The American Medical Association (AMA) has reported that despite prior research suggesting a statistically significant link between the use of lateral wedge insoles and lower pain in medial knee osteoarthritis (OA), current trials comparing wedge insoles with neutral insoles indicate no significant or clinically important link between the use of wedge insoles and reduction in knee pain.
An AMA news release states that Matthew J. Parkes, BSc, University of Manchester, England, and colleagues used a meta-analysis in order to explore the efficiency of later wedge treatments; encompassing shoes and insoles designed to reduce medial knee compartment loading, in reducing pain in medial knee OA patients.
A search of medical literature was also conducted in an effort to pinpoint randomized trials that compared shoe-based treatments, which included lateral heel wedge insoles or shoes with variable stiffness soles, targeting the reduction of medial knee load, with a neutral or no wedge treatment.
Researchers explain that the wedge needed to have 5 degrees to 15 degrees of angulation, a level reportedly shown in prior research to reduce external knee adduction movement. The results when comparing a total of 12 trials indicated an overall effect estimate as a standard mean difference in pain between interventions, exhibiting a moderately significant impact of a lateral wedge on pain reduction. Yet, researchers emphasize that the findings were highly heterogeneous across studies.
Once the trials had been grouped together according to control group treatment, the result suggested that when compared with neutral inserts, lateral wedges had no link to knee pain and heterogeneity was shown to be much lower across trial findings.
According to study authors, the results ultimately indicate that when compared with control interventions, lateral wedges proved to be not efficacious for the treatment of knee pain in persons with medial knee OA.