Glucocorticosteroids are used successfully for both systemic and intra-articular treatment of arthritis. Inhibitors of tumour necrosis factor alpha (TNF-alpha) are effective when administered systemically and this study was performed to compare the effect of intra-articular injection of these two substances.
A randomized, parallel-group, double-blind study with an independent observer. Thirty-eight patients with flare of arthritis in a single joint (wrist, elbow, or knee) were given intra-articular 25 mg etanercept or 40 mg methylprednisolone guided by ultrasound. The primary end-point was the 4-week change in pain in the target joint. The study complied with Good Clinical Practice (GCP) and the Consolidated Standards for Reporting of Trials (CONSORT) statement.
At 4 weeks no difference in pain outcome between treatment groups was demonstrated by analysis of covariance (ANCOVA). Pain on the Visual Analogue Scale (VAS) for etanercept was baseline mean 40.9 (SD 19.6) mm, follow-up 32.7 (29.1) mm (p = 0.29), methylprednisolone baseline mean 47.1 (29.6) mm, follow-up 25.3 (24.7) mm (p<0.001). The investigator's evaluation was for etanercept baseline 30.6 (21.2) mm, follow-up 17.1 (15.5) mm (p = 0.054) and for methylprednisolone baseline 35.4 (26.4) mm, follow-up 11.9 (14.6) mm (p = 0.012). Joint swelling was for etanercept baseline 1.78 (0.73), follow-up 1.25 (0.77) (p = 0.015) and for methylprednisolone baseline 1.74 (0.73), follow-up 0.71 (0.77) (p<0.001). One serious adverse event was seen in a patient treated with methylprednisolone injection.
Although no difference between groups was demonstrated, the within-group effect of methylprednisolone was more marked than that of etanercept. Injections with 25 mg etanercept were well tolerated. However, the cost of etanercept will presumably limit its use to patients with adverse reactions to steroid.