Primary Hip ArthroplastyPrimary Hip ArthroplastyCementedCemented

&&UncementedUncemented

Frank R. Ebert, MDFrank R. Ebert, MD

Union Memorial HospitalUnion Memorial HospitalBaltimore, MarylandBaltimore, Maryland

Johns HopkinsJohns Hopkins

Union MemorialUnion Memorial

Orthopædic Review CourseOrthopædic Review Course

Anatomic ApproachAnatomic Approach

Anterior ApproachAnterior Approach

Anterior-Lateral ApproachAnterior-Lateral Approach

Posterior ApproachPosterior Approach

Medial ApproachMedial Approach

Anatomic ApproachAnatomic Approach

Open Reduction – CDHOpen Reduction – CDH

Pelvic OsteotomiesPelvic Osteotomies

Intra-Articular FusionIntra-Articular Fusion

Rarely Total HipRarely Total Hip

Internervous PlaneInternervous Plane

SuperficialSuperficial

–– Sartorius / TFL Sartorius / TFL ( Femoral/Superior gluteal )( Femoral/Superior gluteal )

DeepDeep

– – Rectus / gluteus mediusRectus / gluteus medius ( Superior gluteal )( Superior gluteal )

Anterolateral ApproachAnterolateral Approach

Most common for THAMost common for THA ORIF of femoral neckORIF of femoral neck Synovial biopsy of the hipSynovial biopsy of the hip

Anterolateral ApproachAnterolateral Approach

Internervous plane – noneInternervous plane – none

TFL / gluteus mediusTFL / gluteus medius

Superior gluteal / Superior glutealSuperior gluteal / Superior gluteal

Lateral ApproachLateral Approach

DangersDangers

– – Superior gluteal nerveSuperior gluteal nerve

– – Femoral nerveFemoral nerve

Medial ApproachMedial Approach

CDH open reductionCDH open reduction

Psoas ReleasePsoas Release

Obturator NeurectomyObturator Neurectomy

Biopsy or Treatment of tumors Biopsy or Treatment of tumors of femoral neckof femoral neck

Medial ApproachMedial Approach

Internervous plane ( only deep )Internervous plane ( only deep )

Superficial :Superficial :

Adductor Longus / gracilisAdductor Longus / gracilis

Deep :Deep :

Adductor Brevis / magnusAdductor Brevis / magnus

Posterior ApproachPosterior Approach

Internervous plane – noneInternervous plane – none

splits gluteus maximussplits gluteus maximus

( inferior gluteal )( inferior gluteal )

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Posterior ApproachPosterior Approach

Total hip replacementTotal hip replacement

ORIF of posterior column fracturesORIF of posterior column fractures

Dependent drainage of hip sepsisDependent drainage of hip sepsis

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Posterior ApproachPosterior Approach

Sciatic NerveSciatic Nerve Inferior gluteal arteryInferior gluteal artery

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Design FeaturesDesign Features SizeSize ShapeShape Device configurationDevice configuration Material / physical propertiesMaterial / physical properties

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Resist Composite FailureResist Composite Failure Prosthetic DeviceProsthetic Device Bone CementBone Cement Cancellous BoneCancellous Bone Cortical BoneCortical Bone

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Design Features Design Features Femoral HeadFemoral Head NeckNeck StemStem Collar Collar AcetabulumAcetabulum

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Prosthetic Hip LoadingProsthetic Hip Loading Changes from externally Changes from externally

loaded system to an internally loaded system to an internally loaded systemloaded system

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Femoral Head DesignFemoral Head Design

Articulating finishArticulating finish

Head diameterHead diameter

DDESIGNESIGN

FFEATURESEATURES

Primary Hip ArthroplastyPrimary Hip Arthroplasty

32 mm Head Size32 mm Head Size Greater acetabular looseningGreater acetabular loosening Greatest volumetric wearGreatest volumetric wear

