Structural effects of whole body electromyostimulation on knee osteoarthritis: the EMSOAT Study.

Objective: Whole-body electromyostimulation (WB-EMS) might be an alternative option to conventional strength training for patients with knee osteoarthritis (OA). Our aim was to compare structural changes of knee OA between patients treated with WB-EMS and a control group (CG) treated with a standard of care approach.

Material and methods: Seventy-two overweight participants with symptomatic knee OA were assigned to either WB-EMS or CG. MRIs were acquired at baseline and 7 months using a 3 T system. MRIs were read according to the MRI Osteoarthritis Knee Score (MOAKS) instrument. Between-group differences in regard to change in cartilage, bone marrow lesions (BMLs), osteophytes, meniscus damage and extrusion, and markers of inflammation were analyzed using Fisher's Exact and Wilcoxon Rank Sum tests.

Results: Fewer knees in the WB-EMS groups showed cartilage worsening compared to the CG (18% vs. 40%, p = 0.046). There were fewer knees in the WB-EMS group showing an increase in BML size score of ≥ 1 (30% vs 46%, p = 0.43). Regarding prevalent BMLs that showed improvement, no change, or worsening, no differences were seen (p = 0.56). Little osteophyte and meniscal changes were observed during the observational period. Differences regarding change in inflammatory markers were not significant.

Conclusion: While there was a difference with fewer subregions showing worsening cartilage damage in the WB-EMS group, no significant differences were observed for change in BMLs, inflammation, osteophytes, and meniscal parameters. The observed improvement in clinical outcome parameters in favor of the WB-EMS group is likely due to other effects than improvement or less worsening of structural changes.