A metacarpal boss not affecting the carpometacarpal joints: a case report

Excerpt

A 54-year-old man presented to our institution with right dorsal carpal pain. He worked as an administrative assistant and had not contracted serious diseases. The pain developed 6 months prior to admission, at which time, he also noted the presence of a lump. Although he played golf regularly, he had no history of trauma involving the hand. Moreover, he did not exhibit a restriction in the range of motion at the wrist or fingers, but he experienced pain in these areas, particularly when he gripped golf clubs. A solid protuberance mimicking a carpal boss was palpable at the dorsal carpometacarpal region. Radiography and a computed tomography indicated the presence of a 12 × 10 × 7 mm connecting bony prominence between and on the dorsal base of the second and third metacarpal bones (Figs. 1a,b and 2a,b); however, this did not affect the carpometacarpal joints. The results of blood tests did not indicate any abnormal findings, and no remarkable findings were noted on radiography of the upper and lower extremities. After 2 months of conservative treatment that did not result in any improvement, surgical treatment was initiated. The boss was located at the region just distal to the enthesis of the extensor carpi radialis brevis tendon, and a simple resection was performed (Fig. 3a,b,c). The dorsal second metacarpal ulnar base distal-third metacarpal radial base distal intermetacarpal (d 2 MC dist-3 MC dist IM) ligament could not be clearly identified. The second and third carpometacarpal joints were found to be intact. A histopathological examination indicated that the boss consisted of cortex and cancellous bone, which suggested reactive bone formation (Fig. 4). After 3 weeks of wearing a fixed splint, the patient was asked to wear a wrist support for another 2 months. At 2 years after surgery, radiography and CT indicated that no bony protuberance was present, and although slight swelling was apparent, complete pain relief was achieved (Fig. 5a,b).

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