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Primary Hip Arthroplasty Cemented & Uncemented Frank R. Ebert, MD Union Memorial Hospital Baltimore, Maryland.

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Presentation on theme: "Primary Hip Arthroplasty Cemented & Uncemented Frank R. Ebert, MD Union Memorial Hospital Baltimore, Maryland."— Presentation transcript:

1 Primary Hip Arthroplasty Cemented & Uncemented Frank R. Ebert, MD Union Memorial Hospital Baltimore, Maryland

2 Johns Hopkins Union Memorial Orthopædic Review Course

3 Anatomic Approach Anterior Approach Anterior Approach Anterior-Lateral Approach Anterior-Lateral Approach Posterior Approach Posterior Approach Medial Approach Medial Approach

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5 Anatomic Approach Open Reduction – CDH Open Reduction – CDH Pelvic Osteotomies Pelvic Osteotomies Intra-Articular Fusion Intra-Articular Fusion Rarely Total Hip Rarely Total Hip

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7 Internervous Plane Superficial –Sartorius / TFL ( Femoral/Superior gluteal ) Deep –Rectus / gluteus medius ( Superior gluteal ) –Rectus / gluteus medius ( Superior gluteal )

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9 Anterolateral Approach Most common for THA Most common for THA ORIF of femoral neck ORIF of femoral neck Synovial biopsy of the hip Synovial biopsy of the hip

10 Anterolateral Approach Internervous plane – none TFL / gluteus medius Superior gluteal / Superior gluteal

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15 Lateral Approach Dangers – Superior gluteal nerve – Femoral nerve

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17 Medial Approach CDH open reduction Psoas Release Obturator Neurectomy Biopsy or Treatment of tumors of femoral neck

18 Medial Approach Internervous plane ( only deep ) Superficial : Adductor Longus / gracilis Deep : Adductor Brevis / magnus

19 Posterior Approach Internervous plane – none splits gluteus maximus ( inferior gluteal ) splits gluteus maximus ( inferior gluteal )

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21 Primary Hip Arthroplasty Posterior Approach Total hip replacement Total hip replacement ORIF of posterior column fractures ORIF of posterior column fractures Dependent drainage of hip sepsis Dependent drainage of hip sepsis

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23 Primary Hip Arthroplasty Posterior Approach Sciatic Nerve Sciatic Nerve Inferior gluteal artery Inferior gluteal artery

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25 Primary Hip Arthroplasty Design Features Size Size Shape Shape Device configuration Device configuration Material / physical properties Material / physical properties

26 Primary Hip Arthroplasty Resist Composite Failure Prosthetic Device Prosthetic Device Bone Cement Bone Cement Cancellous Bone Cancellous Bone Cortical Bone Cortical Bone

27 Primary Hip Arthroplasty Design Features Femoral Head Femoral Head Neck Neck Stem Stem Collar Collar Acetabulum Acetabulum

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29 Primary Hip Arthroplasty Prosthetic Hip Loading Changes from externally loaded system to an internally loaded system Changes from externally loaded system to an internally loaded system

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31 Primary Hip Arthroplasty Femoral Head Design Articulating finish Articulating finish Head diameter Head diameter

32 D ESIGN F EATURES

33 Primary Hip Arthroplasty 32 mm Head Size Greater acetabular loosening Greater acetabular loosening Greatest volumetric wear Greatest volumetric wear Ritter COOR ‘76 Morrey JBJS ‘89

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35 Design Features 22mm Head Size  Greatest linear wear  Greatest acetabular penetration Morrey JBJS 1989

36 Design Features Charnley 22mm head diameter Compromise friction / wear

37 Design Features 28 mm Head Size Stable as 32mm head size Less torque than the 32mm head More favorable direct stress transmission patterns

38 Primary Hip Arthroplasty 28 mm Head Size Compromise Compromise

39 Primary Hip Arthroplasty Design Features Femoral Neck Geometry Neck stem angle – 135º Neck stem angle – 135º Neck stem offset Neck stem offset – large offset... Bending moment – small offset... Decreases moment arm