Ritter COOR ‘76Ritter COOR ‘76Morrey Morrey JBJSJBJS ‘89 ‘89

Design FeaturesDesign Features22mm Head Size22mm Head Size

Greatest linear wearGreatest linear wear

Greatest acetabular Greatest acetabular penetrationpenetration

MorreyMorreyJBJSJBJS 1989 1989

Design FeaturesDesign Features

Charnley 22mm head diameterCharnley 22mm head diameter

Compromise friction / wearCompromise friction / wear

Design FeaturesDesign Features28 mm Head Size28 mm Head Size

Stable as 32mm head sizeStable as 32mm head size

Less torque than the 32mm headLess torque than the 32mm head

More favorable direct stress More favorable direct stress transmission patternstransmission patterns

Primary Hip ArthroplastyPrimary Hip Arthroplasty

28 mm Head Size28 mm Head Size

•• CompromiseCompromise

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Design Features Design Features Femoral Neck GeometryFemoral Neck Geometry Neck stem angle – 135ºNeck stem angle – 135º Neck stem offsetNeck stem offset

– – large offset . . . large offset . . . Bending momentBending moment

– – small offset . . . small offset . . . Decreases moment Decreases moment armarm

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Design FeaturesDesign Features

Femoral StemFemoral Stem

– – LengthLength

– – ShapeShape

– – Material propertiesMaterial properties

– – Surface finishSurface finish

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Femoral Stem DesignFemoral Stem Design Cross sectional geometryCross sectional geometry Defines strength / stiffnessDefines strength / stiffness Avoid sharp cornersAvoid sharp corners

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Femoral Stem DesignFemoral Stem Design Large lateral volumeLarge lateral volume Less tensile stress in the mantle Less tensile stress in the mantle

laterallylaterally Large medial volume less tensile Large medial volume less tensile

stressstress

Primary Hip ArthroplastyPrimary Hip Arthroplasty

CollarCollar

Primary role for optimal load transfer Primary role for optimal load transfer to proximal femurto proximal femur

Crowninshield Crowninshield JBJSJBJS ‘80 ‘80Andriacchi Andriacchi JBJSJBJS ‘76 ‘76

Primary Hip ArthroplastyPrimary Hip Arthroplasty

CollarCollar Reduces adaptive bone Reduces adaptive bone

resorptionresorption Reduce bending stress in the Reduce bending stress in the

componentcomponent Reduce stress in the distal Reduce stress in the distal

cementcement

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Fixation FeaturesFixation Features

PMMAPMMA

Weak linkWeak link

Poor fracture toughnessPoor fracture toughness

Low tensile and fatigue strengthLow tensile and fatigue strength

Elastic modulus 1/3 lower than Elastic modulus 1/3 lower than cortical bonecortical bone

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Fixation FeaturesFixation FeaturesPMMA ImprovementsPMMA Improvements

Carbon FibersCarbon Fibers Decreased cement Decreased cement intrusion / increased intrusion / increased viscosityviscosity

Low ViscosityLow Viscosity Lower fatigue strengthLower fatigue strength

CentrifugationCentrifugation Improved tensile and Improved tensile and fatigue strengthfatigue strength

PMMA ImprovementsPMMA Improvements

CentrifugationCentrifugation 30 sec / 4000 rpm30 sec / 4000 rpm

VacuumVacuum

Burke Burke JBJSJBJS ‘84 ‘84Chin/Stauffer Chin/Stauffer JBJSJBJS ‘90 ‘90

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Material PropertiesMaterial Properties

Stainless SteelStainless Steel —— high elastic modulus / high elastic modulus / low fatigue strengthlow fatigue strength

Cobalt ChromeCobalt Chrome —— highest elastic modulus highest elastic modulus / / better yield / fatigue better yield / fatigue

strengthstrength

TitaniumTitanium —— lower elastic modulus / lower elastic modulus / less stiffnessless stiffness

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Acetabulum DesignAcetabulum Design Metal backedMetal backed All polyethyleneAll polyethylene

Primary Hip ArthroplastyPrimary Hip ArthroplastyCement Fixation :Cement Fixation :

