Microwave Ablation of Synovial Hypertrophy in Recurrent Monoarthritis: the Results of Extended Cohort and Long-Term Follow-Up

Objectives Recurrent monoarthritis (RM) is a major challenge of many rheumatic diseases. Ablation is a well-known technique in the treatment of benign or malign lesions of different aetiologies. We aimed to investigate the success and safety of microwave ablation (MWA) as an adjunctive therapy in a cohort of medical treatment-resistant RM. Methods Patients with RM associated with different inflammatory diseases were included. MWA was performed after measuring the size of synovial hypertrophy with 15 or 20 W power and different durations until microbubbles were shown, indicating necrosis. Both clinical and radiologic data were recorded. Results We applied MWA in total of 24 knee joints of 10 female and 12 male patients aged between 22 and 71 years. Median IA aspiration (IAA) need in the last 6 months before MWA was 5 (0-15). The median follow-up was 10 (3-16) months. Overall IAA count in the last 6 months before MWA in total of 144 months was 129, and decreased to 7 in post-MWA in total of 226 months (0.89 vs 0.03 per month, P < 0.001). The second MWA session was needed for three patients and a third session for one. Functional disability and pain scores were improved significantly (median score from 9 to 1, P < 0.00001, in both). In MRI, follow-up significant regression in synovial hypertrophy size was shown especially after the 6th month. No complication was observed during the procedure or follow-up. Conclusion As a less invasive technique compared with the surgical approach, MWA of synovial hypertrophy showed significant clinical improvement in RM safely. MWA seems promising as a treatment option candidate in the management of RM.