Imaging Shoulder Dislocations

Introduction

Dislocations of the glenohumeral joint are commonly seen in Emergency Departments. This page considers all aspects of radiography of glenohumeral joint dislocations

Anatomy

These videos provide information on the bony and soft tissue anatomy of the shoulder

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Golf Ball on a Tee Analogy

source: unknown	<a class="external" href="http://www.manywallpapers.com/pop_preview.html/-/p/golf-ball/id/71502" rel="nofollow" target="_blank">http://www.manywallpapers.com/pop_preview.html/-/p/golf-ball/id/71502</a>
The glenohumeral joint is the most mobile and least stable joint	The glenohumeral joint has been likened to a “golf ball on a tee”

source: unknown

The Glenoid Labrum -Static stabilizer -contributes 20% to glenohumeral stability -deepens glenoid(50%) -3 purposes: - increases surface contact area - buttress - attachment site for GH ligaments

Clinical Presentation

source: unknown	The anterior dislocation often presents with a highly characteristic appearance. The shoulder will be 'squared off' (black arrow) and a skin depression will be evident (white arrow). -loss of deltoid muscle contour compared to contra-lateral side -humeral head is sometimes palpable anteriorly beneath the coracoid
source: unknown	Following a relocation procedure, the normal shoulder contour is re-established. Note the red skin discolouration- this is caused by the considerable force exerted by the person who relocated the dislocated glenohumeral joint in this male with well developed musculature
<a class="external" href="http://whs.wsd.wednet.edu/Faculty/Blair/sportsmed/shdlrdisl.JPG" rel="nofollow" target="_blank">http://whs.wsd.wednet.edu/Faculty/Blair/sportsmed/shdlrdisl.JPG</a>	Dislocated right shoulder with typical 'squaring off'.

It is worth radiographers learning the distinction between these two appearances. You can receive referrals for shoulder radiography where the referring doctor has confused these two clinical appearances. It is noteworthy that a high grade AC joint dislocation may mimic an anterior dislocation of the GH joint..

Radiographic Appearances of Shoulder Dislocations

Normal Shoulder

Anterior Shoulder Dislocation

	This patient has an anterior shoulder dislocation. The arrowed horizontal line is a lipohaemarthrosis within the shoulder joint.
	The humeral head is located anterior to the glenoid.

Posterior Shoulder Dislocation

Case 1
Case 1
	This possibly a more typical shoulder posterior dislocation AP appearance. The posterior dislocation looks completely different to the other dislocations. One of the important considerations is the increased distance between the glenoid and the articular surface of the humeral head. The humeral head is also said to have a "light bulb"appearance. This appearance can be seen in an enlocated shoulder and therefore is a less reliable sign.
source: unknown	The increased distance between the glenoid and the articular surface of the humeral head on the AP view image is easily explained when you consider what is happening in a posterior dislocation.

Inferior Shoulder Dislocation 1

	This patient has an inferior dislocation of the glenohumeral joint (Luxatio erecta).
	The SI view image shows the humeral head to be dislocated slightly anteriorly.

