Background/Purpose: Diagnosing arthritis remains challenging in a subset of patients despite advances in imaging, serological markers, and clinical scoring systems. Ultrasound-guided synovial biopsy (USG-SB) stands as a potentially valuable tool in clarifying diagnoses and guiding treatment in atypical or refractory joint presentations. The objective is to evaluate the clinical utility and patient-reported outcomes (PROMs) of USG-SB in patients with refractory arthritis in a real-world, secondary care setting. Methods: We conducted a case series of seven patients who underwent knee USG-SB based on clinical indication by the treating rheumatologist. Histological samples were evaluated using the Krenn synovitis score, with scores < 5 indicating non-inflammatory or degenerative pathology, and scores ≥5 suggestive of active rheumatic disease. PROMs were assessed 7–10 days post-procedure via structured questionnaire. Results: USG-SB provided diagnostic clarification or therapeutic guidance in 5 of 7 cases (71%). Inflammatory histological features (Krenn ≥5) were found in 4 patients and led to treatment adjustments in 3 cases. In one case, CD marker analysis guided selection of a biologic agent. Two patients were reclassified as having non-inflammatory arthritis, avoiding unnecessary immunosuppressive treatment.
PROMs showed that 6 out of 7 patients (86%) reported clear and sufficient pre-procedure information, and 6 out of 7 experienced minimal or no pain during the biopsy, with a median visual analogic score (VAS) of 0. Median VAS in the first 24 hours was 1. No patients reported functional limitations or infection at the puncture site. Most patients (86%) resumed normal activities within 3 days. All patients rated healthcare staff attention as “excellent,” and 6 out of 7 (86%) indicated they would repeat the procedure if needed. Conclusion: USG-SB is a safe, well-tolerated, and clinically useful procedure in patients with refractory arthritis. It contributed to diagnostic clarification and therapeutic decision-making in most cases, with minimal discomfort reported by patients. Its implementation in secondary care centers may help expand access to precision rheumatologic care.
