Transcript Complications in Arthroplasty

Primary Hip Arthroplasty
Cemented
&
Uncemented
Frank R. Ebert, MD
Union Memorial Hospital
Baltimore, Maryland
Johns Hopkins
Union Memorial
Orthopædic Review Course
Anatomic Approach

Anterior Approach

Anterior-Lateral Approach

Posterior Approach

Medial Approach
Anatomic Approach

Open Reduction – CDH

Pelvic Osteotomies

Intra-Articular Fusion

Rarely Total Hip
Internervous Plane
Superficial
– Sartorius / TFL
( Femoral/Superior gluteal )
Deep
– Rectus / gluteus medius
( Superior gluteal )
Anterolateral Approach



Most common for THA
ORIF of femoral neck
Synovial biopsy of the hip
Anterolateral Approach
Internervous plane – none
TFL / gluteus medius
Superior gluteal / Superior gluteal
Lateral Approach
Dangers
– Superior gluteal nerve
– Femoral nerve
Medial Approach
CDH open reduction
Psoas Release
Obturator Neurectomy
Biopsy or Treatment of tumors
of femoral neck
Medial Approach
Internervous plane ( only deep )
Superficial :
Adductor Longus / gracilis
Deep :
Adductor Brevis / magnus
Posterior Approach
Internervous plane – none
splits gluteus maximus
( inferior gluteal )
Primary Hip Arthroplasty
Posterior Approach

Total hip replacement

ORIF of posterior column fractures

Dependent drainage of hip sepsis
Primary Hip Arthroplasty
Posterior Approach

Sciatic Nerve

Inferior gluteal artery
Primary Hip Arthroplasty
Design Features

Size

Shape

Device configuration

Material / physical properties
Primary Hip Arthroplasty
Resist Composite Failure

Prosthetic Device

Bone Cement

Cancellous Bone

Cortical Bone
Primary Hip Arthroplasty
Design Features

Femoral Head

Neck

Stem

Collar

Acetabulum
Primary Hip Arthroplasty
Prosthetic Hip Loading

Changes from externally
loaded system to an internally
loaded system
Primary Hip Arthroplasty
Femoral Head Design

Articulating finish

Head diameter
DESIGN
FEATURES
Primary Hip Arthroplasty
32 mm Head Size
 Greater acetabular loosening
 Greatest volumetric wear
Ritter COOR ‘76
Morrey JBJS ‘89
Design Features
22mm Head Size
u
Greatest linear wear
u
Greatest acetabular
penetration
Morrey
JBJS 1989
Design Features
Charnley 22mm head diameter
Compromise friction / wear
Design Features
28 mm Head Size
Stable as 32mm head size
Less torque than the 32mm head
More favorable direct stress
transmission patterns
Primary Hip Arthroplasty
28 mm Head Size
• Compromise
Primary Hip Arthroplasty
Design Features
Femoral Neck Geometry
 Neck stem angle – 135º
 Neck stem offset
– large offset . . . Bending moment
– small offset . . . Decreases moment
arm
Primary Hip Arthroplasty
Design Features
Femoral Stem
– Length
– Shape
– Material properties
– Surface finish
Primary Hip Arthroplasty
Femoral Stem Design
Cross sectional geometry
Defines strength / stiffness
Avoid sharp corners



Primary Hip Arthroplasty
Femoral Stem Design
 Large lateral volume
 Less tensile stress in the mantle
laterally
 Large medial volume less tensile
stress
Primary Hip Arthroplasty
Collar
Primary role for optimal load
transfer to proximal femur
Crowninshield JBJS ‘80
Andriacchi JBJS ‘76
Primary Hip Arthroplasty
Collar