The Femoral SideThe Femoral Side

Results directly related to Results directly related to Surgical TechniquesSurgical Techniques

Primary Hip ArthroplastyPrimary Hip Arthroplasty

Metal BackedMetal Backed

Increased linear and volumetric Increased linear and volumetric wearwear

Increased radiolucency, loosening, Increased radiolucency, loosening, revisionrevision

No series of documented superior No series of documented superior resultsresults

Improved Longevity – Improved Longevity – Femoral SideFemoral Side

Improved Longevity – Improved Longevity – femoral sidefemoral side Plug canalPlug canal Retrograde fillRetrograde fill Avoid varus / valgus > 5ºAvoid varus / valgus > 5º

MulroyMulroyJBJSJBJS ‘95 ‘95

Primary Hip ArthroplastyPrimary Hip Arthroplasty

AA White-OutWhite-Out

BB Complete DistributionComplete Distribution

CC11 Extensive Radiolucent LineExtensive Radiolucent Line

CC22 Thin mantle < 1 mmThin mantle < 1 mm

DD Gross deficienciesGross deficiencies

GradeGrade Radiographic AppearanceRadiographic Appearance

Primary Total HipPrimary Total Hip

1st Generation Cement Technique1st Generation Cement Technique

– – Finger Packing Finger Packing – No pressurization– No pressurization

– – No Canal PrepNo Canal Prep – Cast stem– Cast stem

– – No PlugNo Plug – Narrow med border– Narrow med border

– – No GunNo Gun – Sharp edges– Sharp edges

WH HarrisWH Harris

Primary Hip ArthroplastyPrimary Hip ArthroplastyCement TechniquesCement Techniques

Probable Improved LongevityProbable Improved Longevity

Femoral SideFemoral Side PressurizePressurize CentralizeCentralize Continuous Cement MantleContinuous Cement Mantle

HarrisHarrisCOOR ‘97COOR ‘97

Cemented Long TermCemented Long Term

Primary Total HipPrimary Total Hip22ndnd Generation Cement Generation Cement

William HarrisWilliam Harris Began 1975Began 1975

Gun 71 Gun 71 – – Super alloySuper alloy

Jet lavageJet lavage –– Broad Broad && round round medial bordermedial border

Canal PrepCanal Prep

Cement RestrictionCement Restriction

Primary Total HipPrimary Total HipCemented Long TermCemented Long TermResults 25 year SurvivorshipResults 25 year Survivorship

AcetabulumAcetabulum SurviveSurvive

Age < 40Age < 40 74%74% 40-4940-49 80%80% 60-6960-69 92%92%FemurFemur < 40< 40 83%83% 40-4940-49 82%82% 60-6960-69 95%95% Barry et alBarry et al

19981998

Primary Total HipPrimary Total Hip25 Year Follow-Up25 Year Follow-UpTotal Aseptic Total Aseptic LooseningLoosening

AcetabulumAcetabulum % %

RevisionRevision 14.514.5 RadiologicRadiologic 19.419.4

Total: Total: 33.933.9

FemoralFemoral % % RevisionRevision 6.46.4 RadiologicRadiologic 8.18.1

Callaghan, Johnston, Callaghan, Johnston, JBJSJBJS ‘97. Harris Course ‘98 ‘97. Harris Course ‘98

Cemented Primary Total HipCemented Primary Total HipClinical Results withClinical Results with

2° Generation Techniques2° Generation Techniques

Neumann Neumann (94)(94) 241241 17.6 yrs17.6 yrs 8.3%8.3%

SchulteSchulte 9393 330330 20 yrs20 yrs 3%3%

WroblewskiWroblewski 9393 13241324 20 yrs20 yrs 6%6%

KavanaghKavanagh 9494 333333 20 yrs20 yrs 16%16%

HipsHipsRevisionRevision

RateRateFollowFollow

UpUp

Cemented Primary Total HipCemented Primary Total HipClinical Results withClinical Results with

