What is Carpal Boss and How Can it Be Treated?

Do you have a small bump on the back of your hand? You may have a condition known as carpometacarpal boss, or carpal boss for short. It is an overgrowth of the bone which isn’t usually worrisome unless your wrist becomes swollen and causes you pain. If these masses of bone growth become problematic, especially if it’s affecting your dominant hand, treatments ranging from steroid injections to surgery may be recommended.

At the Fitzmaurice Hand Institute in Scottsdale, AZ, double-board certified, fellowship-trained hand surgeon Michael J. Fitzmaurice, MD provides his patients with treatments and procedures that are optimally effective at providing relief and restoring function. Dr. Fitzmaurice is one of the most experienced hand surgeons in the world, helping patients reduce downtime and improve their outcomes with minimally-invasive procedures.

What is Carpal Boss?

Carpal boss is a condition that manifests as a firm, bony lump that appears on the back of your hand or wrist, just below the index or middle finger where it connects to the carpal bones (the eight small bones that make up your wrist). It develops when the cartilage lining thins out, which in effect, encourages the production of new bone in that area. The result is a visible overgrowth of bone. These masses are often curable. Recurrence can occur but the bumps almost never become cancerous.  The worst cases will involve the carpal boss, causing pain and restricted mobility leading to complications like tendon rupture, inflammation, and degenerative joint disease.

What Causes Carpal Boss?

While the exact cause is unknown, carpal boss is usually associated with:

  • Traumatic injury
  • Repetitive wrist motion (e.g., golf and other racquet sports)
  • Frequent mechanical stress on the wrist
  • Conditions such as osteoarthritis, bursitis, tendon damage, and congenital issues

Carpal boss can occur at any age, but most frequently affects individuals between the ages of 20 and 40. Both men and women can develop carpal boss.


The main symptom of carpal boss is a hard, bony mass on the back of the hand or wrist. It can occur in either one or both hands or wrists. Other signs include:

  • Pain when moving your wrist up or down
  • Snapping of tendons that straighten the fingers over the carpal boss (may be painful)
  • The bump is sometimes tender or painful to the touch
  • The dominant hand is usually affected


If your carpal boss is not painful and does not affect your hand function, leaving it alone will not cause any harm. But if you feel pain and experience a loss of mobility on the hand or wrist, there are treatment options that will help. Dr. Fitzmaurice can meet with you in his Scottsdale office in Arizona to accurately diagnose your condition and explore the best treatment option. Carpal boss is often confused with other conditions like a ganglion cyst (tumor) or a bone spur, so it is best to have a hand specialist rule them out with an X-ray or ultrasound.

Non-surgical treatments for carpal boss include:

  • Wearing a wrist splint to immobilize your wrist and to let it rest
  • Taking over-the-counter pain relievers such as acetaminophen or ibuprofen to reduce the swelling
  • Icing the affected area to contract the blood vessels and reduce inflammation
  • Administering steroid injections to reduce pain and inflammation 

If the pain or limited mobility is already interfering with your hand function or your ability to participate in sports and hobbies, Dr. Fitzmaurice will first recommend conservative treatments. If these steps don’t help, Dr. Fitzmaurice will recommend surgery to remove the excess bone.

Surgery for carpal boss is a common procedure that can be performed by Dr. Fitzmaurice in Scottsdale, AZ. His experience and commitment to the highest level of patient care have led him to develop state-of-the-art techniques that are improving hand surgery. Dr. Fitzmaurice is the innovator behind the EndoTech® minimally-invasive system for the treatment of the upper extremities. This new,  patent-pending system provides the most advanced visualization of any endoscopic hand surgery technique. Its leading-edge technology allows Dr. Fitzmaurice to see all the internal anatomy with extreme clarity, allowing the procedures to be performed in the safest and most effective manner possible. This revolutionary new instrumentation, which will only need 1-2 tiny incisions, offers an outstanding success rate with less pain downtime. EndoTech® is also used to treat other hand and arm conditions such as carpal tunnel syndrome, trigger finger and thumb, and tennis elbow

At the Fitzmaurice Hand Institute, we’ve combined everything into one location. Our exam rooms, operating rooms, and urgent care center are all exclusively focused on hand and wrist treatment, and were designed to make treatments as convenient and comfortable as possible.

Schedule Your Consultation With a Hand Surgery Expert 

If you’d like to remove the unsightly bump on your hand, as well as the pain and inconvenience associated with it, contact the Fitzmaurice Hand Institute in Scottsdale, Arizona. A leader in minimally-invasive hand surgery, Dr. Fitzmaurice and his non-invasive approach will help you achieve optimal results that will allow you to quickly resume your normal activities. To learn more, schedule a consultation with us today. 
Next, find out why hand exercises are an important habit for preserving the function of the hand.

Fitzmaurice Hand Institute
8841 E Bell Rd #201
Scottsdale, AZ 85260