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CeraNews

ISSUE 1/2015

www.ceranews.com

The Orthopedic Landscape Information Journal

Focus: Knee Arthroplasty

Evidence-based Medicine in Orthopedics

©Galina Barskaya (Bücher); Denis (Knie) / fotolia

CeraNews 1/ 2015

Guest Commentary 3

Benazzo F, MD, Pavia, Italy

Focus: Knee Future of Knee Endoprosthetics: 5

Ceramic Components find their Place

Interview with Mittelmeier W, MD, Rostock, Germany

Clinical Cases: Primary Knee Arthroplasty in 8

Patients with Suspected or Confirmed Metal Allergy

Benazzo F, Pavia, Italy

Focus: Evidence Evidence-based Decision-Making and 10

Biological Reactions Related to Materials

Usbeck S, Scheuber LF, Plochingen, Germany

Science Mid-term Results of Modern Ceramic-on-Ceramic 17

Total Hip Arthroplasty

Laforgia R, Bari, Italy

2015 Update on an Evolving Perspective for 20

Taper Corrosion in Total Hip Arthroplasty

Kurtz SM, Philadelphia, USA

Science Report Fretting and Corrosion 22

Discussion of Methods for Assessment and Testing

Pandorf T, Plochingen, Germany

Science Does Bearing Influence Septic Loosening of 24

primary Total Hip Arthroplasty?

Bordini B, Bologna, Italy

Pauwels Commemorative Medal 2014 25

Materials Research The Effect of Chromia Content on Hardness of 26

Zirconia Platelet Toughened Alumina Composites

Kuntz M, Plochingen, Germany

Science Report What´s New in Endoprosthetics in Russia? 28

Tikhilov RM, St. Petersburg, Russia

Tribology: Science and Practice in Korea 30

Zimmermann M, Graessel M, Plochingen, Germany

News Ticker Heinz-Mittelmeier Research Award 32

Congresses & Workshops 34

Reading Tips 36

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TABLE OF CONTENTS

CeraNews 1/ 2015

Guest Commentary 3

Benazzo F, MD, Pavia, Italy

Focus: Knee Future of Knee Endoprosthetics: 5

Ceramic Components find their Place

Interview with Mittelmeier W, MD, Rostock, Germany

Clinical Cases: Primary Knee Arthroplasty in 8

Patients with Suspected or Confirmed Metal Allergy

Benazzo F, Pavia, Italy

Focus: Evidence Evidence-based Decision-Making and 10

Biological Reactions Related to Materials

Usbeck S, Scheuber LF, Plochingen, Germany

Science Mid-term Results of Modern Ceramic-on-Ceramic 17

Total Hip Arthroplasty

Laforgia R, Bari, Italy

2015 Update on an Evolving Perspective for 20

Taper Corrosion in Total Hip Arthroplasty

Kurtz SM, Philadelphia, USA

Science Report Fretting and Corrosion 22

Discussion of Methods for Assessment and Testing

Pandorf T, Plochingen, Germany

Science Does Bearing Influence Septic Loosening of 24

primary Total Hip Arthroplasty?

Bordini B, Bologna, Italy

Pauwels Commemorative Medal 2014 25

Materials Research The Effect of Chromia Content on Hardness of 26

Zirconia Platelet Toughened Alumina Composites

Kuntz M, Plochingen, Germany

Science Report What´s New in Endoprosthetics in Russia? 28

Tikhilov RM, St. Petersburg, Russia

Tribology: Science and Practice in Korea 30

Zimmermann M, Graessel M, Plochingen, Germany

News Ticker Heinz-Mittelmeier Research Award 32

Congresses & Workshops 34

Reading Tips 36

GUEST COMMENTARY

Total Knee Arthroplasty is currently Experiencing

a New Phase

By Benazzo F, MD, Pavia, Italy

T he number of prostheses implanted worldwide every year is constantly increasing for several rea-

sons:

• more surgeons are being educated to perform this particular class of operation;

• more patients now have a longer life span and increased articular damage as a consequence of

the extended utilization of their joints;

• extension of the indications for TKA in a range of young, active patients with damaged knees,

• and implants are becoming more easily available in emerging countries.

Together with the growing number of surgeries, an increased incidence of related problems is also

becoming evident, including:

• residual symptoms in a high percentage of patients (almost 20 %), such as pain, stiffness, and

instability, along with other minor but annoying symptoms;

• material-related problems such as wear in young and active patients; and allergies.

Thus, it is evident that efforts must be made to improve designs (with a strong shift toward more

natural kinematics of the knee), materials (that are not harmful for the patients and have a long and

wear-free life), and techniques and methods of implantation (robotics). There is also new interest be-

ing shown in partial prosthetic replacement of the affected knee (uni-compartmental, bi-unicondylar,

patellofemoral joint replacement).

The Biolox®delta composite ceramics, owing to their manufacturing features such as bending

strength and stress load capacity, could be the new benchmark of biomaterials available for clinical

use, as demonstrated by the cohort of patients treated with knee devices made of Biolox®delta. New

scenarios are therefore opening, specifically in the so-called small-implants field of partial knee re-

placement.

However, the safety and reliability of new implant products for patients must be guaranteed. No lon-

ger can we allow the success of a device to be validated on the basis of biased, by definition, expert

opinion. All the new phases of applied research entail the problem of demonstrating efficacy and

safety, clearly and incontrovertibly. Therefore, they must be validated under the umbrella of the evi-

dence-based medicine (EBM). The evidence pyramid should be the basis for evaluating the properties

and quality of any device, material, or surgical method. Critical evaluation has received enhanced at-

tention with metal-on-metal (MoM) failure and consequent clinically devastating effects, such as ad-

verse reactions to metal debris (ARMD). Critical evaluation has been extended to the “new” materials

such as cross-linked polyethylene (XPE), (for which the claimed lack of wear was not demonstrated),

and to new phenomena, such as corrosion of the metal junction in all prosthetic designs.

Together with the awareness of the potential drawbacks that any innovation could bring, and of the

harm any patient could suffer, research on new applications of proven materials such as Biolox®delta

ceramics will continue and will be monitored in accordance with the EBM principle.

This is the message that the new issue of CeraNews wants to bring to the customers.

Francesco Benazzo, MD

CeraNews 1/ 2015

4GUEST COMMENTARY

Francesco M. Benazzo, MD, studied medicine at the University of Pavia,

graduating in 1980. He devoted himself to electron microscopy during his

studies and early in his career. He pioneered the application of special tech-

niques such as freeze-etching and freeze-fracture to the connective tissue,

and in particular to cartilage and tendons.

He trained as an orthopedic surgeon in Pavia, completing his education in or-

thopedics and traumatology in 1985 with a thesis on a rare genetic disease

involving the long bones (Lipomembranous osteodystrophy), including an

electron microscopic evaluation of the lesions. During the residency program,

he was introduced by his mentor, Prof. Boni, both to cervical spine surgery

and to sports traumatology.

Benazzo served as assistant in the Sports Traumatology Section of the orthopedic clinic and finally as-

sumed an academic position as assistant professor in 1990. In 2000 he became full professor of ortho-

pedics and traumatology, and two years later Chairman of the Orthopedic and Traumatology Depart-

ment of the University of Pavia, San Matteo Hospital. Since then, he has also chaired the Program of

Residency in Orthopedics and Traumatology. In 2002, he became consultant to the Football Club Inter-

nazionale Milano, where he served until 2014 as surgeon.

His main fields of scientific and clinical interest are connective tissue structure and mechanics, tendi-

nopathies in athletes and functional overload injuries, spinal osteoarthritis, cementing techniques, hip

and knee prosthetic surgery, the development of MIS surgical techniques and tools for total knee re-

placement, and tissue engineering with the use of SAOS-2 and stem cells.

In 2005, Benazzo became President of the EFOST (European Federation of National Associations of Or-

thopedic Sports Traumatology). He is a member of IRCS (International Cartilage Repair Society), of ISA-

KOS (International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine), and of the

European Hip Society, and secretary and member of the Italian College of Professors of Orthopedics

and Traumatology.

He designed 3 different hip stems, and one knee prosthesis. Benazzo has been a visiting surgeon (Aus-

tralia, France, South Korea) and an instructor on cadavers for total knee arthroplasty and unicomparti-

mental replacement.

AAOS American Academy of Orthopaedic Surgeons

ARMD Adverse Reactions to Metallic Debris

ASTM American Society for Testing and Materials

BMI Body Mass Index

Co Cobalt

CoC Ceramic-on-Ceramic

CoCr Cobalt-Chromium

CoCrMo Cobalt-Chromium-Molybdenum

CoP Ceramic-on-Polyethylene

Cr Chromium

CT Computer Tomography

DGOOC Deutsche Gesellschaft für Orthopädie und Orthopädische

Chirurgie (German Society of Orthopedics and Orthopedic

Surgery)

DGU German Association for Trauma Surgery

EBM Evidence-Based Medicine

EFORT European Federation of Orthopaedics and Traumatology

EHS European Hip Society

FDA Food and Drug Administration

HHS Harris Hip Score

HOOS Hip dysfunction and Osteoarthitis Outcome Score

HR Hazard Ratio

HV Hardness Vickers

KSS Knee Society Score

LTT Lymphocyte Transformation Test

MoM Metal-on-Metal

MoP Metal-on-Polyethylene

OKS Oxford Knee Score

PE Polyethylene

RoM Range of Motion

SCC Squamous Cell Carcinoma

SF-12® Short Form, Health Survey Score

THA Total Hip Arthroplasty

TJA Total Joint Arthroplasty

TKA Total Knee Arthroplasty

XPE Crosslinked Polyethylene

ZTA Zirconia Toughened Alumina

ACRONYMS

CeraNews 1/ 2015

The Future of Knee Endoprosthetics:

Ceramic Components Find Their Place

Interview with Wolfram Mittelmeier, MD, Rostock, Germany

Why is a knee TEP patient so often dissatisfied?

Mittelmeier: The frequency of patients’ dissatis-

faction is higher in knee endoprosthetics than in

hip endoprosthetics. This is very likely due above all

to the highly complex kinematics of the knee joint

and to the kinematically more demanding operative

technique. There is also probably a certain connec-

tion with the metal/polyethylene procedure, which

is still being carried out, while ceramic components

are the gold standard in hip endoprosthetics.

In hip endoprosthetics the problem of metal

abrasion, corrosion, and fretting with modu-

lar prostheses is currently under intensive dis-

cussion, and the use of ceramic-on-ceramic or

ceramic-on-polyethylene is suggested. Do you

think this will also be an issue in knee endo-

prosthetics?

Mittelmeier: The initial euphoria regarding the use

of metal in hip endoprosthetics has given way to

disillusionment in recent years. In particular, large

metal/metal bearings have been the target of crit-

icism because of pronounced granulomas and in-

creased incidents of early loosening. These problems

of metal ions and metal abrasion apply equally to

knee endoprosthetics, whereby the larger joint vol-

ume with greater capsule surfaces probably consti-

tutes a higher level of tolerance, however. Never-

theless, the long-term application of knee endo-

prostheses with the well-known increase in allergy

problems in our population makes it reasonable to

expect similar problems, although probably not of

the same magnitude.

For which patients would you choose a ceram-

ic prosthesis rather than a metal prosthesis?

Mittelmeier: If an allergy is known and a ceram-

ic solution is available appropriate to the kinemat-

ics, I would favour it. Since no such kinematically

perfected ceramic solution is available for revisions,

improved ceramic coatings must be considered as

an alternative. I would also advise that these ce-

ramic-coated knee components be used for pa-

tients who require a septic revision of their endo-

prosthesis and have been treated with intermittent

cement spacer. In these cases there is an accumu-

lation of zirconium oxide particles in the normal

bone cement, which cannot be reliably removed by

joint lavage even with the most intensive efforts.

Are there differences in the follow-up care of

ceramic and metal implants?

Mittelmeier: No.

Do you see any clinical differences between

all-ceramic and ceramic-coated knee compo-

nents?

Mittelmeier: In this regard we have carried out and

published a retrospective study (comparison of co-

horts) comparing a particular coated, older type of

knee with our ceramic components [1]. These differ-

ences are almost impossible to document in short-

term clinical trials, but in some cases there is slight-

ly increased abrasion with coated components, at

least for the type of implant studied by us. In the

long term, however, I would expect to see a signifi-

cant advantage for the ceramic monoblock solution,

because the thin coatings on the market to date are

subject to constant abrasion and their wearing out

is foreseeable. Newer multiple coatings could yield

better results, but they must still be tested in clini-

cal practice.

Whereas ceramic materials have already been accepted in hip arthroplasty, knee arthroplasties

are still frequently carried out using MoP bearings. However, there are some good arguments

in favor of using ceramic knee components: For example, in patients with known allergies or

where replacements are required as a result of septic loosening, Prof. Mittelmeier recommends

full ceramic or ceramic coated components. The modern alumina matrix composite ceramics

demonstrate enhanced bending strength and stress-load capacity and are therefore appropriate

even for the kinematically demanding artificial knee. Current 5-year data from a European mul-

ticenter study verify that a Biolox®delta ceramic femur condyle shows stable fixation and con-

vincing durability.

