Wearing stable, supportive footwear reduces knee pain to a significantly greater extent than what’s felt with flat, flexible shoes in patients with severe knee osteoarthritis, according to results of a randomized, controlled trial presented at the OARSI 2021 World Congress.
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Clinical guidelines for knee OA emphasize the importance of patients self-managing their condition with exercise, weight control, and appropriate footwear. However, there is limited evidence on which footwear is best, and some guidelines advocate stable supportive shoes based solely on expert opinion, Kade Paterson, PhD, of the University of Melbourne told the conference, sponsored by Osteoarthritis Research Society International.
“Recent research suggests that another type of shoe style – termed flat, flexible shoes – may be more beneficial,” Dr. Paterson said, citing a randomized, controlled trial that found greater improvement in pain and function with flat flexible shoes, compared with neutral tennis shoes. “Flat, flexible shoes are generally lighter, and have thinner, more flexible soles.”
In this study, which was published earlier this year in Annals of Internal Medicine, 164 individuals with knee OA who had experienced knee pain on most days of the past month were randomized to wear either stable, supportive shoes or flat, flexible shoes for at least 6 hours a day for 6 months. Six of each shoe type – three male styles and three female styles – were offered, having been chosen based on a survey in which participants were asked about a selection of commercially available shoes they were most likely to wear.
Researchers found participants who wore the stable, supportive shoes had significantly greater reductions in knee pain on walking during the previous week, representing a mean difference of 1.1 units on an 11-point numerical rating scale. More patients in the stable, supportive shoe arm of the study achieved minimal clinically important difference in pain than did those in the flat, flexible shoe group.
Stable, supportive shoes were also associated with greater improvements in knee-related quality of life scores and greater improvements in overall pain. However, there was no significant difference between the two groups in function. Patients wearing flat, flexible shoes reported significantly more adverse events – mainly onset of or increases in knee pain.
Dr. Paterson said the results were surprising, given previous research suggesting a benefit from lighter flat, flexible shoes. “Some previous research showed that those shoes reduced knee joint forces that were associated with pain and reduced it more than stable, supportive shoes, and based on the biomechanical research, we thought would be flat, flexible shoes,” he said in an interview.
Another observation to come from the study was the poor quality of most patients’ everyday shoes. Dr. Paterson said that most of the participants’ usual shoes were very old, and many were also wearing inappropriate footwear for knee OA, including shoes with heels or slippers.
“We would strongly recommend that clinicians ask patients to even bring in their most commonly worn shoes and then recommend new shoes, and based on our data, certainly stable supportive shoes,” he said.
Commenting on the findings, Jos Runhaar, PhD, of Erasmus University Medical Center in Rotterdam, the Netherlands, said this study provided high-quality evidence for this specific intervention in this specific group of patients, namely those with more severe, end-stage OA who had long-lasting changes in their foot posture and gait.
“Based on this, I would say that restoring the original posture of the foot – because that’s how the stable, supportive shoes are probably designed – is more beneficial than actually supporting the natural gait that people are already adapted to at that stage,” Dr. Runhaar said in an interview.
Dr. Paterson noted that the findings of the study were not generalizable to people with mild knee OA, and also that the study did not compare either shoe type with participants’ usual shoes.
The study and three authors were supported by the Australian National Health and Medical Research Council. No conflicts of interest were declared.