Osteonecrosis/EIN/AVN

Question 1

How is AVN classified?

Answer 1

3 groups:

Bone ends Children (epiphyseal ischemic necrosis)

Bone ends Adults

Medullary Infarcts

Question 2

Most common location of AVN in bone ends of children?

Answer 2

Capital Femoral Epiphysis

Question 3

Most common location of AVN in bone ends of adults?

Answer 3

Femoral head

Question 4

Define Medullary Infarction

Answer 4

A vascular necrosis occurring at nonarticular locations, most commonly metaphysics and diaphysis

Question 5

EIN in children etiology?

Answer 5

Probably related to trauma

Question 6

AVN in adults Etiology?

Answer 6

Spontaneous - usually no identifiable cause

Other causes: trauma, alcoholism, corticosteroids,
Caisson’s disease, Gaucher’s Disease
Hemoglobinopathy, AI disease,
Radiation, pancreatitis, gout

Question 7

Etiology of AVN medullary infarctions?

Answer 7

Frequently undetermined

Question 8

4 stages of AVN

Answer 8

1. Avascular phase
2. Revascularization phase
3. Re-ossification
4. Healed

Question 9

Avascular phase of AVN:

Answer 9

interruption of vascularity, may show joint effusion

Question 10

Revascularization Phase of AVN:

Answer 10

Deposition and resorption of bone creating mottled density change, may have SNOW CAPPED appearance, fragmentation, osseous deformity

Question 11

Re-ossification phase of AVN-

Answer 11

Reconstitution of the epiphysis with normal appearing bone

Question 12

Healed phase of AVN -

Answer 12

Normal appearing bone; persistent deformity

Question 13

Will children heal completely from AVN? if so how long will it take usually?

Will Adults recover from AVN?

Answer 13

Children WILL eventually go through all 4 stages and heal, healing time variable: 2 to 8 years

Adults remain in REVASCULARIZATION phase w/ RAPID progression of secondary DJD

Question 14

EIN in second metatarsal head?

Answer 14

Freiberg’s Disease

Question 15

EIN in the vertebral bodies?

Answer 15

Scheuermann‘ s Disease

Question 16

Most important type of EIN, from the standpoint of incidence and morbidity?

Answer 16

Legg-Calve-Perthes’ Disease

Question 17

EIN in the femoral capital epiphysis

Answer 17

Legg-Calve-Perthes’ Disease

Question 18

Legg-Calve-Perthes AKA

Answer 18

ischemic coxa plana

Question 19

It is important to be able to differentiate LCP disease from _______________.

Answer 19

Femoral head Dysplasia

Question 20

EIN peak Age of Incidence

Answer 20

6 but onset may occur b/n ages of 3-12

Question 21

T/F Aside from Sickle Cell disease, EIN is rarely seen in the negro population

Answer 21

True

Question 22

What is the earliest Roentgen sign of legg-calve-perthes?

Answer 22

Waldenstrom’s sign -
lateral displacement of the femoral head with resultant joint space widening
(Greater than 11 mm distance from lateral margin of pelvic teardrop to the proximal medial femoral metaphysis) = hip involvement

Question 23

Earliest osseous manifestation of AVN? (Legg-calve-perthes)

Answer 23

Crescent sign- subarticular zone of radiolucency in the femoral head with subsequent separation of an arc-like fragment which can be seen best in the frog-leg position

Question 24

1st stage of legg-calve-perthes lasts how long?

Answer 24

2 weeks - 2 months

Question 25

2nd stage of Legg-calve-perthes lasts how long?

Answer 25

6-18 months

Question 26

Predominant feature of 2nd stage EIN? (Legg-calve-perthes)

Answer 26

Fragmentation and flattening of the femoral head (mushroom appearance)

Question 27

The gamut of EIN, according to Reeder and Felson, includes the following common conditions listed in order of incidence:

Answer 27

1. Idiopathic
2. Occlusive vascular disease
3. Osteochondritis dissecans
4. Sickle cell or other primary anemia
5. Steroid therapy
6. Trauma

Question 28

The DDx of AVN/EIN includes:

Answer 28

Tuberculous Arthritis

JRA (Still’s Disease)

Question 29

Differentiate b/n a bone infarct and AVN

Answer 29

Bone infarcts occur in the diaphysis or metaphysis where

Lesions in the Epyphysis are referred to as Avascular necrosis

Question 30

Osteonecrosis definition

Answer 30

Bone death due to a lack of blood supply

Question 31

ETIOLOGY LIST FOR ISCHEMIC NECROSIS

Answer 31

PLASTIC RAGS

Pancreatitis, Pregnancy
Lupus
Alcoholism
Steroids/endogenous or exogenous
Trauma
Idiopathic
Caisson’s
RA, radiation necrosis
Amyloidosis
Gaucher’s
Sickle Cell Disease

Question 32

3 principles of Infarction

Answer 32

1. Intracellular metabolic activity stops
2. This interrupts or alters intracellular enzyme systems
3. Intracellular nuclear and cytoplasmic ultrastructure is disrupted or dissolutes. IRREVERSIBLE