Radiosynovectomy in the treatment of arthritis

Full text: Radiosynovectomy is a useful therapeutic option that involves radiopharmaceutical injections into joints, especially to treat rheumatoid arthritis. The indications included different kinds of arthritis, such as rheumatoid arthritis, psoriatic arthritis, Bechterew's disease, hemophiliac arthritis, osteoarthritis, but also patients with joint prosthesis and synovial effusion. There are three commercial available radiopharmaceuticals for the treatment: yttrium-90 for the knee (185 to 250 MBq), rhenium-186 for larger joints (shoulder and hip with 111 MBq; elbow, wrist, ankle joint with can also rederbium-169 for smaller joints (acromioclavicular joint with 37 MBq, thumb base and MTP I with 30 MBq, MCP and MTP II-V with 22 MBq, PIP with 18.5 MBq, and DIP with 15 MBq, respectively). Decisive for the treatment is a positive sign for arthritis in the two-phase bone scan with 99mTc-HMDP (high uptake in the blood pool phase). Only for radiosynovecotmy in the knee an ultrasound with an evidence of effusion is sufficient. Side effects by the treatment are rare, such as temporary radiation or crystal synovitis, tissue necrosis (extra articular fraction or intra-articular), joint infection (1 of 35,000 joints) or effects due to the immobilisation (thrombosis, pulmonary embolism (immobilization of the knee), lymphoedema or loss of motion. In the treatment of the knee a prophylaxis with heparin is necessary to protect the patients for a pulmonary embolism. The clinical outcome is depending from the primary disease and the stage of arthrosis. Kresnik at al reported in 2190 treated joints an overall response rate of 73 ± 17%. A higher response rate was observed in patients with early stage of arthrosis (73 ± 12%) to patients with advance stage (52 ± 24%). The best results had patients with hemophiliac arthritis (91 ± 4%). In our hospital were treated up to 10.000 joints with a mean response rate of 70-80%. There was a higher response rate in larger joints with 81 ± 5% (knee, ankle joint, shoulder and wrist) in comparison to the smaller joints with 74 ± 4% (MCP, PIP, DIP, thumb base, MTP). Unfortunately, 67% of the treated joints are small joints, especially in patients with rheumatoid arthritis. The duration of response ranged from 3 months to > 6 years. In patients with rheumatoid arthritis the duration of response is depends from the activity and the stage of the disease and these patients need an effective disease modifying treatment. Also patients with advance stage (Larsen 4) showed partial good results, especially patients with haemophiliac arthritis. In large centres the radiation protection for the medical staff is important. We observed a high beta dose of 22.1 μSv/MBq for the forefinger using only a syringe protection in treatments of knees (90Y), this resulted in a annual radiation dose > 1000mSv for 250 treated knees (normal for large centres). The high finger exposure in treatment of the knee (Y-90) could be reduced by around 95% using a simple manipulator (holding-forceps) for the fixation of the needle during the administration of the 90Y. The radiosynovectomy is safe if it performed by trained staff. We observed only one patient with joint infection in the time of introducing the procedure and no case with radio necrosis. Summary: Radiosynovectomy is an effective and fast procedure in the treatment of arthritis with a low rate of side effects. (author)