pediatric elbow dislocations usually occur in older children (10-15 years) and can be associated with other elbow fractures including a medial epicondyle fracture with an incarcerated intra-articular bone fragment.
treatment is usually closed reduction followed by brief immobilization unless the medial epicondyle has an incarcerated fragment in the joint that is blocking reduction.
Epidemiology
incidence
3-6% of all pediatric elbow injuries
demographics
male:female = 3:1
most common in 10-15 year olds
very rare in younger children < 3 years old
Pathophysiology
mechanism of injury
fall onto an outstretched hand
pathoanatomy
posterior dislocation
hyperextension, valgus stress, and supination
anterior dislocation
a direct posterior to anterior force on a flexed elbow
relatively small coronoid process in children cannot resist distal and posterior displacement of ulna
Associated conditions
traumatic
avulsion of the medial epicondyle
medial epicondyle fractures are the most common associated fracture
incarcerated intra-articular bone fragment may block reduction
fractures of proximal radius, olecranon and coronoid process
neurovascular injury
brachial artery and median nerve
may be stretched over displaced proximal fragment
ulnar nerve
at risk with associated medial epicondyle avulsions
most common neuropraxia
congenital
dislocation of radial head
Classification
Anatomic classification
based on the position of the proximal radio-ulnar joint in relation to the distal humerus
includes
posterolateral (most common)
posteromedial
anterior (rare)
divergent
Presentation
Symptoms
painful and swollen elbow
attempts at motion are painful and restricted
Physical exam
inspection
elbow held in flexion
forearm appears to be shortened from the anterior and posterior view
palpation
distal humerus creates a fullness within the antecubital fossa
essential to perform neurovascular examination
assess for brachial artery and median/ulnar nerve injury
Imaging
Radiographs
required views
AP and lateral radiograph of elbow
comparison radiographs of the contralateral elbow may be helpful
findings
loss or radiocapitellar and ulnohumeral relationship but maintained radial and ulnar relationship
look for fractures of medial epidcondyle, coronoid, proximal radius
"elbow dislocation" in very young (<3 years old) most likely represents a distal humerus physeal separation and raises concern for nonaccidental trauma
Treatment
Nonoperative
closed reduction, brief immobilization with early range of motion
indications
dislocation that remains stable following reduction
indicated in the majority of cases
reduction technique (see below)
should be addressed promptly as reduction should not be delayed
brief immobilization
immobilization should be minimized to 1- 2 weeks to minimize risk of stiffness
early therapy
encourage early active range of motion
Operative
open reduction
indications
open dislocation
incarcerated medial epicondyle or coronoid process in the joint
failure to obtain or maintain an adequate closed reduction
significant joint instability (rare)
Technique
Closed reduction technique
posterior dislocations
supine
closed reduction performed with the elbow flexed in forearm supination using gradual traction
prone
forearm hanging from table and anterior directed force on olecranon
anterior dislocations
inline traction to distal forearm with a posteriorly directed force on the forearm and an anteriorly directed force on the distal humerus
post-reduction films should be reviewed to rule out presence of entrapped bone fragment
must locate medial epicondyle on post-reduction radiographs to ensure it is not within the joint
Open reduction
approach
depends on reason for blocked reduction
elbow medial approach
indicated if medial epicondyle avulsion with incarcerated fragment is blocking reduction
Complications
Stiffness
most commonly loss of terminal extension
due to prolonged immobilization
Heterotopic ossification
vigorous reduction increases risk
Neurologic injuries
usually transient
median nerve injury may occur due to nerve entrapment
ulnar nerve most commonly affected if associated medial epicondyle fracture occurs
Vascular injury
brachial artery may be injured (rare)
Compartment syndrome
excessive swelling and immobilization in hyperflexion
Chronic instability (recurrent dislocations)
associated with coronoid and radial head fractures