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41 Primary Hip Arthroplasty Design Features Femoral Stem – Length – Shape – Material properties – Surface finish

42 Primary Hip Arthroplasty Femoral Stem Design Cross sectional geometry Cross sectional geometry Defines strength / stiffness Defines strength / stiffness Avoid sharp corners Avoid sharp corners

43 Primary Hip Arthroplasty Femoral Stem Design Large lateral volume Large lateral volume Less tensile stress in the mantle laterally Less tensile stress in the mantle laterally Large medial volume less tensile stress Large medial volume less tensile stress

44 Primary Hip Arthroplasty Collar Primary role for optimal load transfer to proximal femur Crowninshield JBJS ‘80 Andriacchi JBJS ‘76

45 Primary Hip Arthroplasty Collar Reduces adaptive bone resorption Reduces adaptive bone resorption Reduce bending stress in the component Reduce bending stress in the component Reduce stress in the distal cement Reduce stress in the distal cement

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47 Primary Hip Arthroplasty Fixation Features PMMA Weak link Poor fracture toughness Poor fracture toughness Low tensile and fatigue strength Low tensile and fatigue strength Elastic modulus 1/3 lower than cortical bone Elastic modulus 1/3 lower than cortical bone

48 Primary Hip Arthroplasty Fixation Features PMMA Improvements Carbon FibersDecreased cement intrusion / increased viscosity Low ViscosityLower fatigue strength CentrifugationImproved tensile and fatigue strength

49 PMMA Improvements Centrifugation30 sec / 4000 rpm Vacuum Burke JBJS ‘84 Chin/Stauffer JBJS ‘90

50 Primary Hip Arthroplasty Material Properties Stainless Steel—high elastic modulus / low fatigue strength Cobalt Chrome—highest elastic modulus / better yield / fatigue strength Titanium—lower elastic modulus / less stiffness

51 Primary Hip Arthroplasty Acetabulum Design Metal backed Metal backed All polyethylene All polyethylene

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53 Primary Hip Arthroplasty Cement Fixation : The Femoral Side Results directly related to Surgical Techniques Results directly related to Surgical Techniques

54 Primary Hip Arthroplasty Metal Backed Increased linear and volumetric wear Increased radiolucency, loosening, revision No series of documented superior results

55 Improved Longevity – Femoral Side Improved Longevity – femoral side Plug canal Plug canal Retrograde fill Retrograde fill Avoid varus / valgus > 5º Avoid varus / valgus > 5º Mulroy JBJS ‘95

56 Primary Hip Arthroplasty AWhite-Out BComplete Distribution C 1 Extensive Radiolucent Line C 2 Thin mantle < 1 mm DGross deficiencies GradeRadiographic Appearance

57 Primary Total Hip 1st Generation Cement Technique – Finger Packing – No pressurization – No Canal Prep– Cast stem – No Plug – Narrow med border – No Gun– Sharp edges WH Harris

58 Primary Hip Arthroplasty Cement Techniques Probable Improved Longevity Femoral Side Pressurize Pressurize Centralize Centralize Continuous Cement Mantle Continuous Cement Mantle Harris COOR ‘97

59 Cemented Long Term

60 Primary Total Hip 2 nd Generation Cement William HarrisBegan 1975 Gun 71 – Super alloy Jet lavage–Broad & round medial border Canal Prep Cement Restriction

61 Primary Total Hip Cemented Long Term Results 25 year Survivorship AcetabulumSurvive Age < 4074% % % Age < 4074% % % Femur < 4083% % % Barry et al 1998

62 Primary Total Hip 25 Year Follow-Up Total Aseptic Loosening Acetabulum % Revision14.5 Radiologic19.4 Revision14.5 Radiologic19.4 Total: 33.9 Total: 33.9 Femoral % Revision6.4 Radiologic8.1 Callaghan, Johnston, JBJS ‘97. Harris Course ‘98

63 Cemented Primary Total Hip Clinical Results with 2° Generation Techniques Neumann (94) yrs8.3% Schulte yrs3% Wroblewski yrs6% Kavanagh yrs16% Hips Revision Rate Follow Up

