Imaging Hamate FracturesThis is a featured page

Introduction
Hamate fractures are uncommon, comprising only 2 % of carpal bone fractures. (http://emedicine.medscape.com/article/97813-overview) Fractures of the hook of the hamate are more common than fractures of the body of the hamate. Hamate hook fractures are likely to be best demonstrated on the carpal tunnel view.

Anatomy

hamate fractureThe hamate is the most ulnar carpal bone in the distal row. "The body of the hamate articulates distally with the bases of the 4th and 5th metacarpals, radially with the capitate and proximally with the triquetrum and lunate. The hook of the hamate (hamulus) is the distal border of Guyon's canal, which contains the ulnar artery and nerve. With injury of the hamate one should always assure vascular patency and that sensation is intact in the 5th digit and the ulnar border of the 4th. " (Kevin E. Burroughs)



Mechanism of Injury
Fractures of the hook of the hamate are associated with sports injuries (golf, tennis etc) but may also result from a direct blow.
hamate fracture mechanism of injury
source: unknown
"Type I fractures involving the hook of the hamate are the most common and can occur via several different mechanisms.First, repeated microtrauma to the hook during sports involving swinging clubs, bats, or racquets can result in a hook stress fracture. These usually occur in the nondominant hand and account for approximately one third of hamate fractures.Second, direct trauma can be applied during sports when the butt of the club rests on the hamate and the force of the swing is then transmitted directly to the bone.In addition, indirect trauma can be applied to the hook through its muscular and ligamentous attachments.This can occur either when falling on a hyperextended wrist or during power grips.

Type II fractures involving the body of the hamate are less common than type I fractures and always require direct force.4 Most commonly, these fractures occur with a punch-press injury or dorsopalmar compression of the wrist between heavy weights"

Amy Powell, MD, Hamate Fracture, E medicine




Radiography

Hamate fractures are not always demonstrated well on routine wrist views. A carpal tunnel view should be considered for hook of hamate fractures and a reverse oblique position can demonstrate hamate body fractures well
HAMATE FRACTURE PA
The PA wrist view demonstrates no obvious fracture
HAMATE FRACTURE PA
HAMATE FRACTURE obl
The oblique wrist view is unremarkable
HAMATE FRACTURE obl
HAMATE FRACTURE scaphoid view
The scaphoid view of the wrist is unremarkable
HAMATE FRACTURE scaphoid view
HAMATE FRACTURE lat
The lateral view of the wrist demonstrates a fracture of the
body of the hamate
HAMATE FRACTURE lat


Case 1
This patient presented to the Emergency Department following an injury to his hand/wrist. The mechanism of injury is unknown.
HAMATE FRACTUREHAMATE FRACTUREHAMATE FRACTURE
The PA wrist projection image demonstrates no clearly demonstrated fracture (although the hamate appears suspect)The ulnar aspect of the hamate is irregular on the oblique wrist view image suggesting a hamate fracture.The scaphoid view demonstrates no displaced fracture



HAMATE FRACTURE

A coned oblique view centred on the area of interest suggests a hamate fracture



Case 2
This 34 year old man presented to the Emergency Department following an injury to his hand/wrist. The mechanism of injury is unknown.
hamate fracturehamate fracturehamate fracture
The PA wrist projection image demonstrated some irregularity of the ulnar aspect of the hamateThe ulnar aspect of the hamate is also irregular on the oblique wrist view image suggesting a hamate fracture.The lateral wrist view somewhat pronated. There appears to be a fracture of the hamate in this view. Care should be taken to ensure that this appearance is not from an os styloideum. Subsequent CT imaging suggested that the appearance is a hamate fracture.
hamate fracture CThamate fracture CThamate fracture CT
Axial CT demonstrated a comminuted fracture of the body of the hamateCoronal CT of the wrist demonstrated a comminuted fracture of the body of the hamateSaggital wrist CT demonstrated the hamate body fracture.



Case 3
PA handThis 40 year old male presented to the Emergency Department following a fall. He was examined and found to have a painful wrist and swelling over the dorsum of his right hand. He was referred for right hand and wrist radiography.


There is a fracture of the ulnar aspect of the hamate.

Old injury to the 5th digit noted.
pa wristThis is an enlarged image demonstrating the hamate fracture. The fracture is intra-articular.
oblique handThe oblique hand projection did not demonstrate the fracture of the hamate.
hamate fractureThis is an oblique wrist position with tube angulation (similar to a scaphoid projection). The hamate fracture is demonstrated.
lateral wristlateral wristOff-lateral wrist projections were performed. This was unlikely to demonstrate the fracture given that is was known to be sited at the ulnar aspect of the hamate.





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M.J.Fuller
M.J.Fuller
Latest page update: made by M.J.Fuller , Mar 7 2011, 3:27 PM EST (about this update About This Update M.J.Fuller Edited by M.J.Fuller

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