Femoral Neck Fractures

Brian Boyer, MD

AnatomyPhyseal closure age 16Neck-shaft angle 130 7Anteversion 10 7Calcar Femorale Posteromedial dense plate of bone

Blood SupplyLateral epiphysel arteryterminal branch MFC arterypredominant blood supply to weight bearing dome of headArtery of ligamentum teresfrom obturator arterysupplies anteroinferior headLateral femoral circumflex a.less contribution than MFC

Blood Supplyfracture displacement=vascular disruptionrevascularization of the head intact vesselsvascular ingrowth across fracture siteimportance of quality of reductionmetaphyseal vessels

Epidemiology250,000 Hip fractures annuallyExpected to double by 2050At risk populationsElderly: poor balance&vision, osteoporosis, inactivity, medications, malnutritionincidence doubles with each decade beyond age 50higher in white populationOther factors: smokers, small body size, excessive caffeine & ETOH Young: high energy trauma

ClassificationPauwels [1935]Angle describes vertical shear vector

ClassificationGarden [1961]I Valgus impacted or incompleteII Complete Non-displacedIII Complete Partial displacementIV Complete Full displacement** Portends risk of AVN and NonunionIIIIIIIV

ClassificationFunctional Classification Stable Impacted (Garden I)Non-displaced (Garden II)UnstableDisplaced (Garden III and IV)

TreatmentGoalsImprove outcome over natural historyMinimize risks and avoid complicationsReturn to pre-injury level of functionProvide cost-effective treatment

TreatmentOptionsNon-operativevery limited roleActivity modificationSkeletal tractionOperativeORIFHemiarthroplastyTotal Hip Replacement

TreatmentDecision Making VariablesPatient CharacteristicsYoung (arbitrary physiologic age < 65)High energy injuriesOften multi-traumaHigh Pauwels Angle (vertical shear pattern)ElderlyLower energy injuryComorbiditiesPre-existing hip diseaseFracture CharacteristicsStableUnstable

TreatmentYoung Patients(Arbitrary physiologic age < 65)Non-displaced fracturesAt risk for secondary displacementUrgent ORIF recommendedDisplaced fracturesPatients native femoral head bestAVN related to duration and degree of displacementIrreversible cell death after 6-12 hoursEmergent ORIF recommended

TreatmentElderly PatientsOperative vs. Non-operativeDisplaced fractures Unacceptable rates of mortality, morbidity, and poor outcome with non-operative treatment [Koval 1994]Non-displaced fractures Unpredictable risk of secondary displacement AVN rate 2XStandard of care is operative for all femoral neck fracturesNon-operative tx may have developing role in select patients with impacted/ non-displaced fractures [Raaymakers 2001]

TreatmentPre-operative ConsiderationsSkin Traction not beneficialNo effect on fracture reductionNo difference in analgesic usePressure sore/ skin problemsIncreased costTraction position decreases capsular volumePotential detrimental effect on blood flow

TreatmentPre-operative ConsiderationsRegional vs. General AnesthesiaMortality / long term outcomeNo DifferenceRegional Lower DVT, PE, pneumonia, resp depression, and transfusion ratesFurther investigation required for definitive answer

TreatmentPre-operative ConsiderationsSurgical TimingSurgical delay for medical clearance in relatively healthy patients probably not warrantedIncreased mortality, complications, length of staySurgical delay up to 72 hours for medical stabilization warranted in unhealthy patients

ORIFHemiTHR

Non-displaced FracturesORIF standard of carePredictable healingNonunion < 5%Minimal complicationsAVN < 8%Infection < 5%Relatively quick procedureMinimal blood lossEarly mobilizationUnrestricted weight bearing with assistive device PRN

ORIFIdeal reduction is AnatomicAcceptable: < 15 valgus < 10 AP angulation * may need to open in order achieve reductionFixation: Multiple screws in parallel No advantage to > 3 screwsUniform compression across fractureIn-situ pin impacted fractures * AVN with disimpaction [Crawford 1960]Fixation most dependent on bone density

