Specialized footwear associated with no additional benefit versus conventional footwear for knee osteoarthritis pain
At 6 months, change in pain and function did not differ between those assigned to specialized footwear or those assigned to conventional walking shoes. Global improvements in pain were seen in 54% of participants, and global improvements in function were seen in 44% to 48%.
Specialized footwear for self-management of knee osteoarthritis does not appear to yield greater benefit in pain and function than conventional footwear, according to a new study.
Researchers in Australia performed a randomized, controlled trial to compare the effectiveness of unloading shoes and regular shoes in alleviating symptoms of knee osteoarthritis. Daily use of unloading shoes, defined as shoes with triple-density, variable-stiffness midsoles and mild lateral-wedge insoles designed to unload the medial knee, was compared with daily use of conventional walking shoes. Researchers provided both types of shoes to patients.
Primary outcomes were pain with walking at 6 months, assessed with a numerical rating scale (NRS), and physical function at 6 months, assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes were knee pain and stiffness (assessed with WOMAC), average pain (assessed with NRS), intermittent and constant knee pain (assessed with the Intermittent and Constant Osteoarthritis Pain questionnaire), quality of life (assessed with the Assessment of Quality of Life instrument), physical activity (assessed with the Physical Activity Scale for the Elderly), and global change in pain and function (assessed with Likert scales). Results were published on July 12 by Annals of Internal Medicine.
One hundred sixty-four patients with medial knee osteoarthritis were included in the study, and 160 (98%) completed primary outcome measures at 6 months. Of these, 80 had been randomly assigned to the intervention group and 80 had been assigned to the comparator group. At 6 months, change in pain and function did not differ between groups; the mean difference in pain was 0.0 units (95% CI, −0.9 to 0.8 unit), while the mean difference in function was 0.3 units (95% CI, −3.2 to 3.7 units).
Both groups had clinically relevant improvements in function at 6 months, and the intervention group had a clinically relevant improvement in pain. Secondary outcomes did not differ between groups. Global improvements in pain and function were seen in 54% and 44% to 48% of participants, respectively. No association was seen between increased probability of improvement and use of unloading shoes (odds ratio for pain and function, 0.99 [95% CI, 0.53 to 1.86] and 0.85 [95% CI, 0.45 to 1.61]).
The authors noted that they assessed a single brand of unloading shoe, which limits generalizability, and that their results also may not apply to patients with milder osteoarthritis symptoms or without radiographic medial knee osteoarthritis. In addition, they pointed out that they did not measure changes in joint structure because of the study's relatively short intervention period. However, they concluded that walking shoes with modified midsoles meant to unload the knee appeared to offer no benefit versus conventional walking shoes in patients with symptomatic medial knee osteoarthritis. They called for future studies to examine the potential effects of unloading shoes on structural progression of knee osteoarthritis over time.
An accompanying editorial said that the trial performed “a good head-to-head comparison of two footwear groups” but pointed out that the lack of difference in the results might be due to the fact that the control group had been provided with new, supportive shoes and that a group of patients wearing their usual shoes was not included in the study. They recommended that future studies recognize the heterogeneity of knee osteoarthritis as well as the need to target patient subgroups that might benefit the most from joint-alignment interventions.
“The fact that both treatment groups received new shoes and improved over the 6-month study highlights the promise of simple biomechanical interventions,” the editorialists wrote. “It has been said that ‘Cinderella is proof that a new pair of shoes can change your life.’ Wouldn't it be wonderful if a simple pair of new shoes could help your patients with knee osteoarthritis?”