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5/4/2015
Ceramic Bearings Should Be
Routinely Used in THA
Gwo-Chin Lee, MD
Assistant Professor
University of Pennsylvania
Philadelphia, PA USA
University of Pennsylvania Department of Orthopaedic Surgery
Disclosures
• Consultant
– Stryker
– Depuy
• Educational Honoraria
– Depuy
– Ceramtec
– Medtronic
• Research Support
– Zimmer
– Smith and Nephew
– NIH
– CD Diagnostics
– Cempra Pharmaceuticals
1
5/4/2015
Newer Polyethylene
• Forgiving
• Reliable
• No wear (?)
Good
Enough !
The Posterior Approach
The Historical Concerns
• Most common reasons for revision:
– Instability/Dislocation : 22.5%
– Mechanical Loosening: 19.7%
– Infection: 14.8%
TREND TOWARDS USING
LARGE HEADS
JBJS-A
2003
2
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Volumetric Wear ?
Do we have the tools to measure
wear?
University of Pennsylvania Department of Orthopaedic Surgery
Osteolysis Threshold 0.1 mm/yr (Dumbleton JH, J
Arthroplasty 2002)
Negative Wear?
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SMALL OSTEOLYTIC
LESIONS (1CM)
VISIBLE
Today’s Patients
• Younger
• More Active
• Obese
• Life expectancy
will increase
4
5/4/2015
The Problem: Wear and Osteolysis
40 YO Female 7 years s/p THA
We Can Do Better
Ceramics
University of Pennsylvania Department of Orthopaedic Surgery
Resurgence of Ceramics
• Appetite for larger
heads
• Increased number
of head sizes,
options, and
reliability
• Trunionosis
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Wear characteristics are important
Bragdon et al. 2006, Greenwald et al. 2006, Manning et al. 2005, Martell et al. 2003, Zichner et al. 1992, 1977
Hydrophilic
Wetting of alumina ceramic (left) and
metal (right) ball heads. The smaller
the wetting angle the better the
lubrication.
Garino, JBJS, 2001
INERT AND
BIOCOMPATIBLE
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Author
Journal
Year
F/U
Hips Survivorship
Boyer
Orthop
Traumatol
Surg Res
2010
10.0y
83
92%
Capello
J Arthroplasty
2008
10.0y
380
95.9%
Mesko
J Arthroplasty
2011
8.3y
325
96.8%
Kim
Int Orthop
2010
11.1y
93
100%
Sugano
J Arthroplasty
2011
14.0y
100
97.9%
Solarino
J Orthop
Traumatol
2012
13.0y
68
97%
Aldrian
Silke
Hip Internat
2009
7.6y
229
98.2%
Lewis
J Arthroplasty
2010
8.1y
56
100%
Chevillotte
Int Orthop
2010
8.8y
100
96%
Park
Orthopedics
2010
9.6y
112
95%
Kress
Int Orthop
2011
10.5y
75
99%
Yeung
JBJS-A
2012
10.9
301
98%
D’Antonio
CORR
2012
10.1y
216
97.9%/95.2%
99% @ Mean 14.6
Years Follow Up
7
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Clinically Relevant Durability
Harris Hip Scores
100
80
60
40
20
0
Pre-op
5 years
10 years 12.5 years
Lee GC et al. Seminars in Arthroplasty 2014
COC vs MOP
Author
Year
F/U
COC
MOP
Capello
2008
8.5y
95.9%
91.3%
Mesko
2011
10y
96.8%
92.1%
Yoon
2008
17y
81%
74.4%
D’Antonio
2012
10
97.9%
91.3%
Less Osteolysis and
Less Measurable Wear
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Why not ceramics in everyone?
