R3 Design Rationale 00438V1

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We would like to thank the following surgeons for their

participation as part of the R3™ Acetabular System design team:

Robert Barrack, MD

St. Louis, Missouri

Robert Bourne, MD

London Health Sciences Center

London, Ontario, Canada

Jonathan Garino, MD

University of Pennsylvania School of Medicine

Philadelphia, Pennsylvania

Wayne M. Goldstein, MD

Clinical Professor of Orthopaedics

University of Illinois at Chicago

Illinois Bone and Joint Institute

Chicago, Illinois

Richard Kyle, MD

Minneapolis, Minnesota

Stephen J. McMahon MB BS,

FRACS(Orth), FA(Orth)A

Senior Lecturer Monash University

Malabar Orthopaedic Clinic

Melbourne, Australia

John L. Masonis, MD

OrthoCarolina

Hip & Knee Center

Charlotte, North Carolina

Henrik Malchau, MD

Associate Professor Harvard Medical School

Codirector The Harris Orthopaedic

Biomechanics and Biomaterials Laboratory

Massachusetts General Hospital

Boston, Massachusetts

Michael Ries, MD

University of California

San Francisco, California

Cecil Rorabeck, MD

Professor of Orthopaedic Surgery

University of Western Ontario

London, Ontario, Canada

Van Paul Stamos, MD

Illinois Bone and Joint Institute

Glenview, Illinois

Clinical Instructor of Orthopaedic Surgery

Northwestern University Medical School

Chicago, Illinois

Contents

1

Introduction ..............................................2

Advanced bearing capabilities

VERILAST™ Technology Oxidized Zirconium

on XLPE .........................................................3

Ceramic-on-ceramic ......................................6

Stability

Larger head sizes ........................................ 10

Locking mechanism .....................................12

STIKTITE™ Porous Coating ............................ 14

Instrumentation .................................... 16

2

Polished inner surface to

minimize backside wear

NO HOLE, THREE

HOLE, and MULTI HOLE

hemispherical

shell offering

STIKTITE™ Porous Coating

for enhanced scratch-t feel

and enhanced initial xation

General features

R3volution in motion

The R3™ Acetabular System combined with the Smith & Nephew

portfolio of hip stems provides an advanced hip replacement

system with:

• Wide range of advanced bearing options

• Excellent primary stability

• Flexible instrumentation

3

Ceramic-on-ceramic

offered in BIOLOX® Forte

XLPE

Offered in 0 and 20 degree,

0 and 20 degree +4mm

lateralized, and

constrained options

R3™ Liner options

4

Advanced bearing surfaces: VERILAST™ Technology

Oxidized Zirconium with XLPE

R3™ system with VERILAST

Technology is an advanced

bearing option

VERILAST™ Technology for hips from

Smith & Nephew uses the exclusive bearing

combination of proprietary OXINIUM™ and

highly cross-linked polyethylene, which

provides superior clinical survivorship and

biocompatibility without sacricing

versatility or introducing the risk of

ceramic-like fracture.1

Most importantly, VERILAST Technology

provides low wear, corrosion avoidance

and real-life results.OXINIUM material

along with 10 Mrad XLPE provides the

wear performance of hard bearings

along with the intraoperative options

of hard-on-soft bearings.

Wear performance

VERILAST Technology for total hip arthroplasty

has been tested and shown to provide superior

wear performance compared to CoCr on highly

crosslinked polyethelene, for up to 45 million

cycles.2 With advanced materials designed

to last, VERILAST Technology helps restore

patients to their active lifestyles, allowing joint

pain to be addressed earlier.

4

Cumulative volumetric wear comparison2

CoCr (32mm) against CPE

700

600

500

400

300

200

100

010 20 30 40 50

0

CoCr (36mm) against 10-XLPE

OxZr (36mm) against 10-XLPE

80%

Reduction in volumetric wear

after 7.8 million cycles 67%

Reduction in volumetric wear

after 45 million cycles

Real life results

Oxidized Zirconium has a clinical history of

more than 10 years. Over 190,000 components

have been implanted successfully to date.

