Term
| Describe the normal blood supply of long bones? |
|
Definition
-Proper nutrient artery: medullary cavity, inner 2/3 of cortical bone
-Proximal/distal metaphyseal aa: minor contribution, hypertrophy with damage to nutrient a
-Periosteal aa: outer 1/3 of cortical bone
-epiphyseal aa: epiphysis only (don't cross the physis) |
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Term
| What happens to the blood supply with long bone fractures? |
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Definition
-medullary circulation is initially disrupted
-transient extraosseous vascular supply
-periosteal circulation predominates |
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Term
| What is fracture healing? |
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Definition
| -biologic process that occurs after cartilage and bone disruption, which restores tissue continuity |
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Term
| What are the three goals of fracture healing? |
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Definition
-encourage healing
-restore function to bone and surrounding S.T.
-obtain a cosmetic appearance |
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|
Term
| What are the 3 stages of fracture healing? |
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Definition
-inflammation
-repair
-remodeling |
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Term
| What are the clinical signs of the inflammatory phase of fracture healing? |
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Definition
-swelling
-erythema
-pain
-impaired tissue function
-vasodilation (inc vascular perm) & hematoma formation: vasoactive mediators
-organized hematoma: fibrin + platelets bind to collagen => clot
-clot
-removal of devitalized osteocytes
-proliferation of extraosseous blood vessels |
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Term
| What is the purpose of the clot that forms during the inflammatory phase of fracture healing? |
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Definition
| -early scaffold for migration of reparativ celsl |
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Term
| What happens in the repair phase of fracture healing? |
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Definition
-replacement of necrotic and damaged tissue by new cells/matrix
-undifferentiated mesenchymal cells migrate to injured site via inflammation (synthesizes new matrix)
-callus: scaffold |
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Term
| What happens during the remodeling phase of fracture healing? |
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Definition
-reshaping and reorganizing reparative tissue (removal, replacement, reorganize callus)
-highly disorganized initially
-with pregression: cell density dec, vascularity dec, matrix fibrils reorient along the lines of stress
-cartilage => bone
-late stages: woven bone replaced by lamellar bone |
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Term
| What happens with direct bone healing? |
|
Definition
-fracture surfaces contact one another
-rigid stability
-osteoblasts cross the fracture gap at fracture site
-callus formation not necessary |
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Term
|
Definition
| -direct bone formation in gaps at the fracture line |
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Term
| Outline the stages of gap healing? |
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Definition
-Stage 1: gap filled with fibrous bone
-Stage 2: Haversion remodeling, longitudinal reconstruction of bone |
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Term
| What happens during indirect bone healing? |
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Definition
-endochondral bone formation
-fracture instability present
-fracture ends do not contact
-callus formation |
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Term
| How does motion relate to callus formation? |
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Definition
| -more motion = more callus |
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Term
| How often do we take rads of postop healing bones? |
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Definition
|
|
Term
| What do we evaluate postop healing bones for on rads? |
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Definition
-apparatus: implant integrity
-activity: evidence of bone formation/healing
-alignment of bone
-aposition
-complications |
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Term
| How does direct bone healing appear on rads? |
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Definition
| -fracture line becomes fuzzy |
|
|
Term
| How does indirect bone healing appear on rads? |
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Definition
|
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Term
| What possible complications of bone healing do we look for on rad check-ups? |
|
Definition
-infection
-loose implants
-lack of healing |
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Term
|
Definition
-fracture has not healed within an expected time
-there IS evidence of fracture healing |
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Term
| What do you do when you face a delayed union? |
|
Definition
-wait
-bone graft can be added to speed up
-ensure implants are stable/rigid
-remove loose implants |
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Term
|
Definition
-fracture has no radiographic evidence of progression toward healing
-FDA = for 3 consecutive months |
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Term
| How do we handle nonunion fractures? |
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Definition
|
|
Term
| What are the two most common causes of nonunions? |
|
Definition
-instability
-poor blood supply |
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|
Term
| What are the classifications of nonunions? |
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Definition
-vascular (viable)
-avascular (nonviable) |
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Term
| What does a vascular (viable) nonunion look like? |
|
Definition
-varying degrees of callus formation
-persistent radiolucent line at the fracture site
-adequate biologic environment
-lack of stability |
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Term
| How do we treat vascular nonunion fractures? |
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Definition
-remove loose implants
-functional alignment
-treat infection
-rigid stabilization |
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Term
| What does an avascular nonunion fracture look like? |
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Definition
| -little or no callus inadequate biologic environment |
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Term