64 Cemented Primary Total Hip Clinical Results with 2º Generation Techniques Barrack yrs 0% Madey yrs 1% Mulroy yrs 2% Smith yrs 5% Hips Revision Rate Follow Up

65 Primary Total Hip Clinical Results Cemented Total Hip: 2 nd Generation year follow-up – 102 hips Femoral loosening2% revised Femoral loosening2% revised Acetabular loosening10% revised Acetabular loosening10% revised 42% radiologic 42% radiologic Mulroy, Harris, JBJS ‘95; COOR ‘97

66 Cemented Primary Total Hip Clinical Results — Acetabular Side Sullivan94Charnley8913%37% Smith98CAD6523%26% Callaghan98Charnley9319%15% ProsthesisHips Rev. Rate Loosen- ing

67 Primary Total Hip 3 rd Generation Cement Technique Bill Harris – Began 1982 Porosity reduction Porosity reduction Rough surface Rough surface Centralization Centralization Pressurization Pressurization Pre-coat Pre-coat

68 Primary Total Hip Plug and retrograde fill Plug and retrograde fill Avoid excessive varus/valgus Avoid excessive varus/valgus Strive for 3-5 mm prox/med > 2mm distal Strive for 3-5 mm prox/med > 2mm distal Do not ream / remove good cancellous bone Do not ream / remove good cancellous bone Conclusions — Cemented

69 Primary Total Hip Clinical Results Hybrid Construct Galante -95 f/u 5 years Femoral 2% rad loose Femoral 2% rad loose Acetabulum 2% rad loose Acetabulum 2% rad loose Woolson -96 f/u 6 years Femoral 5%revision Femoral 5%revision Acetabulum 0% revision Acetabulum 0% revision

70 Design Features POROUS IMPLANT

71 Uncemented THA Definition Press Fit Macrointerlock Macrointerlock Microinterlock Microinterlock

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73 Design Features Pore Size — Animal Studies 50 to 400 µm Optimal bone ingrowth 50 to 400 µm Optimal bone ingrowth Bobyn: Clinical Orthopedics; 1980 Engh: JBJS; 1987 Collier: Clinical Orthopedics; 1988

74 Micromotion 40 Micron Motion Bone Ingrowth (JBJS 79-A) 150 Micron Motion Fibrous Ingrowth (CORR, 208)

75 Design Criteria – Long Term Implant Stability Initial Implant Stability Initial Implant Stability Implant micromotion < 50 mm of displacement Implant micromotion < 50 mm of displacement Level of implant coating Level of implant coating Type of coating Type of coating Kienapfel H. J. Arthroplasty 1999

76 Design Criteria Uncemented Total Hip Arthroplasty Key —Resistance to Rotation Around the Long Axis Key —Resistance to Rotation Around the Long Axis

77 Design Criteria Uncemented Total Hip Arthroplasty Resist translation in 3 planes Resist translation in 3 planes — Axial — Medial - lateral — Anterior - posterior

78 Design Criteria – Uncemented Implants Level of Implant Coating Level of Implant Coating —Apply circumferential —Avoid patch porous coats —Smooth surface – high failure rate

79 Design Criteria – Uncemented Implants Type of Coating 1. Macro-texturing — doesn’t work 2. Roughened titanium 3. Porous coating made of CoCr or Ti 4. Ti wire mesh 5. Plasma-sprayed Ti 6. Bioactives —Hydroxyapatite / tricalcium phosphate

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81 Design Features Sintered Micro/Macro Beads Cr-Co-Mo/Ti Pore dimensions 100 to 400  m AML ; PCA

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83 Forged90600 Cast35250 Sintered25150 Sintered with controlled coating30200 ProcesspsiMPa Fatigue strength *Data from Pilliar, R.M. Clin. Orthop. 176:42-51, 1983.

