Pediatric elbow radiographs are commonly encountered in the emergency department and, when approached in a systematic fashion, are not as difficult to interpret as most people think!
On this page:
Systematic review
Ossification
Check that the ossification centers are present and in the correct position. They appear in a predictable order and can be remembered by the mnemonic CRITOE (age of appearance are approximate):
capitellum (age 1)
radial head (age 3)
internal epicondyle (age 5)
trochlea (age 7)
olecranon (age 9)
external epicondyle (age 11)
Alignment
Check the anterior humeral line:
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it does not, think supracondylar fracture
(under the age of 4, the line will intersect the anterior 1/3)
Check the radiocapitellar line:
drawn along the radial neck
should always intersect the capitellum
-
if it does not, think radial head dislocation
check for an accompanying fracture, e.g. Monteggia fracture-dislocation
Effusion
Check for raised fat pads:
visible posterior fat pad always indicates an elbow effusion
visible anterior fat pad may be seen in normal patients and should only be thought of as an indicator of an elbow effusion when massively raised
if there is an effusion in a pediatric patient, think supracondylar fracture or intra-articular fracture, e.g. lateral condyle fracture
Bone cortex
Check around every bone on the film:
helps to find subtle injuries, e.g. minimally displaced supracondylar fracture or olecranon fracture
look at areas where common injuries occur first (distal humerus and radial neck)
Common pathology
Supracondylar fracture
over 60% of all pediatric elbow injuries
peak age: 5-7 years
mechanism: fall onto a hyperextended elbow
extra-articular fracture
there may be posterior displacement of the distal segment
more: supracondylar fracture
Lateral condyle fracture
10-20% of all pediatric elbow injuries
peak age: 6-10 years
mechanism: usually varus force applied to an extended elbow
unstable intra-articular fracture
prone to displacement due to the pull of forearm extensors
more: lateral condyle fracture
Medial epicondyle avulsion
10% of all pediatric elbow injuries
usually older children and adolescents
mechanism: FOOSH with full elbow flexion, or posterior elbow dislocation
most common avulsion injury
Radial head dislocation
5% of all pediatric elbow injuries
typically seen in infancy and childhood
mechanism: isolated traumatic injury
the radial head is dislocated anteriorly
check for associated ulnar fracture (Monteggia fracture-dislocation)
more: radial head dislocation
Radial neck fracture
5% of all pediatric elbow fractures
peak age: 8-11 years
mechanism: FOOSH with extended elbow and supinated forearm
most fractures involve the physis
more: radial neck fracture
Don't miss...
Olecranon fracture
<5% of all pediatric elbow injuries
less common in children than adults
mechanism: either a direct blow, fall on an outstretched hand with flexed elbow, avulsion fracture or stress fracture
frequently associated with radial neck fracture and elbow dislocation
more: olecranon fracture
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