Osteonecrosis/EIN/AVN Flashcards
How is AVN classified?
3 groups:
Bone ends Children (epiphyseal ischemic necrosis)
Bone ends Adults
Medullary Infarcts
Most common location of AVN in bone ends of children?
Capital Femoral Epiphysis
Most common location of AVN in bone ends of adults?
Femoral head
Define Medullary Infarction
A vascular necrosis occurring at nonarticular locations, most commonly metaphysics and diaphysis
EIN in children etiology?
Probably related to trauma
AVN in adults Etiology?
Spontaneous - usually no identifiable cause
Other causes: trauma, alcoholism, corticosteroids,
Caisson’s disease, Gaucher’s Disease
Hemoglobinopathy, AI disease,
Radiation, pancreatitis, gout
Etiology of AVN medullary infarctions?
Frequently undetermined
4 stages of AVN
- Avascular phase
- Revascularization phase
- Re-ossification
- Healed
Avascular phase of AVN:
interruption of vascularity, may show joint effusion
Revascularization Phase of AVN:
Deposition and resorption of bone creating mottled density change, may have SNOW CAPPED appearance, fragmentation, osseous deformity
Re-ossification phase of AVN-
Reconstitution of the epiphysis with normal appearing bone
Healed phase of AVN -
Normal appearing bone; persistent deformity
Will children heal completely from AVN? if so how long will it take usually?
Will Adults recover from AVN?
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
EIN in second metatarsal head?
Freiberg’s Disease
EIN in the vertebral bodies?
Scheuermann‘ s Disease
Most important type of EIN, from the standpoint of incidence and morbidity?
Legg-Calve-Perthes’ Disease
EIN in the femoral capital epiphysis
Legg-Calve-Perthes’ Disease
Legg-Calve-Perthes AKA
ischemic coxa plana
It is important to be able to differentiate LCP disease from _______________.
Femoral head Dysplasia
EIN peak Age of Incidence
6 but onset may occur b/n ages of 3-12
T/F Aside from Sickle Cell disease, EIN is rarely seen in the negro population
True
What is the earliest Roentgen sign of legg-calve-perthes?
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
Earliest osseous manifestation of AVN? (Legg-calve-perthes)
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
1st stage of legg-calve-perthes lasts how long?
2 weeks - 2 months
2nd stage of Legg-calve-perthes lasts how long?
6-18 months
Predominant feature of 2nd stage EIN? (Legg-calve-perthes)
Fragmentation and flattening of the femoral head (mushroom appearance)
The gamut of EIN, according to Reeder and Felson, includes the following common conditions listed in order of incidence:
- Idiopathic
- Occlusive vascular disease
- Osteochondritis dissecans
- Sickle cell or other primary anemia
- Steroid therapy
- Trauma
The DDx of AVN/EIN includes:
Tuberculous Arthritis
JRA (Still’s Disease)
Differentiate b/n a bone infarct and AVN
Bone infarcts occur in the diaphysis or metaphysis where
Lesions in the Epyphysis are referred to as Avascular necrosis
Osteonecrosis definition
Bone death due to a lack of blood supply
ETIOLOGY LIST FOR ISCHEMIC NECROSIS
PLASTIC RAGS
Pancreatitis, Pregnancy Lupus Alcoholism Steroids/endogenous or exogenous Trauma Idiopathic Caisson’s RA, radiation necrosis Amyloidosis Gaucher’s Sickle Cell Disease
3 principles of Infarction
- Intracellular metabolic activity stops
- This interrupts or alters intracellular enzyme systems
- Intracellular nuclear and cytoplasmic ultrastructure is disrupted or dissolutes. IRREVERSIBLE
