AVN of Femoral Head

Question 1

What is AVN if unknown cause also called in adults

Answer 1

Chandlers disease (primary cause)

Question 2

Ratio of M:F and % bilateral for AVN of femoral head

Answer 2

4:1 M:F

50% bilateral

Question 3

Common look of phase 2 AVN in femoral head

Answer 3

• Jt inflamation
• articular margins decreased density
• Sclerotic borders around head with no good trabecuale patterning
• potential of flattened head appearence

Question 4

Typical look of AVN in femoral head in T2 MRI

Answer 4

High signal inside head with low signal rim

Question 5

Bone scan of epiphyseal osteonecrosis- when will it be seen

Answer 5

initially if performed early it may show cold area then will appear hot on bone scan and stay hot for many years during repair

Question 6

Legg-Calve-Perthes disease- what is it, when will it occur, time lines

Answer 6

AVN of femoral head before closure of physis (younger indvs)

• Self limiting 2-8 years
• 5:1 M:F
• 10 bilat

Question 7

What are the 3 key imaging signs you will see in legg calve perthes disease

Answer 7

• Short wide femoral neck
• Enlarged greater trochanter (rises above femoral head)
• Sagging rope sign (sclerotic border below neck)

(flattening later, Fragemnted head)

Question 8

When is it ok to weight bear again with legg calves perthes

Answer 8

If there is normal trabeculation again

Question 9

Initail tx of osteonerosis of head

Answer 9

anti inflamatory, bed rest, crutches
bracing
surgery pot
Hip abd and rot ex