Hand Conditions

Basilar Thumb Joint Arthritis


The joint at the base of the thumb, called the trapeziometacarpal joint, is a common point of arthritis and can become very painful when the cartilage surfaces get worn down.

Thumb arthritis, or basilar arthritis, involves degenerative changes of the CMC (carpal metacarpal) joint and affects the trapezium bone at the base of the thumb. Either the dominant or non-dominant hand may be affected.

The trapezium bone is surrounded with cartilage that becomes eroded with time, causing sclerosis and bone spurs. Degenerative changes of the CMC (carpal metacarpal) joint. Radiographs demonstrate joint space narrowing (collapse), osteophytes (bone spur) and possible hyperextension of the MCP (metacarpophalangeal joint). Radiographs of the hand rarely indicate the severity of symptoms.

The causes of thumb arthritis include trauma, genetics, lifelong use of the hand, and inflammation.


  • Pain, swelling and crepitus at the base of the thumb.
  • Pain increases with pinching and grasping type activities.


  • Thought to be due to attenuation of the anterior oblique ligament (Beak ligament) that leads to instability, subluxation and degradation of the CMC joint.
  • Associated with carpal tunnel syndrome up to 50%.



  • Rest, activity modifications, removable splint, ice and NSAIDs (ibuprofen)
  • Thumb spica splinting
  • Corticosteroid injection performed in the office


After steroid injection

  • You will have numbness and pain in the thumb for up to 2 weeks after injection
  • Typically, 5-7 days after injection, the pain in the thumb will begin to resolve.
  • Injections usually last 3-6 months before pain returns.