Intra-articular (IA) injections with glucocorticoid are a valuable therapeutic intervention for patients with rheumatoid arthritis (RA) and wrist synovitis. Jones et al have demonstrated that half of the wrist blind injections were considered to be extra-articular.1 Musculoskeletal ultrasound (US) allows for the proper real-time allocation of the needle during the injections, limiting the risk of damage to the cartilage, tendons, nerves and peripheral blood vessels.2

In this study we compare the efficacy of blind and US-guided IA injections in patients with RA with wrist synovitis. The accuracy of the techniques used to inject the drug into wrist joint is also investigated.

A prospective, double-blind, randomised controlled study was conducted enrolling 60 patients with RA and wrist synovitis. Patients were blindfold and equal numbers were randomly allocated to receive intra-articular wrist injections by blind IA injection or US-guided IA injection (fig 1) with a solution of 1.0 ml of 2% lidocaine, 1.5 ml of triamcinolone hexacetonide, 0.5 ml of non-ionic contrast and 0.5 ml of air. An experienced rheumatologist performed all procedures.

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Figure 1 Sonographic-guided injections approach into the radiocarpal joint. The needle appears as a hyper-reflective line (arrow).

An independent investigator blinded for the procedures performed clinical evaluations at baseline (T0) and at 1 (T1), 4 (T4), 8(T8) and 12 (12) weeks after the procedure. Instruments used were as follows: visual analogue scale for pain at rest and for oedema, Health Assessment Questionnaire, Disabilities of the Arm, Shoulder and Hand Questionnaire and adverse effects. Radiographic films taken during the procedures were analysed at the end by a blinded radiologist.

The sample was homogeneous for all the variables analysed at baseline. No statistically significant difference between groups was observed for the presence of IA contrast agent after the procedure. After the 12-week follow up no statistically significant difference was seen between groups (table 1).

Several studies have demonstrated low accuracy of blind injections to reach the IA cavity even for larger joints.1 3 4 Some authors have reported better precision for US-guided joint and soft tissue aspiration.5 6

Two previous studies have compared blind injection with the US-guided procedure. Kane et al compared the use of these techniques for the management of plantar fasciitis. After a 12-week follow-up, no statistically significant difference was seen between groups.7 In another study, 41 patients with a painful shoulder were randomised to undergo these techniques. After 6 weeks of follow-up, there was a significant improvement for patients undergoing US-guided injection as compared with those who had the blind procedures.8

The wrist is a joint with multiple ligaments and narrow articular spaces that can make IA injections difficult.9 10 During the US-guided IA injections the needle placement can be visualised by continuous sonographic monitoring, which can reduce the risk of damaging ligaments.

Our study demonstrated that US did not increase the accuracy of wrist injections when they were performed by an experienced rheumatologist. Further studies will be needed to evaluate the benefit of US-guided interventions for IA injection in deep joints and periarticular anatomical sites as well as for doctors not so well trained in the blind procedure.