Hamate Fracture

Hook of the hamate fractures account for 2% of all carpal bone fractures, it’s more often seen in golf, baseball, and hockey player.
Related Anatomy
The hamate bone is a cuneiform bone and contributes to the medial wall of the carpal tunnel. The flexor retinaculum is attached to the hook of the hamate.
The hamate articulates with three carpal bones and two metacarpals:
- The medial surface articulates with the triquetrum and by association with the pisohamate ligament, the pisiform.
- The lateral surface articulates with the capitate.
- On its distal aspect the hamate articulates with the fourth and fifth metacarpal heads.
The hook of the hamate is palpated just distal and radial (in the direction of the thumb web space) to the pisiform on the anterior (palmar) aspect. Locating the hamate can be made easier if the clinician places the middle of the distal phalanx of the thumb on the pisiform, with the thumb pointing between the web space between the index and long finger.
The clinician flexes the IP joint of the thumb and presses into the hypothenar eminence to feel the firm hook. The hook of the hamate is concave laterally, and the ulnar nerve’s superficial division, which is just lateral and proximal to the hook, can be rolled on it.
See Also: Wrist Anatomy

Mechanism of Injury
Hook of the hamate fractures occur following falls on an outstretched arm or, more commonly, as a result of trauma to the palm when playing racquet sports or baseball or golf.
The body of the hamate is fractured through an axial load applied to the fourth or fifth metacarpal and frequently occurs concurrently with a metacarpal fracture. The body may also be fractured secondary to a direct blow.
Symptoms & Signs
Acutely, the patient will describe sharp pain dorsally and/ or volarly in the ulnar palmar and wrist region. Swelling in the hypothenar eminence may be present. The patient may experience tenderness during firm palpation of the hamate.
The multiple attachments to the hook of the hamate result in pain when the fifth finger is actively abducted or adducted or when flexion and abduction are resisted. Pain occurs during passive extension of the fifth finger.
An unstable hamate can compress the ulnar nerve as it passes through Guyon’s canal, leading to paresthesia of the fourth and fifth fingers. Decreased innervation of the fifth slip of the FDP can lead to its rupture.
The hook of the hamate pull test has been described as highly associated with hook of the hamate fractures. The patient’s wrist is ulnarly deviated with resistance applied to finger flexion. This position creates a pull of the finger flexor tendons against the hook of the hamate and reproduces the sharp pain associated with the original injury.
Bipartite hamate, which may be differentiated from a fracture by its smooth cortical surfaces.


Radiology
Radiographs are obtained using the carpal tunnel view and with the wrist supinated but may miss many hamate fractures. CT scans are more specific for fractures of the hamate.


Hook Of Hamate Fracture Treatment
Individuals with suspected hamate fractures should be immobilized with the wrist in slight flexion and the fourth and fifth MCP joints fully flexed.
Hook of the hamate fractures are often treated with surgical excision, which is associated with an excellent outcome.
References
- David TS, Zemel NP, Mathews PV. Symptomatic, partial union of the hook of the hamate fracture in athletes. Am J Sports Med. 2003 Jan-Feb;31(1):106-11. doi: 10.1177/03635465030310010201. PMID: 12531766.
- Wright, TW, Moser, MW, and Sahajpal, DT: Hook of the hamate pull test. J Hand Surg, 35:1887, 2010.
- Abraham, MK, and Scott, S: The emergent evaluation and treatment of hand and wrist injuries. Emerg Med Clin N Am, 28:789, 2010
- Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
- Millers Review of Orthopaedics -7th Edition Book.
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