Background/Purpose:

Joint and soft tissue injections are commonly performed in clinical practice. An increasing number of patients are prescribed warfarin. Joint and soft tissue injections are frequently indicated in these patients. The limited available evidence suggests that joint and soft tissue injections are safe in therapeutically anti-coagulated patients receiving warfarin. Many authorities, including the New England Journal of Medicine, continue to recommend reversal of anti-coagulation in patients receiving warfarin who require these procedures. The aim of this study was to evaluate the safety of two approaches to the management of patients prescribed warfarin requiring joint or soft tissue injection

Methods:

The protocol in our department prior to September 2011 was to hold warfarin and replace it with low molecular weight heparin for joint and soft tissue injections. A systematic literature review was performed which provided support to the performance of these procedures in patients on warfarin with an INR <3. A retrospective chart review was initiated at this point to assess the safety of the existing protocol. A new protocol was introduced whereby warfarin was continued with an INR check within 1 day of the procedure. The procedure was performed if the INR was <3. All patients receiving joint or soft tissue injections under the care of our service are provided with a helpline phone number to contact if symptoms worsen. In the event of persistent worsening symptoms >48 hours post-procedure arthrocentesis would be performed.

Results:

In patients in whom warfarin was held, 32 procedures were performed in 18 patients. Of these 30 were joint injections (24 knee, 5 glenohumeral, 1 elbow) and there were 2 soft tissue injections (1 trochanteric bursa, 1 subacromial bursa). Conditions requiring injection were 13 rheumatoid arthritis, 11 osteoarthritis, 5 spondyloarthritis, and 1 each of adhesive capsulitis, rotator cuff tendinopathy and trochanteric bursitis. There were no clinical hemarthroses or complications. In patients who continued warfarin, 32 procedures were performed in 21 patients. Of these 27 were joint injections (24 knee, 1 glenohumeral, 1 elbow, 1 metatarsophalangeal) and there were 5 soft tissue injections (4 subacromial bursa, 1 carpal tunnel). Conditions requiring injection were 11 rheumatoid arthritis, 7 osteoarthritis, 6 crystal arthritis, 4 rotator cuff tendinopathy, 2 spondyloarthritis and 1 each of adhesive capsulitis and carpal tunnel syndrome. There were no clinical hemarthroses or complications. Full details of the study population are shown in Table 1.

Table 1: Comparison of Procedures Performed with Warfarin Held or Continued

	Warfarin held	Warfarin continued
Procedures, n	32	32
Patients, n	18	21
Joint injections, n (%)	30 (94%)	27 (84%)
Soft tissue injections, n (%)	2 (6%)	5 (16%)
Male, n (%)	14 (44)	14 (44)
Age, mean	77	74
INR, median (IQR)	1.2 (1.1 – 1.5)	2.4 (2.1 – 2.6)
Aspirin, n (%)	3 (9%)	1 (3%)
Clopidogrel, n (%)	0 (0%)	0 (0%)
Complications, n	0	0
Clinical haemarthroses, n	0	0

Conclusion:

Joint and soft tissue injections appear to be safe in patients receiving warfarin anti-coagulation with an INR <3. Continuation of anti-coagulants reduces staff workload and patient inconvenience with no evidence of increased risk of complications.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/safety-of-joint-and-soft-tissue-injections-in-patients-on-warfarin-anti-coagulation/