This Issue's Rounds Question -
Please tell us:
How is the repair of a fractured adult bone similar to endochrondal bone formation?

(responses to be published in next issue)

In the last issue of Body Cast, Rounds asked: What is a carpal boss, or carpe bossu?

The following responses were received:

From Bernie Arseneault:

"Carpal Boss" may be caused by repetitive use of the carpometacarpal joints. A bony accessory ossification centre, referred to as the Os Styloideum, may fuse to the base of the second and third metacarpal in the majority of cases. It may also show physical signs of a prominent bony/soft tissue mass.

Symptoms related to this pathology are arthrosis, irritation and mechanical pinching to adjacent extensor tendons. It may also show differential diagnoses of a ganglion cyst. Management includes splinting, anti-inflammatory treatment or surgical incision of bony spur.

From Edd Hayes:

A carpal boss is a bony prominence at the second or third metacarpal base dorsal aspect of the wrist. In my limited experience, I have seen patients live with a carpal boss, or have surgery. A small incision is made over the carpal boss, then shaving it down until cartilage is seen. This surgery is not always successful. A lot of people have this, but not all need anything done. You'd be surprised how many patients come into the fracture room with this, but have no painful symptoms.

From Tom Yorke:

It is an unremarkable bony protuberance. It is found in people between the ages of 30 to 50 years of age, most commonly in women. It is located on the dorsum of the wrist at the base of the second and third metacarpals, adjacent to the capitate and the trapezoid bones. This bony prominence may represent degenerative osteophyte formation and the presence of an os styloideum, an accessory ossification centre that occurs during embryonic development.

The symptoms of a carpal boss are pain and limitation of motion of the affected hand. This can be caused by an overlying ganglion or bursitis, an exterior tendon slipping over the bony prominence, or from osteoarthritic changes in the wrist at the site.

To get the best x-ray of the area, a lateral view using 30° of supination and ulnar deviation of the wrist should be used. Treatments of this condition are the use of nonsteroid anti­ inflammatory medications, limited use of the wrist, or surgical excision of the bony prominence.

Responses were also received from: Livain Arseneau, Tony Bellon, Lhea Burk, Alex Carlos, James Carragher, Eric Christiansen, Edward Clancey, Adrian Crossman, Norm Ellsworth, Melvin Gillingham, Richard Grenier, Caleb Griffith, Suzanne Groulx, Lena Head, Jean Hohs, Johnny Humeniuk, Roger Ip Fung Chun, Mary Anne Lash, Brian Lavallee, Kimberley Leslie, Cam Longphee, Doug Longphee, Lynn Lough, Lori MacDonald, Blair Matheson, Gary Marshall, Joe Maulucci, Jay Meraj, Javad Movasseli, Earl Oborowsky, Ray Passmore, James Wong, Neuville Yao and Mary Young.