Download Shoulder Trauma

Shoulder Trauma
Normal anatomy
• Standard AP shoulder series demonstrates
most of the essential anatomy
– Internal rotation, external rotation, abduction
(baby arm)
• Specialized views
may be required
to reduce overlap
of certain
structures
•
http://eorif.com/Shoulderarm/XrayShoulder.html
http://www.ski-injury.com/specific-injuries/shoulder
Clavicle Fractures
• 15% of all fractures; most common
fracture during birth
• Usually direct trauma
• Males 2/3 of all clavicle fractures
• More common in children and
adolescents; incidence decreases with
age
Clavicle fractures by location
• Medial 1/3- least common (5%)
• Middle 1/3- most common (75%)
– If fracture is complete, medial fragment will
be elevated by action of SCM and lateral
fragment will be depressed
by the weight of the upper
extremity
• Distal 1/3- (20%)
– Fracture may extend and
become intra-articular
http://eorif.com/Shoulderarm/Clavicle%20medial.html
Clavicle fracture complications
• Child and adolescent heal without
complication 95% of the time
• Increased chance of complications in
adults
• Complications include:
– Neurovascular damage
– Non-union
– Mal-union
– Degenerative arthritis
– Post-traumatic osteolysis
Neurovascular damage
• Most commonly
subclavian artery; less
commonly subclavian
vein; occasionally
brachial plexus and
sympathetic chain
http://bestpractice.bmj.com/best-practice/monograph/592/basics/aetiology.html
Non-union
• 5% of cases
• Lack of callous formation by 6 weeks
post-injury signifies non-union
• Radiographic signs:
– Fracture margins become sclerotic and
rounded with smooth
contours over time
• May require surgery
http://www.gentili.net/fracture.asp?ID=16
Malunion
• If bones overlap and massive callus
develops, cosmetic deformity and
functional impairment results
• May require surgery
http://www.sciencedirect.com/science/article/pii/S1058274604002678
Degenerative Arthritis
• Painful arthritis follows untreated intraarticular fractures
• Radiographic signs are the usual findings
in OA
http://www.drmaffet.com/shoulder-surgery-houston/ac-joint-arthosis-2/
Post-traumatic Osteolysis
• Bone resorption of distal clavicle
• First becomes radiographically visible 2- 3
months after the injury
– Distal cortex becomes
hard to define and may
become tapered over time
• Injury may be trivial, not
necessarily fracture or
dislocation
• Common in weightlifters
http://radiopaedia.org/images/631648
Scapular fractures
• 80% have other fractures due to severity of
trauma required to fracture scapula
• May be seen on other shoulder views, but
special projections may be required
• 80% involve body and neck
• Coracoid or acromion
less often
• Glenoid fractures occur
with humeral dislocations
(Bankhart and reverse
Bankhart lesions)
http://www.feinberg.northwestern.edu/emergencymed/
residency/ortho-teaching/shoulder/case42/case42answer.html
Humerus Fractures
• Classified by anatomic location
– Anatomic neck, greater tuberosity, lesser
tuberosity, surgical neck, proximal shaft
• Complications:
– Non-union, malunion, DJD,
AVN of humeral head, myositis
ossificans, neurovascular
damage
http://www.shoulderdoc.co.uk/article.asp?article=735
Anatomic Neck Fractures
• Isolated neck fractures are
rare
– Usually associated fractures
• High incidence of AVN
• Hill-Sachs and reverse
Hill-Sachs lesions
– Impaction fractures of
humeral head when it
bangs against glenoid
during dislocation
http://web.me.com/radrep/Radiographers_Reporting/The_Shoulder..html
Greater Tuberosity Fracture
• AKA Flap fracture
• May occur by direct trauma or avulsion
• Frequently fractured
during anterior humeral
dislocation
• Best seen on external
rotation view
http://en.wikipedia.org/wiki/File:GreatertrochanerAP.png
Lesser Tuberosity Fracture
• Can't be directly impacted, but may be
associated with other fractures
http://www.medscape.com/viewarticle/420763
http://www.internationalshoulderjournal.org/viewimage.
