RESUMEN
BACKGROUND: Intra-articular botulinum toxin A injection might have analgesic effects in patients with joint diseases. We aimed to compare the effects of intra-articular botulinum toxin A injection with those of intra-articular saline injection for patients with painful base-of-thumb osteoarthritis. METHODS: RHIBOT was a double-blind, randomised, controlled, phase 3 trial conducted at Cochin Hospital, Paris, France. We recruited adult patients with x-ray evidence of trapeziometacarpal osteoarthritis who fulfilled the 1990 American College of Rheumatology criteria for hand osteoarthritis and reported a pain intensity score of at least 30 on an 11-point numeric rating scale (0: no pain to 100: maximal pain). Participants were randomly assigned (1:1), using a computer-generated randomisation list with permuted blocks of variable size (4 or 6), to receive an ultrasound-guided injection of either botulinum toxin A (50 Allergan units) in 1 mL of saline (experimental group) or 1 mL of saline alone (control group) in the trapeziometacarpal joint, in addition to custom-made rigid splinting. The primary outcome was the mean change from baseline in base-of-thumb pain in the previous 48 h on a numeric rating scale at 3 months after injection, analysed by intention to treat. This study is registered with ClinicalTrials.gov, NCT03187626. FINDINGS: Between Nov 2, 2018, and Nov 3, 2020, we assessed 370 individuals for eligibility and recruited 60 (16%) participants (mean age 64·9 years [SD 9·4], 47 [78%] women and 13 [22%] men), of whom 30 (50%) participants were randomly assigned to the experimental group and 30 (50%) to the control group. At baseline, base-of-thumb pain score was 60·0 of 100·0 (SD 15·9). At 3 months, the mean reduction in base-of-thumb pain was -25·7 (95% CI -35·5 to -15·8) in the experimental group and -9·7 (-17·1 to -2·2) in the control group (absolute difference -16·0 [-28·1 to -3·9]; p=0·043). Overall, 51 adverse events were reported in both groups: 27 (53%) in the experimental group and 24 (47%) in the control group. During follow-up, 14 (47%) participants in the experimental group and two (7%) participants in the control group reported mild transient motor deficit of the thenar muscle. No serious adverse events were reported. INTERPRETATION: Botulinum toxin A could be considered as a fast-acting, intra-articular therapy targeting chronic pain in individuals with base-of-thumb osteoarthritis. Future studies are needed to investigate the potential mechanism of the effects observed in this trial, to replicate our findings, and to assess the effects of repeated injections over time and their clinical effectiveness, including an analysis of cost-effectiveness. FUNDING: Assistance Publique-Hôpitaux de Paris.
RESUMEN
INTRODUCTION: Recent studies have suggested that intra-articular injection of botulinum toxin A (BTA) may have analgesic effects in degenerative joint diseases. We aim to assess the efficacy of intra-articular injection of BTA associated with splinting in patients with trapeziometacarpal osteoarthritis (TMC OA). METHODS AND ANALYSIS: We will conduct a randomised double-blind controlled trial. Overall, 60 individuals with TMC OA fulfilling adapted 1990 American College of Rheumatology criteria for hand OA will be recruited in one tertiary care centre in France and randomised to receive splinting + a single ultrasound-guided injection in the TMC joint of 50 Allergan Units of BTA resuspended in 1 mL saline or splinting +1 mL saline. Randomisation will be centralised. The allocation ratio will be 1:1. The primary outcome will be the mean change from baseline in base-of-thumb pain on a self-administered 11-point Numeric Rating Scale in 10-point increments at 3 months after injection. Secondary outcomes will be the mean change in base-of-thumb pain at 1 and 6 months, mean change in hand-specific activity limitations assessed by the self-administered Cochin Hand Function Scale, proportion of responders assessed by the Osteoarthritis Research Society International -Outcome Measures in Rheumatology (OMERACT) criteria and consumption of analgesics and non-steroidal anti-inflammatory drugs assessed by a self-administered 4-class scale at 3 and 6 months. Cointerventions will be allowed in both groups and will be self-reported. Adverse events will be recorded at 3 and 6 months. Participants, care providers and statisticians will be blinded to the allocated treatment. ETHICS AND DISSEMINATION: The RHIBOT trial has been authorised by the Agence Nationale de Sécurité du Médicament and approved by the Comité de Protection des Personnes de Tours Ouest-1. The findings of the study will be disseminated in peer-reviewed journals and at conferences. If the results are positive, intra-articular BTA could be an efficient and safe complementary therapeutic option for patients with TMC OA. DATE AND VERSION IDENTIFIER OF THE PROTOCOL: 8 January 2018, V. 2.0. TRIAL REGISTRATION NUMBER: NCT03187626; Pre-results.