CeraNews 1/ 2015

6INTERVIEW

What must be taken into consideration when

a ceramic component is implanted?

Mittelmeier: The alumina matrix composite (Bio-

lox®delta), from which the current knee compo-

nents – Multigen Plus Ceramic Knee (Limacorpo-

rate S.p.A.) (Fig. 1), BPK-S ceramic knee (Peter

Brehm GmbH) – are manufactured, demonstrate

considerably greater bending strength and stress-

load capacity. Nonetheless, as with every materi-

al, a certain maximum load limit remains. The ce-

ramic components should be inserted without a so-

called wedge load and thus without a strong press

fit. Hammer blows should be used very cautious-

ly, analogous to proven practice for ceramic heads

in hip arthroplasty.* Likewise, the saw cuts in the

knee joint must be precisely executed. It should be

noted that we now know to what extent a strong

press fit situation and sharp blows on metal com-

ponents lead to internal stress with possible con-

sequential damage. In the past few years we have

learned to be even more careful with all of our im-

plants, particularly with all instruments.

What is your experience with the Multigen

Plus Ceramic Knee following 5 years of clini-

cal use?

Mittelmeier: We began to introduce the Delta

Ceramic Knee Joint (femur condyle made of Bio-

lox®delta) very carefully in 2007. By carefully I mean

that we worked under strict observation criteria as

part of a multicenter study. The patients were in-

formed in detail and the surgeons were selected

and appropriately trained. Our experience with the

ceramic knee here in Rostock and the experiences of

the various centers in Germany, Italy, and Spain that

participated in the study have meanwhile been pub-

lished [2]. The 5-year results are very convincing. In

the German center there was one ceramic fracture;

otherwise we observed a very convincing stable fix-

ation and durability of the implants. The recorded

fracture that took place during the study observa-

tion was the direct result of a trauma and was treat-

ed accordingly [3]. The 10-year results will hopefully

be published in good time.

How important is cement-free knee arthro-

plasty in your opinion?

Mittelmeier: In the majority of cases, particular-

ly with older patients, we can perform cemented

knee arthroplasty without hesitation. The frequen-

cy of cement allergies in the population appears

to be increasing; however, we still do not know

enough about the extent to which the cement al-

lergy actually affects the tissue. The release of ions

and particles (particle surface) is clearly decisive for

the development of the allergy. Since the cement

should not lie in the primary situation of the fric-

tional load of the joint surfaces, the cement allergy

will probably not be as significant as the metal al-

lergy. Nevertheless, cement-free knee replacement

should be able to draw upon stable, safe solutions

as well, also in relation to ceramics. For this reason

we will also need cement-free ceramic solutions

for the knee joint.

Does an ideal treatment cascade already ex-

ist in knee arthroplasty? How does it look, in

your opinion?

Mittelmeier: I very much hope that we will have

ceramics available in the various treatment cas-

cades, that is, from unicompartmental knee arthro-

plasty, to total knee replacement, up to and includ-

ing posterior stabilized prostheses and all revision

endoprostheses.

How does the future of ceramic knee arthro-

plasty look to you?

Mittelmeier: There were several failures in the

development of ceramics in hip arthroplasty more

than 40 years ago, which were the fault of the ear-

ly material development. Ceramic materials have

been significantly improved in the meantime and

offer considerably better conditions for hip and

for knee arthroplasty. I expect that there will have

to be a new, very strong trend to develop ceram-

ic knee arthroplasty with regard to long durability,

the least possible ion release and solutions for re-

vision arthroplasty. Current solutions already being

tested in laboratories are very promising.

Partial resurfacing of the knee or preferably

corrective osteotomy – where are the indica-

tion boundaries?

Mittelmeier: A surgical intervention for corrective

osteotomy must also have a sufficiently long-last-

ing effect. The same is true for partial knee arthro-

plasty. The two interventions must be carefully

* According to the LIMA operation surgical technique, the weight of the

recommended hammer, eventually used, must be less than 500 gr.

Figure 1: Multigen Plus delta Ceramic Knee (Limacorporate)

CeraNews 1/ 2015

weighed with regard to the patient’s needs and the

condition of the joint. The best possible joint-pre-

serving solution via corrective osteotomy takes pri-

ority in making the decision for younger patients.

It is my personal view that the early implantation of

metallic or metal/polyethylene partial components

in the knee joint is not yet a perfected mode of

treatment. Here as well we will be able to choose

ceramic solutions and then have a presumably wid-

er indication. The effects of metal ions and parti-

cles on the surrounding, still largely intact cartilage

cannot be considered beneficial.

Robotics at the knee – a necessity or just

marketing?

Mittelmeier: The very adverse results of using ro-

botics on the hip joint in the past have led to a

great deal of mistrust towards the use of robots in

endoprosthetics. The newer types of robots that

are presently being used in abdominal surgery un-

der the optical and tactical control of an experi-

enced surgeon promise a better development. It is

still not clear to what extent these modern robot

types will actually become established on the mar-

ket in our country, because the profits that can be

made with endoprostheses – a prerequisite for fur-

ther useful developments – have already reached

the bottom limit. A relatively large amount is be-

ing, and must be, saved on implants nationwide

instead of making room for qualitatively better de-

velopments. On the other hand, a possible future

form of robot-supported endoprosthetics will have

to undergo very rigorous clinical testing in advance

with respect to applicability, application errors and

error tolerance. In addition, there must then also

be a detailed clinical evaluation of the extent to

which a robot system actually offers advantages

compared with standard treatment by an experi-

enced surgeon.

Knee arthroplasty with preservation of the

anterior cruciate ligament – is that the fu-

ture?

Mittelmeier: The preservation of the anterior cru-

ciate ligament may be a sensible approach in knee

arthroplasty. To date, however, it has been very

difficult to achieve kinematically satisfactory solu-

tions, as the kinematics of the knee joint is physio-

logically very individual, and for the anterior cruci-

ate ligament in particular, very high standards are

set regarding the surgical technique and the im-

plant.

How do you envision the future of knee re-

placement?

Mittelmeier: I believe that, as international de-

velopments show, knee replacement will have to

be refined. Along with the continually increasing

number of knee replacement worldwide – with the

exception of the German region – the number of

Wolfram Mittelmeier, MD, is a professor of

orthopedics and the Director of the Orthopedic

Clinic and Polyclinic at the University Medicine in

Rostock.

Following his doctoral studies and his qualifica-

tion as a specialist in orthopedics, Mittelmeier

worked first as a consultant and later as a se-

nior consultant at the University Hospital of Lü-

beck, before moving to the Technical Universi-

ty of Munich as senior consultant in the Hos-

pital for Orthopedics and Sports Orthopedics. There he established the

biomechanics laboratory and the cell laboratory. In 1999 he received his

postdoctoral lecturing qualification; 4 years later he accepted a chair at

the University of Rostock in the field of orthopedics. Since 2004 he has

served as the director of the orthopedic division of the University Hospi-

tal in Rostock.

His main clinical focus is on arthroplasty, revision surgery, children’s or-

thopedics, and joint-preserving operations. His scientific focus is on bio-

mechanics, implant technology, and worst-case simulations. Since 2005,

he has been a member of the board of the German Society of Orthope-

dics and Orthopedic Surgery (DGOOC) and of the board of the Associa-

tion for Orthopedic Research, where he served as president from 2009

until 2013.

Mittelmeier developed the basis of a quality management system for en-

doprosthesis centers, which became EndoCert; it is audited by commit-

tees of the German Society for Orthopedics and Trauma Surgery (DGOU)

and has been implemented nationwide since 2012. Since 2011 he has

been the deputy chairman of the advisory board on orthopedic technolo-

gy of the German Association of Orthopedic Technology.

In 2014 he served as president of the OTWorld / World Congress of Or-

thopedic Technology.

revisions will obviously also increase temporarily.

It will be important to establish good procedures

that are as long-lasting as possible with very well-

trained operators in order to keep the revision load

as small as possible. ■

References

1. Bergschmidt, Philipp et al., Total knee replacement system with a ceramic

femoral component versus two traditional metallic designs: a prospective

short-term study, J Orthop Surg (Hong Kong). 2013 Dec;21(3):294-9.

2. Bergschmidt, Philipp et al., Prospective multi-centre study on a com-

posite ceramic femoral component in total knee arthroplasty: Five-year

clinical and radiological outcomes, The Knee 2015, DOI: http://dx.doi.

org/10.1016/j.knee.2015.02.003

3. Krueger A P et al., Ceramic Femoral Component Fracture in Total Knee

Arthroplasty:An analysis using fractography, fourier-transform infrared

microscopy, contact radiography and histology, J Arthroplasty 2013, doi:

10.1016/j.arth.2013.11.003)

CeraNews 1/ 2015

8CASE REPORTS

Primary Knee Arthroplasty in Patients with

Suspected or Confirmed Metal Allergy

Benazzo F, Ghiara M, Rossi SMP

Clinica Ortopedica e Traumatologica, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy

Primary TKR for advanced arthritis

Diagnosis

A 68-year-old woman with a history of hyperten-

sion, coronary artery disease, and multiple allergies

(asthma, dust). The patient had had a painful right

knee due to arthritis for two years. The preopera-

tive X-rays clearly showed severe valgus osteoar-

thritis with involvement of the lateral compartment

and patellofemoral joint as well as a lateralization

of the mechanical axis (Fig. 1a).

Indication was for primary TKR with a Multigen

Plus ceramic knee implant (Lima) to avoid cross-

linked reaction due to suspected metal allergy.

Therapy

Surgery was performed via a mini mid-vastus ap-

proach. Replacement of the knee was done with a

fixed Ti tibial plate (size 2) and a ceramic CR femoral

component (Biolox®delta Multigen Plus, size 3) and

and a poly liner with a height of 12 mm (Fig. 1b).

Postoperative therapy included a femoral nerve

block (naropin) for analgesia and fast rehabilitation

of the knee: The patient began to exercise to regain

range of motion on the first postoperative day, and

she walked with two canes on the second postoper-

ative day. She took non-steroidal anti-inflammatory

drugs (indomethacin) for 3 weeks, as did the other

patients who underwent TKR.

After 4 weeks she was able to do without one cane

and she had very mild pain, which had disappeared

at the 3-month follow-up. The range of motion was

0–115° and the excellent results were confirmed at

the last follow-up. X-rays showed a good restoration

of limb alignment and no radiolucent lines at 6 years

of follow-up (Fig. 1c). The final clinical KSS was

98 points (excellent), the final functional KSS was

100 points (excellent), and the final OKS was 47.

CASE REPORT 1

Figure 1: Primary TKA 68-year old woman: a) lateralization of mechanical axis preoperative, b) postoperative situa-

tion, c) follow-up after six years: good limb alignment (© Benazzo)

a b c

CeraNews 1/ 2015

Primary TKR for advanced arthritis

Diagnosis

The patient was a 75-year-old woman with a history

of hypertension, pancreatic neuroendocrine cancer,

diabetes and glaucoma. She had had diffuse pain

in the left knee for 4 years which had been treated

without success with hyaluronic acid injections. The

X-rays showed a primary knee arthritis and a varus

knee. The cartilage degeneration involved all three

compartments (Fig. 2a), particularly the medial

side and the patellofemoral joint, and the mechani-

cal axis was medialized. She also had a metal allergy

(nickel), so we decided to use a the Multigen Plus

delta ceramic knee.

Therapy

Surgery was performed via a mini mid-vastus ap-

proach to the knee. Replacement of the knee was

performed with a fixed Ti tibial plate (size 1) and a

ceramic CR femoral component (Biolox®delta Mul-

tigen Plus, size 1) and a poly liner with a height of

12 mm (Fig. 2b).

Postoperative drug therapy consisted of peridural

analgesia, which allowed fast rehabilitation of the

knee: The patient began to exercise to restore the

range of motion on the first postoperative day, and

she walked with two canes on the second postop-

erative day. She took, as usual after a TKA, non-ste-

roidal anti-inflammatory drugs (indomethacin) for 3

weeks.

After 4 weeks she was able to do without one

cane and she had no pain. The range of motion was

0–110° and increased to 0–120° at 6 months.

The excellent results were confirmed at the last fol-

low-up at 2 years, and X-rays showed no radio-

lucent lines, a good patellar height and good pa-

tellofemoral tracking (Fig. 2c). The final clinical

KSS was 99 points (excellent), the final functional

KSS was 100 points (excellent), and the final OKS

was 46. ■

Corresponding Author:

Francesco Benazzo, MD

Director

Clinica Ortopedica e Traumatologica

Fondazione IRCCS Policlinico San Matteo

Viale Camillo Golgi 19

27100 Pavia (Italy)

E-mail: f.benazzo@smatteo.pv.it

CASE REPORT 2

Figure 2: Knee of a 75-year old woman: a) preoperative status (lateral/patella), alle three compartments show arthritis damage, b) postoperative

with fixed tibial plate and ceramic femoral component (lateral/frontal), c) two years after surgical intervention (lateral/patella) (© Benazzo)

b c

CeraNews 1/ 2015

10 SCIENCE

TOPIC 1: EVIDENCE-BASED MEDICINE IN ORTHOPEDICS: WHERE IS THE EVIDENCE?

