The 1st Carpometacarpal joint (1st CMC Jt) is one of the most common areas of symptomatic arthritis especially in post-menopausal women. Present at @50-70 yrs. Often a positive family history of mum/sister/grandmother having had a similar problem.
Complain of pain @ base of thumb, but also in the thenar eminence and up the thumb. Poor grip causes difficulty in opening jars etc.
The thumb base can be swollen and prominent. The thumb often becomes adducted into the palm secondary to the subluxation at the 1st CMC Jt. With the thumb stuck down in the palm, over time, the metacarpo-phalangeal joint (MCP) becomes hyper-extended due to compensation. This is the classic “Z” deformity that can occur in chronic conditions.
Palpation is painful at the 1st CMC jt and circumduction and compression (the “Grind” test) is painful.
Other causes of radial sided wrist/thumb pain include
Plain Radiographs will confirm the diagnosis. The views which are needed are a Roberts view (true AP – forearm in maximal pronation & dorsum of thumb resting on the x-ray cassette) and a lateral.
The therapeutic ladder is the best way to treat this condition, as in any arthritic joint condition:-
1. Extension metacarpal osteotomy – only rarely used
2. Arthroscopic 1st CMC Jt debridement – very rarely used
3. Trapeziectomy – the main stay treatment for most surgical patients
4. 1st CMC Jt fusion – best in manual working men
5. 1st CMC Jt replacement – only in relatively young patients with a well preserved STT Jt. Long term results are not known
When to Refer
A large number of patients can be successfully treated in primary care with the non-surgical techniques above.
If symptoms continue after a period of months of conservative measures then referral is suitable.
Patients need to know that surgical techniques are successful in the majority of patients, but post operative rehabilitation is lengthy and can take up to 4-6 months to reach full benefit.
Please refer to section on steroid injections.
What’s the Evidence ?
It’s my opinion that a maximum of 2 injections in a treatment cycle (i.e 1 year) is allowed. Too many lead to skin and fat atrophy which makes surgery more risky.
How to Inject