84 Design Criteria – Uncemented Implants Implant Geometry – Implant Stability 1) Wedge-shaped metaphyseal filling 2) Single wedge-shaped implants 3) Tapered stems 4) Diaphyseal fixation — cylindrical or fluted stems

85 Design Criteria Uncemented Implants Requires cortical fixation Requires cortical fixation — Metaphysis — Metaphysis – Diaphysis — Diaphyseal

86 Design Criteria – Uncemented Implants Bioactives — Osteoconductive Tricalcium dissolves more rapidly than hydroxyapatite Tricalcium dissolves more rapidly than hydroxyapatite Thickness 50 mm Thickness 50 mm More crystalline hydroxyapatite slows resorption More crystalline hydroxyapatite slows resorption

87 Uncemented Primary Total Hip Clinical Results Femoral Side — Titanium = Cobalt Chrome — Cobalt Chrome increased stress- shielding — Straight Stems with varying degrees of medullary fill often used — Anatomic Stems have not been a great advantage

88 Design Features  Straight Stem  An Anatomic Stem

89 Design Features Proximal Coating

90 Design Features  Proximal coating – Anatomic design  Maximum fit in certain priority areas  Maximal load transfer  Resist axial loading and torsional loads Poss: Clinic

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92 Design Features  Both greater distal motion at interface — Compared with proximal motion Compared with proximal motion Callaghan, JBJS ‘92

93 The HGP stem (courtesy of Zimmer)

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95 Design Features Porous Implant   Proximal coating Fully coated

96 Design Features — Porous Surface  2/3 or fully coated 2 to 4 x increase in bone resorption 2 to 4 x increase in bone resorption Engh: Clinical Orthopedics; 1988

97 Design Features Fully Coated Porous Surface  Transfers stress distally under axial load – Engh: Clinical Orthopedics; 1988 Proximal bone resorption

98 Retrieval Studies Engh Femur 57% ingrowth Femur 57% ingrowth Acetabulum 32% ingrowth Acetabulum 32% ingrowth

99 Radiographic Criteria for Bone Ingrowth Engh et al, (CORR 257) Absence of Reactive Lines Absence of Reactive Lines Spot Welds Endosteal Bone Spot Welds Endosteal Bone Implant Instability 2 mm Implant Instability 2 mm Pedestal Pedestal Calcar Atrophy / Stress Shielding Calcar Atrophy / Stress Shielding

100 Uncemented Primary Total Hip Clinical Results Femoral Side Straight Stem Design % loosening AML507 hips5-14 yrs1.2% Harris/ Galante121 hips3-6.2 yrs3.3% Omniflex 88 hips2-5.2 yrs3.4% Taperloc145 hips yrs0.7% Trilock 71 hips> 10 yrs0%

101 Uncemented Primary Total Hip Clinical Results Femoral Side % Anatomic Stem Design loosening APR-1100 hips5-9.4 yrs11% APR-2148 hips2-5 yrs 0% PCA539 hips6-8 yrs7.6% 100 hips> 7 yrs2.0%

102 Screw Fixation Less Micromotion, Better Ingrowth Conduit for Particulate Debris Neurovascular Injury

103 Acetabular Design Hemisphere Screw Fixation Locking Mechanism

104 Uncemented Primary Total Hip — Main Recurrent Concern Poly Wear – Osteolysis

105 Uncemented Primary Total Hip Clinical Results Acetabular Side Femoral head size – Acetabular thickness Femoral head size – Acetabular thickness —PCA26 mm head no osteolysis —PCA32 mm head 26% osteolysis

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108 Uncemented Primary Total Hip Clinical Results Acetabular Side % loosening ARC 72 hips12 yrs1.4% Harris/Galante 136 hips5-10 yrs0% PSL smooth HA316 hips6-10 yrs12% beaded HA2.7% PCA241 hips2-9 yrs11% 539 hips 7 yrs13.2% 100> 7 yrs 4% rev.

