(HealthDay News) – For patients with knee osteoarthritis, the use of lateral wedges offers no significant benefit vs. a neutral insole comparator, according to research published in the Aug. 21 issue of the Journal of the American Medical Association.

Matthew J. Parkes, from the University of Manchester in the United Kingdom, and colleagues conducted a meta-analysis involving 12 trials with 885 participants to examine whether lateral wedge insoles are associated with reduction in pain for patients with medial knee osteoarthritis. Of the participants, 502 received lateral wedge treatment.

The researchers found that based on the pooled standardized mean difference (SMD) there was a favorable association with lateral wedges vs. control, but considerable heterogeneity was seen (SMD, −0.47; I² = 82.7%). The effect size correlated with a 2.12 point reduction on the Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scale. A null association was suggested by larger trials with a lower risk of bias. In meta-regression analyses, higher effect sizes were seen in trials using a no wedge treatment control group, and lower effect sizes were observed when the study method was deemed at low risk of bias. Compared with a neutral insole control treatment, lateral wedges had no effect on WOMAC, with little heterogeneity between studies (I² = 7.1%).

“Although meta-analytic pooling of all studies showed a statistically significant association between use of lateral wedges and lower pain in medial knee osteoarthritis, restriction of studies to those using a neutral insole comparator did not show a significant or clinically important association,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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