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21 Cards in this Set
- Front
- Back
What is the most important thing to consider for a successful bone repair?
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Adequate blood supply
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What are the two types of bone healing? What is the difference? Which takes longer?
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Indirect- healing by intermediate callus formation
Direct- healing by primary osteonal reconstruction Direct |
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In what situations does indirect healing occur? What does a larger callus indicate?
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-Unstable mechanical environment
-Gap > 1mm b/w fragments -Impaired blood supply Higher stability |
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What are the three stages of indirect bone healing? How long does each last? What is the main outcome of each phase?
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1) Inflammatory phase- lasts 3-4 days, with development of clot
2) Repair phase- begins 4-5 , days post break and lasts 6-10 weeks, callus formed 3) Remodeling- can last 6-9 years in humans, bone adapts to regain optimal strength and function |
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When does extraosseous blood supply develop?
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Within hours of break
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What are the two types of direct bone healing? What is the difference?
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Gap- < 1mm
Contact- < 0.01mm |
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How is bone laid down in gap healing? Contact? Are bony union and remodeling separate or combined events in gap healing? Contact?
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Perpendicular to long axis
Longitudinal to long axis Separate Simultaneous |
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Does cancellous/trabecular bone heal by callus formation?
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No
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How will a fracture in a the zone of hypertrophy heal? Zone of proliferation?
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By continued growth of physeal cartilage
Will heal by endochondrial ossification |
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What are the biomechanical approaches to bone healing? What is compromised to achieve this?
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Anatomical reduction and rigid fixation
Soft tissue |
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What is the more favored approach to fracture repair?
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Biological osteosynthesis-emphasizes the role of soft tissue integrity
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With plates and external fixation are you more likely to get direct or indirect healing? With pins, wires, nails and ESF? Casts and splints?
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Direct
Direct or indirect Indirect |
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What type of hardware effects blood supply? Which don't?
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Plates, intermedullary pins and nails
Wires and external fixation pins |
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What are four causes for a bone graft?
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-Comminuted fractures
-Fractures with bone loss -Fractures of joints -Delayed or non-union fractures |
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What are the three types of bone grafts?
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1) Autogenous- patients own bone
2) Allograft- bone from the same species 3) Xenograft- bone from a different species |
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What are the three osteo functions of bone grafts?
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1) Osteogenesis- laying down of new bone
2) Osteoinduction- recruitment of host mesenchymal cells to form new bone 3) Ostoconduction- provide a scaffold for the growth of new bone |
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What is the most common type of bone graft? What are the advantages? Disadvantages?
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Autogenous
Provides osteogenesis, readily available, no rejection (high cellularity if cancellous) Mechanically weak, pain at donor site, increased surgery time |
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What are the advantages of an cancellous allograft? Disadvantage?
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Readily available, no donor site problems
Lacks osteogenic properties |
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What are the four phases of cancellous bone graft healing?
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I- inflammation, hours
II- revascularization and osteoinduction, 2 weeks III- osteoconduction, 3-4 wks IV- mechanical support, up to 12 weeks |
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What do cortical bone grafts provide? What "osteo" properties? What do they lack?
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Structural support
Osteoconductive Osteogenic properties, b/c acellular |
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What is "creeping substitution"?
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Osteoclasts reabsorb bone graft, then osteoblasts lay down new bone
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