Base of Thumb Osteoarthritis
Base of Thumb Osteoarthritis (also known as Carpometacarpal (CMC) Joint Osteoarthritis) is a common form of arthritis that affects the joint at the base of the thumb, where the thumb meets the wrist.
Base of Thumb Osteoarthritis
What is Base of Thumb Osteoarthritis?
Base of Thumb Osteoarthritis (also known as Carpometacarpal (CMC) Joint Osteoarthritis) is a common form of arthritis that affects the joint at the base of the thumb, where the thumb meets the wrist. This joint is critical for gripping, pinching, and many daily hand movements. When the protective cartilage wears away, it can cause pain, stiffness, and loss of strength, making everyday tasks like turning keys, opening jars, or writing more difficult.Anatomy & Causes
The base of the thumb joint is formed by the trapezium bone in the wrist and the first metacarpal bone of the thumb. This joint allows a wide range of movement, but is prone to wear and tear over time.Causes and risk factors include:
- Age-related degeneration of cartilage
- Repetitive use and strain on the thumb joint
- Previous injury or fracture around the thumb or wrist
- More common in women, particularly post-menopause
- Genetic predisposition to arthritis
Common Symptoms
- Pain at the base of the thumb, especially with pinching or gripping
- Swelling and tenderness around the joint
- Loss of thumb strength, making fine motor tasks difficult
- A grinding or clicking sensation with movement
- Visible deformity in more advanced cases
Diagnosis
Diagnosis is usually made through a physical examination. Your surgeon may move the thumb to reproduce pain or assess joint stability. X-rays are often used to confirm cartilage loss, bone spurs, or joint changes.Treatment Options
Non-Surgical Management
- Splints or braces to support the thumb and reduce pain during activity
- Anti-inflammatory medications or topical gels
- Hand therapy and exercises to maintain strength and flexibility
- Corticosteroid injections for longer-lasting pain relief
Surgical Treatment
If conservative management fails, surgery may be recommended. Options include:- Trapeziectomy: Removal of the trapezium bone to relieve pain
- Ligament Reconstruction and Tendon Interposition (LRTI): Stabilising the thumb using nearby tendon tissue after trapeziectomy
- Joint Fusion (Arthrodesis): Fusing the bones of the joint for stability (often for younger or high-demand patients)
- Joint Replacement (Arthroplasty): Artificial joint implants to restore movement and reduce pain
Post-Surgery Care
- The thumb is usually immobilised in a splint or cast initially
- Hand therapy is important to restore mobility and strength
- Recovery typically takes several weeks to months, depending on the procedure
- Most patients achieve excellent pain relief and improved function
Risks & Outcomes
Surgical and non-surgical treatments are highly effective at reducing pain and improving function. Risks may include:- Stiffness or reduced range of motion
- Scar tenderness
- Rare complications such as infection or implant issues (if replacement performed)
- Recurrence of symptoms in some cases