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19.02.09
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J BONEJOINTSURGAM.VOLUME91-A . NUMBER1 . JANUARY2009
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TOFIXORNOTTOFIXEARLY.
Riska (1976), Boulanger (1997) and Bone LB(1989) have suggested that early stabilization ofmajor long-bone fractures (most commonly
femur fracture) will reducethe incidence ofpulmonary complications and mortality
Crowl (2000), Pape (2000) and Giannoudis(2003) have suggested that internal fixation oflong-bone fractur
es, either with intramedullary
nailing or plateing, may have potentiallydeleterious effectsin the acute setting, whensystemic hypoperfusion and inflammation mayincrease susceptibility to end-organ injury and
increase morbidity
Whereas Rixen (2005) and Dunham (2001)demonstrated no differencein morbidity or
mortality between early and late operative
treatment of femoral shaft fractures.
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MATERIALANDMETHODS
Sampling
National Trauma Data Bank
567trauma centers around the US
Nearly one million incident trauma casesthat occurred overthe five-year period)2000 to 2004)
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MATERIALANDMETHODS
Sampling
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MATERIALANDMETHODS
Confounders
Potentially confounding covariates:
age,sex,race,Glasgow Coma Scale score on arrivalfirst systolic blood pressure
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MATERIALANDMETHODS
Treatment Variables
t0 12 hrs
t1 1224 hrs
t2 2448 hrs
t3 48120 hrs
t4 > 120 hrs
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MATERIALANDMETHODS
Hypothesis
Authors hypothesize that additionalphysiologic stress from definitive fracturesurgery could activate an adverse systemic
responseleading to end-organ injury,multiple organ failure, and excessmortality.
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MATERIALANDMETHODSMain Outcome Measure
Authors believe in the absence of patient-centered outcomes (i.e., health-relatedquality of life) and systematic assessment
of morbid events after treatment,mortality is the most objective, andtherefore likely valid, end point.
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MATERIALANDMETHODSStatistical Methods
Marginal Structural Study (MSM)
Inverse Probability of Treatment
Weighting (IPTW) Potential for differences of treatment
effect (effect modification) four different
subgroups (head or neck, chest,abdominal, or additional extremity/pelvicinjury)
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MATERIALANDMETHODSStatistical Methods
Hypothesis that patients with seriousinjuries (AIS 3) in any one of these fourgroup would have a greater relative risk
reduction with fixation delayed beyond thefirst twelve hours of hospitalization thanthose without such associated injuries
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MATERIALANDMETHODSStatistical Methods
Test performed by modified bootstrapapproach (non-parametrical)
The level of significance p < 0.05
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RESULTS
More than
50 % cases
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RESULTS
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RESULTS
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In general, more
severely injuredpatients appear tobenefit morestrongly fromdelaying surgery for
at least twelve hours
RESULTS
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RESULTS
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Authors emphasized on cautious approachto early definitive femoral shaft fracturefixation in patients with multisystem
trauma (especially abdominal injuries).
This finding was supported by otherinvestigations including Ziran et al (1997)and White et al (2004)
DISCUSSION
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Hypoperfusion resulting from trauma mayprime the immune system for aninflammatory response if such treatment
is undertaken prior to adequateresuscitation and can lead to substantialend-organ injury.
DISCUSSION
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The realization of this phenomenon hasled to the description of so-calledDamage Control Orthopaedics, whereby
definitive treatment is delayed untilresuscitation of the patient has beenadequately achieved.
DISCUSSION
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Retrospective observational study
Marginal Structural Study (MSM)
Inverse Probability of TreatmentWeighting (IPTW)
Methodology well designed
HINTS
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Methodology - well designed
Objective achieved
Confounding factors included
Was the cut point of 12 hoursappropriate...?
Practically useful. mmm!!!