Impressive clinical wear performance of

OXINIUM heads has been reported in global

registry data. In the 2013 Australian Registry,

the ceramicized metal/cross-linked polyethylene

category, which includes the exclusive OXINIUM

alloy from Smith & Nephew, had the highest

survivorship of all bearing categories at ve

years: 98.0%.1

5

Biocompatibility

Protect against taper corrosion

There is a growing concern in the orthopaedic

community about fretting and corrosion at the

head neck taper junction.With its biocompatible

properties, due to its use of Oxidized Zirconium,

VERILAST Technology has shown to reduce

taper corrosion in total hip arthroplasty,

minimizing the concern of trunnionosis.

A study by Pawar et al. used an acidic

fretting test to compare the potential corrosive

and fretting responses of OXINIUM™ (OxZr),

cobalt chrome (CoCr) and stainless steel

(StSt) femoral heads. As the study states,

“The OxZr heads coupled with Ti-6Al-4V

and SS trunnions showed the least chemical

attack on either the head or the trunnion.”3

Standard unirradiated polyethylene

5 Mrad irradiated crosslinked poly, showing

an increase in the number of particles in

conjunction with a decrease in average size

High magnication images of captured particles

10 Mrad irradiated R3™ XLPE showing a

reduction in total number of particles

Ti64

CoCr OxZr

Ti64

StSt

StSt

OxZr

StSt

Image from Pawar et al., ASMI 2004.

Not your average

cross-linked poly

The Smith & Nephew 10 Mrad, fully annealed

XLPE is the only crosslinked polyethylene

proven to produce less volume of wear debris

particles in all size ranges.4,5 Less wear debris

provides a reduced chance for osteolysis.

All currently marketed crosslinked poly

indicates a signicant improvement in the

volume of wear debris, which would lead one

to assume all crosslinked poly is the same.

However, Smith & Nephew investigated more

closely and found that not all crosslinked poly

minimizes the amount of particles generated.

Because the wear particles of crosslinked poly

can be smaller in size than with UHMWPE,

it is possible to reduce the volume but

actually increase the number of particles.4,5

The Smith & Nephew crosslinked polyethylene

signicantly reduces the number of particles

generated. The gravimetric wear rate of R3

XLPE is not measurable in a hip simulator, but

the number of particles generated is reduced

by 80% compared to traditional CoCr on

conventional poly bearing.6

OxZr (36mm) against 10-XLPE

6

R3™ ceramic-on-ceramic

bearing couple

Ceramic-on-ceramic bearing surfaces

have been used worldwide in total hip

replacement for more than 30 years.

Renewed interest in ceramics as an alternate

bearing surface has been driven by the

following:

• New technology

• Improved manufacturing processes

and standards

• New designs

This translates into improvements in

the following:

• Mechanical and physical properties

• Wear characteristics

• Optimized biocompatibility

• Reliability expected by today’s more

active patients

Due to the reduced grain size, ceramic

components are harder than before. That has

led to wear rates as low as 0.001mm/year.7,8

Neck impingement

In ceramic bearing systems, increases

wear and decreases implant longevity.9

The ush-seating liners of the R3 ceramic

acetabular system in combination with Smith

and Nephew femoral stem neck geometry:

• Increases the range of motion and

consequently, may reduce the likelihood

of impingement.9

• Mitigates the risks of metal transfer and

increased friction imposed by designs with

a raised rim.10

Advanced bearing surfaces: ceramic-on-ceramic

6

Titanium support ring for added strength

The unique feature about R3 ceramic liners

is that they come with a titanium support

ring around the periphery of the liner. The

support ring and ceramic liner are precisely

assembled utilizing a cold pressing process,

which assures that the material properties of

the ceramic and titanium are not altered.

The support ring offers greater

protection against chipped edges.

The R3 system’s ceramic design is an

assembled combination of:

• A ceramic component made from orthopaedic

industry standard material, BIOLOX® Forte

• A precision-machined support ring made of

a Titanium alloy (Ti-6Al-4V) that is commonly

used in orthopaedic implants.

