FRACTURE OF HAMULUS OF HAMATE
Fractures of the hamulus (hook) of the hamate are uncommon and are often missed on the initial examination. The usual cause of a hamate fracture is a fall on the outstretched hand, but this injury is also commonly seen in golfers and baseball players. For example, as a golfer hits the ground forcibly with a club, the impact may fracture the hamate.
Although the injury causes acute pain and swelling, routine anteroposterior and lateral radiographs often fail to demonstrate the fracture. The initial physical findings include a dull ache over the hypothenar eminence, tenderness over the hamate, decreased grip strength, and, occasionally, signs and symptoms of ulnar nerve impingement. The Allen test may be positive, suggesting compression of the ulnar artery. If these signs and symptoms are present but routine radiographs show no evidence of fracture, a carpal tunnel view is indicated. Often, the extreme wrist extension needed to appropriately obtain a carpal tunnel view is impossible secondary to pain and swelling from the injury. Computed tomography of the carpus has become the standard of care for evaluating a suspected hook of the hamate fracture.
The rate of union after these fractures is not clearly documented, but many, if not most, probably fail to heal. Vascularity to the hamulus arises from vessels penetrating the radial base and ulnar tip, with a poor anastomosis between the two. This resultant vascular watershed predisposes even nondisplaced fractures to nonunion. As primary treatment, most authorities advocate surgical excision of the fracture fragment of the hamate. Most patients regain good function and strength after excision of the hook.