What Is Carpometacarpal Bossing?

Carpometacarpal bossing is the formation of a bony mass at the top of the wrist due to trauma, strain, or a congenital condition. In some patients, it may be benign, requiring no action unless it grows or begins to cause problems. Other patients need treatment to address pain, soreness, or limited joint mobility. Conservative treatment options are successful in many cases, while surgery can be an option if the patient doesn’t respond to other treatments.

Some patients are born with carpometacarpal bossing, while others develop signs of the condition in middle age. A swelling can appear on the wrist, right where the metacarpal bones articulate. This should feel firm to the touch, and may be hot because of inflammation. The condition is sometimes confused with a ganglion cyst, making it important to receive a thorough evaluation to determine the cause of swelling on the upper portion of the wrist to make absolutely sure the patient has the right diagnosis.

A history of trauma can be a potential indicator, as can repetitive stress. Chronic inflammation around the joint may lead to the formation of a bone spur that grows over time. Basic treatment for the carpometacarpal bossing can include antiinflammatory drugs to lower swelling and stop the growth. Splinting and proper support can also help, especially if repetitive strain is the culprit. Patients who continue to experience pain and stiffness with these measures can discuss more aggressive options.

In surgery, a care provider can remove the spur and smooth the surrounding bone to discourage a recurrence of the condition. Sometimes a ganglion cyst forms alongside the carpometacarpal bossing, in which case it also needs to be removed. During healing, the patient may wear braces to support the joint and promote recovery. These can be removed once the doctor indicates it is safe. Periodic checkups may be required to determine if the bone spur is growing back, which can be a cause for concern in some cases.

People with a history of carpometacarpal bossing may want to pay close attention to the affected wrist to spot signs of recurrence as early as possible. Failed surgeries can occur if the doctor fails to remove all of the growth or doesn’t shave down the surrounding bone enough. Medications may also fail to suppress a return of the spur, especially if the patient stops taking them or doesn’t take them regularly. Imaging studies can be used to track the carpometacarpal bossing over time to allow doctors to identify changes that might be a cause for concern.