Objective The aim of this study was to compare the efficacy of intramuscular versus ultrasound (US)-guided intratenosynovial glucocorticoid injection in providing disease control after 2, 4 and 12 weeks in patients with rheumatoid arthritis(RA) with tenosynovitis.

Methods Fifty patients with RA and tenosynovitis were randomised into two double-blind groups: (A) ‘intramuscular group’, receiving intramuscular injection of betamethasone and US-guided intratenosynovial isotonic saline injection and (B) ‘intratenosynovial group’ receiving saline intramuscularly and US-guided intratenosynovial betamethasone injection. All patients were in stable disease-modifying anti-rheumatic drug treatment prior to and during the study. Patients were excluded, and considered non-responders, if any treatments were altered during the follow-up period. ‘US tenosynovitis remission’, defined as US tenosynovitis grey-scale score ≤1 and colour Doppler score=0, was assessed at week 4 (primary outcome), and weeks 2 and 12, using non-responder imputation for missing data.

Results US tenosynovitis remission at week 4 was achieved in 25% (6/24) in the ‘intramuscular group’ versus 64% (16/25) in the ‘intratenosynovial group’, that is, a difference of −39 percentage point (pp) (CI −65pp to −13pp), Fisher exact test p=0.001. Corresponding values for the ‘intramuscular group’ versus the ‘intratenosynovial group’ at 2 and 12 weeks were 21% (5/24) versus 48% (13/25), that is, a difference of −27pp (CI −53pp to −2pp), p=0.072 and 8% (2/24) versus 44% (11/25), that is, difference of −36pp (−58pp to −13pp), p=0.003. Most US, clinical and patient-reported scores improved more in the ‘intratenosynovial group’ at all follow-up visits.

Conclusions In this randomised double-blind clinical trial, patients with RA and tenosynovitis responded significantly better to US-guided intratenosynovial glucocorticoid injection than to intramuscular glucocorticoid injection, both at 4 and 12 weeks follow-up.

Trial registration number EudraCT nr: 2013-003486-34.