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33 Cards in this Set
- Front
- Back
What is the principal determinant of fracture healing?
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Blood supply
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What are the three components of the sequence of changes in blood supply after fracture?
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Immediate decrease in blood supply
Increased vascularity fmaximal at 2 weeks) Return to normal by 3 to 5 months |
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What is the effect of reaming?
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Destroys endosteal blood supply
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What are the three effects of nicotine on fracture healing?
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Increased time to fracture healing
Increased risk of nonunion Decreased fracture callus strength |
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Nicotine use is associated with increased risk of fractures at which locations?
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Increases risk of wrist and hip fractures
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How does smoking affect lumbar fusion rates?
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Increases the pseudarthrosis rate of lumbar fusion by 500%
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What is the two-step sequence of callus types formed after fracture?
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Bridging (soft) callus within 2 weeks
Replaced by woven bone (hard callus) |
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Callus is ultimately remodeled over what period?
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Remodeled to lamellar bone within 7 years
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What two types of bone formation are seen with cast treatment of fracture?
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Periosteal bridging callus
Enchondral ossiiication |
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ls there any difference with intramedullary (IM) nail treatment?
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IM nail treatment also results in medullary callus formation late
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Under what two conditions can intramembranous bone formation (no cartilage precursor) be seen after
fracture? |
Low strain
High oxygen tension |
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What type of chondrocytes are present in the first 10 days after fracture?
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Proliferative chondrocytes
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What collagen type do they produce?
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Type II
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What other collagen type is present in the chondroid phase?
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Type IX: cross-linking function
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After 14 days, what chondrocyte type is present?
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Hypertrophic chondrocytes
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What type of collagen do they produce?
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Type X
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What are the next three steps?
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Calcification
Osteoclasts resorb matrix Osteoblasts lay down new bone |
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How do hypertrophic nonunions heal?
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Mineralization of fibrocartilage
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What other treatment modality has a similar mechanism?
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Pulsed electromagnetic field treatment (bone stimulator)
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Rate the four tissue types from highest to lowest strain tolerances?
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Granulation tissue (100% strain tolerance)
Fibrous tissue Cartilage Bone |
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At what phase of fracture healing does direct current exert an effect?
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Inflammatory-response phase
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At what phase of fracture healing does alternating current exert an effect?
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Repair phase (callus)
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What is the effect of pulsed electromagnetic fields?
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lnitiates fibrocartilage calcification
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What is the classic application of this technology?
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Nonhealing pseudo-jones fracture
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What are the two benefits of pulsed low-intensity ultrasound?
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Accelerated fracture healing
Increased callus strength |
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What are the two detrimental effects of radiation?
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Decreased cellularity
Decreased callus strength |
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How long should the latency phase last?
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5 to 7 days
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What is the desired rate of distraction during distraction phase?
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1 mm/day
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What is the duration of the consolidation phase?
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Twice as long as the distraction phase
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What is the weight-bearing status throughout treatment?
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Weight-bearing as tolerated (WBAT)
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What changes are seen in blood vessels?
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Proliferation of vasa vasorum
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What is the oxygen tension with distraction osteogenesis?
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High oxygen tension
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So what type of bone formation is seen tension conditions?
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lntramembranous bone formation (no under these low-strain, high oxygen cartilage precursor)
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