7

Stability: head/shell ratios

Optimized head/shell ratios

Use of larger diameter femoral heads has

been clinically reported to decrease the

probability of dislocation in patients.11-14

• Large heads increase the ROM of the joint11-13

• Large heads reduce the incidence of neck impingement

with soft tissue or the edge of the shell14

8

With the R3™ Acetabular System, surgeons have the option

of using larger head sizes in smaller acetabular shells:

R3 OXINIUM™ alloy on XLPE acetabular system:

36mm head in a 52mm cup size

XLPE Ceramic

Cups 22 28 32 36 40 44 28 32 36

40

42

44

46

48

50

52

54

56

58

60

62

64

66

68

70

72

74

76

78

80

Stability: head/shell ratios continued

9

R3™ locking mechanism for secure liner stability

R3 locking mechanism design features:

• Locking taper that supports ceramic liners

• Double-channel lock design that provides axial stability for poly liners

• 12 large anti-rotational tabs on the poly liner that provide rotational stability

Intraoperative adjustments to the liner position

may be performed with true condence.

Independent researchers conrm that in some

competitive locking designs, the liner can be

signicantly damaged by extraction, which

prohibits liner repositioning.15 Laboratory tests

of the R3 locking mechanism have shown it

withstands consecutive insertions of the same

liner without damaging its locking integrity.16

Anti-rotation tabs

Constrained liner

locking mechanism

XLPE locking

mechanism

Hard-bearing taper

locking mechanism

Stability: locking mechanism

10

Push-out and torque-to-failure tests of the R3™ locking mechanism demonstrate

that it offers the benet of a secure and stable liner. The R3 lock can withstand over

1112N of push-out force in any of its liner options and over 40 N-m of torque.

0

200

400

600

800

1000

1200

1400

Push-out Load (N)

REFLECTION™

R3

0

5

10

15

20

25

30

35

40

45

Torque-to-failure (N-m)

REFLECTION

R3

Maximum predicted in-vivo torque = 2.4 N-m

17

18

Stability: locking mechanism continued

11

Enhanced stability and xation

with STIKTITE Porous Coating

Utilizing STIKTITE coating on the R3™ Acetabular

Shells allows for a true scratch-t feel

during the shell seating and a clinically

proven in-growth surface for long-term

implant success.19

Stability: STIKTITE™ Porous Coating

12

0.0

0.3

0.6

0.9

1.2

1.5

Cancellous bone

Cortical bone

Frictional coefficient

Porous tantalum,

EDM-shaped

Porous tantalum,

net-shaped

STIKTITE coating

STIKTITE coating is a sintered three-dimensional asymmetric

titanium powder that has a porosity of about 60%. Increased

porosity allows for potentially greater bone ingrowth, which

can enhance long-term xation and implant stability. STIKTITE

coating provides enhanced initial mechanical stability, which

is particularly important in damaged or less biologically active

bone. The average pore size of STIKTITE coating (200 µm) is

within the 100– to 500–µm range for optimal bone ingrowth.

Frictional coefcients of bone ingrowth structures against

cancellous and cortical bone (n=96 to 100)

20

STIKTITE Porous Coating demonstrated a higher coefcient of

friction compared to porous tantalum when tested by the same

method.

20

The mean coefcient of friction for STIKTITE coating

was higher than that of porous tantalum against both cancellous

and cortical bone. These results indicate that STIKTITE coating

should have superior friction, scratch-t feel and initial xation

stability as compared to porous tantalum.

Stability: STIKTITE™ Porous Coating continued

13

Instrumentation

Preassembled alignment ring

on all hard bearing liners.

Alignment ring allows for easy placement of

the hard bearing liner in the shell. The liner

impactor can then be inserted through an

opening in the alignment ring and the liner

can be seated with an impaction force.

Upon impaction the ring will

disengage and remain on the liner

impactor for later disposal.

The hard bearing liner is now

perfectly seated in the shell.

Streamlined instrumentation

improves surgical efciency

This seemingly simple technique is a very

effective way of precisely placing the hard

bearing liners inside the shell without the

issue of improper seating due to misalignment

as seen in other competitive systems.21-22

Cocking of a ceramic liner, in particular, during

impaction can lead to a fracture of the liner.

References

1 Australian Orthopaedic Association National Joint Replacement Registry Annual report. Adelaide: AOA; 2013.

2 Parikh, P. Hill, V. Pawar and J. Sprague, “Long-term simulator wear performance of an advanced bearing technology for THA,”

Orthop Res Soc, San Antonio, TX, Jan 26-29, 2013, 1028.

