Elbow Dislocations

Introduction

Elbow dislocations are reported to be the second most common dislocation behind shoulder dislocations. (Conwell, H.E. 1961 in John Harris et al, The Radiology of Emergency Medicine, 3rd Ed, Williams and Wilkins, 1993, 344). This page examines the radiography of elbow dislocations and associated fractures.

Types of Elbow Dislocations

The most common elbow dislocation is a posterior dislocation of the radius and ulna with respect to the distal humerus. Associated fractures may be hidden on the initial plain film imaging and may show only on the post-reduction plain film imaging.

Case 1

This 14 year old girl fell onto an outstretched left hand and reported that she thought her left elbow had "popped out". The left elbow was painful and deformed. She was referred for elbow radiography.

		The radius and ulna are dislocated. The medial condyle has been avulsed (black arrow). The donor site is marked with a white arrow.
		The avulsed medial condyle is sited midline and slightly posterior to the elbow joint

Case 2

This 18 year old male presented to the Emergency Department with an unknown history. His right elbow was painful and deformed. He was referred for elbow radiography.

		The AP elbow view is over-rotated into an oblique position. The elbow is partially flexed producing a partial en face view of the radial head. There is a bony fragment overlying the radial head which is unexplained.
		The lateral view image demonstrates a posterior dislocation of the radius and ulna. The bony fragment seen on the AP view image is probably seen again superimposed over the articular surface of the ulna. It would have been good radiographic practice to perform supplementary view to establish the donor site of the unexplained fragment.

Case 3

This 70 year old lady presented to the Emergency Department after falling onto her right side. She was examined and found to have a painful and deformed right elbow and was referred for radiography of her right elbow.

	The patient was in considerable pain and distress with a fixed flexed elbow. The radiographer chose to perform an axial view as a first view in the series. The axial view image demonstrates complete dislocation of the elbow joint.
	The lateral view similarly shows complete disruption of the elbow joint with 90 degree rotation of the radius and ulna with respect to the humerus.
	On close examination of the lateral image, there is a possible unexplained bony fragment (arrowed). It would be good radiographic to undertake supplementary view to establish the donor site for this fragment of bone.

Case 4

This 34 year old man presented to the Emergency Department after falling from a roof. He was examined and found to have a painful and deformed left elbow and was referred for radiography of his left elbow.

	The lateral elbow view is underexposed and malpositioned. There was no obvious abnormality
The axial view shows the olecranon to be dislocated.	Comparison View Compare with the normal axial elbow above.
	The AP elbow view demonstrates that the olecranon and radial head are dislocated. There is also evidence of a radial head fracture

Case 5

This 57 year old lady presented to the Emergency Department after falling onto her left side. She was examined and found to have a painful and deformed left elbow and was referred for radiography of her left elbow.

	The AP view was taken with the elbow slightly flexed. There are a number of bony defects seen. The radius does not line up with the capitellum. The large bony fragment seen medial to the ulna is probably sourced from the coronoid process.
	The lateral view shows a posterior dislocation of the elbow joint.

Comment

This patient had her elbow dislocation reduced in theatre. On follow-up appointments, the elbow joint was found to be unstable. The patient was referred for CT imaging of her left elbow which revealed multiple fractures including fractures of the coronoid and olecranon. This case demonstrates the common finding that posterior dislocations of the elbow are often accompanied by fractures. There is a danger of satisfaction syndrome when the initial imaging is performed- the radiographer should be aware of the potential for concomittant fractures and ensure that every effort is made to account for the source of the bony fragments demonstrated.

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