OCEBM Levels of Evi-

dence download here:

www.cebm.net/ocebm-

levels-of-evidence/

Evidence-based Decision-Making and

Biological Reactions Related to Materials

Usbeck S and Scheuber LF

CeramTec GmbH, Plochingen, Germany

Evidence-based medicine continues to grow in im-

portance. Evidence-based medicine came to the fore

in the early 1990s and has been defined as "the in-

tegration of best research evidence with clinical ex-

pertise and patient values" (Sackett et al. 2000)

[1]. Evidence has always contributed to clinical de-

cision-making. Murray et al. reviewed the evidence

for THA in 1995 [2]. They found that only 30 % of

hip-joint replacements available contained any evi-

dence and emphasized the need for evidence-based

data.

Additional researchers have concluded that the need

for good-quality evidence in the orthopedic litera-

ture has remained vital. Unfortunately, the continu-

ous lack of a level of evidence has been established in

many publications. The quality of these publications

is very heterogeneous, making it difficult for clini-

cians to evaluate the actual evidence level of individu-

al results and recommendations. However, efforts are

being made, e.g. by scientific journals, to bring more

quality and transparency to the subfields of ortho-

pedic surgery and considerably improve knowledge

transfer ("knowledge translation") of science and re-

search into concrete medical practice.

National joint registers have been established to

monitor and improve the outcomes. However, regis-

ters differ in methods of data analysis and reporting,

which limits the interpretation of the data. These dif-

ferences make comparisons among registries difficult

or impossible.

Konan and Haddad, University College Hospitals

London, 2013 summed up the situation in a paper,

saying [3]: "We now routinely rely on registry data

to guide our debates and decisions but we would

be wise to remember that they have inherent weak-

nesses that limit the interpretation of the data. Com-

pliance issues associated with any data collection

and reporting process limit the quality of the regis-

try data. No robust system is in place to tackle con-

founding data, and to capture underreported or un-

reported outcomes. Registries were set up to monitor

survival but the ancillary data that are collected are

not validated. Caution must therefore be exercised

when using registries as high-level evidence. In par-

ticular, registry-based results cannot infer causal re-

lationships. Any trend identified should be used as

a trigger for further study rather than as a rigid con-

clusion."

Evidence-based data should be founded both on re-

sults of well-designed studies and on registers that

are able to collect data in large populations and to

identify trends.

Evidence-based medicine includes a classification sys-

tem that enables a defined evaluation, based on the

so-called evidence level, of the quality of the stud-

ies and particular publications. This system of grading

offers clinicians a simplified rating for clear compar-

ison of performance based on relevant clinical crite-

ria ( Fig. 1).

Figure 1: Evidence of clinical effectiveness: the evidence pyramid (modified from Sackett et al.

2000, [1])

Validity

Strength

idence

Level

III

Level

Systematic reviews /

Metaanalysis

Guidelines

Randomised

controlled trials

Cohort studies

Case-control studies

Case series, case reports

Expert opinion

Bias

CeraNews 1/ 2015

TOPIC 2: XPE-INDUCED OSTEOLYSIS AND SURFACE DAMAGES

Low wear rates and longer lasting bearing surfaces with biologically inert characteristics are of specific

interest in addressing the needs of patients with a long life expectancy and a high activity level. Highly

cross-linked polyethylene (XPE) has been used in an effort to combat osteolysis and aseptic loosening. Al-

though XPE is more resistant to wear than conventional polyethylene, it remains unknown whether XPE

decreases wear-associated failure of THA and improves longevity at mid-term to long-term follow-up. It

is hypothesized or predicted in publications that the substantial reduction in wear rates observed for XPE

compared with conventional PE may have the biological effect of reducing the rate of periprosthetic os-

teolysis after THA.

However, at the AAOS 2014, researchers reported about their concerns with XPE in THA in long-term use.

Holubowycz, Howie et al., presented the results of a randomized controlled trial showing that XPE ar-

ticulations lead to periacetabular osteolytic lesions at 7–10 years after primary THA [6, 7]. Osteolytic lesions

were detected in the absence of clinically significant wear. Moreover, in that study, the incidence was sim-

ilar in articulations with 28-mm and 36-mm ball head diameter.

A systemic review of randomized controlled trials has now found that wear advantages of XPE did not

translate into less osteolysis and aseptic loosening. XPE-induced osteolysis seems to occur without sub-

stantial wear. There is a need to better characterize factors that influence the development of osteolysis

with XPE articulations. There are numerous different XPE materials on the market, produced with various

manufacturing methods which may influence the clinical performance. We also currently know very little

about the bioactivity of these XPE wear particles.

SYSTEMATIC REVIEW OF LEVEL-1 RANDOMIZED CONTROLLED TRIALS

XPE does not decrease osteolysis and wear-related revision rate

Shen et al. 2014 included eight randomized con-

trolled trials (RCT) with mid- to long-term fol-

low-ups comparing XPE with PE in THA [8]. The fol-

low-up periods of the RCT ranged from 5 to 12

years; 735 patients were included in their study.

The studies reviewed were published between

2009 and 2012. This meta-analysis of RCT demon-

strated for the first time that the linear wear rate

was lower in the XPE group than in the PE group,

but the incidence of osteolysis and wear-related re-

vision incidence did not differ significantly between

the XPE and PE groups. Although wear of XPE in-

serts appears to be lower than of conventional PE

inserts, the risk of periacetabular osteolysis around

articulations with XPE has not been eliminated, and

the true incidence remains unknown.

Hence the authors emphasized that XPE has no ad-

vantage or clinical benefit over conventional PE in

terms of reducing osteolysis and wear-related revi-

sion. This meta-analysis demonstrated that reduced

in vivo XPE wear rates did not improve the clinical

outcome. For this reason, the researchers called for

further long-term RCT on this topic.

The concept of the so-called osteolytic wear thresh-

old remains controversial. Dumbleton et al. 2002

suggested that osteolysis is infrequent with a wear

rate less than 0.1 mm/year and almost absent at a

wear rate less than 0.05 mm/year [9]. Osteolysis is

a complex process and depends on many factors,

including the biological activity of generated wear

particles. Although much is known regarding wear

The Dutch Strategy

Verheyen et al. 2014 and Poolman et al. 2015

[4, 5] reported about the Dutch strategy at a meet-

ing of the European Hip Society 2014 and in a cur-

rent publication (2015). Problems with large num-

bers of MoM hip replacements prompted Dutch

orthopedic surgeons to re-evaluate patient safe-

ty. The Dutch Orthopedic Association (Nederlandse

Orthopeadische Vereniging, NOV) initiated a task-

force to classify the quality of hip replacements

based on survivorship. New implants or prosthe-

ses that do not meet the criteria may be implant-

ed only in the scope of a research program with

approval by the institution's medical ethics re-

view board. NOV offers patients insights into ev-

idence-based quality of the hip implants. The au-

thors are convinced that this will facilitate shared

decision-making by empowering patients with

knowledge about available hip implants.

CeraNews 1/ 2015

12 SCIENCE

RETRIEVAL STUDY

XPE demonstrated surface damage similar to PE

Pang et al. 2015 compared wear and surface dam-

age in matched retrieved XPE and PE inserts. The

XPE inserts represented all the FDA-approved XPE

inserts of a specific design implanted for at least 1

year [11]. This XPE group was matched to a PE group

of identical design retrieved in the same time peri-

od. The authors found no difference between the

groups for total damage score or for the bearing,

rim or backside surface damage scores. Moreover, in

that study, the most common damage modes in the

XPE group were abrasion, scratching, and cold flow.

The most common damage modes in the PE group

were burnishing, abrasion, and cold flow. The mean

abrasion damage score was significantly higher in

the XPE group than in the PE group. With respect to

the lesser amount of volumetric wear measured in

the XPE group compared with the PE group, these

findings were similar to those of other studies.

This paper pointed out the need for further investi-

gations and long-term studies to determine the ef-

fects on implant longevity.

References

1. Sackett DL. Straus SE, Richardson WS, Rosenberg W, Haynes RB. Evi-

dence-based medicine: how to practice and teach EBM. 2nd ed., Churchill

Livingstone, Edinburgh 2000

2. Murray DW, Carr AJ, Bulstrode CJ. Which primary total hip replacement? J

Bone Joint Surg Br 1995;77:520-527

3. Konan S, Haddad FS. Joint registries. A Ptolemaic model of data interpre-

tation? Bone Joint J 2013;95-B:1585-1586

4. Verheyen CCPM, Schreurs BW, Born PA, Verhaar JAN, Nelissen RGHH,

Goosen J, Poolman RW. Selecting the right hip implant for our patients.

The Dutch strategy. Abstracts from 11th EHS Congress, Stockholm, Swe-

den, 9-11 October 2014, Hip Int 2014;24(5):526

5. Poolman RW, Verhaar JAN, Schreurs BW, Bom LPA, Nelissen RGHH, Koot

HWJ, Goosen JHM, Verheyen CCPM. Finding the right hip implant for

patient and surgeon: the Dutch strategy – empowering patients. HipInt

2015; DOI: 10.5301/hipint.5000209

6. Holubowycz O, Howie D, Solomon LB, Moran CR. Osteolysis and wear of

large and standard metal on highly cross-linked polyethylene articula-

tions. AAOS 2014: Paper 253

properties of cross-linked polyethylenes, there is lit-

tle information and knowledge regarding the bi-

ological activity of the wear particles generated.

Illgen et al. 2008 demonstrated that XPE particles

exhibited an altered bioactivity which was unrelated

to particle size [10]. The scientific issue of whether

and how XPE particles interact with various types

of cells must be investigated further. Some re-

searchers have demonstrated that XPE wear parti-

cles are smaller than 1 µm and more inflammatory

than conventional PE particles. In vitro cell culture

studies predicted that submicron wear debris from

XPE might show osteolytic potential comparable to

that of conventional PE over time. It will therefore

be important to understand the bioactivity of XPE

wear particles compared with conventional PE wear

particles, since there is little information and a pau-

city of available data so far.

To understand the biological response to XPE wear

particles and to determine which material factors,

wear characteristics, and other mechanisms have a

substantial impact on the pro-inflammatory activi-

ty of these particles, further studies and research in

this area are needed, as the number of young pa-

tients receiving THA continues to grow.

7. Howie DW, Holubowycz OT, Moran CR, Solomon LB. Osteolysis and wear

of large and standard metal on highly cross-linked polyethylene articula-

tions. Annual Meeting ORS 2014: Poster 1773

8. Shen C, Tang ZH, Hu JZ, Zou GY, Xiao RC, Yan DX. Does cross-linked poly-

ethylene decrease the revision rate of total hip arthroplasty compared

with conventional polyethylene? A meta-analysis. Orthop Traumatol Surg

Res 2014;100(7):745-750

9. Dumbleton JH, Manley MT, Edidin AA. A literature review of the associa-

tion between wear rate and osteolysis in total hip arthroplasty. J Arthro-

plasty 2002;17(5):649-661

10. Illgen RL, Forsythe TM, Pike JW, Laurent MP, Blanchard CR. Highly cross-

linked vs conventional polyethylene particles – an in vitro comparison of

biologic activities. J Arthroplasty 2008;23:721-731

11. Pang HN, Naudie DDR, McCalden RW, MacDonald SJ, Teeter MG. Highly

crosslinked polyethylene improves wear but not surfaces damage in re-

trieved acetabular liners. Clin Orthop Relat Res 2015;473:463-468

CeraNews 1/ 2015

TOPIC 3: CORROSION

The issue of taper wear and corrosion at the head-neck junction is not a new phenomenon, but the prob-

lems detected with the use of larger metal femoral ball heads in THA have made it more prevalent. Corro-

sion of metal in medical devices could cause health problems to patients. It has been demonstrated by a

research group led by Hallab and Jacobs 2010 that both soluble metal ions and metal debris produced

during corrosion induce pro-inflammatory responses in human monocytes / macrophages [12]. Corrosion at

the taper junction is still poorly understood as regards relevant clinical pictures and entities. A comprehen-

sive systematic review of the medical publications that determine patient characteristics, implant designs,

symptomatology, clinical pictures and treatment strategies regarding corrosion at this interface is still lack-

ing in the literature. This gap is now being filled by a recent publication from Canadian researchers.

SYSTEMATIC REVIEW AND CASE SERIES

Clinically significant corrosion at the taper junction

Carli et al. 2015 illustrate in a systematic review

and case series that symptomatology following cor-

rosion tends to occur in the intermediate follow-up

period and most often presents within the clinical

picture of aseptic loosening, unexplained thigh pain

or an adverse reaction to metal debris (ARMD) [13].

A total of 24 articles represented 776 cases (754 pa-

tients) with documented head-neck corrosion found

at revision surgery. The bearing couples most fre-

quently utilized were MoM (419; 53.9 %) and MoP

(351; 45.4 %), with 13 being cross-linked polyeth-

ylene. The head diameters in MoM bearings were

larger (median and mode of 46 mm) than those

used in MoP (median and mode of 36 mm).

