Characterization and Epidemiology of the Carpal Boss Utilizing Computed Tomography

Recurrence rate and patient-reported outcomes after wedge excision of carpal boss

The treatment of carpal boss is primarily conservative. Surgical treatment by performing a wedge excision of the bony protrusion, is possible. However, a common belief exists that carpal boss should not be operated because of the high recurrence rate. Additionally, little is known about the clinical outcomes of wedge excision and the preferred post-operative treatment. Patients with carpal boss and persisting pain who underwent wedge excision after conservative treatment were included. They received questionnaires before and three months after surgery. The primary outcomes were pain and hand function measured using patient-reported wrist evaluations (PRWE). Secondarily, recurrence, patient satisfaction and time until return to work were evaluated. These clinical outcomes were also compared between patients who received a plaster splint or a pressure dressing post-operatively. 76 patients were included. Three months after surgery, a significant improvement in PRWE was seen, for both pain and function. A re-operation rate for recurrent carpal boss of 13% was observed. After three months, 58% of patients were satisfied and 73% had returned to work. While no differences in clinical outcomes were found, patients were more satisfied after receiving a pressure dressing than a plaster splint post-operatively. The current study demonstrates encouraging early outcomes after wedge excision, and a low recurrence re-operation rate. Furthermore, a pressure dressing seems preferable post-operatively compared to a plaster splint.

Imaging of Anatomical Variants Around the Wrist and Hand

Wrist and hand anatomy may present several clinically relevant variants that involve bones, muscles, tendons, and nerves. Thorough knowledge of these abnormalities and their appearance in imaging studies is useful for proper management. In particular, it is necessary to differentiate the incidental findings that do not represent a trigger for a specific syndrome from those anomalies causing symptoms and functional impairment. This review reports the most common anatomical variants encountered in clinical practice and briefly discusses their embryogenesis, related clinical syndrome if present, and their appearance using different imaging techniques. The information each diagnostic study (ultrasonography, radiographs, computed tomography, and magnetic resonance imaging) may provide is described for each condition.

MRI of a painful carpal boss: variations at the extensor carpi radialis brevis insertion and imaging findings in regional traumatic and overuse injuries

OBJECTIVE

To report patterns of MRI findings involving carpal boss and extensor carpi radialis brevis (ECRB) tendon insertion in individuals with overuse-related or post-traumatic wrist pain.

MATERIALS AND METHODS

Eighty-four MRI cases with carpal bossing between December 2006 and June 2015 were analyzed by two fellowship-trained musculoskeletal radiologists. The following MRI findings were reviewed: type of carpal bossing (bony prominence, partial coalition, os styloideum), insertion of ECRB tendon (to the 3rd metacarpal, to carpal boss or to both), bone marrow edema (BME), insertion site, and tenosynovitis/tendinosis of ECRB tendon. Clinical information on wrist pain was available on 68 patients.

RESULTS

Fused carpal bossing was detected in 21%, partial coalition in 35%, and os styloideum in 44% of the cases. Regional BME was observed in 64% of the cases. When BME specifically at the carpal boss was assessed, 78% of stable and 50% of unstable bosses showed BME (p = 0.035). ECRB tendon inserted on a carpal boss in 20%, on the 3rd metacarpal bone in 35%, and on both sites in 45% of the cases. As BME at the carpal boss was assessed, BME was detected at the respective insertion sites in 71%, 35%, and 66% of the cases (p = 0.015). Dorsal wrist pain was associated with BME as 75% of the patients had regional BME in the vicinity of the carpal boss (p = 0.006).

CONCLUSION

A spectrum ranging from complete fusion of a boss to an entirely unfused os styloideum exists with a variable ECRB insertional anatomy. BME at the carpal boss is a consistent MRI finding.