The information - thumb-base osteoarthritis
GP and primary care lead for Arthritis Research UK, Dr Tom Margham, continues our series with a look at osteoarthritis of the thumb
The patient's unmet needs (PUNs)
A 68-year-old woman attends with pain at the base of her thumb. She was seen by a colleague a few months ago when the symptoms began. No specific diagnosis was made and she was given NSAIDs with a PPI, which has helped a little. She's concerned that she's developing arthritis, which apparently her mother suffered from. She is keen for you to confirm the diagnosis and wants to know what other management options are available.
The doctor's educational needs (DENs)
Wrist or thumb pain is common in general practice. What pointers in the history suggest arthritis rather than a more transient problem such as tendonitis?
Thumb-base osteoarthritis (OA) describes OA in the main articulations of the thumb carpal and metacarpal joints. The most commonly affected articulation is the trapezio-metacarpal joint, where patients complain of thumb and hand symptoms. Less commonly a patient may report pain radiating up the wrist, in which case the trapezio-scaphoid joint may be affected.
Hand OA typically presents with a degenerative history. Pain is often intermittent with insidious onset, felt on initiating movement and possibly associated with crepitus. There may be mild morning and inactivity stiffness and pain may worsen towards the end of the day.
Patients sometimes describe instability in the thumb and difficulty performing activities such as precision pinch or a strong grip – for example, lifting the kettle and removing lids from jars.
Family history of OA is a risk factor. In this case, it is important to elicit whether her mother had OA or rheumatoid arthritis and what concerns she has, given her mother's experience.
Tenosynovitis usually affects younger people with a history of recent increased activity. Also rule out recent trauma, particularly a fall onto the outstretched hand, as a scaphoid fracture can present with pain at the base of the thumb.
What physical signs confirm the diagnosis? Is there any value in arranging an X-ray?
Inspection of the hand may demonstrate other joints affected by OA, and Heberden's and Bouchard's nodes.1 In more advanced cases, swelling may be present with the characteristic ‘squared-off' appearance of the base of the thumb.
Check for pain on palpation of the carpometacarpal joint and do the axial grind test – gently push the thumb along its long axis towards the base – which reproduces the pain in OA. If the base of the thumb is fixed and the distal end moved in a circular motion, crepitus may be felt and patients may report that the joint feels unstable.
Patients' symptoms correlate poorly with X-ray appearance – and normal X-rays do not rule out OA. Plain radiographs can be used if the diagnosis is in doubt or for morphological assessment. Classical features are joint space narrowing, osteophyte, subchondral bone sclerosis and subchondral cysts.
A confident clinical diagnosis of OA can be made without further tests in patients over 40 presenting with thumb-base pain and a corroborative history and examination.
What is the prognosis in thumb-base OA? Patients often try over-the-counter remedies such as chondroitin and glucosamine – is there any evidence of benefit?
Thumb-base OA generally has a worse prognosis than hand OA, which mostly becomes asymptomatic after a few years. Thumb-base OA can cause continuing pain, weakness and instability, and disability can be as severe as in rheumatoid arthritis.
The debate around chondroitin and glucosamine for OA continues – overall, there has been less research into their efficacy in thumb-base OA than in hip and knee OA. The most recent guidelines do not recommend either.2,3
Advise patients on pain management strategies such as topical NSAIDs and capsaicin, which are both effective and safe treatments for thumb-base OA and are preferred over systemic treatments – especially for mild to moderate pain.2,3,4
Are splints helpful? If so, which are most suitable? What other conservative measures can relieve symptoms?
Splints are recommended for thumb-base OA.
In primary care, most patients will present with trapezio-metacarpal OA – in these patients, a short, hand-based, soft thumb spica can be tried. These can be purchased from many pharmacies or online.
For patients with trapezio-scaphoid OA, who have more wrist pain, a combination thumb and wrist splint is better. I would suggest referring to a hand therapist to advise on appropriate splinting in these cases. Go online to pulsetoday.co.uk/tools-and-resources to download a patient booklet on splints from Arthritis Research UK.
Advise patients to aim for thumb stability, not mobility. Osteoarthritic thumbs collapse on active and resistive movement, so encourage patients to carry out daily activities with thumbs in mid-range as far as possible. Avoid hand exercise that aims for full range of thumb movement, as this will make an unstable thumb even worse.
Other practical advice includes using two hands to carry, lifting close to the body and avoiding repetitive grasping, pinching and twisting motions.
Patients can use devices such as enlarged grips for writing, small non-slip cloths for opening objects, and electric can openers to help in daily life.
Early referral to a hand therapist is advised for patients not responding to first-line treatments.
Are cortisone injections effective? When should surgery be considered? What procedures are used?
Steroid or local anaesthetic injections are recommended for painful flares of thumb-base OA. This may be performed by a suitably trained GP, but don't inject more than every three months.
Only refer for surgery after other conservative treatments, including input from a hand therapist, have failed.4 But do refer before there is prolonged and established functional limitation and severe pain.
The most common form of surgery for hand OA is a trapeziectomy – also known as an excision arthroplasty – which has excellent outcomes in terms of pain relief. This involves removing the trapezium and replacing it with an augmented tendon or ligament reconstruction. The thumb joint can also be replaced, which offers a stronger pinch grip but carries the risk of dislocation. Or the joint can be fused, sacrificing joint mobility for stability – this may be the best option in young patients or manual workers.
Risk factors for thumb-base OA
- Age over 40
- Family history
- Joint laxity
- Prior hand injury
- Occupational or recreational use
- Some 20% of people over 55 have symptomatic thumb-base OA
- Joint pain lasting three months or more that is worse with use and may be associated with joint instability and loss of strength
- Morning stiffness for less than 30 minutes
- Functional problems, including difficulty with pinch grip
- Association with OA of other joints
Main differential diagnoses
- De Quervain's tenosynovitis
- Carpal tunnel syndrome
- Inflammatory arthritis
- Joint sparing advice
- Aerobic and strengthening exercises
- Topical NSAIDs or capsaicin
- Early referral to a hand therapist
Dr Tom Margham is a GP in Hackney, east London, and primary care lead for Arthritis Research UK
Arthritis Research UK produces a wide range of information for patients on arthritis and musculoskeletal conditions. Hands On and Synovium, sent out three times a year in association with the British Journal of General Practice, contains up-to-date information on managing common musculoskeletal disorders seen in primary care. If you would like to receive the publication, access information for your patients or find out about GP training bursaries and awards, go to arthritisresearchuk.org.
1 Zhang W, Doherty M, Leeb B et al. EULAR evidence-based recommendations for the diagnosis of hand osteoarthritis: report of a task force of ESCISIT. Ann Rheum Dis 2009;68:8-17
2 Zhang W, Doherty M, Leeb B et al. EULAR evidence-based recommendations for the management of hand osteoarthritis: report of a task force of ESCISIT. Ann Rheum Dis 2007;66:377-88
3 Hochberg M, Altman R, April K et al. American College of Rheumatology 2012. Recommendations for the use of non-pharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee. Arthritis Care Res April 2012; 64(4); 465–74
4 NICE. Osteoarthritis: the care and management of osteoarthritis in adults. 2008;CG59
- Arthritis Research. Joint protection: looking after your joints. arthritisresearchuk.org/arthritis-information/arthritis-and-daily-life/looking-after-your-joints.aspx (accessed 3 August 2012)
- Arthritis Research UK. Self-help and daily living: splints for arthritis of the wrist and hand booklet. arthritisresearchuk.org/~/media/Files/Arthritis-information/Living-with-arthritis/2275-Splints-for-the-wrist-and-hand.ashx (accessed 3 August 2012)