Ferrill DSA: Elbow pain in a child Flashcards
Looking at an elbow x-ray
Look at cortical lines
Look at alignment of bones
- Radiocapitellar line
- —- Radial dislocation
- Anterior humeral line
- —- Supracondylar fractures
Fat pad sign
- Sign of effusion and occult fracture
Ossification centers
- Kid elbows look different
elbow ossification centers
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)
Check the anterior humeral line:
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it doesn’t, think supracondylar fracture
Check the radiocapitellar line:
drawn along the radial neck
should always intersect the capitellum
if it doesn’t, 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 paediatric 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
Common pathology
- Supracondylar fracture
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
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
5. Medial epicondyle avulsion 10% of all paediatric elbow injuries usually older children and adolescents mechanism: FOOSH with full elbow flexion, or posterior elbow dislocation most common avulsion injury more: medial epicondyle fracture
6. Radial head dislocation 5% of all paediatric 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
7. Radial neck fracture 5% of all paediatric 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 paediatric 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
Types of fractures
complete: all the way through the bone
transverse: straight across the bone
oblique: oblique line across the bone
spiral: looks like a cork-screw
comminuted: more than 2 parts to the fracture
incomplete: the whole cortex isn’t broken
bowing: the long bone has been bent
buckle: the fracture is of the concave surface
greenstick: the fracture is on the convex surface
Salter-Harris
Where is the fracture?
The next thing to describe is the bone that is involved and what part of the bone is affected:
Diaphysis: the shaft of the bone
Metaphysis: the widening portion adjacent to the growth plate
Epiphysis: the end of the bone adjacent to the joint
Displacement comes in three flavours:
angulation
translation
rotation
describing a fracture
I: Describe the film II: What type of fracture? III: Where is the fracture? IV: Is it displaced? V: Is something else going on?
Fat pad sign
Indicates joint effusion
May be the only sign of
occult fracture in children
in trauma displacement of the posterior fat pad is virtually pathognomonic of the presence of a fracture. Displacement of the anterior fat pad alone however can occur due to minimal joint effusion and is less specific for fracture.
Greenstick fracture, distal humerus
Fracture without cortical bone disruption
Most common type of fracture in children
Physeal fractures
(also called Salter-Harris fractures) are important childhood fractures that involve the physeal plate. They are relatively common and important to differentiate from other injuries because the involvement of the physis (growth plate) may cause premature closure resulting in limb shortening and abnormal growth.
clinical presentation of physeal fractures
most common in 10-15 year old children cit. They most commonly occur following trauma although at the hip, SUFE (slipped upper femoral epiphysis) is a type I fracture that can occur without an acute traumatic event.
The Salter-Harris classification
type I
slipped
5-7%
fracture plane passes all the way through the growth plate, not involving bone
cannot occur if the growth plate is fused cit
good prognosis
type II
above
~75% (by far the most common)
fracture passes across most of the growth plate and up through the metaphysis
good prognosis
type III
lower
7-10%
fracture plane passes some distance along the growth plate and down through the epiphysis
poorer prognosis as the proliferative and reserve zones are interrupted
type IV
through or transverse or together
intra-articular
10%
fracture plane passes directly through the metaphysis, growth plate and down through the epiphysis
poor prognosis as the proliferative and reserve zones are interrupted
type V ruined or rammed uncommon <1% crushing type injury does not displace the growth plate but damages it by direct compression worst prognosis
Others
There are a few other rare types which you should probably never include in a report as almost no one will know what you are talking about. Nonetheless they are:
type VI: injury to the perichondral structures
type VII: isolated injury to the epiphyseal plate
type VIII: isolated injury to the metaphysis, with a potential injury related to endochondral ossification
type IX: injury to the periosteum that may interfere with membranous growth