2º Generation Techniques2º Generation Techniques

Barrack Barrack 9292 5050 12 yrs12 yrs 0% 0%

MadeyMadey 9797 356356 15 yrs15 yrs 1% 1%

MulroyMulroy 9595 162162 15 yrs15 yrs 2% 2%

SmithSmith 9898 161161 18 yrs18 yrs 5% 5%

HipsHipsRevisionRevision

RateRateFollowFollow

UpUp

Primary Total HipPrimary Total HipClinical ResultsClinical Results

Cemented Total Hip: 2Cemented Total Hip: 2ndnd Generation Generation

14-17 year follow-up – 102 hips14-17 year follow-up – 102 hips Femoral looseningFemoral loosening 2% revised2% revised Acetabular looseningAcetabular loosening 10% revised10% revised 42% radiologic42% radiologic

Mulroy, Harris, Mulroy, Harris, JBJSJBJS ‘95; COOR ‘97 ‘95; COOR ‘97

Cemented Primary Total HipCemented Primary Total HipClinical Results — Acetabular SideClinical Results — Acetabular Side

SullivanSullivan 9494 CharnleyCharnley 8989 13%13% 37%37%

SmithSmith 9898 CADCAD 6565 23%23% 26%26%

CallaghanCallaghan 9898 CharnleyCharnley 9393 19%19% 15%15%

ProsthesisProsthesis HipsHipsRev.Rev.RateRate

Loosen-Loosen-inging

Primary Total HipPrimary Total Hip33rdrd Generation Cement Technique Generation Cement Technique

Bill Harris – Began 1982Bill Harris – Began 1982 Porosity reductionPorosity reduction Rough surfaceRough surface CentralizationCentralization PressurizationPressurization Pre-coatPre-coat

Primary Total HipPrimary Total Hip

Plug and retrograde fillPlug and retrograde fill Avoid excessive varus/valgusAvoid excessive varus/valgus Strive for 3-5 mm prox/med > 2mm Strive for 3-5 mm prox/med > 2mm

distaldistal Do not ream / remove good Do not ream / remove good

cancellous bonecancellous bone

Conclusions — CementedConclusions — Cemented

Primary Total HipPrimary Total HipClinical ResultsClinical Results

Hybrid ConstructHybrid Construct

Galante -Galante - 95 f/u 5 years95 f/u 5 years Femoral Femoral 2% 2% rad looserad loose Acetabulum Acetabulum 2% 2% rad looserad loose

Woolson -Woolson - 96 f/u 6 years96 f/u 6 years Femoral Femoral 5%5% revisionrevision Acetabulum Acetabulum 0% 0% revisionrevision

Design FeaturesDesign Features

POROUS IMPLANTPOROUS IMPLANT

Uncemented THAUncemented THA

DefinitionDefinition

Press FitPress Fit

MacrointerlockMacrointerlock

MicrointerlockMicrointerlock

Design FeaturesDesign Features

Pore Size — Animal StudiesPore Size — Animal Studies

50 to 400 µm50 to 400 µm Optimal bone ingrowthOptimal bone ingrowth

Bobyn: Bobyn: Clinical OrthopedicsClinical Orthopedics; 1980; 1980Engh: Engh: JBJSJBJS; 1987; 1987Collier: Collier: Clinical OrthopedicsClinical Orthopedics; 1988; 1988

MicromotionMicromotion

40 Micron Motion Bone Ingrowth40 Micron Motion Bone Ingrowth ((JBJSJBJS 79-A) 79-A)

150 Micron Motion Fibrous Ingrowth150 Micron Motion Fibrous Ingrowth (CORR, 208)(CORR, 208)

Design Criteria –Design Criteria –Long Term Implant StabilityLong Term Implant Stability

Initial Implant StabilityInitial Implant Stability Implant micromotion < 50 mm Implant micromotion < 50 mm

of displacementof displacement Level of implant coatingLevel of implant coating Type of coatingType of coating

