Clinical course in patients with chronic undifferentiated arthritis of the elbow after arthroscopic synovectomy

Background: Surgical treatment can be considered for patients with undifferentiated arthritis (UA) limited to the elbow joint. The purpose of this study was to analyze the clinical outcomes of arthroscopic synovectomy. Methods: Nineteen patients who underwent arthroscopic synovectomy for chronic UA of the elbow between 2006 and 2019 were enrolled in this study. One patient was excluded because of evidence of tuberculosis in the biopsy. Chronic UA of the elbow was defined as (1) localized synovitis diagnosed by magnetic resonance imaging, (2) no specific cause, and (3) no response to conservative treatment for >3 months. We compared baseline characteristics and clinical outcomes between the remission and disease progression groups. Results: Postoperatively, synovitis was controlled in 13 patients. In 5 patients, the symptoms disappeared after surgery without any medical treatment. Four patients discontinued disease-modifying antirheumatic drugs. Nine patients were classified as in remission. The disease progression group had a longer symptom duration, elevated rheumatoid markers, and higher Larsen grading. However, the difference was not statistically significant. Conclusions: Arthroscopic synovectomy achieved remission in approximately 47% of patients with chronic UA of the elbow. Although arthroscopic synovectomy did not prevent RA, it can be considered for rapid resolution of synovitis and diagnostic purposes.