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.
