Thumb arthritis is a common problem. The CMC (carpometacarpal) joint at the base of the thumb is the usual culprit.
Symptoms typically present as aching pain at the base of the thumb (sometimes felt 'in the wrist') radiating toward the thumb tip and index finger. The pain is often worse after physical useage - especially activities such as turning the lid on stiff jars or bottles.
Typical age of onset can be young eg 40 years but it is more common around 50 - 70 years old. Symptoms often 'wax and wane' and may, happily, diminish with passage of time - but not in every case.
At present there's no cure for osteoarthritis but there are things that can help.
Treatment options
Taking care to avoid overstressing the joint (get someone else to open that stiff jar!) is helpful and simple non-steroidal anti inflammatory medications such as ibuprofen can be taken for short periods of time.
There is quite a lot of discussion on the internet about dietary factors and it may be the case that anti-inflammatory foods are beneficial but there isn't any validated evidence to confirm this and the degree of difference diet makes, if any, is quite probably very small.
Special thumb base splints help to support the joint. These can be bought over the counter or they can be custom-made by a specialised Hand Therapist. The splints can be worn as often or as little as needed.
Thumb taping and exercises can also help and, ideally, these can be directed by a specialised Hand Therapist. Videos of the appropriate exercises can be found on the CW Hand Therapy App (exercise numbers 40-44) - available on the app store (see logo below).
The next step up the treatment ladder may be steroid injections - which typically provide pain-relief for several months. There are small risks attached including post injection flare of pain for 1-3 days, pigmentation of the skin and, extremely rarely, infection or tendon weakening. Other injectables including hyaluronic acid, PRP etc are available.
If the above measures fail to control the symptoms then the final resort may be surgery.
There are a few different operations available.
The simplest and 'smallest' surgical option is a 'denervation' which is minimalist regarding surgical trauma but less predictable regarding degree of improvement produced. It involves simply dividing small nerves that transmit pain from the arthritic thumb joint. A pre-operative local anaesthetic injection test may help predict if this is worth considering. The effects after denervation may not last so long as with other procedures.
Occasionally, in early stages of osteoarthritis, a 'metacarpal osteotomy' (cutting and realigning the thumb basal long bone) can be performed.
Traditional surgery involves removing the bone under the base of the thumb (trapezium). This may be combined with using some soft tissue eg a tendon sling to support the metacarpal bone or inserting a silastic trapezium replacement. Leaving a gap under the metacarpal bone does mean forces act to potentially cause the rest of the thumb to descend into it over time - hence the additional techniques designed to minimise the risk of that.
Increasingly popular in the UK for certain cases is a CMC joint replacement that resembles a tiny 'hip replacement' which doesn't necessitate removal of the trapezium. In my experience this results in a thumb that more closely resembles a 'normal' thumb compared to a trapeziectomy. It also allows better pinch strength without the risk of metacarpal descent. This procedure is only suitable in certain cases and has its own risks including risk of dislocation, infection, loosening etc - but is well worth considering if appropriate.
If you think you may have thumb base arthritis and would like more information please get in touch.
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