CMC arthritis, also known as carpometacarpal arthritis or thumb arthritis, is a degenerative condition that affects the joint at the base of the thumb (carpometacarpal or CMC joint).

Common Symptoms

• Pain, aching, and stiffness at the base of the thumb, especially with gripping, pinching or applying force
• Swelling and tenderness at the base of the thumb. Sometimes a grinding or popping sensation.
• Decreased strength and range of motion when pinching or grasping objects
• Difficulty opening jars
• Bony enlargement or bump at the base of the thumb

Cause & Anatomy

CMC arthritis commonly occurs with aging as the cartilage at the ends of the bones wears away, causing friction and joint damage. Prior injuries or fractures to the thumb joint can also increase the risk.

The CMC joint connects the base of the thumb (metacarpal bone) to the wrist (trapezium bone of the carpal bones). This joint allows the thumb to move in various directions for gripping and pinching.

Diagnosis

Diagnosis is typically made through a physical exam, checking for pain, swelling, and limited range of motion. X-rays can confirm cartilage deterioration and bone spurs.

Prevention

Minimizing trauma or fractures to the thumb joint and using protective gear when moving heavy objects can help reduce the risk. Repetitive activities with strong pinching can aggravate the pain and worsen the use of the thumb.

Treatment

• Activity modification and splinting to rest the joint
• Ice, anti-inflammatory medications, arthritis creams
• Steroid injections
• Occupational/physical therapy to strengthening the surrounding muscles
• Surgery for severe cases not responding to non-surgical treatment

Surgery

Surgical options include joint fusion (fusing the bones to reduce friction), joint replacement (removing part of the joint), or suspending the thumb using a tendon graft (most common).

Rehabilitation

Involves wearing a cast/splint for 6 weeks, followed by physical/occupational therapy to regain strength and motion. Full recovery can take several months.

FAQ’s

• CMC arthritis is more common in women and those over 40 years old.
• Repetitive stress from occupations/activities can increase the risk.
• Early treatment focuses on reducing pain/inflammation and preserving joint function.
• Surgery aims to relieve pain and improve grip strength/mobility when non-surgical options fail