Imaging - LE

Question 1

Ottawa Ankle Rules

Answer 1

Malleolar Zone - bony tenderness in post 1/2 distal tib or fib (tip of med/lat mall)
Midfoot - tenderness over nav/base of 5th

Question 2

X-ray Sets

Answer 2

Ankle - A/P, Lat, IO/Mort (modified AP, foot IR 15-30 deg to view mortise and distal tibfib)

Foot - A/P, Lat, Oblique

Question 3

Tillaux Fx

Answer 3

SH III fx - A/L tib epip
skeletally immature person
severe ankle sprain or OCD lesion on talar dome
Initial X-ray but CT best view for bony involvement

Question 4

Danis Weber Ankle Fx Classifications

Answer 4

A - below ankle
B - at joint, tibfib lig intact
C - above, syndesmotic lig tears

Question 5

Maisonneuve

Answer 5

ER force to IO membrane exiting through prox fib fx

Question 6

Lisfranc

Answer 6

Fx of 2-5th MT with lateral dislocation
MOI - foot caught in stirrup
MRI best, medial plantar bruising hallmark sign

• med/lat border of 1st MT aligned with med/lat border of med cuneiform
• med of 2nd with med of mid
• med of 4th with med of cuboid on oblique
• med/lat on lat cuneiform with med/lat 3rd MT

Question 7

5th MT Fx

Answer 7

stress, jones, avulsion (distal to proximal)

Question 8

Pelvis

Answer 8

• Osseous ring - likely to have 2nd fracture if you see 1
• lots of soft tissue that can be disruptive (urethral and bladder injuries)
• AP only needed (inlet - AP transverse, outlet - ceph/caud transverse)
  pub symph < 1 cm wide normal (if > , look for SI widening)
• clinical exam 100% Sn

Question 9

Criteria for not using Hip imaging

Answer 9

> 3 yo, no impaired consciousness, no pelvic pain, no signs of fx on inspection, painless compression of iliac/pub symph, painfree hip flex/rot

Question 10

Hip

Answer 10

• AP and frog leg
• post dislocation most common (head displaced sup/lat)
• Fem neck - osteoporosis, stress fx may be sclerotic
• Intertroch fx - trauma, shortened leg with IR
• nondisplaced fx - use MRI

Question 11

Altman Criteria and CPR for hip OA

Answer 11

Cluster 1 - hip pain, IR < 15, flex < 115
Cluster 2 - IR pain, > 50 yo, AM stiff < 60 min

CPR - squat pain, flex = lat pain, scour with add = lat/groin pain, ext = pain, ir = 25

Question 12

SCFE

Answer 12

Frog leg, Klein line should intersect epip

- epip remains in acet, metaphysis moves ant/sup

Question 13

Developmental Dysplasia

Answer 13

< 4 mo (US), > 4 mo (AP X-ray)

Question 14

AVN

Answer 14

fem head flattened, irregular, sclerotic

• AP, frog leg; MRI best
• LCP in 4-10 yo

Question 15

Fem Neck Stress Fx

Answer 15

local deep ant pain, compression (medial) vs tension (lateral) side
bone scan for occult, Plain otherwise

Question 16

Knee X-ray

Answer 16

AP - jt space narrowing, cart calc
Lat (slight flex) - patella, jt effusion (sup to patella, ant to femur)
Sunrise/Merchant - patella vs ant femur
Tunnel - tibial spines, fem condyles

Question 17

Pittsburgh Rules

Answer 17

blunt trauma or fall as MOI, < 12 or > 50; 4 steps

Question 18

Ottawa Knee Rules

Answer 18

55+, tender over patella, fib head tender, can’t flex > 90, 4 steps

Question 19

Bipartate Patella

Answer 19

normal variant may appear as fx

Question 20

Tib Plat Fx

Answer 20

hard to see, best in AP

Question 21

Segond Fx

Answer 21

cortical avulsion fx off prox lat tibia - distal to tib plat at insertion of mid 1/3 LCL

excessive IR and varus stress
75-100% of ACL, 66-75% meniscal, PCL; MRI recommended

Question 22

OCD

Answer 22

X-ray first, then MRI

85Z% med fem condyle (most - post lat aspect)

Question 23

OS vs SLJ

Answer 23

OS - tib tub

SLJ - pat tendon