Kienapfel H.Kienapfel H.J. ArthroplastyJ. Arthroplasty 1999 1999

Design CriteriaDesign Criteria

Uncemented Total Hip ArthroplastyUncemented Total Hip Arthroplasty

Key —Key — Resistance to Rotation Resistance to Rotation Around the Long AxisAround the Long Axis

Design CriteriaDesign Criteria

Uncemented Total Hip Uncemented Total Hip ArthroplastyArthroplasty Resist translation in 3 planesResist translation in 3 planes

— AxialAxial

— Medial Medial - - laterallateral

— Anterior - Anterior - posteriorposterior

Design Criteria –Design Criteria –Uncemented ImplantsUncemented Implants

Level of Implant CoatingLevel of Implant Coating

— Apply circumferentialApply circumferential

— Avoid patch porous coatsAvoid patch porous coats

— Smooth surface – high failure Smooth surface – high failure raterate

Design Criteria –Design Criteria –Uncemented ImplantsUncemented Implants

Type of CoatingType of Coating

1. 1. Macro-texturing — doesn’t workMacro-texturing — doesn’t work

2. 2. Roughened titaniumRoughened titanium

3. 3. Porous coating made of CoCr or TiPorous coating made of CoCr or Ti

4. 4. Ti wire meshTi wire mesh

5. 5. Plasma-sprayed TiPlasma-sprayed Ti

6. 6. Bioactives —Bioactives — Hydroxyapatite / Hydroxyapatite / tricalcium phosphatetricalcium phosphate

Design FeaturesDesign Features

Sintered Micro/Macro BeadsSintered Micro/Macro BeadsCr-Co-Mo/TiCr-Co-Mo/Ti

Pore dimensions 100 to 400 Pore dimensions 100 to 400 mm

AML ; PCAAML ; PCA

ForgedForged 9090 600600

CastCast 3535 250250

SinteredSintered 2525 150150

Sintered withSintered withcontrolled coatingcontrolled coating 3030 200200

ProcessProcess psipsi MPaMPa

Fatigue strengthFatigue strength

*Data from Pilliar, R.M. *Data from Pilliar, R.M. Clin. OrthopClin. Orthop. 176:42-51, 1983.. 176:42-51, 1983.

Design Criteria –Design Criteria –Uncemented ImplantsUncemented Implants

Implant Geometry – Implant StabilityImplant Geometry – Implant Stability

1) 1) Wedge-shaped metaphyseal fillingWedge-shaped metaphyseal filling

2) 2) Single wedge-shaped implantsSingle wedge-shaped implants

3) 3) Tapered stemsTapered stems

4) 4) Diaphyseal fixation — cylindrical Diaphyseal fixation — cylindrical or or fluted stemsfluted stems

Design CriteriaDesign Criteria

Uncemented ImplantsUncemented Implants Requires cortical fixationRequires cortical fixation

— MetaphysisMetaphysis

— Metaphysis – DiaphysisMetaphysis – Diaphysis

— DiaphysealDiaphyseal

Design Criteria –Design Criteria –Uncemented ImplantsUncemented Implants

Bioactives — OsteoconductiveBioactives — Osteoconductive Tricalcium dissolves more rapidly Tricalcium dissolves more rapidly

than hydroxyapatitethan hydroxyapatite Thickness 50 mmThickness 50 mm More crystalline hydroxyapatite More crystalline hydroxyapatite

slows resorptionslows resorption

Uncemented Primary Total HipUncemented Primary Total HipClinical Results Clinical Results •• Femoral Side Femoral Side

— — Titanium = Cobalt ChromeTitanium = Cobalt Chrome

— — Cobalt Chrome increased stress- Cobalt Chrome increased stress- shielding shielding

— — Straight Stems with varying degrees Straight Stems with varying degrees of medullary fill often used of medullary fill often used

— — Anatomic Stems have not been a Anatomic Stems have not been a great advantage great advantage