• Fewer options
• Risk of fracture
• Risk of squeaking
• Less forgiving
• Cost
Author
Year
Hips
Fractures
Rate
Squeaking
Boyer
2010
83
1 liner
1.2%
1 (1.2%)
Capello
2008
380
2 liners
0.5%
3 (0.8%)
Mesko
2011
325
2 liners
1 head
0.9%
9 (2.7%)
Kim
2010
93
0
0%
2 (2%)
Sugano
2011
100
1 liner
1%
0 (0%)
Solarino
2012
68
0
0%
NR
Aldrian Silke
2009
229
3 heads
(extra long
necks)
1.3%
NR
Lewis
2010
56
0
0%
0 (0%)
Chevillotte
2010
100
0
0%
6 (6%)
Park
2010
112
2 liners
1.7%
0 (0%)
Kress
2011
75
0
0%
NR
Yeung
2012
301
0
0%
1 (0.3%)
D’Antonio
2012
216
1
0.4%
2 (1%)
14 out of 2138
(0.6%)
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Incidence of Modern Alumina Ceramic and Alumina Matrix Composite Femoral Head Failures in Over 5.7 Million THA
Gwo-Chin Lee, MD(1)(2-Ceramtec, 3B-Stryker, Depuy) and Raymond H. Kim, MD(2)(2-Ceramtec, Convatec, 3B-Stryker)
1- University of Pennsylvania, Philadelphia, PA, United States; 2- Colorado Joint Replacement, Denver CO
Mating Surfaces (Forte )
Introduction
Ball head size greater than 28mm were significantly less likely to fracture
compared to 28 mm ceramic ball heads (p<0.001)
While conventional total hip arthroplasty (MOP) have been shown to be durable and reliable,
concerns remain.
Improved wear properties, increased head and neck options, and concerns with trunionosis have led
to an increasing utilization of ceramic ball heads (1).
Concerns of ceramic fractures and increased implant costs remain the principal barriers to wide
adoption of ceramics (2).
)
Mating Surfaces (Delta)
Objectives
Taper Influence
Short taper 28mm ball head was more likely to fracture compared to other neck lengths (p<0.01).
The purpose of this study is to evaluate the risk of ceramic ball head fracture through analysis of the
quality control program of a major ceramic implant manufacturer.
Taper mismatch at the root of significant number of delta ball head fractures (over 50%).
Goals:
1) Determine the fracture rate of modern 3rd and 4th generation alumina and alumina matrix
composite ball heads
2) Determine the factors (timing, ball head size, and taper influence) on ceramic ball head fractures
Taper contamination also common in forte ball head fractures (over 50%).
Discussion
Manufacturer reported rates of fracture are lower compared to reported clinical fracture rates (2,3).
Massin et al. reported 3rd generation alumina fracture rates of 0.18% compared to 0.0013% for 4th
generation alumina composite ball heads (3)
Materials and Methods
Ceramtec (Plochingen, Germany) Reporting and Surveillance Program (1/1/2000-12/31/2013)
The reported fracture rate of ceramic ball heads have decreased over time
3.2 million pure alumina (Biolox forte)
2.52 million alumina matrix composite balls (Biolox delta)
0.100%
BIOL…
Fr
Analysis of reported failures with respect to time to failure, head size and other factors
Reporting of ceramic component failures to Ceramtec by orthopaedic implant manufacturers
mandated through contracts.
Destructive analysis of retrieved implants including scanning electron microscopy (SEM) when
permitted.
Evaluation for taper compatibility, metal transfer, fracture crack propagation, and
taper contamination.
Results
Fourth generation alumina matrix composite ceramic ball heads were more reliable compared to 3 rd
generation pure alumina ball heads
672 Biolox forte fractures (0.021%)
1 in 5000
26 Biolox delta fractures (0.001%)
1 in 100,000
Limitations
Reliability of reporting
Numerator is unknown
Look at the trends
Small delta sample size
Underpowered
0.000%
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Reliability of Reporting
Many factors leading to ceramic ball head fractures such as taper compatibility and contamination
are under a surgeon’s control.
No surgical and clinical data
No clinical correlation.
Summary
Alumina matrix composite ball heads are more reliable compared to pure alumina ball heads.
Fractures typically occur early during the implant’s life of service
Larger ball heads have lower risk for fractures.
Taper mismatch and contamination greatly influence the reliability of ceramic ball head
components.
References
1. Lehil MS, Bozic KJ. Trends in total hip arthroplasty implant utilization in the United States. J Arthroplasty 2014; 29(10): 1915-1918.
2. Fritsch EW, Gleitz M. Ceramic femoral head fractures in total hip arthroplasty. Clin Orthop Relat Res 1996; 328: 129-136.
