention group, which was quite exciting.”

Beyond the quantitative measures of effectiveness, participants in the study expressed enthusiasm for both the approach and the results. One participant said, “I don’t have to take a drug or wear a device… it’s just a part of my body now that will be with me for the rest of my days, so that I’m thrilled with.”

Participants’ ability to adhere to the intervention over long periods of time is one of its potential advantages.

“Especially for people in their 30s, 40s or 50s, osteoarthritis could mean decades of pain management before they’re recommended for a joint replacement,” Uhrlich said. “This intervention could help fill that large treatment gap.”

Before this intervention can be clinically deployed, the gait retraining process will need to be streamlined. The motion-capture technique used to make the original foot-angle prescription is expensive and time-consuming; the researchers envision this intervention to eventually be prescribed in a physical therapy clinic and retraining can happen while people go for a walk around their neighborhood.

“We and others have developed technology that could be used to both personalize and deliver this intervention in a clinical setting using mobile sensors, like smartphone video and a ‘smart shoe,’” Uhlrich said. Future studies of this approach are needed before the intervention can be made widely available to the public.

Those interested in participating in future studies can contact Scott Uhlrich’s Movement Bioengineering Lab by filling out this web form.

Training the New Walking Pattern

Both groups returned to the lab for six weekly training sessions. During these sessions, participants walked on a treadmill while wearing a device on the shin that provided vibration feedback. The vibrations helped them keep their assigned foot angle while walking.

After the six week training period, participants were encouraged to practice the walking pattern for at least 20 minutes each day. The goal was for the movement to become automatic. Follow up visits showed that, on average, participants stayed within one degree of their prescribed foot angle. After one year, participants reported their knee pain levels and underwent a second MRI so researchers could measure changes in cartilage health.

A Drug Free Option for a Long Treatment Gap

For some participants, one of the most appealing parts of the approach was that it did not require pills, surgery, braces, or a device worn all day. One participant said: “I don’t have to take a drug or wear a device…it’s just a part of my body now that will be with me for the rest of my days, so that I’m thrilled with.”

That long term adherence could be one of the intervention’s biggest strengths. Many people develop osteoarthritis decades before they are candidates for joint replacement. During that time, they may rely heavily on pain medications and other symptom management strategies.

“Especially for people in their 30’s, 40’s, or 50’s, osteoarthritis could mean decades of pain management before they’re recommended for a joint replacement,” Uhrlich said. “This intervention could help fill that large treatment gap.”

A 2026 conference abstract in Osteoarthritis and Cartilage also highlighted continued interest in placebo controlled trials of foot progression angle retraining, underscoring that researchers are still trying to determine which gait strategies work best and for whom. However, this area remains under active study, and the 2025 Lancet Rheumatology trial is still one of the strongest clinical demonstrations of a personalized approach.

Why Patients Should Not Try This Alone

Although the findings are promising, the researchers emphasized that this is not a simple “turn your toes in” or “turn your toes out” recommendation. The benefit depended on careful measurement and personalization. For some people, the wrong adjustment could increase stress on the knee rather than reduce it.

That is why the process still needs to be simplified before it can be used widely in clinics. The motion capture system used to prescribe each person’s walking change is expensive and time consuming. The research team envisions a future version that could be delivered through physical therapy, with retraining taking place during normal walks rather than only inside a lab.

“We and others have developed technology that could be used to both personalize and deliver this intervention in a clinical setting using mobile sensors, like smartphone video and a ‘smart shoe’,” Uhlrich said. Future studies of this approach are needed before the intervention can be made widely available to the public.

The study, titled “Personalised gait retraining for medial compartment knee osteoarthritis: a randomised controlled trial,” was published in The Lancet Rheumatology. Co lead authors are Valentina Mazzoli of NYU’s Department of Radiology and Julie Kolesar of Stanford’s Human Performance Lab. Coauthors include Amy Silder, Andrea Finlay, Feliks Kogan, Garry Gold, Scott Delp and Gary Beaupre of Stanford and the VA Palo Alto Medical Center. The research was supported by federal research grants from the Department of Veterans Affairs, National Institutes of Health and National Science Foundation.

Evan Lerner Director of communications, John and Marcia Price College of Engineering ‭(908) 370-7621‬ evan.lerner@utah.edu

Source University of Utah

References

Uhlrich SD, Mazzoli V, Silder A, Finlay AK, Kogan F, Gold GE, Delp SL, Beaupre GS, Kolesar JA. Personalised gait retraining for medial compartment knee osteoarthritis: a randomised controlled trial. Lancet Rheumatol. 2025 Oct;7(10):e708-e718. doi: 10.1016/S2665-9913(25)00151-1. Epub 2025 Aug 12.

Further reading
Song CN, Stenum J, Leech KA, Keller CK, Roemmich RT. Unilateral step training can drive faster learning of novel gait patterns. Sci Rep. 2020 Oct 29;10(1):18628. doi: 10.1038/s41598-020-75839-3.

Also see
Study reveals gait retraining could help treat knee osteoarthritis Stanford Report
New Study Shows Gait Retraining Could Significantly Reduce Knee Pain From Osteoarthritis and Potentially Slow Cartilage Damage John and Marcia Price College of Engineering, The University of Utah
Personalized gait retraining for knee osteoarthritis Model Health