Shoulder Trauma

1. Shoulder Trauma

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. Degenerative Arthritis • Painful arthritis follows untreated intra-articular fractures • Radiographic signs are the usual findings in OA http://www.drmaffet.com/shoulder-surgery-houston/ac-joint-arthosis-2/

10. 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

11. 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

12. 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

13. 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

14. 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

15. Lesser Tuberosity Fracture • Can't be directly impacted, but may be associated with other fractures http://www.internationalshoulderjournal.org/viewimage. asp?img=IntJShoulderSurg_2011_5_2_50_83198_u3.jpg http://www.medscape.com/viewarticle/420763

16. 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

17. 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

18. 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%

19. Glenohumeral Joint Dislocation • Classified by direction of displacement of humeral head • Anterior (most common), posterior, inferior or superior

20. 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/

21. 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

22. 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

23. 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 appearance- cystic appearance of humeral head in its malposition • Superior displacement of humeral head - Rare, but could have reverse Hill- Sachs (impaction fx. of anteromedial aspect of head) or reverse Bankart (posterior glenoid fx.) http://imageinterpretation.co.uk/images/shoulder/POSTERIOR%20DISLOCATION2%20AP.jpg

24. 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

25. Superior dislocation • Rare • Requires great force with elbow flexed and adducted • More likely to have superior displacement of head due to torn rotator cuff

26. 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

27. 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/

28. 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

29. 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 ligament is actually 2 ligaments - Conoid and trapezoid ligaments Trapezoid Conoid http://www.conquestchronicles.com/pages/The_Shoulder_Sprain

30. 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

31. 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

32. 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

33. Sternoclavicular Joint Dislocation • Rare • Requires severe trauma • Posterior displacement of clavicle at SC joint is potentially life-threatening • CT is modality of choice

34. Scapulothoracic Joint Dislocation • AKA locked scapula • Rare • Severe trauma or post-thoracoplasty

35. References Yochum, T.R. (2005) Yochum and Rowe’s Essentials of Skeletal Radiology, Third Edition. Lippincott, Williams and Wilkins: Baltimore.