12 articles of this review representing 24 cases report-

ed that the trunnion (or male taper) was found in-

tact. In 15 cases this led to revision of only the fem-

oral ball head and the acetabular component, while

the stem remained in situ. Ceramic femoral ball heads

were used with ceramic or polyethylene inserts. Since

the trunnions were used, the recommendation to en-

sure safe usage of ceramic femoral ball heads would

be to use one with a sleeve (Helwig et al. 2013) [14].

However, Carli et al. remark that sleeves provide

an additional interface for micro-motion and ion ex-

change to occur. Concerning this aspect it might be

useful to take further data into account.Yet Thorey

et al. 2012 pointed out that they had followed up a

relatively large cohort of patients (91) who had un-

dergone revision from MoP (53), MoM (2), CoC (15),

and CoP (21) bearings to a CoC or CoP bearing with a

sleeve, mostly due to acetabular component loosening

[15]. They did not observe any ceramic ball head frac-

tures or complications related to the sleeve–taper junc-

tion such as corrosion / fretting. Jack et al. 2013 used

ceramic ball heads with titanium sleeves in revision

surgeries, placing the sleeves on used trunnions [16].

They did not record any metal ions or radiological evi-

dence of metal wear debris. In a case report by White-

house and Duncan 2014, the authors describe the

case of a patient with a painful MoXPE THA [17]. Hip

arthroscopy confirmed the diagnosis of trunnion cor-

rosion. Due to persistent symptoms, the patient was

revised to a CoXPE bearing, utilizing a ceramic femoral

ball head with a sleeve, which was placed on the cor-

roded trunnion. This relieved the patient’s symptoms.

In an in-vitro study, Preuss et al. 2012 also ad-

dressed the issue of taper fretting and corrosion for

large ceramic bearings used with an adapter sleeve

(made of Ti-6Al-4V) [18]. The aim of this study was

to investigate the risk of fretting corrosion and wear

and the risk of loosening of the head-taper junction

of such large-diameter CoC bearing devices for revi-

sion surgery. The current results from this study con-

firm that an accurate placement and assembly of

the components as given by the instructions for use

by the manufacturer result in sufficient resistance of

the interfaces against fretting corrosion and wear.

In their retrieval analysis Huot Carlson et al. 2012

also found that metal femoral ball heads were sig-

nificantly more prone to corrosion of the head taper

(54 %) as compared with titanium-sleeved ceram-

ic ball heads (18 %) [19]. Metal femoral ball heads

were also more associated with corrosion of the

stem compared with ceramic or sleeved ceramic ball

heads. To summarize, there is still a need for further

research and evidence including clinical conditions.

Carli et al. 2015 describe the symptoms among

patients in their own case study group as consist-

ing of groin pain, a palpable mass, recurrent dislo-

cation and adverse local soft-tissue reactions [13].

They also found disproportionately elevated serum

cobalt levels relative to chromium in their case se-

ries. They point out that this finding has also been

reported in a large randomized series involving

large-diameter MoM implants. The authors hypoth-

esize that this disproportion could potentially serve

as a diagnostic indicator of an ongoing corrosive

process, and they therefore call for additional stu-

dies. Further analysis is also needed to investigate

the overall prevalence of clinical symptomatology.

CeraNews 1/ 2015

14 SCIENCE

Corrosion in large femoral ball heads

Level-I studies support the use of large femoral ball heads in order to decrease the risk of postoperative in-

stability following primary and revision THA. When selecting the appropriate head diameter in hip surgery,

the surgeon must balance the potential risk for dislocation in his patient with the risks inherent in large

femoral ball heads. Corrosion at the modular head-neck taper has been identified as a potential concern.

Symptomatic adverse local tissue reactions can occur secondary to metal debris resulting from corrosion

of the head-neck taper and have been described in the literature.

SYSTEMATIC REVIEW AND CASE SERIES

Ceramic femoral ball heads are more protective against ARMD

Cooper and Della Valle 2014 pointed out in their

paper that ceramic femoral ball heads reduce the

risk of modular taper corrosion at the head-neck

junction [20]. According to the authors, retrieval

studies by various researchers have demonstrated

that the risk of corrosion is not completely eliminat-

ed; however, the degree of metal release from taper

junctions is significantly lower compared with met-

al femoral ball heads. Ceramic femoral ball heads,

which are excellent electrical insulators, resulted in

less stem taper corrosion than reported with metal

femoral ball heads. To summarize, it must be em-

phasized that ceramic femoral ball heads are more

protective against ARMD than metal femoral ball

heads.

TOPIC 4: IMMUNO-ALLERGOLOGICAL INTOLERANCE REACTION TO METAL DEBRIS

RETRIEVAL STUDY

Scratching on MoM bearings as a cause for ARMD

A recent study by Burbano et al. 2014 evaluated

the bearing surface characteristics of MoM implants

revised due to ARMD using different microscopy

techniques [21]. The modular taper junctions were

also evaluated. The aim was to analyze possible fail-

ure mechanisms associated with MoM implants and

their correlation to the formation of ARMD.

Severe mechanical scratching was a common char-

acteristic found in all of the MoM retrievals evaluat-

ed. The remarkable level of scratching detected in-

dicates that these MoM implants generated a large

amount of metal particle release in vivo. The lack

of evidence of corrosion in the interfaces evaluat-

ed suggested that mechanical factors (scratching,

wear) seemed to be a major trigger for ARMD. The

authors pointed out that severe scratching, wear

and metal ion release may have been the principal

cause for adverse peri-implant tissue reactions in

the revised cases. Third-body wear (i.e. bone frag-

ments) could also have played a role.

Amini et al. 2014 pointed out that a better under-

standing of the diagnosis and treatment of metal

hypersensitivity is essential for orthopedic surgeons

[22]. The authors noted that metal hypersensitivity

is estimated to be responsible for 5 % of TJA fail-

ures. The Medline literature database was searched

to identify articles related to patch testing or LTT for

metal hypersensitivity with TJA. They reviewed 14

TKA and 6 MoM THA case reports involving met-

al allergy. Half of the patients had a previous met-

al allergy. One patient had a history of dermatitis or

eczema. The most common presenting symptoms

were pain (55 %), swelling (45 %), and warmth

(20 %). Eczema over the surgery was present in

35 % of cases. 90 % of these symptoms presented

in the first 3 months after implantation. Cobalt and

nickel were found to be the most common metals

causing allergic reactions.

The authors emphasized that metal hypersensitivity

is a diagnosis of exclusion, and that other potential

diagnoses should be carefully excluded. Patch test-

ing and LTT remain the tools of diagnosis both in pa-

tients for TJA and in patients with implant failure.

They concluded that options in THA include the use

of CoP and CoC bearing surfaces to minimize the

risk of a hypersensitivity reaction.

The diagnosis, treatment, and clinical outcome of

patients with metal hypersensitivity remains an ac-

tive area of research.

CeraNews 1/ 2015

CASE REPORT

Chromium-induced diffuse dermatitis and lymph-node involvement by

Langerhans cell histiocytosis: CoC THA led to resolution of symptoms

Bizzotto et al. 2014 hypothesized that micropar-

ticles of cobalt-chromium and PE may elicit lymph-

adenopathy with histiocytosis, but a combined dif-

fuse dermatitis and lymph-node involvement by

Langerhans cell histiocytosis induced by chromium

after MoM hip resurfacing have not been previously

described [23].

General clinical signs such as skin redness, prolonged

generalized pruritus, and psoriatic-like dermati-

tis with desquamation may be related to delayed

type-IV hypersensitivity reaction. The authors report-

ed that lymphadenopathy with diagnosis of spe-

cial Langerhans cell histiocytosis may be due to pro-

longed activation of the type-IV immune response.

In their reported case, a 60-year-old male patient

presented with a 3-year history of diffuse dermatitis

5 years after implantation of MoM hip resurfacing.

The symptomatic patient had a prolonged pruritus

unresponsive to antihistamines and corticosteroids.

Dermatological treatments were not successful. The

patient had no past history of atopy or metal-con-

tact dermatitis. Diffuse lymphadenopathy on both

sides of the inguinal region was detected. A skin

biopsy showed nonspecific perivascular lymphocytic

infiltrate in the upper dermis associated with histio-

cytes. A patch test revealed chromium-sulfate hy-

persensitivity. Higher chromium and cobalt levels

in serum were measured. The biopsy of an ingui-

nal lymph node demonstrated large aggregates of

Langerhans cells, suggesting delayed type-IV hyper-

sensitivity.

The authors pointed out that only replacement of

the hip implant using non-MoM surfaces may defi-

nitely resolve such clinical symptoms. Metallosis was

observed intraoperatively. The stable MoM hip im-

plant was replaced by a cementless THA using a

CoC bearing (Biolox®delta). The dermatitis resolved

3 months after revision surgery. The lymph nodes

decreased in volume. The serum chromium level

normalized, and the patient was completely free of

any symptoms 1 year after revision surgery.

The authors are concerned that chromium and co-

balt toxicity may be under-recognized and that phy-

sicians who are not familiar with this issue may

therefore misdiagnose systemic symptoms and lack

adequate treatment.

CASE REPORT AND ANIMAL STUDY

Chronic allergic contact dermatitis caused by an orthopedic metal implant promotes

skin cancer

Long-term consequences of chronic contact derma-

titis caused by an orthopedic metal implant are still

poorly understood. This remains an active area of

research.

Dehmeri et al. 2014 presented a rare clinical case

of an invasive squamous cell carcinoma (SCC) that

developed in the context of nickel allergy from a

subcutaneous metal implant [24]. The 46-year-old

woman had no history of skin cancer. An ankle frac-

ture was repaired with open reduction and internal

fixation with placement of a metal rod on the lateral

aspect of her fibula for stabilization. The patient de-

veloped a non-healing skin lesion on her left ankle

overlying the metal implant and surgical wound site.

She was allergic to nickel in the metal implant. The

implant was removed 1 year after surgery, but the

skin lesion persisted. The patient presented to the

hospital with a 3-year history of the ulcerated skin

lesion. A biopsy demonstrated a well-differentiated,

invasive SCC consistent with a Marjolin ulcer. The

SSC was surgically excised and did not recur during

a 2-year follow-up period.

The authors concluded that the development of

a SCC in a patient without history of skin cancer

strongly suggested the chronic allergic contact der-

matitis surrounding the surgical wound culminated

in cancer formation. They initiated an animal study

(mice) to examine the tumor-promoting potential of

contact dermatitis. Findings confirmed that chron-

ic exposure to a hapten-producing allergen induces

tumor-promoting inflammation in the skin.

Furthermore, the researchers examined the im-

mune environment of the SCC that developed in

the patient and found that the patient’s inflamma-

tion was the driver of the carcinogenesis and not

secondary or reactive to cancer development itself.

The authors therefore concluded that these find-

ings provide clear evidence for the tumor-promot-

ing property of chronic allergic contact dermatitis.

A chronic allergic contact dermatitis caused by con-

stant exposure to an allergen can lead to the de-

velopment of an aggressive and invasive SCC in ar-

eas where a significant burden of preexisting can-

cer-initiated cells is present (i. e., sun-exposed skin).

CeraNews 1/ 2015

16 SCIENCE

It is interesting to note that contact allergy to metal

dental restorations is discussed in scientific publica-

tions as a potential risk factor for development of

intraoral squamous cell carcinoma (Hougeir et al.

2006, Weber et al. 2012) [25, 26].

Moreover, this rare clinical case highlights the im-

portance of patch testing prior to the implantation

of medical devices especially in patients with a re-

ported history of metal allergy. The authors sug-

gested a close monitoring of patients with such im-

plants placed in close proximity to the skin to avoid

a chronic allergic dermatitis and the possibility of

developing SCC. ■

Corresponding Authors:

Sylvia Usbeck (Clinical Affairs Manager)

Leslie F. Scheuber (Senior Product Specialist Recon)

CeramTec GmbH Medical Products Division

CeramTec-Platz 1–9

D-73207 Plochingen (Germany)

E-mail: s.usbeck@ceramtec.de

E-mail: l.scheuber@ceramtec.de

www.biolox.com

References

12. Caicedo MS, Pennekamp PH, McAllister K, Jacobs JJ, Hallab NJ. Soluble

ions more than particulate cobalt-alloy implant debris induce monocyte

costimulatory molecule expression and release of proinflammatory cyto-

kines critical to metal-induced lymphocyte reactivity. J Biomed Mater Res

2010;93A:1312-1321

13. Carli A, Politis A, Zukor D, Huk O, Antoniou J. Clinically significant corro-

sion at the head-neck taper interface in total hip arthroplasty: a systemat-

ic review and case series. Hip Int 2015;25:7-14

14. Helwig P, Konstantinidis L, Hirschmuller A, Bernstein A, Hauschild O, Sud-

kamp NP, Ochs BG. Modular sleeves with ceramic heads in isolated ac-

etabular cup revision in younger patients-laboratory and experimental

analysis of suitability and clinical outcomes. Int Orthop 2013;37:15-19

15: Thorey F, Thiengwittayaporn S , Thiengwittayaporn S , Windhagen H. Ear-

ly results of revision hip arthroplasty using a ceramic revision ball head.

