Osteoarthritis of the thumb
What is it?
Osteoarthritis refers to a process of degradation and degeneration of the cartilage lining a joint, and subsequent changes in the bone adjacent to that joint. The joint at the base of the thumb, between the thumb metacarpal and the trapezium, is the most commonly affected joint in the hand to be affected by 'wear and tear' or osteoarthritis. This joint is variably named the thumb carpometacarpal joint (CMCJ) or the Trapeziometacarpal joint (TMJ). It is unusual in that it is 'saddle-shaped', allowing the versatile range and planes of motion of the thumb ray. Unfortunately this mobility also predisposes the joint to degenerative change. This condition generally affects people over the age of 50, and affects women more often than men.
What are the symptoms?
It causes pain and a reduction in grip strength - particularly pinch grip between the thumb and fingers. Daily activities such as opening jars or turning a key in a lock become difficult, if not impossible. Initially the pain is activity based, but like arthritis in other joints, it can become constant.
How is it diagnosed?
The diagnosis can often be made by examination of the hand, and confirmed by X-rays - only rarely are more elaborate imaging techniques required.
How is it treated?
Treatment of this condition usually progresses from less invasive to more invasive techniques, depending on the level of symptoms and the response of those symptoms to treatment:
- The use of anti-inflammatory and pain killing medication, and activity modification
- The use of splints to support the thumb CMCJ and reduce pain. These can be provided 'off the shelf' or can be custom-made by a hand therapist
- Injection of steroid into the thumb CMCJ. This technique usually yields a temporary improvement in symptoms, for up to 6 months. Mr. Gidwani will generally use this on up to two occasions.
- Removal of the trapezium, in an operation known as a trapeziectomy
Trapeziectomy usually yields good results, although full recovery can take 3 to 6 months. Post-operative use of a resting splint is continued for 4 to 6 weeks, and then rehabilitation is commenced under the guidance of a hand therapist. Mr. Gidwani will be able to explain the risks and benefits of surgery during your consultation.
There are other operations described for treatment of this condition, including the use of tendon slings and joint replacement. There is little evidence to support the use of these more complex operations and they are known to have a higher risk of complications. Their use in selected cases may be appropriate and will again be discussed with you by Mr. Gidwani.