What is base of the thumb arthritis?
Arthritis or osteoarthritis of the base of the thumb is a very common condition particularly in people over the age of 50 years. It is more common in females approximately 40% of post-menopausal women having radiographic (x-ray) changes at the base of the thumb. About 10% of people will seek medical treatment. Patients with this condition report pain at the base of the thumb and weak grip which might shows as difficult with opening jars etc.
Causes
There are two types of arthritis; primary and secondary. Primary is the most common cause and is due to ‘wear and tear’. Abnormal loads across the joint cause the articular cartilage (slippy ends of bones) to wear away, leaving bone on bone ends rubbing together. Secondary arthritis occurs often after a fracture into the joint causing sharp bone surfaces to rub and wear the joint away.
Symptoms
Pain at the base of the thumb is the most common symptom. Aggravating activities include the unscrewing of jar lids, and pinch grip such as when turning a key using the thumb can cause pain.
Other possible symptoms might include:
- Swelling and stiffness at the base of your thumb
- Decreased strength when pinching or grasping objects
- Decreased range of motion
- Enlarged or bony appearance of the joint at the base of your thumb, with a change in shape
Diagnosis
Your surgeon will take a detailed history and discuss your symptoms before performing a physical examination of the thumb and wrist.
Examination may include specific tests such as the Grind Test, where pressure is applied through the thumb to reproduce symptoms, and the Reduction Relocation Test, which assesses joint stability during thumb movement. The surgeon will also assess for tenderness and bony swelling at the base of the thumb, which is more common in advanced arthritis.
Imaging
Imaging with X-rays is typically performed, including specialised thumb and wrist views, to assess joint narrowing, abnormal joint surfaces, and the alignment of the wrist bones, as well as to identify any associated ligament problems.
Treatment
Conservative (Non-operative)
Conservative treatment involves activity modification, resting the hand/thumb and using painkillers. A hand therapist may be recommended for a splint and strengthening alongside a cortisone injection into the affected joint.
Surgical treatment
If non-operative techniques have been unsuccessful in providing long-lasting benefits, some patients may elect to undergo surgery.
The aim of surgery for thumb CMC joint arthritis is to prevent the joint surfaces from rubbing against each other and causing pain. Your surgeon will discuss the most appropriate option for your condition. Surgical treatments may include a trapeziectomy, where the trapezium bone is removed and the space fills with scar tissue; thumb CMC joint fusion, where the trapezium and thumb metacarpal are fused together to create a stable, pain-free joint; or thumb CMC joint replacement, where the damaged joint surfaces are replaced with an artificial implant.
Recovery
This depends on the type of surgery you have, but can take at least 12 weeks. Your surgeon will be able to advise you on this. All surgeries will require assessment and treatment by a hand therapist as part of the rehabilitation/recovery process, and typically with the first review at 2 weeks post-surgery.
It is important to elevate the hand for 48 hours after the surgery, and to open and close your fingers to make a fist. This helps reduce swelling and stiffness.
When can I return to normal activities?
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Work – this depends on your job, but for heavy manual work may be up to 3 months. Light office duties can be returned to with a few days.
Driving – the hand needs to have full control of the steering wheel in case of emergency, and typically is at least 4 weeks after the surgery.
Exercise – Once the wounds are dry and healed you can start cardiovascular exercise, usually not before 14 days. It may be several months before you can use your hand for weight training and gripping type activities.