Intra-articular injection of 169Erbium-citrate (169Er-citrate; radiosynoviorthesis or radiosynovectomy) is an effective local treatment of rheumatic joint diseases. However, its efficacy in corticosteroid-resistant rheumatoid arthritis-affected joints has not been clearly demonstrated.
A double-blind, randomised, placebo-controlled, international multicentre study was conducted in patients with rheumatoid arthritis with recent (< or = 24 months) ineffective corticosteroid injection(s) into their finger joint(s). Eighty-five finger joints of 44 patients were randomised to receive a single injection of placebo (NaCl 0.9%) or 169Er-citrate. Results of evaluation 6 months later were available for 82 joints (46 metacarpophalangeal and 36 proximal interphalangeal joints) of 42 patients: 39 169Er-citrate-injected joints and 43 placebo-injected joints. Efficacy was assessed using a rating scale for joint pain, swelling and mobility.
Intent-to-treat analysis of the results of the 82 joints showed a significant effect of 169Er-citrate compared to placebo for the principal criteria decreased pain or swelling (95 vs 79%; p = 0.038) and decreased pain and swelling (79 vs 47%; p = 0.0024) and for the secondary criteria decreased pain (92 vs 72%; p = 0.017), decreased swelling (82 vs 53%; p = 0.0065) and increased mobility (64 vs 42%; p = 0.036). Per-protocol analysis, excluding 18 joints of patients who markedly changed their usual systemic treatment for arthritis, gave similar percentages of improvement but statistical significance was lower owing the reduced power of the statistical tests.
These results confirm the clinical efficacy of 169Er-citrate synoviorthesis of rheumatoid arthritis-diseased finger joints after recent failure of intra-articular corticotherapy.