ORIFScrew locationAvoid posterior/ superior quadrantBlood supplyCut-outBiomechanical advantage to inferior/ calcar screw [Booth 1998]

ORIFCompression Hip ScrewsSacrifices large amount of boneMay injure blood supplyBiomechanically superior in cadaversAnti-rotation screw often neededIncreased cost and operative timeNo clinical advantage over parallel screws * May have role in high energy/ vertical shear fractures

ORIFIntracapsular Hematomaincidence- 75% have some no difference displaced/nondisplaced? Amount of > 100 mm in 25%sensitive to leg positionextension + internal rotation= badanimal models: pressure= perfusionTheoretical benefit with NO clinical proofbut it doesnt hurt

Displaced FracturesHemiarthroplasty vs. ORIFORIF is an option in elderly** Surgical emergency in young patients **ComplicationsNonunion 10 -33%AVN 15 33%AVN related to displacement Early ORIF no benefitLoss of reduction / fixation failure 16%

Displaced FracturesHemiarthroplasty vs. ORIFHemi associated withLower reoperation rate (6-18% vs. 20-36%)Improved functional scoresLess painMore cost-effectiveSlightly increased short term mortalityLiterature supports hemiarthroplasty for displaced fractures [Lu-yao JBJS 1994] [Iorio CORR 2001]

HemiarthroplastyUnipolar vs. BipolarBipolar theoretical advantagesLower dislocation rateLess acetabular wear/ protrusioLess PainMore motion

HemiarthroplastyUnipolar vs. BipolarBipolarDisadvantagesCostDislocation often requires open reductionLoss of motion interface (effectively unipolar)Polyethylene wear/ osteolysis not yet studied for Bipolars

HemiarthroplastyUnipolar vs. BipolarComplications / Mortality / Length of stayNo DifferenceHip Scores / Functional OutcomesNo significant differenceBipolar slightly better walking speeds, motion, painRevision ratesUnipolar 20% vs. Bipolar 10% (7 years)Unipolar more cost-effectiveLiterature supports use of either implant

HemiarthroplastyCemented vs. Non-cementedCement (PMMA)Improved mobility, function, walking aidsMost studies show no difference in morbidity / mortalitySudden Intra-op cardiac death risk slightly increased: 1% cemented hemi for fx vs. 0.015% for elective arthroplastyNon-cemented (Press-fit)Pain / Loosening higherIntra-op fracture (theoretical)

HemiarthroplastyCemented vs. Non-cementedConclusion:Cement gives better resultsFunctionMobilityImplant StabilityPainCost-effectiveLow risk of sudden cardiac deathUse cement with caution

TreatmentPre-operative ConsiderationsSurgical ApproachPosterior approach to hip60% higher short-term mortality vs. anterior

Dislocation rateNo significant difference [Lu-Yao JBJS 1994]

Total Hip ReplacementDislocation rates:Hemi 2-3% vs. THR 11% (short term)2.5% THR recurrent dislocation [Cabanela Orthop 1999]Reoperation:THR 4% vs. Hemi 6-18%DVT / PE / Mortality no differencePain / Function / Survivorship / Cost-effectivenessTHR better than Hemi [Lu Yao JBJS 1994] [Iorio CORR 2001]

ORIF or Replacement?Prospective, randomized study ORIF vs. cemented bipolar hemi vs. THAambulatory patients > 60 years of age37% fixation failure (AVN/nonunion)similar dislocation rate hemi vs. THA (3%)ORIF 8X more likely to require revision surgery than hemi and 5X more likely than THA THA group best functional outcome

Keating et al OTA 2002

Stress FracturesPatient population:Females 410 times more commonAmenorrhea / eating disorders commonFemoral BMD average 10% less than control subjectsHormone deficiencyRecent increase in athletic activityFrequency, intensity, or durationDistance runners most common

