Ultrasound for Shoulder Dislocation

Point-of-care ultrasonography for the management of shoulder dislocation in ED

American Journal of Emergency Medicine May 2016 - Pubmed Link

Background

Joint dislocations are common, and the shoulder is half of all joint dislocations. In the emergency department, we traditionally confirm the diagnosis on xray, reduce the shoulder (interscalene block anyone?), and then confirm reduction on post reduction xray films. The usual downsides of xray compared to ultrasound apply here - more time, more radiation, and having only a static image. Ultrasound potentially offers a way to diagnose shoulder dislocation, but how well does it perform in doing so?

Questions

How does POCUS compare with xray in diagnosing shoulder xray?

How does POCUS compare with xray in diagnosing fractures and verifying reduction?

Population

Prospective, observational, convenience sample

2 hospitals, one academic

Inclusion:

• greater than 15 years old with suspected dislocation on exam

• Only enrolled during shifts that attendings trained were working

Exclusion:

• younger than 15 (unclear what would happen if they arrived on their 15th birthday)

• multiple trauma

• unstable vital signs

• refused to consent

• fracture diagnosis prior to POCUS

• open dislocation

• those in whom reduction was not accomplished

Who did the scans?

8 emergency physicians

Given special training for the study

• 30 min lecture

• 2 hours of practicing including diagnosing fracture in greater and lesser tubercles, humeral head, humeral neck, and glenoid rim. Also identifying hill sachs and bankart fractures.

Design

Prospective convenience sample when any of 8 study physicians available

No blinding

No Randomization

Intervention

Study patients received POCUS of the shoulder prior to xray and then again after reduction attempt.

Scan

Probe choice: In this study a high frequency linear probe was used. You can also use a curvilinear probe.

Step 1: view shaft of humerus in short axis, posteriorly.

Step 2: slide up to find humeral head

Step 3: slide laterally to view GH joint and posterior glenoid labrum

Step 4: evaluate humeral head, tuberosities and intertubercular groove by sliding around anteriorly

One Minute Ultrasound Video - Shoulder dislocation

Results

103 Patients

98 (95.1%) had dislocation

Primary Findings

POCUS for dislocation: 100% sens and 100% specific for dislocation

Secondary Findings

POCUS for fracture: 100% sensitive, 84.2% specific (only 9 fractures overall)

POCUS for reduction: 100% sensitive (*incorrectly reported in paper as 100% specific - because there were no negative xrays, there were no true negatives, can’t calculate specificity)

In this study, sonologists could not accurately determine anterior versus posterior dislocation.

Limitations

Convenience sample

High incidence of dislocation in this population

Extensive shoulder US use of study sonologists

If unsure if pathology present - instructed to rate as “pathology” --> likely attributed to high sensitivities

Take Home Points

1. Ultrasound can be used to diagnose shoulder dislocation and reduction. In this study 100% sensitive and specific.

2. With training, ultrasound can also recognize shoulder fractures with high sensitivity.

Our score