3. Massin P, Lopes R, Masson B, et al. Does Biolox Delta reduce the rate of component fractures in total hip replacement? Orthop Traumatol Surg Res
2014; 100(6S):S317-S321.
Wear, Big Heads, Trunionosis
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Concessions
• Hard bearings
are less forgiving
– Technically
demanding
– Component
position critical
– Liner insertion
(chipping)
Choices and Decisions
• Patient specific
• Clinically sound
• Economically
responsible
STANDARD: A level of quality or
achievement that is considered
desirable
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5/4/2015
Ceramics Today
• Better wear
• More reliable
• More options
– Larger heads
without concerns
of wear
Summary
• Recognition that there is a role and place
for ceramic on ceramic hips in younger
and active individuals.
• Ceramics has the lowest wear rates.
• Reliability of ceramics continually
improving.
• Modern ceramic on ceramic THA have
excellent clinical track record with low
rates of complications.
Thank You
University of Pennsylvania Department of Orthopaedic Surgery
12
Ceramic Bearings Should be
Routinely used in THA (Con)
Thomas P. Schmalzried, M.D.
Joint Replacement Institute at
St. Vincent Medical Center
Los Angeles, CA
Harbor-UCLA Orthopaedics
Disclosure
Royalties received (DePuy)
No royalties for any bearing
Challenges for COC
Overview
• Recognized low COC wear
• Metrics:
–
–
–
–
Survivorship
Function
Special Risks
Cost
• XLPE at 15 years
– Relative benefits and risks
Challenges for COC
2014 AOA NJR
Survival of COC < XLPE
Challenges for COC
COC
patient
Function
• Comparable function
• Bearing surface material
is not determinant of hip
function
Paris Marathon
Challenges for COC
Squeaking
• Sexton et al. 2011
– Younger patients
– Higher range of post-op.
IR and ER
– Higher activity levels
– Position sensitive
• High acetabular inclination
• High femoral offset
• Lateralization of the hip
center
• High or low acetabular
component anteversion
Challenges for COC
Overview
Fractured COC
Challenges for COC
Revision for Fractured Ceramic
•
•
•
•
•
Low survivorship
Residual ceramic particles
Hard 3rd bodies
Accelerated wear
Osteolysis
XLPE: 13 yrs, 37 Million Cycles
‒ 28, 32mm diam. mean linear penetration at min. 10 years
0.034 mm/yr +0.041 (-0.041-0.88)
− Mean volumetric wear 11.9mm3/year +13.62 (range -11.75 – 33.95)
− Max. linear penetration 0.87mm
− Max. volumetric wear = 435 mm3
No radiographic osteolysis
Decreasing Activity and Wear with Patient Aging
The Osteolysis Threshold
‒ Max. linear penetration = 0.87mm
‒ Max. volumetric wear = 435 mm3
‒ No osteolysis observed in these
hips
‒ Dowd et al. JBJS 2000
• 32mm hips: No osteolysis at 10
yrs with linear wear rate
<0.1mm/yr
• Corresponds to ~650mm3
volumetric wear
Decreasing Activity and Wear with Patient Aging
Predicting Wear
Osteolysis Threshold
Volumetric Wear (mm3)
‒ The First Five Years
Mean volumetric wear rate =
15mm3/yr
‒ 40% mean decrease in wear
from First 5 to 5-13 years
‒ Approximately a 3%
compounded decrease in
wear per year
‒ Life Expectancy for 50 yr old
= 31.0 yrs
‒ Total volumetric wear over
31yrs = 305mm3
‒ Low risk of osteolysis during
lifetime
Wear Projection
700
600
500
400
300
200
100
0
0
5
10
15
20
25
30
35
Years Post-op
XLPE at 15 Years
• Bragdon et al. 2012
– Low wear
– No osteolysis
– Lower wear with time
• Lachiewicz et al. 2015
– Low wear
– Small osteolysis in 12 hips (14%)
– No association with head size or
volumetric wear rate
Challenges for COC
Summary
• Recognized low COC wear, BUT
‒ Survivorship is not better
‒ Function is not better
‒ Squeaking risk in “target”
patients
‒ Fracture risk + low revision
survival
‒ AND it costs more
• Relative benefits and risks
favor XLPE
Indications for Ceramicised
Metal Bearings in THR
R.W. McCalden
Associate Professor
University of Western Ontario
London Health Sciences Centre
London, Ontario, CANADA
Disclosures:
• Consultant for Smith & Nephew
• Institution receives research support
from Smith & Nephew, J&J Depuy and Stryker
What are the issues with
THR in 2015 ?
