Base of Thumb Osteoarthritis (OA)
Other popular names
- Thumb Carpo-metacarpal joint OA, (CMCJ OA)
- Thumb Trapezio-metacarpal joint OA (TMCJ OA)
- Saddle joint OA
Who does it affect?
Osteoarthritis (OA) of the base of the thumb is a very common condition.
Approximately 40% of post-menopausal females have radiographic changes at the base of the thumb, 10% seek medical treatment and 1% are severely afflicted.
Base of thumb OA is more common in females over 50 years. It occasionally occurs in men but usually as a result of a previous fracture.
Why does it happen?
Abnormal loads across the joint cause the articular cartilage (slippy ends of bones) to wear away, leaving bone on bone ends rubbing together. In women we often do not know the cause, but in men, following a fracture into the joint, there may be sharp bone surfaces that wear the joint away.
Localised pain at the base of the thumb is the most common symptom. This can be provoked by various activities including the unscrewing of jars. Pinching with the thumb can also cause pain.
Bony swelling is apparent in advanced cases and local palpation at the base of the thumb is tender. Specific tests include the Axial Grind Test, whereby the thumb is pushed along its long axis towards the base of the thumb. The Reduction Relocation test involves pressing the base of the thumb joint with one hand whilst circumducting the end of the thumb with the other hand.
X-rays of the thumb will reveal the typical features of loss of joint space and osteophyte (extra bone) formation.
- Rest, pain killers (analgesia) and avoidance of provoking activities.
- Resting night splint
- Intra-articular steroid injection.
One of two injections may be given as a pre-cursor to surgery. These are often simple and can be done in the outpatient clinic, with some more complex conditions requiring the use of x-ray for guidance.
Surgery is performed under general anaesthetic or regional anaesthesia (only the arm is made numb). The surgery takes between 30 and 40 minutes. A tourniquet is used; which is like a blood pressure cuff around the upper arm that prevents blood from obscuring the surgeons view. The trapezium (arthritic) bone is removed, leaving a space.
The skin is sutured (stitched) and an immobilising Plaster of Paris slab applied.
You will be fit to go home soon after the operation, normally on the same day. Simple analgesia (pain relief) usually controls the pain postoperatively and will be advised on discharge. The hand should be elevated as much as possible for the first 5 days to prevent swelling in the hand and fingers. Gently bend and straighten the fingers from day 1. The back slab Plaster of Paris is removed on day 2-4, when the wound is cleaned, redressed and a therapy made splint (cast) is applied. The sutures are usually dissolvable and buried under the skin. The splint (cast) is kept for approximately 4 weeks. Therapy exercises will commence to regain mobility and strength. People usually notice that the arthritic pain has gone within 8 weeks and the results continue to improve between 6 and 12 months as the thumb strengthens.
Return to normal routine
Keep your splint (cast) dry.
Return to driving: The hand needs to have full control of the steering wheel and left hand the gear stick. You are advised to avoid driving until you are pain free and can control a car in an emergency.
Return to work: Everyone is involved in different working environments. Return to heavy manual labour should be prevented for approximately 8 weeks. Other occupations may be much sooner. Your consultant will advise on this.
Overall, over 85% are happy with the result. However complications can occur.
There are complications specific to Trapeziectomy and also general complications associated with hand surgery.
General risks (all less than 1%):
- Neuroma (nerve pain)
Reflex Sympathetic Dystrophy - RSD (<1% people suffer a reaction to surgery with painful stiff hands, which can occur with any hand surgery from a minor procedure to a complex reconstruction).
• Failure to completely resolve the symptoms this may be due to arthritis in adjacent joints or a simple problem such as tendonitis. Your should discuss this with your consultant who can advise on a satisfactory course of action to take..