Semin Arthroplasty 2011;22:284-289

16. Jack CM, Molloy DO, Walter WL, Zicat BA, Walter WK The use of ceram-

ic-on-ceramic bearings in isolated revision of the acetabular component.

Bone Joint J 2013;95-B:333-338

17. Whitehouse MR, Duncan CP. Arthroscopy as a diagnostic tool for painful

trunnion corrosion after hip arthroplasty. Knee Surg Sports Traumatol Ar-

throsc 2014;Jul 22 [Epub ahead of print]

18. Preuss R, Haeussler KL, Flohr M, Streicher RM. Fretting corrosion and

trunnion wear – is it also a problem for sleeved ceramic heads? Semin Ar-

throplasty 2012:23:251-257

19. Huot Carlson JC, Van Citters DW, Currier JH, Bryant AM, Mayor MB, Col-

lier JP. Femoral stem fracture and in vivo corrosion of retrieved modular

femoral hips. J Arthroplasty 2012;27:1389-1396

20. Cooper HJ, Della Valle CJ. Large diameter femoral heads. Is bigger always

better? Bone Joint J 2014;96-B(11 Suppl A):23-26

21. Burbano M, Russell R, Huo M, Welch R, Roy D, Rodrigues DC. Surface

characterization of retrieved metal-on-metal total hip implants from pa-

tients with adverse reaction to metal debris. Materials 2014;7:1866-1879

22. Amini MH, Mayes WH, Tzeng A, Tzeng TH, Saleh KJ, Mihalko WM. Evalua-

tion and management of metal hypersensitivity in total joint arthroplasty:

a systemic review. J Long-Term Eff Med Implants 2014;24:25-36

23. Bizzotto N, Sandri A, Trivellin G, Magnan B, Micheloni GM, Zamò A,

Bernardi P, Sbarbati A, Regis D. Chromium-induced diffuse dermati-

tis and lymph node involvement by Langerhans cell histiocytosis after

metal-on-metal hip resurfacing. Br J Dermatol 2014;10, doi: 10.1111/

bjd.13517 [Epub ahead of print]

24. Demehri S, Cunningham TJ, Hurst EA, Schaffer A, Sheinbein DM, Yokoya-

ma WM. Chronic allergic contact dermatitis promotes skin cancer. J Clin

Invest 2014;124:5037-5041

25. Hougeir FG, Yiannias JA, Hinni ML, Hentz JG, El-Azhary RA. Oral metal

contact allergy:a pilot study on the cause of oral squamous cell carcino-

ma. Int J Dermatol 2006;45:265-271

26. Weber ME, Yiannias JA, Hougeir FG, Kyle A, Noble BN, Landry AM, Hinni

ML. Intraoral metal contact allergy as a possible risk factor for oral squa-

mous cell carcinoma. Ann Otol Rhinol Laryngol 2012;121:389-394

Further Reading

Callary SA, Holubowycz O, Howie D. Wear of large metal on highly cross.

linked polyethylene articulations measured by RSA. AAOS 2014: Paper

250

Endo M, Tipper JL, Barton DC, Stone MH, Ingham E, Fisher J. Compari-

son of wear, wear debris and functional biological activity of moderately

crosslinked and non-crosslinked polyethylenes in hip prostheses. Proc Inst

Mech Eng H 2002;216:111-122

Fisher J, McEwen HM, Tipper JL, Galvin AL, Ingram J, Kamali A, Stone

MH, Ingham E. Wear, debris, and biologic activity of cross-linked polyeth-

ylene in the knee: benefits and potential concerns. Clin Orthop Relat Res

2004;428:114-119

Griffin XL, Haddad FS. Evidence-based decision making at the core of or-

thopaedic practice. Bone Joint J 2014;96-B:1000-1001

Ingram JH, Stone M, Fisher J, Ingham E. The influence of molecular

weight, crosslinking and counterface roughness on TNF-alpha production

by macrophages in response to ultra high molecular weight polyethylene

particles. Biomaterials 2004;25:3511-3522

McCulloch P, Altman DG, Campbell WB, Flum DR, Glasziou P, Marshall JC,

et al. No surgical innovation without evaluation: the IDEAL recommenda-

tions. Lancet 2009;374:1105-12

Padman M, Ingram JH, Shaw DL, Fisher J, Ingham E. Biological reaction

to conventional and cross-linked UHMWPE’s in vivo. Annual Meeting ORS

2005: Poster 1688

CeraNews 1/ 2015

Mid-term Results of Modern Ceramic-on-Ceramic

Total Hip Arthroplasty

Laforgia R1, Pelone F2, Porporati AA3, Santovito L1, Piconi C4

1Mater Dei Hospital, Bari, Italy; 2Kingston University and St. George’s, University of London, London, Great

Britain; 3CeramTec GmbH, Plochingen, Germany; 4Catholic University, Orthopedics and Traumatology Ins-

titute, Rome, Italy

The use of CoC bearings in total hip arthroplasty is growing worldwide. Especially bearings larg-

er than 32 mm have been confirmed as a valid option for increased range of motion (RoM) and

stability combined with extremely low wear, and some authors are suggesting that this coupling

is the gold standard in hip arthroplasty. To characterize the outcomes of modern CoC bearings,

a retrospective study was performed on patients who underwent hip arthroplasty with alumina

composite in 3 clinical centers located in the Puglia region of Italy.

The abstract is based on

results of a clinical trial

(Level of Evidence III)

Materials and Methods

142 patients who underwent hip arthroplasty with

CoC bearings (Biolox®delta, CeramTec, Germany)

were enrolled in this study, carried out at 3 clinical

centers located in Puglia, Italy. Mean follow-up time

was 47.6 months (SD: 7.9; minimum 11.7, maxi-

mum: 68.4). Mean patients’ age was 68 (SD: 11;

minimum: 38, maximum: 86). 63 patients (44.4 %)

were male, and the mean BMI was 27.6 (SD: 4.2;

minimum: 18.8, maximum: 45.0).

74 bearings had a diameter of 36 mm (52.1%), and

55 bearings a diameter of 32 mm (38.7 %), while

bearings of 40 mm and 28 mm in diameter were im-

planted in eight (5.6 %) and five (3.5 %) cases, re-

spectively.

A descriptive analysis of the sample was carried

out in terms of mean, standard deviation (SD), and

range for continuous variables and absolute and

relative frequencies for qualitative ones. An assess-

ment of the difference in distribution of the main

demographic and clinical characteristics of the pa-

tients was performed. The Wilcoxon-Mann-Whitney

and Kruskal-Wallis tests were used to evaluate dif-

ferences between groups for quantitative variables.

The chi-square test was used to compare data from

qualitative variables.

The association between quality of life (in terms of

HOOS and SF-12 scores) and bearing characteristics

was tested with linear regression models. Gender,

BMI, and all variables associated with the analyzed

outcomes with a p-value lower than 0.25 were in-

troduced in the linear regression models. Analysis

was performed with the SPSS 13.0 for Windows

software. Statistical significance was set at p=0.05.

Results

The main clinical outcomes are described in

Table 1. No cases of osteolysis and socket in-

stability were observed. One patient suffered from

Socket inclination, degrees [mean (SD)] 45.4 (4.4)

Osteolysis [n (%)] 0 (0)

Socket instability [n (%)] 0 (0)

Stem position [n (%)] Neutral 127 (89.4)

Non-neutral 15 (10.6)

Valgus 3 (2.10)

Varus 12 (8.5)

Stem instability [n (%)] 1 (0.7)

Leg length discrepancy [n (%)] 25 (17.6)

Leg length discrepancy, mm [mean (SD)] 11 (9)

HOOS P [mean (SD)] 92.4 (10.5)

HOOS S [mean (SD)] 91.5 (11.3)

HOOS A [mean (SD)] 91.2 (11.8)

HOOS Sp [mean (SD)] 84.5 (18.5)

HOOS Q [mean (SD)] 84.6 (18.0)

SF12 [mean (SD)] 31.0 (2.7)

Reported noises

(all not reproducible at control)

Squeaking [n (%)] 3 (2.1)

Clicking [n (%)] 3 (2.1)

Snapping [n (%)] 0 (0)

Popping [n (%)] 0 (0)

Grinding [n (%)] 1 (0.7)

Table 1: Main clinical outcomes of the DESIT (DElta Study ITaly) patients (n=142)

CeraNews 1/ 2015

Figure 1: Patients’ satisfaction index versus bearing diameter

SCIENCE

stem instability (0.7 % of all patients). 15 stems

(10.6 %) were in a non-neutral position. 25 pa-

tients (17.6 %) showed leg length discrepancy, with

the average difference in length being 11 mm (SD:

9 mm). Although 3 patients reported squeaking

(2.1 %), a further 3 reported clicking, and one other

patient (0.7 %) grinding, none of these noises could

be replicated at control. No patients reported either

snapping or popping.

Variables tested for association with quality of life in

terms of HOOS and SF-12 at the univariate analysis

were patient type, follow-up time, socket inclina-

tion, stem position (neutral vs. non-neutral – varus

and valgus), and leg length difference (in mm). Os-

Renato Laforgia, MD, is the director of the Orthopedics and Neuro-Reha-

bilitation Unit of the Mater Dei Hospital in Bari, Italy (CBH Group).

He is a representative of the Puglia Region in the National Committee of

the Italian Health Authority (Istituto Superiore di Sanità) for the start-up of

the Italian Orthopedic Prostheses Registry.

Formerly, Laforgia was the director of the Orthopedics and Traumatology

Service in the Matera City Hospital (Italy), after having served as an ortho-

pedic surgeon in Busto Arsizio (Italy), Bari, Wrightington (UK), and Maputo

(Mozambique). He has served as the president of the Apulo-Lucanian Or-

thopedic Society (APLOTO).

During his 30-year career, Laforgia has performed more than 30,000 operations, including more

than 2,000 hip replacements and more than 1,500 knee replacements.

He has taught orthopedics and traumatology at the Universities of Bari and L’Aquila (Italy) and at the

University of Maputo (Mozambique).

His main research interests are the biomechanics of healthy and pathological hips, the technique of

hip surgery, and the development of new osteosynthesis instrumentation. He is a member of the

Standardized Audit of Hip Fractures in Europe (SAHFE) Group for the study of the economic impact

of femoral neck fractures, and a member of the Italian Health Ministry´s working group that assess-

es the feasibility of a neck-fractures registry in Italy.

28 >28°

HOOS P HOOS S HOOS AHOOS Sp HOOS

F 12

100

HOOS:

Hip dysfunction and Osteoarthritis Outcome Score; P = pain; S = symptoms; A = activity limitations in daily living; Sp = function in sport and recreation;

Q = quality of life

Patients´ satisfaction index (%)

teolysis, socket instability and stem instability were

excluded from the analysis because of low or null

variability among the patients.

Higher BMI values were associated with better

quality of life according to the SF-12 scale, while

leg length discrepancy was associated with a worse

outcome. Age was the only variable associated

with health quality outcomes in terms of HOOS

and SF-12 in the multivariate analysis. Specifical-

ly, on multivariate analysis older age was associat-

ed with worse health quality outcomes in terms of

both SF-12 and four of the five patient-relevant di-

mensions of the HOOS questionnaire – i. e., pain

(HOOS P), symptoms (HOOS S), activity limitations

CeraNews 1/ 2015

Figure 2: CoC bearings for hip arthroplasty

in daily living (HOOS A), and function in sport and

recreation (HOOS Sp). None of the analyzed vari-

ables was associated with the HOOS Q outcome at

the multivariate analysis.

No statistically significant differences were ob-

served between unilateral and bilateral interven-

tions in terms of SF-12 and between pain, other

symptoms, function in daily living and function in

sport and re creation according to the HOOS score.

However, statistically significant differences were

observed between the unilateral (mean score:

85.2) and bilateral intervention (mean score: 78.8)

in terms of quality of life according to the HOOS

Q score. Patients with THR bearings larger than

28 mm in diameter showed higher HOOS and SF-

12 scores. The differences were statistically signifi-

cant ( Fig. 1).

Conclusions

In summary, the only bearing-related complications

reported by the patients included in the DESIT study

at about 4 years' mean follow-up are transient nois-

es. Bearing diameter larger than 28 mm was shown

to improve patients’ satisfaction with their hip re-

placements, while absence of osteolysis and of ce-

ramic fractures confirms the excellent mechanical

and wear behavior of CoC bearings ( Fig. 2). ■

Corresponding Author:

Renato Laforgia, MD

Director Orthopedics and Neuro Rehabilitation Unit

Mater Dei Hospital (CBH Group)

10, Via Samuel F Hahnemann

70126 Bari (Italy)

CeraNews 1/ 2015

20 SCIENCE

2015 Update on an Evolving Perspective for

Taper Corrosion in Total Hip Arthroplasty

Kurtz SM

Implant Research Center School of Biomedical Engineering, Science, and Health Systems,

Drexel University, Philadelphia, USA

Taper corrosion is an old issue for today’s modern implants. In recent years, however, taper

corrosion has re-emerged as a clinical concern, first with certain large-head metal-on-metal hip

designs, then also with modular femoral necks, and even in selected cases with modern metal-

on-polyethylene bearing couples. Our group was among the first to identify ceramic femoral

ball heads as a potential solution to taper corrosion [1]. In the past few years we have pursued

research to better understand and quantify the amount of metal that is released from contem-

porary ceramic and CoCr femoral ball heads. The purpose of this article is to briefly summarize

some of our latest findings, presented at the ASTM Symposium on Taper Corrosion 2014 [2] and

in posters at the 2015 Meeting of the Orthopedic Research Society [3, 4]. We want to continue

to share an evolving perspective on this topic based on our group’s recent research.