•
Fixation??
•
Surgical Approach??
•
Component Design??
•
Wear  Bearing Surfaces!!!
•
Trunnionosis!!!
Options To Hip Wear
•
Change Poly (XLPE) ✔
•
Change counterface
•
Eliminate poly
Ceramic ✔
OxZr ✔ ✔
Ceramic-on-Ceramic ✔
Metal-on-Metal
Except RSA
Choosing A Bearing In THA
What do I think about in a young active patient?
•
Bearing Longevity/Osteolysis Potential
Low taper corrosion potential?
•
Which is best?
Using XLPE is an Easy Choice
Average Head Penetration Rate from 2 Year
0.4
CONVENTIONAL
XLPE
Conventional y = 0.0507x + 0.0921
Penetration (mm)
y = 0.0507x + 0.0921
0.3
Significant Difference
(p<0.05)
y = 0.0068x + 0.1795
0.2
XLPE y = 0.0068x + 0.1795
0.1
0
0
1
2
3
Follow (years)
4
5
6
Australian Registry 2014…
So far, HXLPE is a good
thing!!!
Gold Standard
Polyethylene
Polyethylene Wear Related To
Polyethylene Used
(XLPE better)
AND
Counterface
What are the options as a
counterface for XLPE
•
CoCr
•
Ceramic
•
Oxidized Zirconium
(OxZr)
What about CoCr heads?
•
long history with THR
•
most data with XLPE
- excellent results to date
•
inexpensive
•
not scratch resistant
•
potential for taper corrosion
• ‘”standard”
to compare against
Oxidized Zirconium(OxZr) – What is it?
• Zirconium metal component is heated in air
• Surface transforms to ceramic; not a coating
• Ceramic oxide is about 5 microns thick
Air
500oC
Oxygen
Diffusion
Original Surface
Ceramic Oxide
Oxygen Enriched Metal
Metal Substrate
Biocompatibility
• Zirconium: one of most biocompatible metals
• Ranked on passivation and biological response
• Other four: niobium, titanium, tantalum, platinum
• Zr-2.5Nb: metal alloy with niobium and oxygen
IV B
VB
22
47.90
Ti
Titanium
4.5
3130 1812
(Ar) 3d2 4s2
50.94
V
Vanadium
5.96
3530 1730
(Ar) 3d3 4s2
40
41
91.22
Zr
Zirconium
6.4
3580 1852 (Kr)
4d2 5s2
23
92.91
Nb
Niobium
8.4
3300 1950
(Kr) 4d4 5s
*Kovacs and Davidson, ASTM STP 1272
Patients With Metal Allergies
• 3-8%
• No Nickel In Oxidized Zirconium
45 million cycle hip simulator wear test
*Parikh et al., ORS 2013:1028
45 million cycle hip simulator wear test
*Parikh et al., ORS 2013:1028
45 million cycle hip simulator wear test
*Parikh et al., ORS 2013:1028
Effect Of Roughened Heads On HXLPE
• Scratch Resistant Counterface Preferrable
•
Oxidized Zirconium Metal
• Ceramic
Maximizing hip bearing survivorship
Abrasion Resistance
OxZr resists scratching and maintains low wear conditions
simulating in-vivo roughening from retrieved heads
Comparison of CoCr/CPE, OxZr/XLPE
and Delta/XLPE simulator wear
~98%
In Vitro evidence for OxZr
is compelling….
What is the clinical evidence?
Low clinical wear rates in hips*





400 patients
32 mm heads
Martell method
3.7 yr median F/U
98% survivorship
for all groups
 Penetration rates
calculated relative
to 1 yr radiographs
*Jassim et al., ISTA, 2012:136
What is the best source of quality data
about Bearing surfaces?