Design FeaturesDesign Features

Straight StemStraight Stem

An Anatomic StemAn Anatomic Stem

Design FeaturesDesign Features

Proximal CoatingProximal Coating

Design FeaturesDesign Features

Proximal coating – Anatomic designProximal coating – Anatomic design

Maximum fit in certain priority areasMaximum fit in certain priority areas

Maximal load transferMaximal load transfer

Resist axial loading and torsional Resist axial loading and torsional loadsloads

Poss: ClinicPoss: Clinic

Design FeaturesDesign Features

Both greater distal motion at Both greater distal motion at interface —interface —

Compared with proximal motionCompared with proximal motion

Callaghan, Callaghan, JBJSJBJS ‘92 ‘92

The HGP stem (courtesy of Zimmer)The HGP stem (courtesy of Zimmer)

Design FeaturesDesign Features

Porous ImplantPorous Implant

Proximal coatingProximal coatingFully coatedFully coated

Design Features — Design Features — Porous SurfacePorous Surface

2/3 or fully coated2/3 or fully coated

2 to 4 x increase in bone 2 to 4 x increase in bone resorptionresorption

Engh: Engh: Clinical OrthopedicsClinical Orthopedics; 1988; 1988

Design FeaturesDesign Features

Fully Coated Porous SurfaceFully Coated Porous Surface

Transfers stress distally under Transfers stress distally under axial load –axial load –

Engh: Engh: Clinical OrthopedicsClinical Orthopedics; 1988; 1988

Proximal bone resorptionProximal bone resorption

Retrieval StudiesRetrieval Studies

EnghEngh

Femur Femur 57% 57% ingrowthingrowth

Acetabulum Acetabulum 32% 32% ingrowthingrowth

Radiographic Criteria for Radiographic Criteria for Bone IngrowthBone Ingrowth

Engh et al, (CORR 257)Engh et al, (CORR 257)

Absence of Reactive LinesAbsence of Reactive Lines

Spot Welds Endosteal BoneSpot Welds Endosteal Bone

Implant Instability 2 mmImplant Instability 2 mm

PedestalPedestal

Calcar Atrophy / Stress ShieldingCalcar Atrophy / Stress Shielding

Uncemented Primary Total HipUncemented Primary Total Hip

Clinical ResultsClinical Results •• Femoral SideFemoral Side

Straight StemStraight StemDesign Design % loosening% loosening

AMLAML 507 hips507 hips 5-5- 14 yrs14 yrs 1.2%1.2%

Harris/ Harris/ GalanteGalante 121 hips121 hips 3-3- 6.2 yrs6.2 yrs 3.3%3.3%

OmniflexOmniflex 88 hips 88 hips 2-2- 5.2 yrs5.2 yrs 3.4%3.4%

TaperlocTaperloc 145 hips145 hips 8-8- 12.5 yrs12.5 yrs 0.7%0.7%

TrilockTrilock 71 hips 71 hips > > 10 yrs10 yrs 0%0%

Uncemented Primary Total HipUncemented Primary Total HipClinical Results Clinical Results •• Femoral Side Femoral Side

% % Anatomic Stem DesignAnatomic Stem Design looseningloosening

APR-1APR-1 100 hips100 hips 5-9.4 yrs5-9.4 yrs 11%11%

APR-2APR-2 148 hips148 hips 2-5 yrs2-5 yrs 0% 0%

PCAPCA 539 hips539 hips 6-8 yrs6-8 yrs 7.6%7.6%

100 hips100 hips > 7 yrs> 7 yrs 2.0%2.0%

Screw FixationScrew Fixation

Less Micromotion, Better IngrowthLess Micromotion, Better Ingrowth

Conduit for Particulate DebrisConduit for Particulate Debris

Neurovascular InjuryNeurovascular Injury

Acetabular DesignAcetabular Design

HemisphereHemisphere

Screw FixationScrew Fixation

Locking MechanismLocking Mechanism

Uncemented Primary Total HipUncemented Primary Total Hip— Main Recurrent Concern— Main Recurrent Concern

Poly Wear – OsteolysisPoly Wear – Osteolysis

Uncemented Primary Total HipUncemented Primary Total HipClinical Results • Acetabular SideClinical Results • Acetabular Side

