AVN Flashcards
Define avascular necrosis
“ischaemic necrosis of bone predominantly in adults”
Name 6 areas most susceptible to AVN
Femoral head Femoral condyle Head of humerus Capitellum proximal pole of the scaphoid Proximal part of the talus
AVN can be secondary to fractures where? What must these fractures due to cause AVN?
Femoral neck, waist of scaphoid, neck of talus, proximal humerus. they must disrupt blood supply to a portion of bone.
Many cases are idiopathic however some have been tied to alcohol and steroid use/abuse - true/false
True
Why do alcohol and steroid use/abuse increase the chance of AVN?
Alcohol and corticosteroids alter fat metabolism. Fat mobilises and “sludges” up capillaries. Promotes coagulation in prone areas. increase fat content of marrow compresses venous system - causes blood stasis and ischaemia.
AVN is also caused by three of the following options. Pick the correct three: Hypercholesterolaemia thrombophilia hypertension sickle cell disease SLE
thrombophilia
sickle cell disease
SLE - by deficiency of anti-phospholipid.
All increase coagulability and so increase the risk of AVN
Caisson’s disease (decompression sickness/the bends) can cause AVN - true/false. If true - why?
True - nitrogen bubbles form in the circulation from too rapid a decompression and causes ischaemia.
Treatment of AVN depends on __________?
Stage of disease
Radiographic changes cannot be seen early on in the disease but MRI will show changes - true/false?
True
If the articular surface has not collapsed in an amenable site (e.g. the femoral head) how is AVN treated>
Drilling under fluoroscopy to decompress and prevent further necrosis/promote healing.
If the articular surface has collapsed in the hip/shoulder/knee, how is this treated?
Joint replacement is required
If the articular surface has collapsed in the wrist or foot/ankle what may be considered for treatment?
Fusion can be considered.
