Walking with a tweaked foot angle eases knee arthritis pain as well as medication, trial finds

For the roughly one in four adults over 40 living with knee osteoarthritis, the standard options have long been a grim progression: manage pain with pills, and eventually replace the joint. A clinical trial published in The Lancet Rheumatology now points to a third path — one that requires no medication, no device, and no surgery, just a small, carefully chosen change to the angle of the foot while walking.

Lead researcher Scott Uhlrich said that after one year, participants who had learned to walk with a personalized foot position experienced pain relief on a scale comparable to the gap between an over-the-counter option such as ibuprofen and a narcotic such as oxycontin. MRI scans revealed that a cartilage health marker declined more slowly in those participants than in a placebo group — a result the researchers described as meaningful given that no established treatment currently exists to reliably restore cartilage lost to 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. 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.— Scott Uhlrich, assistant professor of mechanical engineering, University of Utah

Co-led by Uhlrich alongside collaborators at New York University and Stanford University and funded by the National Institutes of Health and the U.S. Department of Veterans Affairs, the study is the first randomized, placebo-controlled clinical trial to establish the effectiveness of personalized gait retraining for knee osteoarthritis across a full year.

About 22% of adults over age 40 are affected by osteoarthritis, making it one of the leading causes of disability. Cartilage — the smooth, protective tissue that cushions bone ends — breaks down gradually with the condition, turning routine tasks such as climbing stairs or rising from a chair into sources of increasing pain. The knee's inner section, called the medial compartment, typically carries more load during normal walking, which is why osteoarthritis affecting the inside of the knee is especially common.

The underlying mechanics are simple: angling the toes slightly inward or outward changes the forces the knee absorbs with every step, which can lower stress on already-damaged medial cartilage. The critical insight from this trial, however, is that the same adjustment does not work for everyone — and applying the wrong one can actually increase pressure on the damaged joint.

Previous trials prescribed the same intervention to all individuals, resulting in some individuals not reducing, or even increasing, their joint loading. 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.— Scott Uhlrich, assistant professor of mechanical engineering, University of Utah

Researchers evaluated whether rotating the toes inward or outward — by 5 or 10 degrees — produced the greatest reduction in pressure on each participant's affected knee. Some prospective participants were excluded entirely because none of the tested adjustments successfully reduced their knee loading, a factor the researchers say may explain why earlier gait-retraining studies produced inconsistent results.

Of the 68 participants with mild-to-moderate medial compartment osteoarthritis who qualified, 34 received personalized instructions and 34 received a sham treatment — going through the identical training process but instructed to maintain their natural foot angle. Both groups then attended six weekly lab sessions, walking on a treadmill while wearing a small device on the shin that delivered vibration biofeedback to help them hold the prescribed angle. Once those six weeks concluded, participants were asked to incorporate their new gait into at least 20 minutes of daily practice until it felt natural. Follow-up check-ins indicated that participants were holding their prescribed foot angle to within a degree on average.

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. With the MRIs, we also saw slower degradation of a marker of cartilage health in the intervention group, which was quite exciting.— Scott Uhlrich, assistant professor of mechanical engineering, University of Utah

One participant captured the appeal of the approach in plain terms, saying the new gait had become simply part of how they move through the world.

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.— Trial participant (unnamed)

That quality — becoming habitual — is one of the intervention's practical advantages. Osteoarthritis diagnosed in a person's 30s, 40s, or 50s can mean decades of pain management before joint replacement is recommended. Uhlrich described gait retraining as potentially filling that large treatment gap.

The researchers are clear that the approach is not yet ready for a standard clinic visit. Before it can be widely prescribed, the intake process — currently requiring a specialized treadmill and motion-capture lab — will need to be streamlined so that assessment and retraining can happen in a physical therapy setting, or eventually during an ordinary walk around the neighborhood. Those interested in participating in future studies can contact Uhlrich's Movement Bioengineering Lab at the University of Utah.

Why it matters — For the tens of millions of people managing knee osteoarthritis — often for decades before surgery is an option — a low-cost, drug-free intervention that addresses the mechanical cause of joint deterioration, not just the pain, could fundamentally change how the condition is treated.

Reported by goodnewsnetwork.org, sciencedaily.com