Isolated fracture of the lesser tuberosity of the humerus: a case report.

Fracture of the lesser tuberosity of the humerus often occurs concomitant with posterior shoulder dislocation or proximal humeral fracture, while isolated fractures are extremely rare. We report a case in which an isolated fracture of the lesser tuberosity of the humerus occurred due to a distinctive pathogenic mechanism. A 43-year-old male had his right shoulder forced into internal-rotation (i.e. back reach position) when he fell into a ditch approximately 70 cm wide and 1.5 m deep. Subcutaneous bleeding and tenderness were detected anteriorly in the shoulder, with restricted range of motion. Radiographs indicated a fracture of the lesser tuberosity of the humerus. Three-dimensional computed tomography (CT) confirmed an isolated fracture of the lesser tuberosity, which was displaced anteromedially by more than 5 mm from its previous anatomical position. During operation, the fractured fragment of the lesser tuberosity was reduced easily and fixed by a cancellous bone screw. At postoperative 2 years, the patient has recovered full range of motion with sufficient muscle strength, and has returned to work. The pathogenic mechanisms in this case were unique, differing from those that have been previously reported.