| How do we treat avascular nonunion fractures? |
|
Definition
-curettage of fibrous tissue
-remove loose implants
-functional alignment
-treat infection
-rigid fixation
-concellous bone grafting |
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Term
| What are the possible causes of delayed and nonunion fractures? |
|
Definition
-lack of extraosseous soft tissue
-lack of rigidity/fracture stability
-lack of adequate blood supply
-large fracture gaps
-interposition of soft tissue b/n fracture gaps
-comminuted fractures
-poor nutrition
-advanced age
-infection
-antifoagulant therapy
-corticosteroids
-metabolic disturbances |
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Term
| What is a malunion fracture? |
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Definition
| -healed fractures without anatomic alignment was not achieved |
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|
Term
| What are the results of malunion fractures? |
|
Definition
-results = functional problems
-shortening of limb
-rotation of bone segments OS of adjacent joints
-angular limb deformities |
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|
Term
| What are the possible angular limb deformities that may result of malunion fractures? |
|
Definition
-varus
-valgus
-recurvatum
-procurvatum (antecurvatum)
-torsion
-translation |
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Term
|
Definition
| -distal limb is directed medially |
|
|
Term
|
Definition
| -distal limb is directed laterally |
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Term
|
Definition
| -bone is rotated around its long axis |
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|
Term
|
Definition
-distal segment is displaced in any direction
-longitudinal axis is maintained |
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|
Term
|
Definition
-apex of deformity is caudal
-distal limb is directed cranially |
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|
Term
| What is procurvatum (antecurvatum)? |
|
Definition
-apex of deformity is cranial
-distal limb is directed caudally |
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|
Term
|
Definition
-bone remodels along the lines of stress
-can account for some remodeling of a malunion |
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|
Term
| How can we facilitate bone healing? |
|
Definition
-aseptic principles
-minimize vascular compromise: periosteal and endosteal
-stable implants
-stable bone fragments
-bone grafting techniques |
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|
Term
|
Definition
| -bone or bone substitue placed into spaces around a fracture, or within defects in bone to facilitate healing |
|
|
Term
| What is an autograft (autoenous) bone graft? |
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Definition
| -donor and recipient are the SAME INDIVIDUAL |
|
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Term
| What is an allograft (allogenic) bone graft? |
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Definition
| -donor and recipient are the same SPECIES |
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Term
| What is a xenograft (xenogenic) bone graft? |
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Definition
| -donor and recipient are DIFFERENT SPECIES |
|
|
Term
| Which type of bone graft is the best osteogenic potential? |
|
Definition
|
|
Term
| What are the four functions of bone grafts? |
|
Definition
-osteogenesis
-osteoinduction
-osteoconduction
-osteopromotion |
|
|
Term
|
Definition
| -new bone formation from transferred osteoblasts |
|
|
Term
|
Definition
-promote progenitor cell migration/proliferation
-mediated by bone morphogenic proteins (BMPs) |
|
|
Term
|
Definition
| -graft acts as a scaffold for new bone formation |
|
|
Term
|
Definition
| -enhancement of osteoinduction |
|
|
Term
| What are the four compositions of bone grafts? |
|
Definition
-cortical
-cancellous
-corticocancellous
-synthetic |
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|
Term
| What is the most often banked allograft or ulnar graft type? |
|
Definition
|
|
Term
| Describe cortical bone grafts. |
|
Definition
| -dense outer bone used more for structural support |
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|
Term
| What is cancellous bone grafts? |
|
Definition
-highly cellular trabecular bone (metaphysis)
-fresh autograft or frozen allograft |
|
|
Term
| Where do corticocancellous bone grafts come from? |
|
Definition
|
|
Term
| What composes synthetic bone grafts? |
|
Definition
| -calcium phosphate, bioactive glass |
|
|
Term
| Describe cortical allograft bone grafts? |
|
Definition
-avasuclar, acellular
-structural support for large defects
-contraindicated with infection => sequestrum
-osteoconduction, minimal osteoinduction |
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|
Term
| Describe a cancellous autograft. |
|
Definition
-highly cellular, mechanically weak
-osteogenesis, osteoinduciton, osteoconduction |
|
|
Term
| Descrie a cncellou allograft. |
|
Definition
-osteoconduction, no osteoinduction
-limited mechanical support |
|
|
Term
| What are the advantages of cancellous autografts? |
|
Definition
-no histocompatibility problems
-viable cells
-no risk of disease transmission
-inc bone morphogenic proteins
-cheaper |
|
|
Term
| What are the disadvantages of cancellous autografts? |
|
Definition
-inc operative time
-bleeding: minimal
-potential for cross-contamination
-donor sie pain/morbidity
-limited volume
-must have forethough: surgical prep, patient position |
|
|
Term
| What are the advantages of cancellous allografts? |
|
Definition
-no donor site pain/morbidity
-no difficulty with donor site access
-less operative time
-less blood loss
-readily accessible |
|
|
Term
| What are the disadvantages of cancellous allografts? |
|
Definition
-cost
-loss of living cells
-potential dec in BMPs
-histocompatability reactions |
|
|
Term
| What are the indications of bone grafts? |
|
Definition
-enhance and promote healing: delayed union/nonunion, arthrodesis, osteotomies, fractures prone to delayed union
-bridge defects and establish continuity of bone
-replace cortical segments
-fill cavities or partial thickness defects |
|
|
Term
| What are the donor sites of harvesting bone grafts? |
|
Definition
-proximal humerus: most common
-proximomedial tibia: most common
-distal femur: most common
-also: wing of ilium and proximlateral femur |
|
|
Term
| Describe the technique of harvesting bone grafts. |
|
Definition
-minimize time delay: harvest only when ready
-use separate instruments/gloves if question of infection at repair site
-store in blood, not saline |
|
|
Term
| What are the common complications of bone grafts? |
|
Definition
-seeding donor site: infection, neoplasia
-donor site fracture
-donor site seroma
-donor site dehiscence
-donor site pain/morbidity |
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