Post-traumatic intraosseous sheath development of the extensor carpi radials brevis tendon: a case report

Complications from closed treatment in children are rare but can include growth disturbances and deformities. This case report presents a unique, post-traumatic growth deformity in the distal radius, where the extensor carpi radialis brevis tendon developed an interosseous course.

A 49-year-old Caucasian male presented with chronic, dull pain in the radiodorsal aspect of the right wrist, worsened by weightbearing and terminal flexion and extension. The patient had a history of a distal radius fracture from a motor vehicle accident in adolescence, which was treated nonsurgically. Current X-rays showed a lucent process along the distal lateral radius without aggressive features. Magnetic resonance imaging revealed the extensor carpi radialis brevis tendon in an interosseous position within the distal dorsal lateral radius, with a longitudinal tear of the tendon. A noncontrast computed tomography scan confirmed a complete bone bridge along the tendon's interosseous component, limiting potential surgical access. The patient, found to have a positive Antinuclear Antibody (ANA), was treated with prednisone and later with methotrexate and folic acid, which alleviated symptoms.

This case highlights a rare post-traumatic deformity following a distal radius fracture, where the extensor carpi radialis brevis tendon formed an intraosseous sheath. It underscores the importance of considering unique anatomical changes when planning surgical interventions. This is the first reported case of an interosseous tendon sheath development around a tendon postdistal radius fracture, expanding the spectrum of known complications.