Inferior Shoulder Dislocation 2 Luxatio erecta

	This patient has an inferior dislocation of the glenohumeral joint which is referred to as Luxatio erecta. Inferior shoulder dislocation (1-2%) Luxatio erecta ─ uncommon form of shoulder dislocation Extremity held over head in fixed position with elbow flexed Mechanism · Severe hyperabduction of arm resulting in impingement of humeral head against acromion · Humeral articular surface faces inferiorly <a class="external" href="http://www.learningradiology.com/archives06/COW+200-Luxatio+erecta/luxatioerectacorrect.htm" rel="nofollow" target="_blank">quoted from: www.learning radiology.com</a>
	This patient has an inferior dislocation of the glenohumeral joint.
Source: <a class="external" href="http://www.josr-online.com/content/4/1/40" rel="nofollow" target="_blank">S Saseendar, Dinesh K Agarwal, Dilip K Patro and Jagdish Menon Unusual inferior dislocation of shoulder: reduction by two-step maneuver: a case report Journal of Orthopaedic Surgery and Research 2009, 4:40</a>	"Inferior dislocation of the shoulder (luxatio erecta) is rare accounting for an estimated 0.5% of shoulder dislocations. First described by Middeldorpf and Scharm in 1859, it occurs when the shoulder is forced into hyperabduction with the proximal humerus being levered over the acromion process. It may also result from direct axial loading on the fully abducted arm. The humerus is locked in a position somewhere between 110 and 160 degree of adduction. Severe soft tissue injury or fractures about the proximal humerus occur with this dislocation. It is estimated that 60% of these patients have some neurological deficit (brachial plexus injury) of the upper limb prior to reduction. Axillary artery injury is another possible serious complications. Associated bony injuries include fractures of the greater tuberosity, acromion, clavicle, coracoid process, and glenoid rim. Long-term complications include adhesive capsulitis and recurrent subluxations or dislocations. Radiological investigation will show the shaft of the humerus lying parallel to the spine of the scapula and the articular surface of the humeral head directed inferiorly without contact with the glenoid." quoted from <a class="external" href="http://www.mskcases.com/index.php?module=article&view=120" rel="nofollow" target="_blank">http://www.mskcases.com</a>

Fracture Dislocations of the Shoulder

	In a shoulder fracture/dislocation, the associated humeral fracture is almost always displaced Anterior dislocations are associated with fractures of the greater tuberosity and posterior dislocations are associated with fractures of the lesser tuberosity

Modified Technique for Trauma Patients 1

This patient presented in an erect sitting position with very limited movement. The radiographer used the modified lateral scapula technique by sitting him forward and placing a 45 degree sponge and X-ray cassette behind him and directing the X-ray beam as shown (above right). The image successfully demonstrates an anterior shoulder dislocation.	This technique can be employed with patients who have very limited movement. The basis of the technique is to angle the X-ray beam rather than the patient. I have seen this technique used successfully in a patient who was sitting on a trolley/bed/barouche/gurney.

Modified Technique for Trauma Patients 2

This patient presented in a supine position with very limited movement. The radiographer used a modified lateral scapula technique by positioning the cassette/IR under the affected shoulder and directing the X-ray beam along the blade of the scapula	This technique is a somewhat desperate radiographic act. Consideration should be given to alternate radiographic techniques including SI/IS projections

Modified Technique for Trauma Patients 3

	This patient is sitting leaning back against the DARRIN. A vertical beam is employed. This modified SI technique is useful in patient who are sitting with very limited mobolity.
This patient presented in a supine position with very limited movement. The radiographer used a modified lateral scapula technique by positioning the cassette/IR under the affected shoulder and directing the X-ray beam along the blade of the scapula	This technique is a somewhat desperate radiographic act. Consideration should be given to alternate radiographic techniques including SI/IS projections

Can the Lateral Scapula Projection Reliably Demonstrate Shoulder Dislocation?

My department has utilised the lateral scapula projection as the view of choice for the demonstration of shoulder dislocations for the last 30 years. There are departments that strictly forbid the lateral scapula view for assessment of shoulder dislocation. They can't both be correct ... or can they?

Image 1	Image 2
The exponents of the lateral scapula view would suggest that this glenohumeral joint is normally aligned and I would tend to agree with them	The same people would argue that this patient has an anterior shoulder dislocation, despite the suboptimal positioning. Note that you can't radiographically demonstrate two structures as being separated unless they are separated. Conversely, two structures that are separated in reality can be shown radiographically to be juxtaposed.

The Counter-Argument

The counter argument is that there are several conditions where the results can be equivocal. Amongst these conditions are the pseudosubluxation and the posterior dislocation.

