Arthritis at the base of Thumb
Osteoarthritis (OA) is a common condition of wear and tear involving joints. Some people are more prone to this than others. The most common joint in the hand, which gets OA is the joint at the base of the thumb. It most frequently affects women in their middle age. Small joints of finger also get OA but usually do not cause significant disability.
Pain is the common symptom which is felt at the base of the thumb especially during day to day activities. Difficulty in performing tasks such as opening a jar and turning a door knob are common. Movements of thumb are reduced and there is reduced strength. In advanced cases there can be fixed deformity.
Initial treatment includes limiting painful activities and the use of pain killers and anti-inflammatory medicines. Certain modifications at home such as lubrication of locks, simple grip pads to help with jar lids and thicker pens may all reduce pain. Your doctor may advice the use of a thumb splint to rest the thumb. This often helps the pain but limits function and therefore can only be used for short periods. Use of anti-inflammatory gel may help some patients. Physiotherapy is also helpful in controlling symptoms and improving movements and strength.
A cortisone injection in combination of local anaesthetic given in to the joint can help the symptoms but the effect may not last longer than a few months. Too many injections should be avoided as this can cause thinning of skin.
Operation is the next step if other measures fail. The type of operation depends on the severity of arthritis. Your surgeon will examine your hand and arrange an x-ray examination to help in deciding the type of surgery.
This involves joining the bones at the base of the thumb. Since the painful joint no longer exists, pain relief is excellent. Unfortunately this means there is some loss of movement in the thumb requiring some adjustment on the part of the patient. In addition, if the arthritis other joints of thumb then the operation fails to relieve pain. There is a rate of non-union (failure of the bones to join) with this operation which may mean a repeat operation in some instances.
Excision of Trapezium
In this operation the small bone at the base of the thumb is removed. This bone is called Trapezium and is the bone most severely affected by arthritis. The pain relief is good but strength though improved is less than normal strength. The thumb continues to improve for many months after the operation.
Artificial joint replacement can also be done and the pain relief and strength is good bur there are some doubts about its long term success.
Your surgeon will discuss various options with you before deciding the appropriate operation for you. Risks and benefits of the operation will also be discussed.
Risks include infection, nerve irritation and increased sensitivity of skin. These can be managed successfully. Some pain and weakness may persist after surgery.
Additional surgical procedures may be required and sometimes a final decision about best treatment may have to be made during operation.
The operation is usually performed on a day case basis under General anaesthesia or a nerve block. Your wrist will be in a plaster cast after fusion for up to six weeks but for excision of Trapezium only bandage will be required.. Your will them be allowed to exercise and stretch the thumb sometimes under physiotherapy supervision. Total recovery may take many months and the thumb may continue to improve for up to a year. Ninety percent of the patients are satisfied with the result of the operations.
Consultant Hand Surgeon
FRCS (Trauma & Orth)