Australian Registry 2014
- Large numbers
- Comparable implants to North
America
Australian Registry 2014:
OxZr/XLPE lowest Revision rate at 10 yrs
OxZr against XLPE
Australian Registry 2014:
OxZr/XLPE lowest Revision rate at 10 yrs
Any downside to hard bearings?
Hard Bearings (Ceramic & OxZr) can
be damaged…
Damaged Ox head
RWM
Damaged ceramic head
RWM
How does this happen?
•
Contact of femoral head against the edge
of acetabular shell…
Care with final
reduction!
What about Trunnionosis….
How does OxZr technology help?
Biocompatibility Key Factor in
Trunnionosis
• Choice of head is
critical to reduce
taper corrosion
Biocompatibility: Trunnionosis
CoCr
OxZr
Ti6Al4V
Ti6Al4V
Less Taper
corrosion after
long term wear
test with
Oxinium heads
(45 mCycles)
Retrieved OxZr heads show least
chemical activity on the taper
surface
OxZr
CoCrMo
Ti transfer
Cartner et al ORS 2014
Advantages of Ceramic heads
against XLPE
•
lower wear than CoCr
•
scratch resistant
•
reduced taper corrosion/fretting
Disdvantages of Ceramic heads
against XLPE
•
expensive
•
fracture potential
•
limited modularity
•
surface damage & metal transfer
•
phase transformation possible
Advantages of OxZr heads
against XLPE
•
•
•
•
•
•
•
lower wear than CoCr
- similar to ceramic
scratch resistant
fracture resistant
maintains modularity
reduced taper corrosion/fretting
stable monoclinic phase
excellent clinical results at 10 years
Disdvantages of OxZr heads
against XLPE
•
expensive
•
surface damage and/or metal transfer
Indications for Ceramicised Metal
Bearings in THR:
•
excellent bearing choice for young active
patients
excellent in-vitro & in-vivo wear profiles
•
ideal choice for ‘metal allergy’ patients
•
• very resistant to taper corrosion & fretting
Indications for Ceramicised Metal
Bearings in THR:
OxZr - number of distinct advantages
compared to ceramic heads
- no risk of fracture
- maintains modularity
- stable ceramic phase
- metal/ceramic - ‘Best of both worlds’
• OxZr/XLPE outstanding clinical results at
10 years
•
Other Indications for Ceramicised
Metal Bearings in THR:
•
OxZr in the revision setting
- fractured ceramic head
- taper damaged & well-fixed stem
- failed MOM THR (pseudotumour)
- Rx of trunnionosis
• Ideally, should be used with compatible
taper (ie same manufacturer)
OxZr/XLPE provides an excellent
bearing couple for THR
OxZr/XLPE
OxZr/XLPE provides an excellent
bearing couple for THR
Thank You
5/4/2015
What we know About Trunions in
2015
Scott M. Sporer MD, MS
Co-Medical Director,
Cadence Health Joint Replacement Institute –
Central DuPage Hospital
Associate Professor
Department of Orthopaedic Surgery
RUSH University Medical Center
1
Financial Disclosure
• Consultant:
Zimmer, Smith & Nephew
•Royalties: Smith & Nephew
•Research Support: Zimmer, Cadence Health
•Royalties: SLACK
•Board: American Joint Replacement Registry
2
Modularity in THA
• Benefits of Head-Neck Modularity:
− Intra-operative flexibility
− Ability to change head at later date
− Decreased implant inventory
• Early concerns after introduction
in 1980’s-1990’s
− Fretting and
crevice corrosion
1
2
3
Collier, Clin Orthop 1991
Gilbert, JBMR 1993
Gilbert, JBJS(Am) 1994
• Design improvements minimized corrosion,
leading to near-universal adoption
4
1
5/4/2015
Modularity in THA
• “Dual-taper stems”
− Allow the surgeon to independently control
femoral fixation and hip-center restoration
o Modular necks allow adjustment of leg
length, offset, and version
5
All Good Things Come To An End !!
6
Study Population
• 20 patients revised for ALTR secondary to
corrosion between 1/2009 and 6/2012
Sex
16 women, 4 men
Age
60.9 years (41 – 70)
• All metal-on-poly bearings
• 18 of 20 primary THA’s performed
at our institution (2 referrals)
Cooper, HJ et al. J Bone Joint Surg Am. 2012;94(18):1655-61.