These images are of poor quality- they were taken on night shift using a bedside technique in ICU. The referring doctor was specifically looking for gleno-humeral joint dislocation. There is evidence of shoulder arthropathy. The humeral head appears inferiorly subluxed. There is a defect in the humeral head medially which may represent a reverse Hill-Sachs lesion.	The lateral scapula view is underexposed. Despite this image quality issue, the humeral head is demonstrated to be neither clearly dislocated nor enlocated. This case demonstrates the argument against the lateral scapula view.	The IS view demonstrates a humeral head subluxation. This is a radiographer initiated supplementary view intended to clarify the alignment of the glenohumeral joint.

Discussion

The limitations of the lateral scapula view can be overcome with radiographer training. Radiographers learn to identify cases where the lateral scapula view should be supplemented with views such as the IS/SI view.

In one study, it was found that " .... the axillary view and scapular "Y" view visualized associated pathology equally well" Silfverskiold JP. Straehley DJ. Jones WW. Orthopedics - pcm. [JC:pcm] 13(1):63-9, 1990 Jan quoted in <a class="external" href="http://www.wheelessonline.com/ortho/roentgenographic_evaluation_of_suspected_shoulder_dislocation_a" rel="nofollow" target="_blank">Wheeless on Line</a>

Bilateral Shoulder Dislocations

Bilaterall shoulder dislocations are uncommon. The mechanism of injury is likely to be associated with holding something with both hands that is suddenly pulled away (e.g. while water skiing). In this case the patient was push-starting a car and the car started and accelerated away before the patient released her grip. Bilateral shoulder dislocations can also result from a seizure.

Pseudosubluxation

This patient has fractures of the neck of humerus and greater tuberosity. The humeral head is subluxed inferiorly and this subluxation is likely to be caused by distension of the joint by joint effusion (haemarthrosis). There is a fat/fluid level consistent with lipohaemarthrosis of the shoulder joint (white arrow). This indicates the presence of intraarticular injury. A lipohaemarthrosis will only be seen when patients are imaged with a horizontal beam (i.e. erect).

Lateral Scapula vs SI Shoulder

Some imaging departments have adopted the lateral scapula view as a routine projection for shoulder trauma radiography. Other institutions strictly forbid the lateral scapula view for shoulder trauma radiography. This page examines three cases which are arguably instructive in this debate.

Case 1. Shoulder Fracture Dislocation

	This patient presented to the Emergency Department following a fall. The initial AP shoulder image demonstrated an abnormal looking humeral head and neck. The exact nature of the bony deformity was unclear.
	The lateral scapula image appearance was unusual, particularly the position of the articular surface of the humeral head (arrowed).
	The Infero-superior projection (IS) image revealed that the humeral head was dislocated and impacted on the glenoid resulting in a Hill-Sachs impaction fracture. The patient had an ORIF the following day.

Case 2. Shoulder Fracture Dislocation

	This patient also presented to the Emergency Department following a fall. The initial AP shoulder image revealed a fracture involving the humeral head and neck. One unusual feature of this image was the articular surface of the humeral head appeared to be directed inferiorly (arrow)
	The infero-superior projection (IS) image revealed that the humeral head was dislocated and impacted on the glenoid resulting in Hill-sachs impaction fracture. A closed reduction of the shoulder dislocation was attempted under anaesthetic but was unsuccessful. The patient subsequently underwent an operative reduction internal fixation (ORIF).

Case 3. Shoulder Fracture Dislocation?

This patient presented to the Emergency Department following a fall. The initial AP shoulder image revealed a fracture involving the humeral head and neck. Not unlike the case above, the articular surface of the humeral head appeared to be orientated inferiorly. The radiographers recognised the importance of establishing whether this was a fracture or a fracture/dislocation. Further view(s) were required

The infero-superior projection (IS) image revealed that the humeral head was not dislocated. A closed reduction of the shoulder dislocation was performed under anaesthetic to achieve a more satisfactory fracture position. This case demonstrated once again the importance of the IS/SI view of the shoulder in cases of comminuted fracture of the humeral head/neck.