Reduces adaptive bone
resorption
Reduce bending stress in the
component
Reduce stress in the distal
cement
Primary Hip Arthroplasty
Fixation Features
PMMA
Weak link
Poor fracture toughness
Low tensile and fatigue strength
Elastic modulus 1/3 lower than
cortical bone
Primary Hip Arthroplasty
Fixation Features
PMMA Improvements
Carbon Fibers
Decreased cement
intrusion / increased
viscosity
Low Viscosity
Lower fatigue strength
Centrifugation
Improved tensile and
fatigue strength
PMMA Improvements
Centrifugation
30 sec / 4000 rpm
Vacuum
Burke JBJS ‘84
Chin/Stauffer JBJS ‘90
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
Primary Hip Arthroplasty
Acetabulum Design

Metal backed

All polyethylene
Primary Hip Arthroplasty
Cement Fixation :
The Femoral Side
Results directly related to
Surgical Techniques
Primary Hip Arthroplasty
Metal Backed
Increased linear and volumetric
wear
Increased radiolucency, loosening,
revision
No series of documented superior
results
Improved Longevity –
Femoral Side
Improved Longevity – femoral side

Plug canal

Retrograde fill

Avoid varus / valgus > 5º
Mulroy
JBJS ‘95
Primary Hip Arthroplasty
Grade
Radiographic Appearance
A
B
C1
C2
D
White-Out
Complete Distribution
Extensive Radiolucent Line
Thin mantle < 1 mm
Gross deficiencies
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
Primary Hip Arthroplasty
Cement Techniques
Probable Improved Longevity
Femoral Side
Pressurize
Centralize
Continuous Cement Mantle



Harris
COOR ‘97
Cemented Long Term
Primary Total Hip
nd
2 Generation Cement
William Harris Began 1975
Gun 71
–
Jet lavage –
Super alloy
Broad & round
medial border
Canal Prep
Cement Restriction
Primary Total Hip
Cemented Long Term
Results 25 year Survivorship
Acetabulum
Survive
Age < 40
74%
40-49
80%
60-69
92%
Femur
< 40
83%
40-49
82%
60-69
95%
Barry et al
1998
Primary Total Hip
25 Year Follow-Up
Total Aseptic
Acetabulum
Revision
Radiologic
Total:
Femoral
Revision
Radiologic
Loosening
%
14.5
19.4
33.9
%
6.4
8.1
Callaghan, Johnston, JBJS ‘97. Harris Course ‘98
Cemented Primary Total Hip
Clinical Results with
2° Generation Techniques
Hips
Follow Revision
Up
Rate
Neumann (94)
241
17.6 yrs 8.3%
Schulte
93
330
20 yrs
3%
Wroblewski 93
1324
20 yrs
6%
333
20 yrs
16%
Kavanagh
94
Cemented Primary Total Hip
Clinical Results with
2º Generation Techniques
Hips
Follow Revision
Up
Rate
Barrack
92
50
12 yrs
0%
Madey
97
356
15 yrs
1%
Mulroy
95
162
15 yrs
2%
Smith
98
161
18 yrs
5%
Primary Total Hip
Clinical Results
Cemented Total Hip: 2nd Generation
14-17 year follow-up – 102 hips

Femoral loosening
2% revised

Acetabular loosening 10% revised

42% radiologic
Mulroy, Harris, JBJS ‘95; COOR ‘97
Cemented Primary Total Hip
Clinical Results — Acetabular Side
Prosthesis Hips
Sullivan 94 Charnley
Smith
98 CAD
Callaghan 98 Charnley
89
65
93
Rev.
Rate
Loosening
13%
23%
19%
37%
26%
15%
Primary Total Hip
3rd Generation Cement Technique
Bill Harris – Began 1982

Porosity reduction

Rough surface

Centralization

Pressurization

Pre-coat
Primary Total Hip
Conclusions — Cemented




Plug and retrograde fill
Avoid excessive varus/valgus
Strive for 3-5 mm prox/med > 2mm
distal
Do not ream / remove good
cancellous bone
Primary Total Hip
Clinical Results
Hybrid Construct
Galante - 95 f/u 5 years

