Basal Thumb Arthritis: Causes, Symptoms, and Treatment
In a normal joint, cartilage covers the ends of bones, acting as a shock absorber to allow smooth and pain-free movement. However, in osteoarthritis (OA), the cartilage layer wears away, leading to direct bone contact. This results in pain, deformity, and limited range of motion. The base of the thumb is often affected by OA, particularly the carpometacarpal (CMC) joint, which is formed by the trapezium bone in the wrist and the metacarpal bone in the thumb. The specialized saddle-shaped structure of the CMC joint allows a wide range of motion, but OA can restrict this motion and cause significant pain.
Who Gets Basal Thumb Arthritis?
Basal thumb arthritis is more commonly seen in women over the age of 40. While the exact cause is unknown, several factors may increase the risk, including:
- Genetics: A family history may increase the likelihood of developing OA.
- Previous injuries: Past fractures or dislocations can predispose individuals to arthritis in the CMC joint.
- Joint laxity: Generalized looseness of the joints can make the thumb more susceptible to arthritis.
What Are the Signs and Symptoms?
The most common symptom of basal thumb arthritis is pain at the base of the thumb, which can be aggravated by activities that require pinching, such as:
- Opening jars
- Turning door knobs or keys
- Writing or gripping objects
As the condition progresses, pain may occur at rest or at night. In severe cases, the joint may deteriorate, causing misalignment and a bump at the base of the thumb. This misalignment can limit motion, cause weakness, and make pinching difficult. The joint above the CMC may compensate by hyperextending (bending backward).
How is the Diagnosis Made?
Your doctor will diagnose basal thumb arthritis based on a physical evaluation and your medical history. Common signs include pain with pressure, twisting, or movement of the joint, often accompanied by a grinding sensation. While X-rays are used to confirm the diagnosis, the severity of symptoms does not always correlate with the X-ray findings.
What Are the Treatment Options?
In less severe cases, thumb arthritis can often be managed with non-surgical treatments, including:
- Arthritis medication: To help manage pain and inflammation.
- Splinting: Rigid or non-rigid splints can be worn while sleeping or during activities to support the joint.
- Cortisone injections: To provide temporary relief from pain and inflammation.
If non-surgical treatments fail or if the arthritis is advanced, surgical reconstruction may be necessary. Surgical options include:
- Removal of arthritic bone and joint reconstruction: To restore joint function and reduce pain.
- Joint fusion: Fusing the bones of the joint to eliminate pain, though it can limit motion.
- Bone realignment: To correct deformities and improve function.
If you’re experiencing thumb joint pain, make an appointment with South Florida Hand and Orthopaedic Center to explore your treatment options and find relief.