Femoral head size – Femoral head size – Acetabular Acetabular thicknessthickness

— PCAPCA 26 mm head26 mm head no osteolysisno osteolysis

— PCAPCA 32 mm head32 mm head 26% osteolysis26% osteolysis

Uncemented Primary Total HipUncemented Primary Total HipClinical Results Clinical Results •• Acetabular Side Acetabular Side

% loosening% loosening

ARCARC 72 hips 72 hips 12 yrs12 yrs 1.4%1.4%

Harris/Galante Harris/Galante 136 hips136 hips 5-10 yrs5-10 yrs 0%0%

PSL PSL smooth HA smooth HA 316 hips316 hips 6-10 yrs6-10 yrs 12%12% beaded HA beaded HA 2.7%2.7%

PCAPCA 241 hips241 hips 2-9 yrs2-9 yrs 11%11% 539 hips539 hips 7 yrs 7 yrs 13.2%13.2% 100100 > 7 yrs> 7 yrs 4% rev.4% rev.

Uncemented Primary Total HipUncemented Primary Total HipClinical Results • Acetabular SideClinical Results • Acetabular Side

— — Hemispherical shape — rim fitHemispherical shape — rim fit

— — Under ream No > 2 mmUnder ream No > 2 mm

— — Screws :Screws : produced durableproduced durable results - postopresults - postop

Disadvantage :Disadvantage : posterior sciatic N.posterior sciatic N. Ant supAnt sup – common iliac– common iliac Ant inf Ant inf – obturator art / ner– obturator art / ner

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Complications in Total Hip Arthroplasty Complications in Total Hip Arthroplasty – Heterotopic Ossification– Heterotopic Ossification

TreatmentTreatment—Radiation pre-op or post-op 500 Radiation pre-op or post-op 500

to 1000 Rad to 1000 Rad “Remember to shield implant”“Remember to shield implant”

—IndomethacinIndomethacin—IbuprofenIbuprofen—DiphosphonatesDiphosphonates

Complications In Total Hip Arthroplasty – Complications In Total Hip Arthroplasty – Heterotopic Ossification 0.6% to 61.7%Heterotopic Ossification 0.6% to 61.7%

Associated conditionsAssociated conditions

— Ankylosing spondylitisAnkylosing spondylitis

— Forestier’s diseaseForestier’s disease

— Post traumatic arthritisPost traumatic arthritis

— Bilateral male osteophytic Bilateral male osteophytic OAOA

Complications in Total HipComplications in Total HipArthroplasty – DislocationArthroplasty – Dislocation

Component ImpingementComponent Impingement— Proximal femurProximal femur— Femoral head skirtFemoral head skirt— Acetabular component (elevated liner)Acetabular component (elevated liner)— Osteophytes / cement massesOsteophytes / cement masses

Head SizeHead Size— No difference 22 - 28 - 32No difference 22 - 28 - 32— 28 mm head 28 mm head > > 60 mm acetabulum 60 mm acetabulum

—increased rate—increased rate— 22 mm head22 mm head > > 54 mm acetabulum 54 mm acetabulum

—increased rate—increased rate

Complications In Total Hip Complications In Total Hip Arthroplasty – Dislocation – 3%Arthroplasty – Dislocation – 3%

Posterior approach slightly higher 4.6%Posterior approach slightly higher 4.6% Neuromuscular problemsNeuromuscular problems Previous surgery (rate doubles)Previous surgery (rate doubles) MalpositionMalposition

>> 25º anteversion25º anteversion

>> 60º inclination60º inclination

RetroversionRetroversion

>> 15º femoral anteversion15º femoral anteversion

TreatmentTreatment

BracingBracing

Spica castSpica cast

SurgerySurgery

Complications In Total Hip Complications In Total Hip Arthroplasty – DislocationArthroplasty – Dislocation

Occult infectionOccult infection

TraumaTrauma

Profound weight lossProfound weight loss

Complications In Total Hip Complications In Total Hip Arthroplasty – ThromboembolismArthroplasty – Thromboembolism

