Elbow Trauma
Elbow Trauma
• 6% of all fractures and dislocations involve
elbow
• Most common fractures differ between adults
and children
– M.C. in adults- radial head and neck fxs.
– M.C. in children- supracondylar fxs.
• Complex anatomy requires 4 views for
adequate interpretation
– AP in extension, medial oblique, lateral and axial
olecranon (Jones view)
Normal Elbow Anatomy
• Very important to be aware of pediatric
growth centers
– CRITOE
http://med_practice.byethost7.com/wp2/?p=21
http://www.radiologyassistant.nl/en/4214416a75d87
Normal Alignment
• Anterior humeral line- line drawn along anterior
surface of humeral cortex
should pass through the middle
third of the capitellum
• Radiocapitellar line- Line
drawn through the proximal
radial shaft and neck
should pass through to
the articulating capitellum
http://imageinterpretation.co.uk/elbow.html
Signs of Fracture
• Usual signs may not be readily visible
– Fracture line, cortical disruption, etc.
• Soft tissue signs can indicate fracture
– Fat pad sign
• On lateral, might see fat pad parallel to anterior
humeral cortex, but should never see posterior fat pad
• With effusion, anterior may be displaced and will be
shaped like a sail (sail sign)
Fat Pad Sign
• Posterior fat pad is normally buried in olecranon fossa
and not visible
– Becomes elevated and visible with joint uffusion
• Effusion (acute capsular swelling) can be from any origin (hemorrhagic,
inflammatory, infectious, traumatic, etc.)
• Ant. fat pad may be obliterated, so post. Fat pad is more
reliable when visible
htt p://www.rad
iologyass istant.nl/e n/4214416a75d87
htt p://us morthopaed ic. blogsp ot.c om/2009/06/ how -to -read -elbow-x-ra y-at-glance. html
Distal humerus fractures
• 95% extend to articular surface
• Classified according to relationship with
condyle and shape of fracture line
– Supracondylar, intercondylar, condylar and
epicondylar
Supracondylar Fractures
• Most common elbow fracture in children (60%)
• Fracture line extends transversely or obliquely
through distal humerus
above the condyles
• Distal fragment usually
displaces posteriorly
Normal
htt p:// im age interpre tation.c o.uk/e lbow. html
Intercondylar fracture
• Fracture line extends between medial and
lateral condyles and extends to supracondylar
region
– Results and T or Y shaped configuration for
fracture
• Called trans-condylar if it extends through
both condyles
Epicondylar fracture
• Usually avulsion from traction of respective
common flexor (medial) or extensor (lateral)
tendons
• Medial epicondyle
avulsion common in
sports with strong
throwing motion
(little leaguer’s elbow)
htt p://rad iopaed ia. org/ im ages/445333
Fractures of Proximal Ulna
• Olecranon fx.- direct trauma or avulsion by
triceps tendon
• Coronoid process fx.- avulsion by brachialis or
impaction into trochlear fossa
– Rarely isolated;
usually associated
with post. elbow
dislocation
htt p://www.rad
iologyass istant.nl/e n/4214416a75d87#a421500951381a
Fractures of Proximal Radius
• M.C. adult elbow fx. (50%)
• FOOSH transmits force causing impaction of
radial head into capitellum
• Chisel fracture- incomplete fracture of radial
head that extends to center of
articular surface
• Usual rad. signs (fx. Line, articular
disruption) may not be visible
– May be occult; fat pad sign is good
indicator of occult fx.
htt p:// lear ningrad iology.c om /m obil e/ m sk/ fxsw ithna m es. htm
Fractures of the forearm
• Isolated ulnar fractures
• Isolated radial fractures
• Bony rings usually can't be fractured in one
place without disruption somewhere else in
the ring
• 60% or forearm fractures involve both bones
(BB fractures)
• These fractures usually have associated
displacement with angulation and rotation
Isolated Ulnar Fractures
• Distal shaft (Nightstick fx.)- direct
trauma
http://radiographics.rsna.org/content/24/4/1009/F31.expansion.html
• Proximal shaft (Monteggia’s fx.)fx. of proximal ulna with
dislocation of radius
http://www.wheelessonline.com/ortho/monteggias_fracture
Isolated Radial Fractures
• Most frequent is a Galeazzi’s fx. (reverse
Monteggia’s fx.)
– Fracture of distal radial shaft
with dislocation of distal
radioulnar joint
– Rare, but serious injury
http://www.learningradiology.com/archives05/COW%20157-Galeazzi%20Fx/galeazzicorrect.htm
Dislocations of Elbow
• 3rd m.c. dislocation in adults behind shoulder and
interphalangeal joints
– More common in children
• Classified according to displacement of radius an
ulna relative to humerus
– Posterior, posterolateral, anterior, medial and
anteromedial
• Posterior and posterolateral or more most common
– 85-90% of all elbow locations
– 50% have associated fractures
Pulled Elbow
• AKA nursemaid’s elbow
• Occurs when child’s hand is pulled, tractioning arm
and causing radial head to slip out from under
annular ligament and trapping the ligament in the
radiohumeral articulation
• Immediate pain; stuck in mid-pronation due to pain
• No radiographic pain
• Supination reduces the dislocation and ends pain,
usually during positioning of lateral radiograph
References
• Yochum, T.R. (2005) Yochum and Rowe’s
Essentials of Skeletal Radiology, Third Edition.
Lippincott, Williams and Wilkins: Baltimore.