Carpal boss is one of the most common benign bony tumors of the hand and wrist. A carpal boss is a bony spur that develops due to osteoarthritis at the base of the second or third metacarpal joints.
Carpal boss can be confused with a dorsal ganglion cyst. Proper medical examination and evaluation will help make the proper diagnosis. X-rays aid in the diagnosis of the carpal boss. Special carpal boss views are available and should be requested from the radiology department.
Carpal boss can be sometimes associated with ganglion cysts.
Carpal boss can be asymptomatic. In that case there may no need for an operation. Many times though many patients will elect to have the carpal boss resected for cosmetic reasons. A carpal boss becomes more prominent when one makes a fist.
Otherwise carpal bosses can be associated with pain and inflammation.
Carpal boss treatment is surgical. The boss is approached from a transverse incision over the bony prominence. Once the skin and subcutaneous tissue are incised then the extensor tendons are retracted. The capsule of the boss is then incised. Small rongeurs and osteotomes are used the chisel away the osteo-arthritic osteophytes. It is important to remove all opposing osteo-arthritic surfaces. Normal joint surfaces in opposition should be covered with healthy cartilage. Then the joint space between the carpal and metacarpal bones should be inspected. The same process should be done to all joint surfaces affected. Typically those are the 2nd and 3rd metacarpals. If there is also an associated ganglion cyst present then that should also be removed as well. The cyst wall and contents should be removed. Also the ganglion cyst stalk that may arise from the joint should be removed too.
Following that I like to inspect the rest of joints and then irrigate the wounds before closure. The periosteum and soft tissues should be closed in layers. A cast is applied. Sutures are removed after 10-14 days.