asp?img=IntJShoulderSurg_2011_5_2_50_83198_u3.jpg
Surgical Neck Fracture
• Immediately distal to tuberosities
• Most common of proximal humeral
fractures
• Axial artery and nerve prone to injury at
this location
http://www2.aofoundation.org
http://www.wheelessonline.com/ortho/proximal_humeral_fracture
Proximal Shaft Fracture
• Mechanism is usually direct trauma
• Fracture location in relation to muscular
attachments determines deformity that is
produced
– Proximal to pec M, head abducts and rotates
– Between pec M and delt,
head will adduct
- Distal to deltoid, head
will abduct
http://radiopaedia.org/cases/proximal-humeral-fracture-in-child?fullscreen=true
Shoulder girdle dislocations
• Most common joint in body to dislocate
• Greater than 50% of all this locations
• Four joints of the shoulder girdle
– Glenohumeral joint 85%, acromioclavicular
joint 12%, sternoclavicular joint 2% and
scapula thoracic joint 1%
Glenohumeral Joint Dislocation
• Classified by direction of displacement
of humeral head
– Anterior (most common), posterior, inferior
or superior
Anterior GH Joint Dislocation
• M.C. shoulder dislocation (95%)
• Mechanism is forceful abduction and external
rotation
• Associated fractures during dislocation are
common
• Radiographic signs- interior
medial head displacement,
altered head shape and
presence of Hill-Sachs or
Bankart lesions
• Humerus usually settles
subcoracoid
http://www.feinberg.northwestern.edu/emergencymed/residency/ortho-teaching/shoulder/case49/
Anterior GH Joint Dislocation
• Hill-Sachs lesion (hatchet deformity)
– Impaction fracture of posterior-superior
aspect of head where it
bangs into inferior glenoid
• Bankart lesion
– Fracture of inferior
glenoid by humeral head
impact complications
recurrence
http://www.orthopaedia.com/display/Main/Hill-Sachs+Sign
Posterior GH Dislocation
• Uncommon (2-4%)
• Fixes humeral head in internal rotation
• Caused by epileptic convulsions, electric shock
or extreme trauma, thus
triple “e” syndrome
• Reverse Hill-Sachs and
reverse Bankart lesions
– Impaction of anteromedial
humeral head and posterior
glenoid
http://www.radsource.us/clinic/0506
Posterior GH Dislocation
• Radiographic signs:
–
–
–
–
Rim sign- widening of glenohumeral joint space > 6 mm
Trough line sign- appearance of double articular surface line
Lack of humeral head/glenoid fossa overlap
Vacant glenoid sign- lack of close contact at anterior joint
margin
– Tennis racquet appearancecystic appearance of humeral
head in its malposition
– Superior displacement of
humeral head
- Rare, but could have reverse HillSachs (impaction fx. of anteromedial
aspect of head) or reverse Bankart
(posterior glenoid fx.)
http://imageinterpretation.co.uk/images/shoulder/POSTERIOR%20DISLOCATION2%20AP.jpg
Inferior GH Dislocation
• AKA luxatio erecta
• Mechanism is severe hyperabduction
• In that motion, acromion acts as fulcrum
on humeral neck, which levers humeral
head inferiorly
• Humerus gets stuck in abduction
Superior dislocation
• Rare
• Requires great force with elbow flexed
and adducted
• More likely to have superior
displacement of head due to torn rotator
cuff
Rotator cuff tears
• Incidence increases with age
• May be traumatic or degenerative
• Radiographic sign is superior subluxation of
humeral head (not dislocation)
– Tear produces reduces holding power of infraspinatus
tendon allowing unopposed elevation of humeral
head by deltoid
– Acromiohumeral measurement <7mm signifies tear
– Head may form pseudo-joint superiorly with clavicle
and acromion
Rotator Cuff Tears
• Arthrography- 85% sensitive – shows
extravasation of contrast
• Ultrasound- 60 to 85% sensitive
• MRI up to 100% sensitive if tear is >2cm
http://stemcelldoc.wordpress.com/tag/alternatives-to-rotator-cuff-surgery/
Glenoid Labral Tears
• AKA SLAP lesion (Superior Labrum
Anterior to Posterior
• Occurs during dislocation
• Associated with instability
• MRI is modality of choice
– Demonstrates labral
avulsion, absence or a
cleft
http://www.ericcressey.com/tag/slap-lesion
AC Joint Separation
• Demonstrated with AP projection at 15°cephalic
tube tilt (like clavicle view), but taken with and
without weights
– Needs to be bilateral for comparison measurements
• Coracoclavicular
Trapezoid
ligament is actually
2 ligaments
Conoid
- Conoid and
trapezoid ligaments
http://www.conquestchronicles.com/pages/The_Shoulder_Sprain
AC Joint Separation
• Radiographic features
– AC joint space normally 2-4 mm
– AC joint alignment- should be in good
horizontal alignment
– Coracoclavicular distance- normally 11-13
mm; should be no more than 5 mm difference
from side to side
http://www.emedx.com/emedx/diagnosis_information/shoulder_disorders/shoulder_separation_images.htm
Classification of AC Joint Injuries
• Based on degree of injury
– Type I- No tear; no radiographic signs
– Type II- AC ligaments torn; coracoclavicular
ligaments stretched, but intact
• Radiograph shows increased AC joint space, but
normal coracoclavicular distance
– Type III- Next slide
Classification of AC Joint Injuries
• Type III- AC ligaments AND
coracoclavicular ligaments torn
– Radiographic signs include widened AC joint
space, elevation of distal clavicle above
acromion and coracoclavicular distance >5
mm wider than the opposite side
http://velonews.competitor.com/2010/11/news/shoulder-separations-explained_150447
Sternoclavicular Joint Dislocation
• Rare
• Requires severe trauma
• Posterior displacement of clavicle at SC
joint is potentially life-threatening
• CT is modality of choice
Scapulothoracic Joint Dislocation
• AKA locked scapula
• Rare
• Severe trauma or post-thoracoplasty
References
• Yochum, T.R. (2005) Yochum and
Rowe’s Essentials of Skeletal
Radiology, Third Edition. Lippincott,
Williams and Wilkins: Baltimore.