efficacy of an intra-articular injection of botulinum toxin a associated with splinting for base-of-thumb osteoarthritis

Conditions: Base-of-thumb Osteoarthritis

Summary: the primary purpose of this study is to determine whether a single ultrasound-guided intra-articular injection of botulinum toxin a associated to splinting is effective in reducing pain at 3 months in base-of-thumb osteoarthritis.

base-of-thumb osteoarthritis is a common condition affecting middle-age persons. base-of-thumb osteoarthritis induces pain and hand-specific limitations in activities. for short and midterm effects, therapeutic options usually include splinting, exercise therapy and intra-articular injections of glucocorticoids or hyaluronic acid. however, evidence of efficacy of intra-articular therapies in base-of-thumb osteoarthritis and international guidelines are inconsistent. recently, the use of intra-articular botulinum toxin a as a pain killer has raised intense interest. the exact mechanisms of pain modulation by botulinum toxin a in osteoarthritis are unclear. it has been suggested that botulinum toxin a could directly reduce peripheral sensitization and indirectly reduce central sensitization. indeed, recent studies suggest an inhibitory role of botulinum toxin a on the release of mediators involved in nociception, such as p substance, calcitonin gene-related peptide and glutamate. open and randomized controlled trials of botulinum toxin a in knee osteoarthritis support short to mid-term positive clinical effects on pain. however, no study has reported results for base-of-thumb osteoarthritis

Eligibility criteria:
inclusion criteria: * age ≥ 18 years old * pain intensity on a self-administered 11-point pain numeric rating scale ≥ 30 * pain involving the base-of-thumb * x-ray evidence of base-of-thumb osteoarthritis with at least 2 of the 4 following items involving the trapeziometacarpal joint : osteophytes, joint space narrowing, subchondral bone sclerosis or subchondral cysts * 1990 american college of rheumatology classification criteria for hand osteoarthritis adapted to base-of-thumb osteoarthritis * medical examination * written consent * health insurance * for women of childbearing age, a negative urinary pregnancy test exclusion criteria: * history of thumb surgery * history of inflammatory or crystal-associated rheumatic disease * neurological disorders involving the hands other than carpien canal syndrom * collagen disorders involving the hands : dupuytren, marfan or ehlers-danlos diseases * osteoarthritis predominating at the scaphotrapezial joint on x-ray * hand or wrist trauma ≤ 2 months * hand or wrist intra-articular injections ≤ 2 months * contra-indication to botulinum toxin a injection or to splinting * cognitive or behavioral disorders making the assessment impossible * participant unable to speak, read and write french * bilateral btoa without predominant symptomatic side * pregnancy and breast feeding * persons referred to in articles l 1121-5; 6; 8; 9 of the public health code (protected minors or adults, guardianship or trusteeship, etc.) * patient with epilepsy

Keywords: base-of-thumb osteoarthritis botulinum toxin a intra-articular therapy randomized trial