Hamate hook fracture

Fractures of the hamate hook are classified by the AO/OTA as 74A.

The Hirano classification may also be used.

The hook functions as a pulley for the flexor tendons of the ring and small fingers.

2% of all carpal fractures are hamate hook fractures.

They are usually caused by a direct blow on the hypothenar eminence (golfers, tennis players) or a sudden pull of flexor tendons.

Hamate hook fractures may occasionally be associated with a palmar fracture of the trapezium in high-energy injuries, as these two bones are linked through a ligament.

Nonunion is often a sequel of conservative treatment or caused by delayed presentation. If painful, excision may be indicated.

Conventional x-rays do not always show the fracture.

A CT scan may be helpful to confirm the diagnosis and show the magnitude of any displacement.