HINTS
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URAMANAT -IRAN
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ISFAHAN -IRAN
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Marginal Structural Study (MSM)
In observational studies, estimation of thecausal effect of an exposure on an outcomemay be biased because of confounding
In a point-exposure study, this istraditionally done by modelingtheprobability of disease as a function ofexposure and pretreatment covariates
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Marginal Structural Study (MSM)
First described by Robines in 1990s
Allow proper adjustment for time-
dependent confounding
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Time-dependent confounding
If time-varying covariates aresimultaneously confounders andintermediatesthat is, covariates are
predictors of outcomeand also predictsubsequent exposure, and past exposurehistory predicts resulting covariate level
Such covariates are called time-dependentconfounders, and they pose uniqueanalytical challenges
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Inverse Probability of Treatment Weighting(IPTW)
Frequently used to estimate the causal effectsof treatments and interventions
The consistency of the IPTW estimator reliesnot only on the well-recognized assumptionof no unmeasured confounders (SequentialRandomization Assumption or SRA), butalso on the assumption of experimentation inthe assignment of treatment (ExperimentalTreatment Assignment or ETA).
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This method uses the reciprocal of theconditional probability of a subjectreceiving an assigned treatment given other
covariates as a means of confoundingcontrol in order to determine the effect oftreatment
Inverse Probability of Treatment Weighting(IPTW)
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Abbreviated Injury Scale (AIS)
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C
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SaamMorshed, MD, MPH,
TheodoreMiclau III, MD,
Oliver Bembom, PhD,
Mitchell Cohen, MD,
M. Margaret Knudson, MD,
John M. Colford Jr., MD, PhD
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DELAYEDINTERNALFIXATION OF
FEMORAL SHAFT FRACTURE REDUCES
MORTALITYAMONG PATIENTWITH
MULTISYSTEM TRUAMA
SaamMorshed, MD, MPH,
TheodoreMiclau III, MD,Oliver Bembom, PhD,
Mitchell Cohen, MD,
M. Margaret Knudson, MD,
John M. Colford Jr., MD, PhD
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DELAYEDINTERNALFIXATION OF FEMORAL SHAFTFRACTURE REDUCES MORTALITYAMONG PATIENT
WITH MULTISYSTEM TRUAMA
SaamMorshed, MD, MPH,
TheodoreMiclau III, MD,
Oliver Bembom, PhD,
Mitchell Cohen, MD,
M. Margaret Knudson, MD,
John M. Colford Jr., MD, PhD
TITLE
WRITERS
J BONE JOINT SURGAM. 2009;91:3-13doi:10.2106/JBJS. H. 00338
PUBLICATION
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J BONEJOINTSURGAM.VOLUME91-A . NUMBER1 . JANUARY2009
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To fix or not to fix early
Riska (1976), Boulanger (1997) and Bone LB(1989) have suggested that early stabilization ofmajor long-bone fractures (most commonlyfemur fracture) will reducethe incidence ofpulmonary complications and mortality
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Crowl (2000), Pape (2000) and Giannoudis(2003) have suggested that internal fixation oflong-bone fractures, either with intramedullarynailing or plateing, may have potentiallydeleterious effectsin the acute setting, whensystemic hypoperfusion and inflammation mayincrease susceptibility to end-organ injury and
increase morbidity
To fix or not to fix early
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Whereas Rixen (2005) and Dunham (2001)demonstrated no differencein morbidity ormortality between early and late operativetreatment of femoral shaft fractures.
To fix or not to fix early
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To fix or not to fix early
Crowl (2000), Pape (2000) and Giannoudis(2003) have suggested that internal fixation oflong-bone fractures, either with intramedullarynailing or plateing, may have potentiallydeleterious effectsin the acute setting, whensystemic hypoperfusion and inflammation mayincrease susceptibility to end-organ injury and
increase morbidity
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To fix or not to fix early
Whereas Rixen (2005) and Dunham (2001)demonstrated no differencein morbidity ormortality between early and late operativetreatment of femoral shaft fractures.