Interested in Retrieval Research? How You Can Help.

As our retrieval research continues, access to explanted ceramic heads

and stem pairs with over ten years in vivo, as well as to ceramic heads

incorporating metallic sleeves (e. g., Delta option heads), would be ex-

tremely useful. If you are interested in collaborating with our multi-insti-

tutional retrieval research program by providing explanted devices and

associated (de-identified) clinical data, please do not hesitate to contact

the author (skurtz@drexel.edu). We have established protocols for the

shipping of retrieved implants internationally, and we currently collabo-

rate with over 15 clinical centers in the USA and Europe.

Our group began to study the hip implant retrieval

collection at the Implant Research Center at Drex-

el University to compare taper corrosion in ceram-

ic head systems with that in metal head systems

[1]. We have spent a few years studying carefully

matched implants in the two 50-implant cohorts

(100 patients total) to account for all the variables

influencing taper corrosion and to focus on the

difference between ceramic-metal and metal-met-

al tapers. First of all, we excluded from the study

any hip implant systems with modularity besides

the head-neck interface. This means that there

were no ceramic heads with metal sleeves in the

study, nor were there modular necks or modu-

lar stems. The ceramic heads were all Biolox®,

Biolox®forte or Biolox®delta heads produced by

CeramTec. We observed significantly less corro-

sion among the stems in the ceramic head cohort

as compared with the metal head cohort, and we

published these data in 2013 [1].

Reduced metal release with ceramic

What we didn’t know at the time was to what de-

gree ceramic heads reduced metal release, and

whether metal release was mitigated at the head

taper, stem taper, or both. We spent over a year de-

veloping and validating a highly sensitive technique

to measure the microscopic volumes of metal that

are released in CoCr femoral ball heads and met-

al stem tapers [4]. After re-examining our previous

matched 50–50 cohort of ceramic and femoral ball

heads, we found that the ceramic cohort exhibited

over 90 % less metal release, in terms of volumet-

ric material loss, when compared with the CoCr co-

hort. When focusing on the CoCr head cohort, we

found that the vast majority of the metal release –

again, over 90 % – was liberated from the femoral

ball head rather than from the stem taper. These

CoCr heads were all on MoP bearings.

Mechanical integrity influences corrosion

Retrieval research on taper corrosion continues to

be challenging because of the many relevant and

potentially confounding factors: The implantation

time and flexural rigidity of the stem are two such

factors. We were curious to see if the mechanical in-

tegrity of the taper connection would influence the

corrosion at the head-neck interface [3]. In the lab-

oratory, previous researchers had shown that impac-

tion force can affect the amount of micromotion,

fretting, and corrosion under in vitro conditions [5].

We asked if such a situation might also be applica-

ble in vivo. To answer this question, we studied 46

CeraNews 1/ 2015

retrieved hip systems that did not have the head-

stem taper intraoperatively disassembled. These de-

vices had been revised for infection, loosening, and

periprosthetic fracture. We found that for devices

implanted for between 5 and 10 years, there was

an inverse correlation between the corrosion dam-

age of the taper and the strength of the taper junc-

tion, recorded as the force required to disassemble

the head from the stem taper. In other words, the

weaker the interlock between head and the taper,

the more corrosion was observed at the retrieved

modular taper junction. Keep in mind that this is a

pilot study, but these preliminary data do lend fur-

ther support to the plethora of factors – some well-

known for years, others only being discovered today

– that influence clinical manifestations of corrosion

at the head-neck interface.

Trunnion surface morphology

not relevant

One design factor, namely stem surface roughness,

has recently been suggested to influence taper cor-

rosion based on in vitro experiments [6]. For this rea-

son, we also decided to study the effect of this vari-

able on taper corrosion in explanted hip components

with CoCr femoral ball heads [2]. We asked whether

components with "microgrooved" stem tapers have

higher fretting-corrosion damage scores than com-

ponents with "smooth" stem tapers. In order to an-

swer this question, we performed a retrieval analy-

sis of 398 paired femoral ball head and stem THA

components. Using multivariate analysis of covari-

ance, we found that implantation time (p<0.0001),

apparent engagement length (p<0.0001), flexural ri-

gidity (p=0.008), and head size (p=0.04) were sig-

nificant factors in fretting-corrosion head-damage

scores. Following adjustment for these factors, sur-

face topography (p=0.97) was not associated with

fretting-corrosion damage. Overall, the results of

this study do not support trunnion surface morphol-

ogy as a contributing factor to fretting and corrosion

damage at the modular CoCr head-neck interface.

Our group’s ongoing retrieval research continues

to uncover important implications for metal debris

generation in modular hip systems. It is now clear

that ceramic heads eliminate the potential for met-

al release from the CoCr head and reduce tribo-

corrosion of metal stem tapers to a level that is ex-

ceedingly challenging to measure today. Our pilot

research with retrieved CoCr heads suggests that

mechanical integrity of the taper could play an im-

portant role in its susceptibility to taper corrosion

in vivo. Furthermore, our retrieval data do not sup-

port stem taper morphology (i. e., smooth vs. micro-

grooved stem tapers) as a significant factor to ex-

plain fretting and corrosion taper damage in vivo.

Expect future updates on the status of taper corro-

sion research at conferences in the coming year. ■

Acknowledgements: The author would like to thank Sevi Kocagoz,

Christina Arnholt, Genymphas Higgs, and Dan MacDonald, Drexel Univer-

sity, and Richard Underwood, Ph.D., Exponent, for their contributions to

the corrosion research summarized in this article, as well as for their in-

sights and many helpful discussions.

References

1. Kurtz SM, Kocagoz SB, Hanzlik JA, Underwood RJ, Gilbert JL, Macdonald

DW, Lee GC, Mont MA, Kraay MJ, Klein GR, Parvizi J, Rimnac CM, Do ce-

ramic femoral heads reduce taper fretting corrosion in hip arthroplasty? A

retrieval study. Clin Orthop Relat Res 2013;471:3270–3282

2. Arnholt C, Underwood RJ, MacDonald DW, Higgs G, Chen AF, Klein G,

Hamlin B, Lee GC, Mont M, Cates H, Malkani A, Kraay M, Rimnac CM,

Kurtz SM, Does micro-grooved surface topography influence fretting cor-

rosion of tapers in THA? Classification and analysis of surface topography.

ASTM Symposium on Taper Corrosion in Total Hip Replacement Devices

2014, New Orleans, USA

3. Higgs GB, Siskey RL, Gilbert JL, Mihalko WM, Rimnac CM, Kurtz SM, What

effect does the strength of the taper connection have on taper damage

in retrieved total hip devices? Trans Orthop Res Soc 2015; Poster Session

PS2-154:1741

4. Kocagoz SB, Underwood RJ, MacDonald D, Gilbert JL, Rimnac CM, Kurtz

SM Metal release in ceramic and CoCr heads at the modular junction: a

matched cohort retrieval study. Trans Orthop Res Soc 2015;Poster Session

PS1-065:0887

5. Mroczkowski ML, Hertzler JS, Humphrey SM, Johnson T, Blanchard CR, Ef-

fect of impact assembly on the fretting corrosion of modular hip tapers. J

Orthop Res 2006; 24:271–279

6. Panagiotidou A, Meswania J, Hua J, Muirhead-Allwood S, Hart A, Blunn G,

Enhanced wear and corrosion in modular tapers in total hip replacement

is associated with the contact area and surface topography. J Orthop Res

2013;31:2032–2039

Corresponding Author:

Steve M. Kurtz PhD

Implant Research Center School of Biomedical

Engineering, Science, and Health Systems,

Drexel University

3401 Market Street, Suite 300

Philadelphia, PA 19104 (USA)

E-mail: skurtz@drexel.edu

CeraNews 1/ 2015

22 SCIENCE REPORT

The main purpose of the symposium was to provide

a forum for scientific exchange and an opportuni-

ty to find consensus on common methods for the

assessment and testing of fretting and corrosion,

possibly leading to the development of appropriate

international standards. Many aspects were taken

into account, with special emphasis on the follow-

ing subjects:

• Characterization of fretting, corrosion and the

resulting adverse tissue reactions,

• significance of explants,

• current and prospective test procedures, and

• design parameter for taper connections in joint

endoprostheses.

Approximately 200 participants from science, from

industry, from the Food and Drug Administration

(FDA), and from several legal organizations fol-

lowed the 27 presentations which were divided

into five different sections according to their main

focus. At the end of each section, the participants

had the opportunity to intensively discuss the con-

tents of the presentations with the presenters. Fur-

thermore, altogether 15 research groups took the

opportunity to present their newest results within

a poster session. Organizers and chairmen of the

symposium were A. Seth Greenwald (Cleveland),

Steven Kurtz (Philadelphia), Jack Lemons (Bir-

mingham), and William Mihalko (Memphis).

Adhesion of inflammatory cells could

cause corrosion

In his presentation, Lemons showed the difficulty of

distinguishing between the different possible corro-

sion mechanisms, such as galvanic corrosion, fret-

ting corrosion, crevice corrosion, and pitting corro-

sion, and of simulating these mechanisms in vitro.

Jeremy Gilbert (Syracuse) reported that inflamma-

tory and immune cells attach to CoCrMo surfaces

in vivo and start or amplify corrosion processes. Mi-

croscopical investigations of explanted hip compo-

nents (MoM, MoP) and knee implants supplied for

the first time evidence for this type of corrosion.

These corrosion processes have been observed in-

dependent of the metal alloy, implant design, and

type of polyethylene. It is largely unknown which

stimuli trigger the cell activity.

With the help of 843 examined retrievals, Kurtz il-

lustrated in his presentation that the loss of volume

due to corrosion processes is much larger on the

metal ball head tapers than on the stem tapers. Fur-

thermore, using 398 explanted stems from MoP-

bearings, he provided evidence that the surface to-

pography of the stem tapers does not influence the

qualitative and quantitative degree of corrosion on

either on the metal ball head tapers or the stem ta-

pers.

Legal aspects: large product range,

demand on improved test methods

Carlos Lavernia (Miami) complained about the

large number of different taper designs which may

exist within the product range of a single prosthesis

company, harboring the risk of mix-and-match. He

used the term "lawyeritis", which may prevent fur-

ther proper scientific investigation of the topic.

Fretting and Corrosion

Discussion of Methods for Assessment and Testing

Report on the Symposium on Modularity and Tapers in Total Joint Replacement

Devices, November 10, 2014, New Orleans, USA

Pandorf T

CeramTec GmbH, Plochingen, Germany

In recent years, fretting and corrosion of modular connections in hip endoprosthetics have been

more and more under discussion, leading to an increased number of publications related to the

topic. Also modular connections with ceramic ball heads on stem tapers or ceramic ball heads

with sleeves on stem tapers for revision surgeries have been investigated in this framework.

Nevertheless, the experts are still not in agreement on the means and methods for qualitative

and quantitative assessment of the corrosion events occurring at the taper connections. More-

over, the in-vitro reproduction of the clinically observed corrosion phenomena is a topic of on-

going research. To address these issues, the American Society for Testing and Materials (ASTM)

and the American Academy of Orthopedic Surgeons (AAOS) organized a symposium held in

New Orleans on November 10, 2014, with notable experts on the podium.

CeraNews 1/ 2015

John Goode from the FDA noted that improved

test methods are urgently necessary because all

the implants exhibiting clinically relevant problems

have successfully passed the standardized testing

prior to market release. Two representatives of a

US law office stated that appropriate standards

and guidelines might significantly ease possible lit-

igations. The currently common active recruitment

of patients for litigations increasingly falsifies the

available data and affects the scientific root cause

analysis.

Several important conclusions have been drawn on

the basis of contemporary knowledge: in the test

procedures, more and more attention is given to the

selection of those test parameters having the great-

est influence on the simulation of clinically relevant

failure modes, e. g., the test fluid or the loading sce-

nario. In order to assess these clinically relevant fail-

ure modes with the help of retrievals, it is necessary

to establish uniform cleaning procedures for the ta-

pers. Only then it is possible to assess the retrievals

on the basis of qualitative scores and quantitative

measurements.

Impact of fretting and corrosion

on clinical results

The scientific and technological meeting showed

that remarkable progress has been made in assess-

ing and testing fretting and corrosion since the last

meeting of this kind in November 2013. It also re-

vealed that the complex relationships and the large

number of influencing factors leading to the clini-

cally observed failure modes can be simulated only

roughly in vitro. There was agreement that the im-

portance of fretting and corrosion related to clin-

ical problems for patients requires further exam-

ination: So far, only a few revision surgeries have

been performed due to symptoms which are relat-

ed exclusively to fretting and corrosion, whereas a

large number of retrievals show clear signs of these

phenomena. A necessity to develop different stem

taper designs for ceramic and metal ball heads –

with respect to either the shape or the surface – is

not seen by the experts at this time. ■

References

1. Lemons JE. Experience & Opinions on Modular Connections for Surgical

Implant Devices. ASTM International Symposium on Modularity and Tapers

in Total Joint Replacement Devices, New Orleans 2014, Abstract (talk 1)

2. Kurtz SM et al. Is Taper Fretting Corrosion a Threat to the Clinical Per-

formance of Large-Diameter Highly Crosslinked Polyethylene Bearings?

