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35 Cards in this Set
- Front
- Back
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delayed union
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healing progresses more slowly than average
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slow union
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when fracture line remains clearly visible radiographically but there is no undue separation of the fragments, no cavitation of the surfaces, no calcification, and no sclerosis
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indolent fracture healing may be related to:
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severity of injury
poor blood supply patient age nutritional status |
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nonunion
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failure or arrest of bone healing
typical definition is no evidence of healing clinically or radiographically for at least 3 months |
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hypertrophic nonunion
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nonunion in setting of large volume of callus around fracture site
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atrophic nonunion
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little or no callus forms and bone resorption occurs at the fracture site
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pseudoarthrosis
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nonunion in which cartilagenous tissue forms over the fracture surfaces and the cavity between fills with clear fluid resembling normal joint or bursal fluid - may not be painful but are unstable indefinitively
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fibrous union
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bone ends fill with fibrous or fibrocartilaginous tissue, may be painless and unite fracture fragments but fail to restore normal bone strength
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variables influencing nonunion
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open and high-energy injuries
infections segmental fractures pathologic fractures fractures with soft tissue interposition poor local blood supply systemic diseases malnutrition vitamin D deficiency corticosteroid use poor mechanical fixation iatrogenic interference with healing |
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injury variables to nonunion
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open fractures (soft tissue disruption, bone loss, blood supply, infection)
severity of injury (disrupted soft tissue envelope) intra-articular fractures (instability) segmental fractures (blood supply esp to middle segment) soft tissue interposition (block to reduction) damage to blood supply |
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patient variables to nonunion
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diseases/disorders (DM, HIV)
age nutrition systemic hormones (steroids, T4, calcitonin, insulin) nicotine and other agents (anti-cancer drugs) |
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tissue variables to nonunion
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form of bone (cancellous or cortical)
bone necrosis bone disease (osteoporosis, osteomalacia, tumor, cysts, osteogenesis imperfecta, fibrous dysplasia, Pagets, hyperPTH, infection) infection |
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treatment variables to nonunion
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apposition of fracture fragments
loading and micromotion fracture stabilization |
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FDA definition of nonunion
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fractured bone that has not completely healed within 9 months following injury and shows no progression toward healing on serial radiographs over the course of 3 consecutive months
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theory of NSAID interference with bone healing
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interference with inflammation and prostaglandin synthesis associated with normal fracture healing
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patient dependent risk factors for nonunion
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medical comorbidities
age sex smoking NSAID use genetic disorders (NF, OI, osteopetrosis) metabolic disease nutritional status |
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patient independent risk factors for nonunion
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fracture pattern
fracture location soft tissue envelope status extent of bone loss |
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sites with relatively tenous blood supply
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scaphoid waist
metadiaphyseal region of 5th MT tarsal navicular body |
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patient history of nonunion
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mechanism of injury
open vs closed pain with weight bearing subjective instability infection delayed wound healing |
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physical exam of nonunion
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TTP
motion at fracture site deformity soft tissue evaluation limb vascularity ROM at adjacent joints limb equality |
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radiographic evaluation of nonunion
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orthogonal AP, lateral, oblique
long weight-bearing |
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hypertrophic nonunion
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abundant callus formation without bony bridging
implies adequate biologic capacity for healing implies inadequate mechanical stability |
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atrophic nonunion
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sclerotic bone ends and absence of callus
implies inadequate osteogeneic potential |
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oligotrophic nonunion
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in continuum between hypertrophic and atrophic sharing radiographic and biologic characteristics of each - adequate biologic capacity for healing but little to no callus formation
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which types of nonunion demonstrate increased uptake on Technetium-99 bone scan
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hypertrophic and oligotrophic
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MRI use in nonunion evaluation
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assess presence and extent of marrow changes and surrounding soft tissues when suspect infection
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laboratory workup for nonunion
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CBC with diff
ESR CRP metabolic/endocrine |
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endocrine w/u tests
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calcium
serum 25-OH vitamin D TSH phosphorus alkaline phosphatase |
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markers of bone turnover
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c-telopeptide of type I collagen
c-termal telopeptide of type I collagen pyridinoline deoxypyridinoline tartrate-resistant acid phosphatase osteocalcin bone-specific alkaline phosphatase |
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sensitivity and specificity of CT in diagnosing nonunion
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100% sensitive
62% specificity |
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beneficial effects of extracorpeal shock wave therapy
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increased bone mass and strength
angiogenesis differentiation of mesenchymal stem cells |
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when is conversion to ex fix often considered
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infected nonunion following IMN
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beneficial biologic effects of reaming
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periosteal blood flow
stimulation of periosteal bone formation compression |
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application of adjunctive plate fixation in setting of statically locked IMN
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hypertrophic nonunions requiring improved mechanical stabilization, esp metaphyseal
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why is graft placed through posterolateral approach
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avoid subcutaneous anterior tibia
improved vascular supply enhances incorporation |
