‘Simple’ strategy helps alleviate knee osteoarthritis pain
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Contrary to a hypothesis by a group of researchers, data show patients who wore stable, supportive shoes while walking experienced greater improvements in their knee osteoarthritis pain compared with those who wore flat, flexible shoes.
Kade L. Paterson, BAppSci(Hons) a senior research fellow in physiotherapy at the University of Melbourne in Australia, and colleagues wrote that preliminary, limited evidence suggests that “thinner, flatter, flexible” shoes with no cushioning may be more beneficial than shoes with “thick, shock-absorbing soles and arch supports” in alleviating knee osteoarthritis symptoms.
“Prior to this study, we knew that stable supportive shoes increased knee joint loads more than flat flexible shoes, which made us suspect that perhaps flat flexible shoes would result in less knee pain compared to stable supportive shoes,” Rana S. Hinman, BPhysio(Hons), PhD, study coauthor and deputy director of the Centre for Health, Exercise and Sports Medicine at the University of Melbourne in Australia, told Healio Primary Care. “But there had been no clinical trial to test this hypothesis, which prompted us to conduct this clinical trial.”
The researchers recruited 164 people aged older than 50 years with similar characteristics to a participant-blinded and assessor-blinded randomized trial. The individuals had to have moderate to severe symptomatic radiographic medial knee osteoarthritis, report knee pain most days, knee pain of an average of 4 or greater on an 11-point numerical rating scale while walking in the past week and Kellgren–Lawrence scores of grade 3 (moderate) or grade 4 (severe). The individuals were randomly assigned in a 1:1 ratio to wear either “flat flexible” shoes or “stable supportive shoes” at least 6 hours daily for 6 months.
Paterson and colleagues wrote in Annals of Internal Medicine that there were no data to suggest the trial’s 6-month primary outcomes — meeting the minimum thresholds to “ameliorate symptoms and facilitate function” as measured by the Numeric Rating Scale scores and Western Ontario and McMaster Universities Osteoarthritis Index subscales — had been met. There was a between-group difference in change in pain favoring stable, supportive shoe wearers (mean difference = 1.1 units; 95% CI, 0.5 – 1.8) but not function (mean difference = 2.3 units; 95% CI, –0.9 to 5.5). Improvements in knee-related quality of life (mean difference = –5.3 units; 95% CI, –10 to –0.5) and ipsilateral hip pain (mean difference = 0.7 units; 95% CI, 0–1.4) also favored those wearing stable, supportive shoes.
The researchers also noted that “flat flexible shoes were not superior to stable supportive shoes” for any of the secondary outcomes: Knee Injury and Osteoarthritis Outcome Score subscales of knee pain, sport and recreation, overall quality of life and patellofemoral pain and osteoarthritis. Adverse events (knee, ankle/foot, shin/calf and/or other types of pain, knee swelling and falls) were reported in 12 participants wearing stable, supportive shoes and in 26 of those wearing flat, flexible shoes (risk difference = –0.17; 95% CI, –0.3 to –0.05).
“Drugs have limited short-term effects on pain and surgery is reserved for end-stage disease, so self-management of [knee osteoarthritis] symptoms is really important,” Hinman said. “Footwear is a simple self-management strategy that has the potential to change loading across the knee joint and potentially reduce knee pain.”