Femoral
2% rad loose

Acetabulum 2% rad loose
Woolson - 96 f/u 6 years

Femoral
5% revision

Acetabulum 0% revision
Design Features
POROUS IMPLANT
Uncemented THA
Definition
Press Fit
Macrointerlock
Microinterlock
Design Features
Pore Size — Animal Studies
50 to 400 µm
Optimal bone ingrowth
Bobyn: Clinical Orthopedics; 1980
Engh: JBJS; 1987
Collier: Clinical Orthopedics; 1988
Micromotion
40 Micron Motion Bone Ingrowth
(JBJS 79-A)
150 Micron Motion Fibrous Ingrowth
(CORR, 208)
Design Criteria –
Long Term Implant Stability




Initial Implant Stability
Implant micromotion < 50 mm
of displacement
Level of implant coating
Type of coating
Kienapfel H.
J. Arthroplasty 1999
Design Criteria
Uncemented Total Hip Arthroplasty

Key — Resistance to Rotation
Around the Long Axis
Design Criteria
Uncemented Total Hip
Arthroplasty
 Resist translation in 3 planes
— Axial
— Medial - lateral
— Anterior - posterior
Design Criteria –
Uncemented Implants

Level of Implant Coating
— Apply circumferential
— Avoid patch porous coats
— Smooth surface – high failure
rate
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
Design Features
Sintered Micro/Macro Beads
Cr-Co-Mo/Ti
Pore dimensions 100 to 400 mm
AML ; PCA
Fatigue strength
Process
psi
MPa
Forged
90
600
Cast
35
250
Sintered
25
150
Sintered with
controlled coating
30
200
*Data from Pilliar, R.M. Clin. Orthop. 176:42-51, 1983.
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
Design Criteria
Uncemented Implants
 Requires cortical fixation
— Metaphysis
— Metaphysis – Diaphysis
— Diaphyseal
Design Criteria –
Uncemented Implants
Bioactives — Osteoconductive



Tricalcium dissolves more rapidly
than hydroxyapatite
Thickness 50 mm
More crystalline hydroxyapatite
slows resorption
Uncemented Primary Total Hip
Clinical Results • Femoral Side
— Titanium = Cobalt Chrome
— Cobalt Chrome increased stressshielding
— Straight Stems with varying degrees
of medullary fill often used
— Anatomic Stems have not been a
great advantage
Design Features
u
Straight Stem
u
An Anatomic Stem
Design Features
Proximal Coating
Design Features
u Proximal coating – Anatomic design
u Maximum fit in certain priority areas
u Maximal load transfer
u Resist axial loading and torsional
loads
Poss: Clinic
Design Features
u
Both greater distal motion at
interface —
Compared with proximal motion
Callaghan, JBJS ‘92
The HGP stem (courtesy of Zimmer)
Design Features
u
u
Porous Implant
Fully coated
Proximal coating
Design Features —
Porous Surface
u
2/3 or fully coated
2 to 4 x increase in bone
resorption
Engh: Clinical Orthopedics; 1988
Design Features
Fully Coated Porous Surface
u Transfers stress distally under
axial load –
Proximal bone resorption
Engh: Clinical Orthopedics; 1988
Retrieval Studies
Engh
Femur
57% ingrowth
Acetabulum 32% ingrowth
Radiographic Criteria for
Bone Ingrowth
Engh et al, (CORR 257)
Absence of Reactive Lines
Spot Welds Endosteal Bone
Implant Instability 2 mm
Pedestal
Calcar Atrophy / Stress Shielding
Uncemented Primary Total Hip
Clinical Results • Femoral Side
Straight Stem
Design
% loosening
AML
507 hips
5- 14 yrs
1.2%
Harris/
Galante
121 hips
3- 6.2 yrs
3.3%
Omniflex
88 hips
2- 5.2 yrs
3.4%
Taperloc
145 hips
8- 12.5 yrs
0.7%
> 10 yrs
0%
Trilock
71 hips
Uncemented Primary Total Hip
Clinical Results • Femoral Side
%
Anatomic Stem Design
loosening
APR-1
100 hips
5-9.4 yrs
11%
APR-2
148 hips
2-5 yrs
0%
PCA
539 hips
6-8 yrs
7.6%
100 hips
> 7 yrs
2.0%
Screw Fixation
Less Micromotion, Better Ingrowth
Conduit for Particulate Debris
Neurovascular Injury
Acetabular Design
Hemisphere
Screw Fixation
Locking Mechanism
Uncemented Primary Total Hip
— Main Recurrent Concern
Poly Wear – Osteolysis
Uncemented Primary Total Hip
Clinical Results • Acetabular Side

