Flat flexible vs stable supportive shoes: which is better at reducing knee OA symptoms?

Flat flexible shoes do not appear to be better than stable supportive shoes for patients with knee osteoarthritis (OA) symptoms, according to a study.

“Contrary to our hypothesis, stable supportive shoes improved knee pain on walking more than flat flexible shoes,” the authors said.

This participant- and assessor-blinded randomized trial included 164 patients with moderate to severe symptomatic radiographic medial knee OA. Participants were given either flat flexible (n=82) or stable supportive shoes (n=82), worn for at least 6 hours a day for 6 months.

Primary endpoints were changes in walking pain (measured using an 11-point numerical rating scale) and physical function (assessed using the Western Ontario and McMaster Universities Osteoarthritis Index subscale of 0 to 68 points) at 6 months. Secondary endpoints were additional pain and function measures, physical activity, and quality of life.

Of the patients, 161 (98 percent) completed the 6-month trial. Flat flexible shoes were not superior to stable supportive shoes in primary endpoints. However, a between-group difference was noted in change in pain which favoured the latter (mean difference [MD], 1.1 units, 95 percent confidence interval [CI], 0.5–1.8; p=0.001) but not function (MD, 2.3 units, 95 percent CI, –0.9 to 5.5; p=0.167).

Stable supportive shoes also yielded improvements in knee-related quality of life (MD, –5.3 units, 95 percent CI, –10.0 to –0.5) and ipsilateral hip pain (MD, 0.7 units, 95 percent CI, 0.0–1.4). Flat flexible shoes did not show superiority over stable supportive shoes for any secondary outcome.

Moreover, there were fewer adverse events reported with stable supportive shoes compared with flat flexible shoes (15 percent vs 32 percent; risk difference, –0.17, 95 percent CI, –0.30 to –0.05).

The study was limited by the absence of “usual shoes” control group and by a select patient subgroup, which prevented generalizability of the findings, according to the authors.