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20 Cards in this Set
- Front
- Back
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What is the first step in the development of AVN?
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Osteocyte death
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What are the next three steps? What stage is weakest and thus most likely to result in collapse?
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Inflammation
New woven bone laid onto dead trabeculae Dead trabeculae resorbed and remodeled (weakest stage) |
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What percentage of AVNs are bilateral?
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50 to 80%
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What Ficat/Steinberg stage corresponds to subchondral collapse?
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III
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The Association Research Circulation Osseous (ARCO) classification also classifies AVN progression based on what parameter?
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Percentage of head involvement
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What is the radiographic sign of subchondral collapse? What does it actually represent?
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Crescent sign
Space between articular surface and subchondral bone |
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What imaging study has the highest sensitivity and specificity for detecting early AVN?
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Magnetic resonance imaging (MRI)
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What is the recommended treatment for pre-collapse AVN? which patients respond poorly?
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Core decompression
Poor response in patients with history of taking steroids |
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Does a history of steroids adversely affect the outcome of vascularized fibular grafting?
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Steroid history does not worsen outcomes
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What are the two principal complications of free fibula graft harvest?
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Sensory deficit
Valgus instability |
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What is the 5-year failure rate after vascularized fibular grafting?
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33% convert total hip arthroplasty (THA) in 5 years
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What is the maximum percentage of head involvement for consideration of osteotomy?
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50%
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What is the preferred treatment for advanced AVN? What two complications are more likely in AVN patients?
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Total hip arthroplasty
Loosening Dislocation |
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What patients have been classically associated with transient hip osteoporosis?
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Pregnant women
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What patient population is actually most commonly affected?
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Young males
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What diagnostic imaging modality is safe even in pregnancy?
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MRI
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How can transient osteoporosis be differentiated from AVN on MRI?
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Not sharply demarcated like AVN
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What does the medical treatment of transient osteoporosis consist of?
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Nonsteroidal anti inflammatory drugs (NSAIDs)
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What is the weight-bearing status on the affected extremity?
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Non-weight bearing (NWB)
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What is the usual natural history?
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Spontaneous resolution
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