7
2
5/4/2015
Study Population
• Initial presentation 3.9 years (0.7 – 17.3) after
index procedure
• Presenting symptoms included:
− pain (15)
− swelling / fluid collections (4)
− weakness (3)
− recurrent instability (7)
• Mean HHS score: 58.4 (22 – 79)
8
Study Population
• Components
Femur
Taper
Junction
Acetabulum
VerSys Beaded Fullcoat (14)
12/14
Co-Co
Trilogy
VerSys Epoch Fullcoat (1)
12/14
Co-Co
Trilogy
Zimmer Multilock (1)
6 deg
Ti-Co
HG-2
VerSys Fiber Metal Taper (1)
12/14
Ti-Co
Trilogy
M/L Taper w Kinectiv Modular Neck (1)
12/14
Ti-Co
Trilogy
AML Bantam (1)
10/12
Co-Co
Trilogy
Accolade (1)
V40
Ti-Co
Trident PSL
• Head Sizes
− 28mm (5)
36mm (5)
32mm (9)
40mm or larger (1)
9
Diagnostic Workup
• 8 patients underwent
cross-sectional
imaging, each
demonstrating large
fluid collections
around the hip
10
3
5/4/2015
Metal Levels
• Elevated Co levels in all but one case
• Elevated Cr levels in all but three cases
• Serum Co levels were differentially elevated
(p = 0.014, Wilcoxon signed-rank test)
over serum Cr levels
Ion
Mean
Co
10.27
Cr
2.16
ng/mL
ng/mL
Range
Reference 1
0.13 – 49.83
(0.16 ± 0.10)
0.18 – 9.81
(0.24 ± 0.35)
1
Jacobs, ORS 2002
11
12
Serum Cobalt Levels
12.0
Preop
10.0
8.0
Serum Cobalt
Ion Levels
(ng/mL)
6.0
4.0
2.0
0.0
0
4
8
12
16
20
24
Months Post-Op
13
4
5/4/2015
Modular Neck Study
Cooper, HJ et al. J Bone Joint Surg Am. 2013;95:865-72.
• Multicenter, multi-surgeon series
▫ 11 patients (12 hips) revised for ALTR secondary to
corrosion between 12/2010 and 6/2012
Sex
8 women, 3 men
Age
60.1 years (43 – 77)
• Bearing: Metal-on-Poly (4)
Ceramic-on-Poly (8)
• Single stem design (Rejuvenate)
▫ Titanium alloy (TMZF) stem
▫ Cobalt chromium alloy neck
14
Study Population
• Initial presentation 7.9 months (5 – 13) after
index procedure
• Presenting symptoms included:
− groin pain (11)
buttock pain (5)
− trochanteric pain (4) thigh pain (3)
− limp / weakness (4)
thigh swelling (1)
• Mean HHS score: 43.2 (22 – 71)
15
Diagnostic Workup: MRI
• 10 of 12 hips imaged
with MARS MRI
(Coronal STIR image)
− Large fluid collections
with hypertrophic soft
tissue reactions in 9 of
10 patients
− Images interpreted as
normal in 1 patient
16
5
5/4/2015
Metal Levels
• Obtained in 10 of 12 hips
• Serum Co levels were differentially elevated
over serum Cr levels
Ion
Mean
Range
Reference 1
Ti
3.41 ng/mL
1.56 – 5.80
4.13 (1.10 – 11.17)
0.8 x
Co
5.99 ng/mL
3.89 – 9.48
0.32 (0.15 – 1.59)
18.7 x
Cr
0.61 ng/mL
0.22 – 1.20
0.27 (0.02 – 1.46)
2.3 x
Elevation
1
Jacobs, JBJS 1998
17
18
Etiology of ALTR
• Related to summation of debris released from bearing surfaces and
modular taper junctions through tribocorrosion mechanisms
− ALTR only reported in association with modular junctions involving a CoCr
alloy component
− Have yet to be reported in association with Ti-Ti alloy junctions
o Titanium necks are more susceptible to fracture
• Potentially contributing factors from modularity:
−
−
−
−
−
−
−
Head size
Taper geometry
Material composition
Extended offset neck
Contamination of the taper interface (assembly issues)
Design-related factors (manufacturer dependent)
Alloy (TMZF)
20
6
5/4/2015
Synergistic Effects
• Tribocorrosion (combined corrosion and
wear)
• Third Body Effects
• Cathodic Polarization Effects (electrical
connectivity between tribocorrosive
processes at bearing surface and modular
junctions)
• Sum of metal debris burden from bearing
surfaces (McKellop Mode 1 wear) and
modular junctions (Mode 4 wear)
21
Relevance for MoM
• Consider modular taper tribocorrosion as a
cause/contributor to ALTR in patients with
MoM bearings, particularly if Co is elevated
out of proportion to Cr (Garbuz CORR [2010]
468:318-325).
