Upper extremity lecture 2

Question 1

What is a good “first line test” if you suspect pathology?

Answer 1

Radiograph

Question 2

If an XR comes back negative, but you suspect fracture, what would be a good next step, and why?

Answer 2

CT: high spatial resolution, better for evaluating and characterizing bone

Question 3

What imaging modality would be best for soft tissue injury, such as tendon or ligament pathology?

Answer 3

MRI: high contrast resolution

Question 4

What imaging modality is best for finding abnormal edema?

Answer 4

MRI

Question 5

MRI Standard Planes

Answer 5

axial, sagittal, coronal

Question 6

MRI UE planes to optimize rotator cuff tears

Answer 6

coronal oblique (parallel to long axis of supraspinatus), sagittal oblique (perpendicular to long axis of supraspinatus), axial

Question 7

XR standard view for long bones

Answer 7

2 views: AP and lateral (orthogonal planes)

Question 8

XR standard view for joints

Answer 8

3 views: AP, lateral, oblique

Question 9

XR standard view for shoulder

Answer 9

Trauma series: AP, Y-scapular (oblique), axillary

Nontrauma series: AP views in ER and IR

Question 10

XR standard view for pelvis and hips

Answer 10

AP and frog leg lateral view

Question 11

8 steps for how to read an X-ray

Answer 11

1. Identify normal bones (what lives there?)
2. Look for cortical continuity
3. Look at alignment
4. Look for any extra densities or lucencies within or outside bone
5. Look at soft tissues (swelling, effusion)
6. Look at adjacent joints
7. Compare with prior studies, if any
8. If there is still clinical concern for pathology, order CT or MRI

Question 12

Wrist: Describe 3 arcs used to view X-ray

Answer 12

Arc I: proximal articular surface of scaphoid, lunate, triquetrum
Arc II: distal articular surface of scaphoid, lunate, triquetrum
Arc III: proximal articular surface of capitate and hamate
If there is no arc: dislocation

Question 13

Wrist lateral view: what 4 structures should line up?

Answer 13

Radius, lunate, capitate, 3rd metacarpal

Question 14

How to identify a fracture on an X-ray: 6 signs

Answer 14

1. cortical discontinuity or deformity
2. radiolucent fracture lines
3. abnormally white or dense areas, representing overlapping bony fragments or impaction of bone
4. extra or unexplained bony fragments
5. soft tissue swelling or joint effusion
6. callus formation in healing fractures (look fuzzy)

Question 15

Gamekeeper’s Thumb

Answer 15

disruption of ulnar collateral ligament of first MCP joint, may be avulsion fracture of proximal phalanx at UCL

Question 16

Stener Lesion

Answer 16

Gamekeeper’s thumb; displacement of UCL superficial to adductor pollicis aponeurosis; surgery required to heal avulsion fracture (adductor pollicis in the way)

Question 17

Avascular necrosis of scaphoid: etiology

Answer 17

blood supply (from carpal branch of radial artery) to scaphoid bone begins distally and runs proximally, poor blood supply to proximal pole leads to AVN

Question 18

If a patient has pain over the snuffbox of the wrist and X-ray is negative, what should be done?

Answer 18

if you have a high clinical suspicion of fracture, the wrist should be casted and pt. should get an MRI or repeat radiographs

Question 19

posterior fat pad sign

Answer 19

abnormal radiolucency of posterior fat pad in elbow flexion; fat pad normally pressed into deep olecranon fossa by triceps tendon and anconeus (normally invisible on XR); visible when joint effusion present

Question 20

give 1 pro and 1 con for the axillary view in a shoulder XP

Answer 20

Pro: better view than Y-scapular and more consistent
Con: can be a difficult/painful position for a person with a shoulder injury

Question 21

Hill Sachs lesion: best view for XR

Answer 21

AP internal rotation

Question 22

Hill Sachs lesion: what is it?

Answer 22

a cortical depression in the posterolateral head of the humerus, resulting from forceful impaction of the humeral head against the anteroinferior glenoid rim when the shoulder is dislocated anteriorly.

Question 23

posterior shoulder dislocation: mechanism, etiology

Answer 23

humerus forced posteriorly in internal rotation; usually caused by convulsions, rarely by trauma

Question 24

posterior shoulder dislocation: best imaging to diagnose, other pathology with similar presentation?

Answer 24

can “mimic” adhesive capsulitis; CT or MR best for viewing, often difficult to diagnose with XR

Question 25

most common type of shoulder dislocation

Answer 25

anterior (95-97%)

Question 26

posterior shoulder dislocation: what %?

Answer 26

2-4%

Question 27

inferior (luxation) dislocation: what %?

Answer 27

0.5%

Question 28

best imaging mode to view supraspinatus? best plane?

Answer 28

MRI (good for soft tissue); oblique coronal proton density or oblique sagittal fat sat proton density

Question 29

Radiographic findings: chronic rotator cuff tears (3)

Answer 29

1. high riding humerus (<7mm acromiohumeral distance)
2. faceting and sclerosis in inferolateral acromion and superior aspect of greater tuberosity
3. secondary osteophytosis in GH joint to maintain joint congruity

Question 30

clinical findings: rotator cuff tears (signs and symtpoms-5)

Answer 30

1. weak supraspinatus
2. weak GH external rotation
3. impingement
4. age >/= 60 (>60%)
5. night pain

Question 31

full thickness tear-supraspinatus: imaging characteristics (what is visualized on MR?) (3)

Answer 31

1. fully extends from bursal to articular surface
2. nonvisualization of tendon
3. fluid in expected location of tendon

Question 32

calcific tendinosis

Answer 32

deposition of calcium hydroxyapatite at the insertion of the supraspinatus tendon

Question 33

biceps tenosynovitis

Answer 33

biceps tendon sheath thickened with surrounding edema; visible on MR

Question 34

subacromial subdeltoid bursitis

Answer 34

nonspecific effusion in subdeltoid bursa, not involving biceps tendon