Ultrasound-guided synovial biopsy: A systematic review according to the OMERACT filter and recommendations for minimal reporting standards in clinical studies

Objectives. To describe existing techniques of US-guided synovial biopsy (USG-SB) and critically appraise the literature on this technology through the OMERACT filter. Methods. USG-SB techniques are described and compared. A systematic literature search of PubMed and Embase was performed for original research reports including US and SB. The subjects, procedure protocols and reported results were analysed. A future research agenda is proposed. Results. USG-SB can be performed using a portal-and-forceps or a dedicated semi-automatic guillotine-type biopsy needle approach. Of 50 reports identified, 7 were included in the review. Large, intermediate and small joints were all amenable to USG-SB. We found great heterogeneity with regard to indications for and definition of a successful procedure and of synovitis. Adverse events were assessed in most papers with an overall major complication rate of 0.4%. However, there was a lack of construct validity using a histological comparator. Relatively few papers reported details on the technique used, tissue processing, synovitis scoring and blinding for tissue analysis. Conclusion. USG-SB can be regarded as a valuable tool for large-scale synovial tissue sampling. Standardization of the techniques of USG-SB and tissue processing is needed. Future research should focus on the reliability, responsiveness and feasibility of this procedure in prospective studies.