Patients often need arthrocentesis for diagnostic and therapeutic reasons while on chronic warfarin therapy. Often the procedure is delayed or avoided because of concern about bleeding. The aim of this retrospective study was to determine the safety of arthrocentesis in patients on chronic oral warfarin therapy with INR ≥ 2.0.


We reviewed the records at Regions Hospital and Health‐Partners Medical Group of 514 consecutive patients on chronic warfarin therapy who underwent 640 joint aspiration procedures from January 2001 to November 2008. A total of 456 procedures were performed with INR ≥ 2.0 (group A), and 184 procedures were performed with INR < 2.0 (group B). The end points were: (1) clinically significant bleeding; (2) infection of the joint; and (3) pain in the joint needing emergency room, urgent care, or physician visits. The end points were both early (within 24 hours postprocedure) and late (within 30 days). Indications for arthrocentesis were usually pain/effusion in patients with diseases such as rheumatoid arthritis, osteoarthritis, and gout.


There were no significant differences in age, sex, body mass index, and concurrent use of antiplatelet agents between the 2 groups. Groups were also comparable among all medical comorbidities examined (diabetes mellitus, hypercoagulability, hypertension, liver failure, renal failure, and smoking status). Mean INR at the time of the procedure for group A was higher than that for group B (2.7 ± 0.03 vs. 1.6 ± 0.02). Table 1 shows the early and late complications in both groups. There was no statistically significant difference in the overall complication rate between patients with INR ≥ 2.0 (group A) and patients with INR < 2.0 (group B); P = 0.708. Receiver operating characteristic (Fig. 1) analysis showed that INR offered modest value as a predictive instrument, with a c‐statistic of 0.615.


Arthrocentesis in patients on chronic warfarin therapy with therapeutic INR appears to be safe without an increased risk of bleeding complications. This approach simplifies the periprocedural management of anticoagulation and could lead to improved outcomes and reduced health care costs.


I. Ahmed ‐ none; E. Gertner ‐ none