Patients with osteoarthritis of the thumb carpometacarpal joint, or base of the thumb, commonly present to primary care practitioners and orthopaedic surgeons because of pain and disability. The prevalence of this condition increases with age and is greatest in postmenopausal women. There is broad agreement regarding the prevalence of base of the thumb osteoarthritis. The largest longitudinal cohort study found a 15% prevalence in adults in Finland,1 and a smaller British study of postmenopausal women found a prevalence of 33%.2 This is likely to increase as populations age and people stay active for longer. Presentation and diagnosis may be delayed because patients try to adapt by adjusting their hand position, using splints, and adopting preferential hand use to limit disability. For most patients the primary treatment is non-operative and can be delivered effectively by primary care doctors, physiotherapists, and occupational therapists. Patients with symptoms that persist despite conservative treatment require referral to a specialist and possibly surgery.3

Various studies have looked at osteoarthritis at the base of the thumb, including large epidemiological and patient cohort studies; biomechanical research; and smaller …