SR4-AVN & Related Conditions

Question 1

Which of the following names does not belong?
Avascular necrosis
Ischemic necrosis
Aseptic necrosis
Hemochromatosis
Osteonecrosis
Bone infarct

Answer 1

Hemochromatosis

Bone infarct is the same pathophysiologically, but it occurs in the metaphysis or diaphysis

Question 2

List the two AVNs of the hip:

Answer 2

Legg-Calve-Perthe’s

Adult AVN

Question 3

AVN in the wrist? Two names

Answer 3

1. Keinbock’s

2. Preiser’s

Question 4

AVN in the shoulder? (1)

Answer 4

1. Hass’ disease

Question 5

Osteochondritis dissecans, SONK, and Blount’s disease are AVN of the ____

Answer 5

Knee

Question 6

Freiberg’s and Kohler’s are AVN of the ____

Answer 6

Foot

Question 7

AVN in the spine? (1)

Answer 7

Scheuermann’s

Question 8

Name the AVN:

• Affects the capital epiphysis (femoral head) of children between 2 and 12
• 3:1 Male predominance
• Can be bilateral
• Pain is presenting complaint, can refer to knee
• Alteration of gait

Answer 8

LCP

Question 9

The measured distance between the inside of the acetabulum and the femoral epiphysis is called?

Answer 9

Tear-drop distance

Question 10

The line drawn on an x-ray along the medial femoral neck/shaft, that should line up nicely with the upper obturator foramen is called?

Answer 10

Shenton’s line

Question 11

AVN of the lunate?

Answer 11

Keinbock’s disease

Question 12

AVN of the scaphoid?

Answer 12

Preiser’s disease

Question 13

The “feeder” vessel of the Scaphoid bone enters the middle (waist) of the bone and feeds proximal/distal?

Answer 13

Proximal (kind of backwards)

Question 14

AVN of the humeral head?

Answer 14

Haas’ Disease

Question 15

___ affects the LATERAL portion (slope) of the medial femoral condyle, while ___ affects the MEDIAL portion (weight bearing) of the medial femoral condyle

Answer 15

Osteochondritis dissecans (OCD), Spontaneous Osteonecrosis of the Knee (SONK)

Question 16

Tibial vara. Affects the medial growth plate, epiphysis, and metaphysis. Unknown cause

Answer 16

Blount’s Disease

Question 17

An “infarction”. Causes flattening and fragmentation of the head of the metatarsal (usually 2nd)

Answer 17

Freiberg’s Disease

Question 18

AVN of the navicular bone.

Answer 18

Kohler’s Disease

Question 19

Wavy, serpiginous calcifications, most common in the knee with the same risk factors as AVN. These occur in the metaphysis or diaphysis.

Answer 19

Medullary bone infarct

Question 20

A common DDX of medullary bone infarcts?

Answer 20

Enchondroma w/popcorn calcification

Question 21

A common type of soft tissue cancer, NOT common in bone. BUT pre-existing bone infarcts can give rise to this in bone.

Answer 21

Malignant Fibrous Histiocytoma (MFH)

Question 22

The “T and 6 S’s” for the risk factors of AVN are?

Answer 22

1. Trauma
2. Sickle cell anemia
3. SLE
4. Steroids
5. Scuba divers
6. Sterno abusers (alcoholics)
7. Storage disease (Gaucher’s disease)

Question 23

The teardrop distance should be no more than __-__mm side-to-side

Answer 23

1-2

Question 24

Most common route of bone contamination?

Answer 24

Blood-borne (hematogenous) (infections spread!

Question 25

Mandibular osteomyelitis from tooth infection is an example of what route of bone contamination?

Answer 25

Direct spread from contiguous source

Question 26

A compound fracture is an example of ______, a route of bone contamination.

Answer 26

Direct implantation

Question 27

Post-operative infection is an example of a ____ route of bone contamination.

Answer 27

Iatrogenic

Question 28

90% of all bone and joint infections are caused by _____

Answer 28

Staphylococcus aureus (bacteria)

Question 29

Osteomyelitis in children can look like what two bone tumors/conditions?

Answer 29

Ewing’s sarcoma, osteosarcoma

Question 30

The radiographic features of acute osteomyelitis are similar to what?

Answer 30

Primary bone malignancy - permeative/moth eaten bone destruction - periosteal response - cortical destruction

Question 31

A way to potentially differentiate osteomyelitis from a primary bone malignancy on x-ray is ___ of the fat/muscle interface (in osteomyelitis)

Answer 31

Blurring

Question 32

A dead fragment of bone that is the source of re-infection unless removed

Answer 32

Sequestrum

Question 33

Heavy periosteal new bone surrounding infection

Answer 33

Involucrum

Question 34

A channel that develops due to pressure so that pus can escape

Answer 34

Cloaca

Question 35

Subacute osteomyelitis: a smoldering infection that doesn’t get better or worse. Due to low virulence of the organism and/or good immunity of the host. What is this called?

Answer 35

Brodie’s Abscess

Question 36

DDX for Brodie’s Abscess?

Answer 36

Osteoid Osteoma

Question 37

This can happen secondary to chronic osteomyelitis with a draining sinus (smells). Skin cancer tracks down the sinus into the bone

Answer 37

Epidermoid Carcinoma (poor prognosis)

Question 38

An organism deposits in vertebral endplate and quickly spreads to the disc causing “discitis”

Answer 38

Spinal osteomyelitis

Question 39

Radiographic signs: - loss of disc height - ill-defined endplates w/erosions - soft tissue swelling (where applicable)

Answer 39

Spinal Osteomyelitis

Question 40

T/F: The “Vacuum Phenomenon” which sometimes shows up in the discs of patient’s w/DDD will also occasionally show up in patients w/spinal osteomyelitis

Answer 40

FALSE

Question 41

Are osteophytes and subchondral sclerosis seen in both DDD and spinal osteomyelitis?

Answer 41

No, just DDD

Question 42

There is a classification system in endplate changes due to infection called?

Answer 42

Modic Changes

Question 43

There are 3 types of Modic changes. Initially water/liquid shows up on T1 as LOW signal, and T2 as HIGH signal. Which type of Modic change?

Answer 43

Type 1

Question 44

Modic type 2 shows up HIGH T1 and HIGH T2 and is due to ____

Answer 44

Fat

Question 45

Modic 3 shows up as LOW T1 and LOW T2, and is due to _____

Answer 45

Bone (marble)

Question 46

Which phase of Modic changes can be captured on plain film?

Answer 46

3 (bone)