ASTM International Symposium on Modularity and Tapers in Total Joint

Replacement Devices, New Orleans 2014, Abstract (talk 9)

3. Higgs GB et al. Characterizing the Strength of the Taper Connection & its

Effect on Taper Damage in Retrieved Total Hip Devices. ASTM Internation-

al Symposium on Modularity and Tapers in Total Joint Replacement Devic-

es, New Orleans 2014, Abstract (talk 10)

4. Gilbert JL. State-of-the-Art Understanding of In Vivo Modular Taper Cor-

rosion & In Vitro Testing. ASTM International Symposium on Modularity

and Tapers in Total Joint Replacement Devices, New Orleans 2014, Ab-

stract (talk 18)

5. Laverna CJ et al.The Role of Design Parameters and Microstructure in

the Corrosion and Fretting of Hip Taper Interfaces: A Retrieval Study.

ASTM International Symposium on Modularity and Tapers in Total Joint

Replacement Devices, New Orleans 2014, Poster

Corresponding Author:

Thomas Pandorf PhD

(Senior Manager Applied Science)

CeramTec GmbH

CeramTec Platz 1 – 9

73207 Plochingen (Germany)

E-mail: t.pandorf@ceramtec.de

CeraNews 1/ 2015

24 SCIENCE

Does Bearing Influence Septic Loosening of

primary Total Hip Arthroplasty?

Bordini B, Caputo D, Stea S

RIPO Register c/o Medical Technology Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy

Beginning on January 1, 2000 a Register for Or-

thopedic Prosthetic Implants (RIPO) was estab-

lished in the Italian region of Emilia Romagna. The

ments and revision surgery performed in public

and private hospitals of the region [1]. Surgeons

provide data on specific register forms, which are

completed before patients are discharged. The

pal outcome measure is time to revision surgery,

defined as removal or exchange of at least one

single component. Among reasons for revision,

septic loosening represents 6.3 % of all possible

causes. This is not such a high percentage, but

septic loosening often has the worst outcome for

the patient.

The aim of the analysis was to determine whether

there is an influence of articular coupling on septic

loosening.

Methods

To achieve this aim, only uncemented total hip ar-

throplasties implanted in the period from january

2000 to december 2013 in primary coxarthrosis and

coxarthrosis secondary to developmental dysplasia

were considered due to a possible bias related to

the presence of antibiotic in the cement. The final

dataset is presented in Table 1.

Possible risk factors for sepsis are not equally dis-

tributed among the four groups, so the Cox propor-

tional hazard method was applied, with revision of

total hip arthroplasty (THA) for septic loosening as

the end point.

Results

The analysis showed that age at surgery and body

mass index (BMI) do not influence septic loosen-

ing, while type of articular coupling and gender

do. More specifically, CoC coupling reduces sig-

nificantly the risk of septic failure compared with

MoM with a hazard ratio of 3.1 (1.6–6.2). CoC

A cohort of 36,396 implants of primary total hip arthroplasties was considered, extracted from

the italian Register of Prosthetic Orthopedic Implants (RIPO). Of these, 49 % have CoC articu-

lar coupling, 23.4 % CoP, 19.5 % MoP, and 8 % MoM. Survival analysis was performed, the end

point being revision due to sepsis. It was shown that age at surgery and body mass index do

not influence septic loosening, while articular coupling and male gender do. In detail, CoC

coup ling reduces the risk of septic failure compared with MoM. Men have a higher risk than

women.

Coupling Number of

implants (n)

Age, mean

(years)

and range

Prop.

of obese

(%)

Prop.

of female

(%)

Revisions

for septic

loosening (n)

CoC 17,858 65.7 (13–93) 65 59 22

MoP 7,104 71.1 (20–95) 67 62 13

CoP 8,524 70.3 (22–92) 65 62 13

MoM 2,910 61.4 (16–87) 64 48 14

Table 1: Cohort of 36,396 uncemented primary implants analyzed statistically

Hazard ratio 95% lower

bound

95% upper

bound

p-value

Gender

(reference male)

0.6 0.3 0.9 0.03

BMI class

(reference obes)

0.9 0.7 1.3 0.97

Bearing

(reference CoC)

0.98 0.95 1.0 0.09

MoM 3.1 1.6 6.2 0.003

MoP 1.2 0.6 2.3 0.66

CoP 1.2 0.6 2.3 0.66

Table 2: Results from Cox model: A hazard ratio (HR) >1 indicates risk increase, a HR <1 risk

reduction (significant data are in boldface)

The abstract is based on

results of a clinical trial

(Level of Evidence III)

CeraNews 1/ 2015

Barbara Bordini, senior statistician of the Reg-

ister, has a statistics degree from the University

of Bologna. Since 1999, she has been working

at the Istituto Ortopedico Rizzoli, at the Medical

Technology Laboratory. She is responsible for the

statistical analysis of the Register of Prosthetic

Orthopedic Implants (RIPO). She identifies groups

of patients to start on clinical experiments also

by surveying the regional and local data banks.

does not influence the risk compared with CoP or

MoP. Women have approximately half the risk of

men ( Table 2).

The results are unchanged when only late infections

(revision surgery after at least 60 days from implant)

are considered.

Conclusions

It can be concluded that articulation without met-

al components reduce the risk of precocious amd

late septic failure of THA, although significance was

only reached in comparison with MoM. Male gen-

der shows a higher risk for septic loosening com-

pared with female gender. A limitation of this study

is that comorbidities that may affect the outcome of

sepsis were not considered.

Acknowledgements: All surgeons of orthopedic units in the Region

Emilia Romagna are gratefully acknowledged for sending their data to

the register.

References

1. RIPO annual report, https://ripo.cineca.it, last downloaded February 15,

2015

Corresponding Author:

Barbara Bordini

Statistician

RIPO Register c/o Medical Technology Laboratory,

Istituto Ortopedico Rizzoli

Via di Barbiano 1/10

40136 Bologna (Italy)

E-mail: barbara.bordini@ior.it

Pauwels Commemorative Medal 2014

Werner Zimmerli, MD, was awarded the Pauwels commemorative medal by the German Society for

Orthopedics and Orthopedic Surgery (DGOOC). His lecture during the award ceremony was entitled:

"Orthopedic Prosthetic Joint Infections: Pathogenesis und Therapy".

Zimmerli is a well-known infectious diseases specialist with more than thirty years working experience

in the field of internal medicine and infectious diseases. Since 1979 his research focus has been on the

pathophysiology and treatment of implant infections. A major breakthrough in the treatment of these

infections was the proof of rifampicin´s effectiveness against biofilm infections. Working together with

the orthopedist Peter Ochsner and the infection specialist Andrej Trampuz he developed a treatment

algorithm for prosthetic-joint infections [1].

Zimmerli was also a member of the commission of the Infectious Diseases Society of America (IDSA), that published guidelines

for the diagnosis and treatment of prosthetic joint infections. These are based on the published treatment algorithm and have

since become the international standard.

Since retiring as a medical chief physician Zimmerli has been working as a medical consultant for orthopedic infections at the

Kantonsspital Liestal, Switzerland.

He is a advisory board member of the Pro-Implant Foundation and teaches in the foundation´s workshops (https://www.pro-

implant-foundation.org/en/about/who-we-are).

Reference: 1. Zimmerli W, Trampuz A, Ochsner PE. Prosthetic-Joint Infections. N Engl J Med 2004;351:1645-1654

AWARD

CeraNews 1/ 2015

26 MATERIALS RESEARCH

The Effect of Chromia Content on Hardness of

Zirconia Platelet Toughened Alumina Composites

Kuntz M

CeramTec GmbH, Plochingen, Germany

Description of tests and results

A test series of 4 ZTA variants with different chromia

content was produced in the CeramTec laboratory.

The chromia content in Biolox®delta , as a reference,

is 0.32%. For comparison, samples with lower and

higher chromia content and even 0 % chromia have

been produced. Manufacturing conditions like mill-

ing, pressing, sintering and hard machining for all

specimens are identical. The ceramic microstruc-

ture, i. e., grain size and grain distribution of the

material components alumina, zirconia, and plate-

lets, are within the normal range. As an example,

Figure 1 shows the microstructure of a speci-

men with 0 % chromia content versus Biolox®del-

ta reference.

Hardness of ceramics is usually measured using the

Vickers 4-sided diamond pyramid. Today the use of

a test load of HV 1, or Hardness Vickers load balance

of 1 kg (=9.8 N), is recommended. In the past, sev-

eral studies also used other test loads like HV 0.5 or

HV 10. It was thus decided to include these 3 load

levels in this study.

Furthermore, the preferred unit of hardness values

has been changed over time. Today, using the ratio

of load versus projected imprint area for the hard-

Biolox®delta is a zirconia toughened alumina ceramic (ZTA) for biomedical applications. The

success of this material relies on its extraordinary combination of material properties such as

strength, toughness, hardness and biocompatibility. The composition of Biolox®delta includes

SrO, Y2O3, and Cr2O3. Strontia is added for the formation of platelets inside the matrix, which

support the toughness of the material. Yttria is added in order to control the transformation

mechanism of the zirconia phase.

According to Burger et al., it was previously stated that the addition of chromia leads to im-

proved hardness in a ZTA material [1]. However, later studies on this subject reveal a measur-

able increase in hardness only at a chromia content much higher than is present in Biolox®del-

ta [2]. Further scientific literature suggests that the addition of chromia within a limited range

does not influence the hardness of a ZTA material [3]. CeramTec undertook a comprehensive in-

vestigation in order to isolate the impact, if any, of chromia on hardness in Biolox®delta. The re-

sults of this analysis are described here.

CeraNews 1/ 2015

Figure 2: Results of the hardness measurements of the 4 variants

ness value is recommended, which makes gigapas-

cal [GPa] the relevant unit. In historic data, a unit-

less number was preferred. Such numbers can be

directly compared using the factor 0.009807. As

an example, a hardness value of 2000 [-] equals

19.61 GPa.

Figure 2 shows the results of the analysis. Mean

values ±1 x standard deviation with the error bar are

plotted. As already well known, the hardness values

are higher at lower load levels of the indentation

(at least within the load range of this study). For all

load levels, no measureable influence of the chro-

mia content to hardness is found. For the reference

hardness value HV1, all results are virtually identical.

Influence of test load and strontia

These results demonstrate that the presence or

non-presence of chromia in a ZTA material that is

otherwise identical to Biolox®delta has no influ-

ence on the hardness of the material, at least in

the range of the amount of chromia investigated

here (0–0.5 % by weight). For the study of Burger

et al., the load level HV 0.5 was used which is not

recommended today [1]. This may be one source of

inaccurate results due to high measurement uncer-

tainty. In addition, the sample in [1] that contained

chromia, also contained SrO, which was absent

from the chromia-free sample. Unfortunately, the

result of the study [1] from 2001 has often been

cited in publications referring to the material profile

of Biolox®delta. However, the statistically substan-

tiated test results discussed here demonstrate that

the chromia content of Biolox®delta does not mea-

surably influence the hardness. ■

References

1. Burger W, Richter HG, High Strength and Toughness Alumina Matrix Com-

posites by Transformation Toughening and „In Situ“ Platelet Reinforce-

ment (ZPTA) – the New Generation of Bioceramics, Key Engineering Ma-

terials 2001;191-195:545–548

2. Bradt RC, Cr2O3 Solid Solution Hardening of Al2O3, Journal of the Ameri-

can Ceramic Society 1967;50:54–55

3. Magnani G, Brillante A, Effect of the composition and sintering process

on mechanical properties and residual stresses in zirconia alumina com-

posites, Journal of the European Ceramic Society 2005; 25:3383-3392

4. ISO 14705 Fine ceramics (advanced ceramics, advanced technical cera-

mics) – Test method for hardness of monolithic ceramics at room tempe-

rature

HV0.5 HV1 HV10

0 0.14 0.32 0.50

19.0

18.5

18.0

17.5

17.0

16.5

chromia content (%)

Vickers Hardness (GPa)

HV0.5 HV1 HV10

0 0.14 0.32 0.50

19.0

18.5

18.0

17.5

17.0

16.5

chromia content (%)

Vickers Hardness (GPa)

Corresponding Author:

Meinhard Kuntz PhD

(Manager Oxide Development)

CeramTec GmbH

CeramTec-Platz 1–9

D-73207 Plochingen (Germany)

E-mail: m.kuntz@ceramtec.de

CeraNews 1/ 2015

28 SCIENCE REPORT

What's New in Endoprosthetics in Russia?