109 Uncemented Primary Total Hip Clinical Results Acetabular Side — Hemispherical shape — rim fit — Under ream No > 2 mm — Screws :produced durable results - postop Disadvantage : posterior sciatic N. Ant sup– common iliac Ant inf – obturator art / ner Disadvantage : posterior sciatic N. Ant sup– common iliac Ant inf – obturator art / ner {

110 Complications in Total Hip Arthroplasty – Heterotopic Ossification Treatment Treatment —Radiation pre-op or post-op 500 to 1000 Rad “Remember to shield implant” —Indomethacin —Ibuprofen —Diphosphonates

111 Complications In Total Hip Arthroplasty – Heterotopic Ossification 0.6% to 61.7% Associated conditions Associated conditions — Ankylosing spondylitis — Forestier’s disease — Post traumatic arthritis — Bilateral male osteophytic OA

112 Complications in Total Hip Arthroplasty – Dislocation Component Impingement Component Impingement —Proximal femur —Femoral head skirt —Acetabular component (elevated liner) —Osteophytes / cement masses Head Size Head Size —No difference —28 mm head > 60 mm acetabulum —increased rate —22 mm head> 54 mm acetabulum —increased rate

113 Complications In Total Hip Arthroplasty – Dislocation – 3% Posterior approach slightly higher 4.6% Posterior approach slightly higher 4.6% Neuromuscular problems Neuromuscular problems Previous surgery (rate doubles) Previous surgery (rate doubles) Malposition Malposition >25º anteversion >25º anteversion >60º inclination >60º inclination Retroversion Retroversion >15º femoral anteversion >15º femoral anteversion

114 Treatment Bracing Spica cast Surgery

115 Complications In Total Hip Arthroplasty – Dislocation Occult infection Occult infection Trauma Trauma Profound weight loss Profound weight loss

116 Complications In Total Hip Arthroplasty – Thromboembolism Most common complication Most common complication DVT–70%to 8% DVT–70%to 8% PE –1%to2% PE –1%to2%

117 Complications In Total Hip Arthroplasty – Thromboembolism Activation of clotting cascade Activation of clotting cascade Local vessel injury Local vessel injury Stasis in the femoral vein Stasis in the femoral vein

118 Ultra-High Molecular Weight Polyethylene is defined as what type of material ? 1.Elastic 2. Viscoelatic-plastic 3. Rigid 4. Shear thinning 5. High friction

119 The degradation of polyethylene following gamma irradiation is related to what factor ? 1.Increased ionic bonding 1.Increased ionic bonding 2.Surface ion implantation 2.Surface ion implantation 3.Free radical formation 3.Free radical formation 4.Decreased covalent cross- linking 4.Decreased covalent cross- linking 5.Decreased polymer density 5.Decreased polymer density

120 Why is cobalt-chrome alloy preferred over a titanium alloy for a cemented femoral component in a total hip arthroplasty ? 1.Less particulate metal debris 2.Less stiffness 3.Elastic modulus closer to bone cement 4.Cost-effectiveness 5.Better cement bonding ability

121 What is the most common long-term complication of cemented total hip arthroplasty in patients under 50 years of age? 1.Age 1.Age 2.Dislocation 2.Dislocation 3.Periprosthetic femur fracture 3.Periprosthetic femur fracture 4.Acetabular component loosening 4.Acetabular component loosening 5.Femoral stem fracture 5.Femoral stem fracture

122 During a posterior approach to the hip joint, profuse bleeding is encountered during incision of the quadratus femoris. The bleeding is most likely from which artery? 1.Superior gluteal. 2.Inferior gluteal. 3.Lateral femoral circumflex. 4.Medial femoral circumflex. 5.Posterior femoral circumflex.

123 Which is the correct order of the elastic modulus of the following materials, from the lowest to highest modulus? 1.Polyethylene, cancellous bone, cortical bone, titanium alloy, cobalt chrome alloy 2.Cancellous bone, cortical bone, polyethylene, titanium alloy, cobalt chrome alloy 3.Cancellous bone, cortical bone, polyethylene, cobalt chrome alloy, titanium alloy 4. Cancellous bone, polyethylene, cortical bone, cobalt chrome alloy, titanium alloy 5.Cancellous bone, polyethylene, cortical bone, titanium alloy, cobalt chrome alloy

124 Thank You


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