Stress FracturesClinical PresentationActivity / weight bearing related Anterior groin painLimited ROM at extremes Antalgic gaitMust evaluate back, knee, contralateral hip

Stress FracturesImagingPlain RadiographsNegative in up to 66%Bone ScanSensitivity 93-100%Specificity 76-95%MRI100% sensitivity / specificityAlso Differentiates: synovitis, tendon/ muscle injuries, neoplasm, AVN, transient osteoporosis of hip

Stress FracturesClassificationCompression sidedCallus / fracture at inferior aspect femoral neckTension sidedCallus / fracture at superior aspect femoral neckDisplaced

Stress FracturesTreatmentCompression sidedFracture line extends < 50% across neckstableTx: Activity / weight bearing modificationFracture line extends >50% across neckPotentially unstable with risk for displacementTx: Emergent ORIFTension sidedUnstableTx: Emergent ORIFDisplacedTx: Emergent ORIF

Stress FracturesComplicationsTension sided and Compression sided fxs (>50%) treated non-operativelyVarus malunionDisplacement30-60% complication rateAVN 42%Delayed union 9%Nonunion 9%

Femoral Neck NonunionDefinition: not healed by one year0-5% in Non-displaced fractures9-35% in Displaced fracturesIncreased incidence withPosterior comminutionInitial displacementInadequate reductionNon-compressive fixation

Femoral NeckNonunionClinical presentationGroin or buttock painActivity / weight bearing relatedSymptoms more severe / occur earlier than AVNImagingRadiographs: lucent zonesCT: lack of healingBone Scan: high uptakeMRI: assess femoral head viability

Femoral NeckNonunionTreatmentElderly patientsArthroplastyResults typically not as good as primary elective arthroplastyGirdlestone Resection ArthroplastyLimited indicationsdeep infection?

Femoral NeckNonunionYoung patients (must have viable femoral head)Varus alignment or limb shortenedValgus-producing osteotomyNormal alignmentBone graft / muscle-pedicle graftRepeat ORIF

Osteonecrosis (AVN)Femoral Neck Fractures5-8% Non-displaced fractures20-45% Displaced fracturesIncreased incidence withINADEQUATE REDUCTIONDelayed reductionInitial displacementassociated hip dislocation?Sliding hip screw / plate devices

Osteonecrosis (AVN)Femoral Neck FracturesClinical presentationGroin / buttock / proximal thigh painMay not limit functionOnset usually later than nonunionImagingPlain radiographs: segmental collapse / arthritisBone Scan: cold spotsMRI: diagnostic

Osteonecrosis (AVN)Femoral Neck FracturesTreatmentElderly patientsOnly 30-37% patients require reoperationArthroplastyResults not as good as primary elective arthroplastyGirdlestone Resection ArthroplastyLimited indications

Osteonecrosis (AVN)Femoral Neck FracturesTreatmentYoung PatientsNO good option existsProximal OsteotomyLess than 50% head collapseArthroplastySignificant early failureArthrodesisSugnificant functional limitations** Prevention is the Key **

Femoral Neck FracturesComplicationsFailure of FixationInadequate / unstable reductionPoor bone qualityPoor choice of implantTreatmentElderly: ArthroplastyYoung: Repeat ORIF Valgus-producing osteotmy Arthroplasty

Femoral Neck FracturesComplicationsPost-traumatic arthrosisJoint penetration with hardwareAVN relatedBlood TransfusionsTHR > Hemi > ORIFIncreased rate of post-op infectionDVT / PEMultiple prophylactic regimens existLow dose subcutaneous heparin not effective

Femoral Neck FracturesComplicationsOne-year mortality 14-50%Increased risk:Medical comorbiditiesSurgical delay > 3 daysInstitutionalized / demented patientArthroplasty (short term / 3 months)Posterior approach to hip

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