3 Pawar V, Jones B, Sprague J, Salehi A, Hunter G. Acidic Fretting Tests of Oxidized Zr-2.5Nb, CoCr, and SS Femoral Heads, ASMI, 2004.

4 Scott M, Morrison, Mishra SR, Jani S. A method to quantify wear particle volume using atomic force microscopy. ORS Transaction. 2002:27:132.

5 Ries MD, Scott ML. Relationship between gravimetric wear and particle generation in hip simulators: conventional versus crosslinked polyethylene.

Scientic exhibit at American Academy of Orthopaedic Surgeons; Feb 27-March4, 2001; San Francisco, CA.

6 Good V, Widding K, Heuer D, Hunter G. Reduced wear using the ceramic surface on oxidized zirconium heads. InL Lazennec JY, Dietrich M, eds.

Bioceramics in Joint Arthroplasty. Darmstadt, Germany; Steinkopff; 2004:93-98.

7 Biolox-ceramics for hip arthroplasty. CeramTec AG, MT 060003: GB.5.000-0612. Germany.

8 CeramTec Technical Monograph. Current perspective on the use of ceramics in total hip arthroplasty. CeramTec AG, 060003: GB.5.000-0612, 2007.

9 Elkins JM, O’Brien MK, Stroud NJ, Pedersen DR, Callaghan JJ, Brown TD. Hard-on-Hard Total Hip Impingement Causes Extreme

Contact Stress Concentrations. Clin Orthop Relat Res (2011) 469:454–463; 16 October 2010.

10 Knahr K. Total Hip Arthroplasty, Tribological Considerations and Clinical Consequences. Orthopaedic Hospital Vienna-Speising, Vienna, Austria, 2013.

11 Berry DJ, von Knoch M, Schleck CD, Harmesen WS. Effect of femoral head diameter and operative approach on risk of dislocation after primary total

hip arthroplasty. J Bone Joint Surg AM. 2005 Nov;87(11):2456-2463.

12 Barrack RL, Butler RA, Laster DR, Andrews P. Stem design and dislocation after revision total hip arthroplasty: clinical results and computer

modeling. J Arthroplasty. 2001 Dec;16(8 Suppl 1):8–12.

13 Barrack RL. Dislocation after total hip arthroplasty: implant design and orientation. J Am Acad Orthop Surg. 2003 Mar-Apr;11(2):89–99.

14 Barrack RL, Lavernia C, Ries M, Thornberry R, Tozakoglou E. Virtual reality computer animation of the effect of component position and design on

stability after total hip arthroplasty. Orthop Clin North Am. 2001 Oct;32(4):569–577, vii.

15 Tradonsky S, Postak P, Frimson A, Greenwald A. Performance characteristics of two piece acetabular cups. Cleveland, OH: The Orthopaedic

Research Laboratory, Mt. Sinai Medical Center. 1992.

16 Data on le.

17 Data on le.

18 FDA guidance document for testing acetabular cup prosthesis. US Food and Drug Administration. May 1995.

19 Bourne R. Randomized controlled trial to compare acetabular component xation of two porous ingrowth surfaces using RSA analysis.

London, Ontario, Canada: London Health Science Center. 2007. Internal report on le at Smith & Nephew, Memphis, TN.

20 Heiner AD, Brown TD. Frictional coefcients of a new bon ingrowth structure. Poster no. 1623 presented at: Orthopaedic Research Society Annual

Meeting; Feb 11-14, 2007; San Diego, CA.

21 Padgett DE, Miller AN, Du EP, Bostrom MPG, Nestor BJ. Ceramic liner malseating in total hip arthroplasty. Poster P097 at American Academy of

Orthopaedic Surgeons; Feb 14-18, 2007; San Diego, CA.

22 Langdon AJ, Pickard RJ, Hobbs CM, Clarke HJ, Dalton DJ, Grover ML. Incomplete seating of the liner with the Trident acetabular system: a cause for

concern? J Bone Joint Surg Br. 2007 Mar;89(3):291-295.

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00438 V1 04/14