Background Arthrocentesis is a common procedure in rheumatology clinical practice, usually to obtain synovial fluid for diagnostic purposes or as a therapeutic procedure for glucocorticoid intra-articular injection. There is a generally held belief amongst rheumatologists that needle arthrocentesis is a safe and well-tolerated procedure. Previous reports of the safety of needle arthrocentesis have been in the context of glucocorticoid injection (1). The safety of diagnostic arthrocentesis has not been previously studied systematically.
Objectives To determine the frequency of adverse events of diagnostic arthrocentesis in patients suspected to have gout.
Methods Consecutive patients with recent joint swelling or possible tophus underwent arthrocentesis or nodule tissue aspiration as part of a cross-sectional diagnostic study for gout. All patients were evaluated at 6 weeks by telephone or in the clinic to determine any adverse events (AE) following the arthrocentesis. The 95% confidence intervals for the percentage frequency of AE were obtained by bootstrapping.
Results Arthrocentesis was performed in 910 patients and 887 of these patients (97.5%) were evaluated for AE. Any adverse event was observed in 12 participants (1.4%, 95%CI 0.6 to 2.1). The commonest AE was pain (5 events), nearly all of which were rated as mild. Other non-serious AE reported were bruising (2 events), and joint swelling (4 events). There was 1 case (0.1%, 95% CI 0 to 0.34) of septic arthritis subsequent to the arthrocentesis who required hospitalization and antibiotics.
Conclusions Diagnostic arthrocentesis is safe and associated with a very low frequency of adverse events, which are generally mild. However, septic arthritis rarely occurs with an estimated (bootstrapped 95% CI) frequency of between 0 and 3.4 per 1000 patient-procedures.
Acknowledgements This study was supported by the American College of Rheumatology, European League against Rheumatism, Arthritis New Zealand, Association Rhumatisme et Travail, and Asociaciόn de Reumatόlogos del Hospital de Cruces.
Disclosure of Interest None declared