Femoral head size – Acetabular
thickness
— PCA
26 mm head
no osteolysis
— PCA
32 mm head
26% osteolysis
Uncemented Primary Total Hip
Clinical Results • Acetabular Side
% loosening
ARC
72 hips
12 yrs
1.4%
Harris/Galante 136 hips
5-10 yrs
0%
PSL
smooth HA
beaded HA
316 hips
6-10 yrs
12%
2.7%
241 hips
539 hips
100
2-9 yrs
7 yrs
> 7 yrs
11%
13.2%
4% rev.
PCA
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
{
Complications in Total Hip Arthroplasty
– Heterotopic Ossification

Treatment
—Radiation pre-op or post-op
500 to 1000 Rad
“Remember to shield implant”
—Indomethacin
—Ibuprofen
—Diphosphonates
Complications In Total Hip Arthroplasty –
Heterotopic Ossification 0.6% to 61.7%

Associated conditions
— Ankylosing spondylitis
— Forestier’s disease
— Post traumatic arthritis
— Bilateral male osteophytic OA
Complications in Total Hip
Arthroplasty – Dislocation


Component Impingement
— Proximal femur
— Femoral head skirt
— Acetabular component (elevated liner)
— Osteophytes / cement masses
Head Size
— No difference 22 - 28 - 32
— 28 mm head > 60 mm acetabulum
—increased rate
— 22 mm head > 54 mm acetabulum
—increased rate
Complications In Total Hip
Arthroplasty – Dislocation – 3%




Posterior approach slightly higher 4.6%
Neuromuscular problems
Previous surgery (rate doubles)
Malposition
> 25º anteversion
> 60º inclination
Retroversion
> 15º femoral anteversion
Treatment
Bracing
Spica cast
Surgery
Complications In Total Hip
Arthroplasty – Dislocation

Occult infection

Trauma

Profound weight loss
Complications In Total Hip
Arthroplasty – Thromboembolism

Most common complication
DVT –
PE
–
70% to 8%
1%
to 2%
Complications In Total Hip
Arthroplasty – Thromboembolism

Activation of clotting cascade

Local vessel injury

Stasis in the femoral vein
Ultra-High Molecular Weight Polyethylene
is defined as what type of material ?
1.
2.
3.
4.
5.
Elastic
Viscoelatic-plastic
Rigid
Shear thinning
High friction
The degradation of polyethylene following
gamma irradiation is related to what factor ?
1.
2.
3.
4.
5.
Increased ionic bonding
Surface ion implantation
Free radical formation
Decreased covalent crosslinking
Decreased polymer density
Why is cobalt-chrome alloy preferred over
a titanium alloy for a cemented femoral
component in a total hip arthroplasty ?
1.
2.
3.
4.
5.
Less particulate metal debris
Less stiffness
Elastic modulus closer to bone cement
Cost-effectiveness
Better cement bonding ability
What is the most common long-term
complication of cemented total hip arthroplasty
in patients under 50 years of age?
1.
2.
3.
4.
5.
Age
Dislocation
Periprosthetic femur fracture
Acetabular component loosening
Femoral stem fracture
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.
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
Thank You