Basal Joint Arthritis (Arthritis of the Thumb)

Basal joint arthritis (also known as Basilar Joint arthritis) affects the base of the thumb, known as the basal joint or carpometacarpal (CMC) joint.  It is, in fact, the range of motion permitted by this joint that most distinctly separates the hand movement of humans within the animal kingdom – as it’s function and wide range of motion is unlike any other.

Bones which comprise the basal joint of the thumb.

The basal joint, or the CMC joint, is an interesting joint consisting of the small bone of thewrist known as the trapezium and the first (metacarpal) bone of the thumb.  This joint allows the thumb to reach a unique range of motion – permitting not only up and down movement but also the ability to span across the palm and achieve a “pinching” position.

This type of arthritis of the thumb results when the cartilage, which cushions the meeting point of the bones comprising the joint, deteriorates.  In the absence of sufficient cartilage, the bones are allowed to rub together during movement – causing pain at the base of the thumb and in severe cases deformity as the thumb collapses into the palm.

Pain may hinder many daily activities when the basal joint is irritated during such activities as turning knobs, opening lids, and writing.

It is one of the most common forms of arthritis of the hand, and it is thought that those suffering from a previous fracture or dislocation which affected the joint may be at higher risk for developing basal joint arthritis. Those suffering from osteoarthritis may also suffer from this type of arthritis.

Diagnosing Basal Joint Arthritis

The first steps in diagnosing this type of arthritis may include a physical examination, a discussion of patient history, and review of the pain and limitations experienced. A grind test and an X-ray may also be used to help confirm the diagnosis.

Treating Basal Joint Arthritis

There are a number of nonsurgical treatments for less severe cases of basilar joint arthritis, including:

  • Hand Therapy, which includes: therapeutic hand splints to support the thumb and wrist during rest; posture modification exercises to reduce joint irritation during certain activities; and massage, heat and ice therapy.
  • Non steroidal anti inflammatory medications (NSAIDS) – ibuprofen, aspirin, naprosyn.
  • Injection therapy – such as steroid, viscosupplementation, etc.

More severe cases of basal joint arthritis may require joint reconstruction or other surgical intervention to restore joint stability.

Learn more about this type of arthritis and other conditions affecting the hand, wrist and elbow.