8th Vreden's Readings Conference, St. Petersburg, Russia

Tikhilov RM1, Shubnyakov II1, Atzrodt V2

1Research Institute for Traumatology and Orthopedics R.R. Vreden, St. Petersburg, Russia;

2CeramTec GmbH, Plochingen, Germany

On three days, 102 scientific presentations and six

lectures were held on the subject of endoprosthetic

replacements of the large joints. The lectures were

delivered in Russian and English and simultaneously

translated. The conference was accompanied by an

exhibition by the 60 leading enterprises in the medi-

cal technology industry. Numerous workshops were

devoted to the newest methods in endoprosthetics

and to the conservative treatment of pathologies of

the locomotor system.

The topics with which Russian specialists and experts

are currently dealing in the field of endoprosthetics

are also the main focus of orthopedics worldwide:

• complex revision surgery,

• the therapy of infection-related complications,

• highly complex pathologies of the large joints,

• the optimization of care of young and active pa-

tients

• and issues of safety and quality in endoprosthet-

ics.

Russian orthopedists are also confronted with spe-

cific problems regarding the treatment of frequent-

ly occurring dysplasias in certain regions ( case

report), above all in the southern regions of Rus-

sia, and the traditionally determined preference for

classical solutions (e.g., osteotomy rather than en-

doprosthesis).

Focus: Basic and advanced training

The rapid development of endoprosthetics in Rus-

sia, with an average yearly growth of 15–20 %, in

some regions even 40–50 %, must be accompa-

nied by rigorous schooling and advanced training

of orthopedic surgeons. The conference made clear

that continuous basic and advanced training are of

particular importance for the professional compe-

tence of the operating surgeon, for results analysis,

and for the comprehensive assurance of rehabilita-

tion, without which high-quality results cannot be

achieved.

During the conference, attention was focused in

particular on implant pathologies and implant al-

lergies and on the role played by implant mate-

rials and designs in adverse reactions to abrasion

and corrosion products. It became apparent that

the problems in their complexity can be solved only

on a multidisciplinary basis, and that the experts in

the specialized disciplines must join forces to meet

this challenge. As a result of an interesting discus-

sion about contributions by Russian and German

experts it was agreed to carry out further studies

together.

In recent years, the "Vreden's Readings" conference has developed into an excellent forum for

Russian orthopedics, and the number of participants from abroad grows year by year. Approx-

imately 800 orthopedists from various regions of Russia and numerous visitors from 29 coun-

tries, among them the USA, France, Germany, Italy, Great Britain, Austria and Japan, took part

in the eighth conference. The Eastern European states were represented by specialists from

Lithuania, Latvia, the Ukraine, Belarus, and Kazakhstan.

9th Vreden's Readings Conference 2015:

8–10 October 2015, St. Petersburg, Russia

This year's conference will take place in St. Petersburg from the 8th to

the 10th of October. One topic of the scientific program will be peri-

prosthetic joint infection (PJI).The infection expert Prof. Andrej Trampuz,

Charité Berlin (https://www.pro-implant-foundation.org/en/) will or-

ganize the PJI session with German and Russian experts, who will present

and discuss the modern concepts of prevention, diagnosis, and therapy.

The subject area foot surgery will be included in the scientific program for

the first time. The results of the conference will be published and made

accessible to all interested persons (congress link http://www.vreden-

readings.org/eng/program.php)

We invite you to a stimulating conference with interesting encounters.

R.M. Tikhilov, MD

CeraNews 1/ 2015

Contributions on the

subjects of implant aller-

gies, implant pathologies

and hip revision can be

accessed here in Russian

and in English with the

QR code.

Some of the contributions to the "Vreden's Read-

ings" conference 2014 were published in the journal

Traumatology and Orthopedics of Russia (issues 3

and 4, 2014, Russian and English) and can be down-

loaded (http://journal.rniito.org/num_en.html).

References

1. Krenn V, Thomas P, Thomsen M, Usbeck S, Scheuber L, Boettner F, Rüther

W, Hopf F, Müller S, Krukemeyer MG, Gehrke T, Kendoff D, Tiemann A, Hu-

ber M. Implant-associated pathology: an algorithm for identifying par-

ticles in histopathologiy synovialis / SLIM diagnostics.Traumatology and

Orthopedics 2014;3:1

2. Thomas P, Thomsen M, Krenn V, Summer B. Patients with suspected me-

tal implant allergy: Potential clinical pictures and allergological diagnostic

approach (review). Traumatology and Orthopedics 2014;3:142–146

3. Thomsen M, Krenn V, Thomas P, Kretzer JP. Clinical cases of patients with

arthroplasty and heightened blood concentration of metal ions.Traumato-

logy and Orthopedics 2014;4:85–89

Corresponding Author:

Raschid M. Thikhilov, MD

R. R. Vreden Russian Research Institute of

Traumatology and Orthopaedics

Acad. Baikov Str. 8

195427 St. Petersburg (Russia)

E-mail: info@rniito.org

Treatment of dysplastic coxarthrosis

Diagnosis

A 47-year-old female patient with left-sided dyspla-

stic coxarthrosis (Fig. 1) had been treated conser-

vatively during her childhood. This involved retenti-

on with a plaster cast in order to reduce the luxati-

on of the left hip. On admission to the hospital she

complained of pains, reduced leg length, and res-

tricted mobility in her left hip joint. The patient was

barely able to walk due to the one-sided leg length

difference (3 cm) and the flexion contraction in the

hip joint. She had a pronounced limp and required a

walking aid. In addition, there was pain in the area

of the lumbar spine.

Therapy

The left hip joint was replaced with a cement-free

endoprosthesis via lateral access. Because of the pa-

tient's age and her activity demands a ceramic-cera-

mic bearing was used. Reconstruction of the cup

was done with autologous bone material (Fig. 1).

It was decided not to perform a complete leg-

length equalization due to the existing changes in

the lumbar spine. The resulting leg-length differen-

ce was 0.8 cm (Fig. 1). The Harris Hip Score had

improved from 38 to 92 points at the time of the

most recent follow-up examination.

Two years following the operation the cup and

the stem are stable, and no postoperative complica-

tions are detectable. The flexion contraction has im-

proved significantly. The patient can walk normally,

requires no walking aid, and is satisfied with the re-

sult. ■

CASE REPORT

Figure 1: Female patient with dysplastic coxarthrosis Crowe II, from left to right: preoperative X-ray image, postoperative X-ray image, X-ray image 2 years postop-

CeraNews 1/ 2015

30 SCIENCE REPORT

Tribology: Science and Practice in Korea

Pick from a Bearing Congress in Seoul (South Korea)

Zimmermann M, Graessel M

CeramTec GmbH, Plochingen, Germany

Although total hip arthroplasty (THA) is a very successful type of surgery, it is well-recognized

that clinical outcomes are influenced, among other factors, by the quality of the implants used.

In particular, the choice of materials for the bearing couple plays an important role. In order to

provide the latest updates in this regard, Jun-Dong Chang, MD, Chairman of Department of Or-

thopaedic Surgery and Director of Arthroplasty Center of Hallym University Dongtan Sacred

Hospital, Seoul (South Korea), organized a full-day congress dedicated specifically to "Tribolo-

gy: Science and Practice". The event was held at his hospital and was attended by more than

150 Korean surgeons. Eight international faculty members from Germany, Italy, Switzerland,

the USA, China, Japan and India highlighted the meeting with their contributions.

According to Chang, the most important issue in

THA in Korea is to minimize wear and impingement.

Tribology of the bearing surfaces is a topic that con-

tinues to be discussed. Therefore, the scientific pro-

gram of the "Tribology: Science and Practice" con-

gress focused on issues regarding materials, wear

particles, taper corrosion, infection risks related to

bearing surface, current status of bearing surface,

evolution of ceramic bearings, differences between

Asian and Western patients, technical aspects, and

registry.

Given that patients today have a substantially lon-

ger life expectancy, it is anticipated that wear-relat-

ed issues will predominate. Furthermore, it is well-

known that Korean as well as other Asian patients

differ from Western patients in their specific anato-

mies and lifestyles. Their daily routine requires a par-

ticularly large range of motion, and a large propor-

tion of Asian patients are young: Such differences

should be considered as the important issue in ar-

throplasty in Korea.

Asked about the bearing choice algorithm in Korea,

Chang stated: "All these considerations explain why

the clinical results with conventional polyethy lene in

Korean patients were poorer than those in Western

patients. Accordingly, alternative bearing surfaces

have been predominantly used for THA in Korea.

Among the alternative bearing surfaces, MoM, of-

ten used for resurfacing, has been associated with

an increased risk of osteolysis, local soft-tissue reac-

tions, tissue and bone necrosis, and potential long-

term toxicity. These adverse effects led to a substan-

tial decrease in the use of this kind of hard-on-hard

bearing surface for hip arthroplasty. This explains

why the use of ceramic bearings has become very

popular in Korea, showing the most reliable results

up to now among Korean patients. Another reason

for the popularity of CoC bearing couples in Ko-

rea is the cost-effectiveness with the nationally con-

trolled insurance system."

"Finally, the introduction of Biolox®delta ceramic in

Korea substantially improved the clinical outcomes in

comparison with previous pure alumina ceramic gen-

erations, especially regarding breakage and squeak-

ing. This enhanced ceramic also allowed the use of

a large ball head to improve stability and reduce im-

pingement in patients with small sockets, which is

common in Koreans. Breakage of Biolox®delta is

very rarely reported in Korea, and I have never expe-

rienced any fractures of liner or femoral head with

Biolox®delta ceramic." The acceptance of ceramic

bearings in Korea is very high, with an 85,46 % share

of CoC used in primary THA (data on file, South Ko-

rea Health Insurance Review and Assessment Service

2014). Thus, clinical outcomes and issues were ex-

tensively analyzed and discussed at the meeting. The

Korean situation was reflected in the presentations

by Kyong-Ho Moon, MD, Inha University, Incheon,

and Kyung-Hoi Koo, MD, Seoul National University

Bundang Hospital.

Long-term results of third-generation

CoC bearings in Korea

Moon presented the long-term results with the

third generation of CoC bearings. From April 2001

to January 2008, 349 cementless THA were per-

CeraNews 1/ 2015

formed with CoC (Biolox®forte, alumina) bearings

in 331 patients. The patients' mean age at the time

of surgery was 54.6 years (range: 23–87 years). The

most common indication was osteonecrosis, in 191

cases. After a mean follow-up of 8.9 years (range:

6.5–13 years), there was no radiologic evidence of

osteolysis or cup migration. The two main observed

complications were dislocation in nine cases (2.9 %)

and periprosthetic fracture in seven cases (2.2 %).

In three cases (0.9 %) a fracture of the ceramic

component was observed, including one case ob-

served intraoperatively (liner chipping). In five cases

(1.6 %) squeaking occurred, however, without re-

quiring revision. In conclusion, the long-term results

of third-generation CoC bearings in cementless pri-

mary THA were excellent.

Delta ceramic bearing: Will it guarantee

better results?

Koo reported on the retrospective findings from sev-

eral cohorts of patients all treated with CoC bear-

ings but with different stem and cup systems [1, 2,

3] (Level of Evidence III and IV).

Between 1998 and 2008, he used the Biolox®forte

ceramic and since March 2008 he is using Biolox-

®delta. The lessons learned from 10 years’ experi-

ence with the third generation of ceramic articula-

tion are that we should

• not use sandwich-type ceramic liners,

• not use 28-mm-short neck heads,

• not use metal shells with an elevated rim, and fi-

nally,

• we should inform the patients not to squat.

Between March 2008 and September 2011, 570

Bio lox®delta CoC hips were implanted in 492 pa-

tients. The mean age of the patients at surgery was

50 years (range: 16–83 years), with osteonecrosis

being the main reason for surgery in 311 cases. Af-

ter a mean follow-up of 42 months, neither oste-

olysis nor wear has been observed. The only case

of ceramic liner fracture was due to intraoperative

malpositioning of the liner. The use of ceramic ball

heads 32 mm or 36 mm in diameter clearly reduced

the risk of dislocation compared with 28-mm ball

heads [4] (Level of Evidence I). ■

References

1. Ha YC, Koo KH, Jeong ST, Joon Yoo J, Kim YM, Joong Kim H. Cementless

alumina-on-alumina total hip arthroplasty in patients younger than 50

years: a 5-year minimum follow-up study. J Arthroplasty 2007;22:184–8

[Level of Evidence IV study]

2. Ha YC, Kim SY, Kim HJ, Yoo JJ, Koo KH. Ceramic liner fracture after ce-

mentless alumina-on-alumina total hip arthroplasty. Clin Orthop Relat

Res 2007;458:106–10 [Level of Evidence III study]

3. Koo KH, Ha YC, Jung WH, Kim SR, Yoo JJ, Kim HJ. Isolated fracture of the

ceramic head after third-generation alumina-on-alumina total hip ar-

throplasty. J Bone Joint Surg Am 2008;90:329–36 [Level of Evidence III

study]

4. Lee YK, Ha YC, Koo KH. Comparison between 28 mm and 32 mm ceram-

ic-on-ceramic bearings in total hip replacement. Bone Joint J 2014;96–

B(11):1459–63 [Level of Evidence I Study]

Additional Selection of recently published ceramic bearing

CeraNews_1 15_umbruch_engl Cera News 1 2015 Engl

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