Background Intra-articular glucocorticoid (eg. betamethasone (BM)) injections are commonly used during flares in rheumatoid arthritis (RA)¹. Currently, evidence on the best approach to treat tenosynovitis (TS) is lacking.

Objectives To compare the effect of intramuscular (im) and ultrasound (US) guided peritendinous BM injection for TS in RA patients, after 4 and 12 weeks.

Methods Fifty RA patients with TS were randomised into two double-blinded groups: Group A (“i.m. BM group”) received im injection of 14 milligrams (2 ml) of BM and US-guided saline injection in up to two tendon sheaths (maximum 1 ml saline for each tendon sheath) and group B (“US guided peritendinous group”) received 2 ml of saline im and US guided BM injection in up to two tendon sheaths (maximum 7 milligrams (1 ml) of BM for each tendon sheath). All patients were in stable anti-inflammatory treatment prior to and during the study. Patients were excluded, and considered non-responders, if treatment changes were made during the follow-up period. TS was assessed at baseline, 4 and 12 weeks using the semi-quantitative scoring system for Grey scale (GS) (0–3) and Colour Doppler (CD) (0–3) proposed by the OMERACT US group and a patient reported visual analogue scale (0–100 mm) for pain TS (VAS TS). If two tendon sheaths were treated, the mean score was used for statistical calculation. For US assessment a GE Logiq E9 US unit with a high frequency linear 6–15 ML probe and CD settings according to published recommendations were used. The predefined primary outcome was a US-TS GS score ≤1 and CD score =0, at week 4, with a non-responder imputation (NRI) used for missing data. The same outcome was used at week 12, with a NRI used for missing data.

Results Forty-nine patients received treatment, 24 in group A and 25 in group B. The completion rate for group A/B was 23/25 at 4 weeks and 15/18 at 12 weeks. There was no significant baseline difference between the groups, except that two tendon sheaths were injected more often in group A (10) compared to B (3). The chance of achieving the primary outcome at week 4 was 0.25 (95% Confidence limits; 0.08; 0.42) in group A and 0.64 (0.45; 0.83) in group B and for 12 weeks 0.08 (0.00; 0.19) in group A and 0.40 (0.21; 0.59) in group B (Chi-Square; 4 weeks =0.008; 12 weeks =0.020). Likewise VAS TS showed significant better response in group B versus group A (Mann-Whitney U test; 4 weeks =0.027; 12 weeks =0.003). Baseline values and 4 and 12 weeks changes for GS, CD and VAS TS are presented in table 1.

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Conclusions In a randomized double-blind clinical trial, RA patients with tenosynovitis responded significantly better to US guided peritendineus glucocorticoid injection compared to i.m. glucocorticoid injection, both at 4 and 12 weeks, both when assessed by US and patient-reported outcomes.

1. Hetland ML, Ostergaard M, Ejbjerg B, et al. Short- and long-term efficacy of intra-articular injections with betamethasone as part of a treat-to-target strategy in early rheumatoid arthritis: impact of joint area, repeated injections, MRI findings, anti-CCP, IgM-RF and CRP. Annals of the Rheumatic Diseases 2012;71

Disclosure of Interest None declared