Radiography

It is common to experience difficulty with the IS view in bedbound patients with shoulder fractures. The patients are reluctant to move and the patient's neck sometimes limits medial positioning of the cassette. It can be useful to employ a very long ffd ie instead of placing the X-ray tube beside the patient's torso, increase the ffd/SID such that it is more inferior than the patient's feet (approximately 180cm ffd). Another positioning technique is to place the cassette above the patient's head. Irrespective of the approach that you use, innovation may be required and the image may not be aesthetically pleasing. The lack of image aesthetics should not mitigate against utilising this view (function before form).

Discussion

It might appear by the choice of cases that I have taken a clear position in favour of the IS view over the lateral scapula projection. This is not the case. Both of these cases were drawn from a hospital that does not require the IS/SI view as a routine view in trauma radiography of the shoulder. The routine views adopted by this institution are AP shoulder and lateral scapula. In the first two cases, the radiographer identified the case as a potential fracture-dislocation from the AP and lateral scapula images and performed the SI view to prove the suspicion.

You could safely argue that the institutions that have adopted the IS/SI view as routine in shoulder trauma radiography have taken a safer position. It could also be argued that the institutions that require routine AP shoulder and lateral scapula views, and that have a comprehensive radiography continuing education program, will allow the radiographers to exercise judgment in these types of cases and perform supplementary views as required.

Lipohaemarthrosis

Lipohaemarthrosis refers to a condition in which an intra-articular fracture has allowed fat to be released from bone marrow into the joint. The fat floats on the blood in the joint and results in an fat/blood "fluid level". This is akin to the air/fluid level seen on erect abdominal plain film images- the difference being that there are two immiscible fluids (fat and blood) rather than a gas and a fluid (air and water). Lipohaemarthrosis is one of the few reasonably reliable soft tissue signs of fracture. Lipohaemarthrosis is usually associated with intrarticular knee fractures but can occur (in theory) in just about any synovial joint and is occasionally seen in the shoulder joint. Where a shoulder fracture is subtle, a lipohaemarthrosis is a useful soft tissue indicator of intra-articular fracture.

This patient has a neck of humerus fracture, pseudosubluxation of the GH joint, and lipohaemarthosis.

Case Studies

Case 1

	This 19 year old male presented to the Emergency Department following a sports injury. His left shoulder was painful. The contour of his left shoulder was "squared off". There is an anterior dislocation of the left shoulder. The patient is appropriately rotated LPO producing a correctly positioned AP shoulder view.
	The lateral view image confirms the anterior dislocation. The patient is leaning too far forward resulting in foreshortening of the scapula. This can be corrected with caudal tube angulation if performed PA and cephalic tube angulation if performed AP (or equivalent patient repositioning).

Case 2

	This 51 year old male presented to the Emergency Department by ambulance after a RTA/MVA. He was examined in the resus room and a variety of radiographic examinations were requested including left shoulder. The patient was experiencing considerable pain in the left hemithorax and sternum and could therefore not be moved from the supine position. The patient's shoulder was in internal rotation. An AP shoulder projection was achieved with the patient ina supine position with tube angulation towards the left shoulder (35 - 45 degrees). A <a class="external" href="http://www.carestreamhealth.com/PublicContent.aspx?langType=1033&id=448841" rel="nofollow" target="_blank">CARESTREAM DRX-1</a> System was utilized with no grid. The patient tolerated the DRX cassette directly under the shoulder.
	Using the DRX cassette the cassette could be left under the patient fro the lateral scapula projection. The beam was angled 35 - 45 degrees towards the right shoulder to good effect. The resultant image is distorted (elongated) but acceptable under the circumstances.

Relevant WikiRadiography Links

• Lateral Scapula Radiography
• Clavicle Radiography

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