The effect of radiation synovectomy with phosphorus-32 on the pain and swelling in 31 RA patients with resistant monoarthritis of the knee

Introduction Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by symmetric polyarthritis. RA is routinely treated by various systemic drugs; on the other hand, administration of intra-articular corticosteroids or different types of synovectomies can be used in case of systemic medication’s failure. Chemical, radio isotopic, and surgical synovectomies are being used as therapeutic options for chronic synovitis to improve joint function. Chemical synovectomy is not well tolerated, and the long-term response is relatively low. Surgical synovectomy has a better success rate, but it recommends higher expenses. In radiation synovectomy, radioactive labeled particles are applied directly in the articular cavity, followed by homogeneous distribution in joint. Next, the radioactive particles are transported in the depth of synovia and phagocytized by inflammatory cells. Finally, the radiation leads to fibrosis and sclerosis of formerly inflamed synovial membrane; thus, it stops the inflammation and reduces the symptoms. It has a success rate of 40–100% and its effect can be similar to surgical synovectomy. Materials and methods Thirty-one patients with resistant monoarthritis of the knee were enrolled in this study. One millicurie of phosphorus-32 was injected into patients’ knee via US guide. Saline was injected afterwards to prevent leakage. Direct pressure was performed after removing the needle and the knee was flexed slowly to ensure homogenous distribution and fixed with a splint for 1 to 2 weeks. Patients were followed up after 2 weeks, 1 month, 2 months, and 6 months. The following variables were assessed by the treating rheumatologist: patients’ pain, joint tenderness, effusion, and ROM. At the time of injection and after the first week, patients were investigated for any complication including infection, necrosis, pain, and swelling. The effect of clinical characteristics and demographic data on existing complications and the changes of pain, joint tenderness, effusion, and ROM was assessed. Results Thirty-one patients with the mean age of 54.5 ± 12.2 years and the mean disease duration of 12 ± 6.5 years were enrolled in this study. Mean DAS-28 ESR score for our patients was 4 ± 0.7. The pain, effusion, and reduced ROM were decreased significantly after all follow-up intervals. Knee tenderness was not affected in the first 2 weeks, but it was reduced significantly after 1, 2, and 6 months. No serious complications like infection a