Most common complicationMost common complication

DVTDVT –– 70%70% to to 8%8%

PE PE –– 1%1% toto 2%2%

Complications In Total Hip Complications In Total Hip Arthroplasty – ThromboembolismArthroplasty – Thromboembolism

Activation of clotting cascadeActivation of clotting cascade

Local vessel injuryLocal vessel injury

Stasis in the femoral veinStasis in the femoral vein

Ultra-High Molecular Weight PolyethyleneUltra-High Molecular Weight Polyethyleneis defined as what type of material ?is defined as what type of material ?

1.1. ElasticElastic

2. 2. Viscoelatic-plasticViscoelatic-plastic

3. 3. RigidRigid

4. 4. Shear thinningShear thinning

5. 5. High frictionHigh friction

The degradation of polyethylene following The degradation of polyethylene following gamma irradiation is related to what factor ?gamma irradiation is related to what factor ?

1.1. Increased ionic bondingIncreased ionic bonding

2.2. Surface ion implantationSurface ion implantation

3.3. Free radical formationFree radical formation

4.4. Decreased covalent cross- Decreased covalent cross- linkinglinking

5.5. Decreased polymer densityDecreased polymer density

Why is cobalt-chrome alloy preferred over Why is cobalt-chrome alloy preferred over a titanium alloy for a cemented femoral a titanium alloy for a cemented femoral component in a total hip arthroplasty ?component in a total hip arthroplasty ?

1.1. Less particulate metal debrisLess particulate metal debris

2.2. Less stiffnessLess stiffness

3.3. Elastic modulus closer to bone cementElastic modulus closer to bone cement

4.4. Cost-effectivenessCost-effectiveness

5.5. Better cement bonding abilityBetter cement bonding ability

What is the most common long-term What is the most common long-term complication of cemented total hip arthroplasty complication of cemented total hip arthroplasty in patients under 50 years of age?in patients under 50 years of age?

1.1. AgeAge

2.2. DislocationDislocation

3.3. Periprosthetic femur fracturePeriprosthetic femur fracture

4.4. Acetabular component looseningAcetabular component loosening

5.5. Femoral stem fractureFemoral stem fracture

During a posterior approach to the hip joint, During a posterior approach to the hip joint, profuse bleeding is encountered during profuse bleeding is encountered during incision of the quadratus femoris.incision of the quadratus femoris.

The bleeding is most likely from which The bleeding is most likely from which artery?artery?

1.1. Superior gluteal.Superior gluteal.

2.2. Inferior gluteal.Inferior gluteal.

3.3. Lateral femoral circumflex.Lateral femoral circumflex.

4.4. Medial femoral circumflex.Medial femoral circumflex.

5.5. Posterior femoral circumflex.Posterior femoral circumflex.

Which is the correct order of the elastic Which is the correct order of the elastic modulus of the following materials, from the modulus of the following materials, from the lowest to highest modulus?lowest to highest modulus?

1.1. Polyethylene, cancellous bone, cortical bone, Polyethylene, cancellous bone, cortical bone, titanium alloy, cobalt chrome alloytitanium alloy, cobalt chrome alloy

2.2. Cancellous bone, cortical bone, polyethylene, Cancellous bone, cortical bone, polyethylene, titanium alloy, cobalt chrome alloytitanium alloy, cobalt chrome alloy

3.3. Cancellous bone, cortical bone, polyethylene, Cancellous bone, cortical bone, polyethylene, cobalt chrome alloy, titanium alloycobalt chrome alloy, titanium alloy

4. 4. Cancellous bone, polyethylene, cortical bone, Cancellous bone, polyethylene, cortical bone, cobalt chrome alloy, titanium alloycobalt chrome alloy, titanium alloy

5.5. Cancellous bone, polyethylene, cortical bone, Cancellous bone, polyethylene, cortical bone, titanium alloy, cobalt chrome alloytitanium alloy, cobalt chrome alloy

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