Sheffield Centre for Rheumatic Diseases, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK
SIR, Radiation synovectomy is a well-established method of reducing the incidence of recurrent haemarthroses in patients with haemophilia [1]. Intra-articular bleeding is also seen in patients taking oral anticoagulants [25], occurring with a frequency of 0.15 per 100 patient-years of treatment [6]. Episodes are usually quickly reversible on withdrawal of the drug but this is not feasible in every case. We present two patients where radiosynovectomy was used successfully to abolish warfarin-related haemarthroses.
Case 1. A 77-yr-old gentleman who had recently been commenced on warfarin for atrial fibrillation and valvular heart disease was referred to the Rheumatology Department with an acute, right knee effusion. There was no history of trauma. On examination, the knee was warm and movement was painful. A knee radiograph revealed early osteoarthritic change only. Joint aspiration was performed and 20 ml of blood was obtained. This fluid was sterile and did not contain any urate or calcium pyrophosphate crystals. A diagnosis of warfarin-related haemarthrosis was made. Despite meticulous control of his international normalized ratio (INR) he had five further intra-articular bleeds over the next 12 months. Each episode led to a prolonged hospital admission for pain relief and rehabilitation. Anticoagulation was continued as it was felt that the risk of a major embolic event was very high.
In an attempt to reduce the frequency of haemarthroses radiosynovectomy was performed: 270 MBq of yttrium-90 silicate and 40 mg of depot methyl prednisolone acetate were injected into the knee and a splint was applied for 48 h. The procedure was repeated after 2 months and in the following 3 yr before his death, he had no further haemarthroses.
Case 2. This 59-yr-old man developed a seronegative inflammatory arthropathy in his twenties following a total colectomy for ulcerative colitis. Treatment consisted of oral prednisolone and later sulphasalazine. Inflammatory episodes were not marked, but by 1992 there was radiographic and clinical evidence of degenerative change in both knees. In 1993 he had a myocardial infarction and in 1995 he developed a right hemiparesis. Echocardiography revealed intra-cardiac thrombus and apical hypokinesia. He was therefore anticoagulated with warfarin. Unfortunately, he continued to have multiple transient ischaemic attacks, which were only abolished when the INR was maintained above 3.5. At these levels, he regularly developed spontaneous haemarthroses of his left knee, and spent several weeks in hospital. After six episodes, radiosynovectomy was performed using an intra-articular injection of yttrium-90. In the year following this he had no further episodes of bleeding despite the INR being greater than 6 on several occasions.
These two cases illustrate a disabling complication of warfarin therapy. As the use of oral anticoagulation increases especially in the elderly population, recurrent articular bleeding is likely to become more prevalent. Prolonged hospital admission is usually necessary because of the severity of pain and consequent immobility. In most cases the haemarthrosis occurs when the patient is over anticoagulated [4]. Reducing the prothrombin time or discontinuing warfarin may therefore prevent further bleeds. However, as in case 1, the complication can also occur when the INR is satisfactory [2].
Both of our patients had evidence of pre-existing joint damage, which appears to increase the risk of haemarthrosis. However, without further imaging or an invasive procedure such as arthroscopy, the exact cause and site of bleeding cannot be ascertained. Hyperaemic synovium or exposed subchondral bone are likely candidates. The presence of blood within the joint may then accelerate the pathological process. In vitro studies of the effect of blood on human cartilage have shown that irreversible damage can occur after only 4 days' incubation due in part to cytotoxic oxygen metabolites [7]. Joint destruction following warfarin-induced haemarthroses has been described previously [4, 5] and in haemophiliacs the progression from a normal joint to chronic synovitis and articular destruction is well recognized.
The medical co-morbidity in these warfarin-dependent patients is likely to preclude arthroscopic or open synovectomy. To our knowledge the treatment of warfarin-induced haemarthrosis with yttrium-90 radiation synovectomy has not been reported previously. In both of these cases the procedure was effective and no complications arose from the aspiration of the haemarthroses, the instillation of yttrium-90 or in the post-injection period. The safety and cost-effectiveness of radiation synovectomy has been proven in other situations [8]. More importantly, the procedure is very acceptable to patients and can lead to a dramatic improvement in the quality of their lives.
References