Elbow Dislocations
“Elbow dislocation refers to a disruption of the elbow joint in which the humeral surface becomes disarticulated with the ulnar surface…”
CASE
A 21-year-old male presents with pain, swelling, and obvious deformity to his right elbow after falling on his outstretched right hand while taking a turn too sharply on his motorcycle.
Figure 1: Obvious right elbow deformity
DIAGNOSIS
Elbow dislocation
DISCUSSION
Elbow dislocation refers to a disruption of the elbow joint in which the humeral surface becomes disarticulated with the ulnar surface. They are classified both by their anatomy as well as by their complexity:
Posterolateral dislocations, in which the olecranon moves posterolaterally to the humerus, are the most common, accounting for 80% of all elbow dislocations, followed by posterior. Anterior and other types of dislocations are rare.
Figure 2: Elbow dislocation classifications
Complexity:
Simple: dislocation with no associated fracture (50-60%)
Complex: dislocation with associated fracture (40-50%)
Terrible triad: traumatic injury pattern consisting of elbow dislocation (usually posterolateral), radial head/neck fracture, and a coronoid fracture
Figure 3: Depiction of the “terrible triad” in elbow dislocations
Epidemiology:
Elbow dislocations are common: second most common large joint dislocation in adults, most common joint dislocation in children, accounting for 10-25% of all elbow injuries.
Most commonly occur in males aged 10-20 years of age, most commonly as sports injuries
Associated fractures (complex dislocations) as common as 50%
Mechanism of injury:
Because the elbow joint is very stable, a large force is required for dislocation.
A fall onto an outstretched hand (FOOSH) is the usual mechanism, resulting in elbow hyperextension, arm abduction, and forearm supination and posterior dislocation.
Anterior dislocations are rare, caused by direct force to the posterior forearm while the elbow is in flexion.
Due to the high amount of force required for dislocation, most dislocations have associated ligamentous injuries. These usually progress laterally to medially, with the strong medial collateral ligament (MCL) being the last to be injured. The MCL is usually intact after injury.
Physical exam findings:
Posterior dislocation:
Olecranon is prominent and out of plane with epicondylar heads; elbow is usually held in flexion
Anterior dislocation:
Upper arm appears shortened, forearm is supinated and appears elongated; elbow is held in full extension
As with any dislocation, as part of your exam ALWAYS assess:
Skin to evaluate for evidence of open fracture and/or skin compromise
Evidence of compartment syndrome
Joint above and below (concomitant shoulder or wrist injuries occur in 10-15% of elbow dislocations)
Neurovascular status:
Always perform prior to radiographs and manipulation, as well as after manipulation
Assess median, radial, and ulnar nerve distributions – median and ulnar nerves are most susceptible to damage
Brachial artery, which runs through joint, is most commonly injured vessel, usually in anterior or open dislocations.
Figure 4: Neurovascular supply of the elbow
Imaging:
Obtain AP and lateral x-ray views on every patient; additionally, obtain oblique views in any patient suspected to have complex dislocation
Check for associated fractures (remember to check for the terrible triad!)
Medial/lateral epicondyle (12-34%)
Radial head (5-10%)
Coronoid process (5-10%)
Figure 5: Normal elbow anatomy
Figure 6: Posterior dislocation, in which the olecranon rests posteriorly to the humerus.
ED management:
Always consult orthopedic specialists immediately with concern for neurovascular compromise or open dislocation/fractures
Simple dislocations:
Simple dislocations can be treated with closed reduction by an EM physician:
Apply inline traction while supinating forearm (shifts coronoid under trochlea) and flexing elbow with direct pressure on olecranon
Palpable clunk often observed
Post-reduction assessment:
Repeat neurovascular exam
Assess range of motion— instability with extension often observed
Post-reduction immobilization:
Long arm posterior splint, elbow in 90 degrees flexion for 1-2 weeks
Follow-up with orthopedics outpatient in 1 week for repeat radiographs
Complex dislocations:
Usually treated operatively, however some may be definitively managed with splinting if radial head fracture is minimally or non-displaced
Most common complications of non-operative management of complex dislocations are joint instability and restricted ROM
Prognosis:
Usually quite good
Stiffness of joint is most common complication, with difficulty with terminal extension
Early, active ROM can help prevent this
Recurrent dislocations are rare
Contracture/stiffness is correlated with immobilization beyond 3 weeks; immobilization should not extend beyond 2 weeks
TAKE-AWAYS
Elbow dislocations are common in children and adults, usually posterolateral or posterior due to FOOSH-like injury mechanisms.
As with any dislocation, physical exam must include skin assessment, compartment check, and neurovascular check, and checks of joints above & below.
Simple dislocations can be reduced in the ER and splinted with orthopedic follow-up.
Complex dislocations, neurovascular compromise, or open fractures warrant discussion with specialist.
AUTHOR: Emmy Shearer, MD, is a current third-year emergency medicine resident at Brown Emergency Medicine Residency
FACULTY REVIEWER: Michelle Myles, MD, is a clinician educator and attending at Brown Emergency Medicine Residency
References
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Iordens GI. et al. Early mobilisation versus plaster immobilisation of simple elbow dislocations: results of the FuncSiE multicentre randomised clinical trial. Br J Sports Med. 2015 Jul 14. [Epub ahead of print] PMID: 26175020
Kuhn MA, Ross G. Acute elbow dislocations. Orthop Clin North Am 2008; 39: pp. 155-161. PMID: 18374806
Mehlhoff TL et al. Simple dislocation of the elbow in the adult: Results after closed treatment. J Bone Joint Surg Am 1988 Feb;70(2):244-9.PMID: 3343270
Najarian, Sandra L. Chapter 171. Forearm and Elbow Injuries. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011