• Volumetric wear from tribocorrosion at
modular connections can exceed that from the
bearing surface (Langton et. al. Bone Joint Res
[2012] 1:56–63).
22
Relevance for MoM
• In modular acetabular components with metal
on metal bearings simple acetabular liner
exchange may not address the primary debris
generator – the trunion should also be carefully
assessed.
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5/4/2015
Questions I Would Like To Know
• Do Large Femoral Heads Make A Difference?
• Does the Trunion Design Matter?
• Are Taper debris particles more bioreactive than
articular surface particles?
• Should I be using a ceramic head on everyone?
• Is there a threshold Cobalt and/or Chromium level to be
concerned?
• Do patients with Cobalt/Chrome heads need different
surveillance?
• Is Changing the head and liner adequate treatment?
24
Femoral Head Size
• 69 Patients – Metal on Poly Cementless Hip
2009
• 43 Patients cobalt and chromium levels
− 12 patients 28 mm, 18 patients 36 mm, 13 patients
40 mm
• Increased Cobalt levels 36 mm
• Normal Chromium levels
Craig, P.; Bancroft, G.; Burton, A.; Collier, S.; Shaylor, P.; and Sinha, A.: Raised levels
of metal ions in the blood in patients who have undergone uncemented metal-onpolyethylene Trident-Accolade total hip replacement. Bone Joint J, 96(1): 43-7.
25
Trunion Design
• 40 retrieved MOM heads
• Graded for fretting and corrosion
• Head Diameter did not correlate with fretting
• Trunion diameter and engagement length
important
• Head/Neck Corrosion correlated with soft
tissue loss
Nassif NA, Nawabi DH, Stoner K, Elpers M, Wright T, Padgett DE. Taper
Design Affects Failure of Large-head Metal-on-metal Total Hip
Replacements. Clin Orthop Relat Res. 2013
26
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5/4/2015
Trunion Design
• 161 failed MOM components
− Head 128
− Stem 33
• Female taper noted to have ridges – “Imprinting”
(Ridged microthread introduced to minimize burst
of ceramic heads)
• Corrosion primarily in area of imprinting
• Corrosion and Imprinting scores related
Hexter A, Panayiotidou A, Singh J, Skinner J, Hart A. Mechanism of corrosion
in large diameter head metal-on-metal total hip arthroplasty: a retrieval
analysis of 161 components. Bone Joint J. 2013:95–B Supp 12, 4.
27
Trunion vs. Articular Particles
• 369 MOM bearings
− Revised for ARMD
− THA patients compared to Resurfacing
• Resurfacing explants revised for ARMD higher volumetric
wear than THA
• Combined volumetric bearing + taper wear in THA revisions
still less than resurfacing
• Tissue destruction and extent of ALVAL greater in THA
• Taper particles more bioreactive
Langton D, Sidaginamale R, Lord J, Joyce T, Natu S, Nargol A. Metal debris release from
taper junctions appears to have a greater clinical impact than debris released from
metal on metal bearing surfaces. Bone Joint J. 2012:95–B Supp 1 1.
28
Clinical Questions
• Should I be using a ceramic head on
everyone?
• Is there a threshold Cobalt and/or
Chromium level to be concerned?
• Do patients with Cobalt/Chrome
heads need different surveillance?
• Is Changing the head and liner
adequate treatment?
29
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5/4/2015
THANK YOU
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