Post on 03-Mar-2020
Pourous CoatingProduct Rationale
Introduction 2
Proven Clinical Heritage of POROCOAT® 4
Built on the foundations of POROCOAT 5
Super Textured Asperity Topography (STAT) 6
High Coefficient of Friction 7
Gradient, High Volume Porosity 8
Optimal Pore Size 9
Manufacturing Process 10
Clinical Applications 12
GRIPTION Product Rationale DePuy Synthes 1
Contents
GRIPTION exhibits “a superior scratch fit
leading to increased primary stability”
due to one of the industry’s highest
coefficients of friction.10-12
Introduced in 1977, POROCOAT porous
coating has more than 30 years of
clinical experience.1-9 In 2009 GRIPTION
porous coating was introduced
to build on the foundation of the
POROCOAT porous coating.
GRIPTION® porous coating is an evolutionary development in implant fixation technology designed for patients with an additional need of initial stability or a diminished implant contact area with the host bone.
DePuy Synthes GRIPTION Product Rationale2
GRIPTION has an average pore size
of 300 microns13,23 which lies within
the optimal range for tissue in
growth into the structure and enables
vascularisation.14,16
GRIPTION exhibits a proprietary gradient
porosity which is engineered with a
clinically advantageous 80-percent
surface volume porosity designed
to facilitate bone in-growth13,14 and
a favorable mechanical loading
environment for bone formation.15
GRIPTION porous coating’s advanced structure is called ‘Super‑Textured Asperity Topography’ (STAT) and is a random array of
sintered, irregularly shaped, commercially pure titanium (CPT) particles forming a three‑dimensional network of interconnecting pores.
GRIPTION Product Rationale DePuy Synthes 3
Proven Clinical Heritage
POROCOAT Porous Coating is a small-beaded,
metal surface coating that sits proud on the surface
of the implant and is designed for long-term
cementless fixation.
Introduced in 1977, POROCOAT porous coating
has more than 30 years of clinical experience.1-9
POROCOAT is supported by multiple peer reviewed
published clinical papers reporting “excellent
results” which is a testament to this well established
technology.1-9 Peer-reviewed surgeon series of
acetabular cups with POROCOAT porous coating show
excellent survivorship rates.1,2,4 100% of DURALOC®
acetabular implants had bone ingrowth into the
porous-coated surface, with 0% aseptic loosening
at 16 years,1 100% survivorship at 10 years of the
DURALOC 300 cup2 and 96.1% survivorship at 8 years
with the PINNACLE cup.4 These results are supported
by multiple National Joint Registry results reporting
10-year survivorship rates of DURALOC at 94%
survivorship in the Norwegian17 registry. The National
Joint Registry for England, Wales, Northern Ireland
and the Isle of Man reported 97.19% survivorship
at 10 years for ceramic on polyethylene bearings
and 96.84% survivorship at 10 years for metal on
polyethylene bearings.18 POROCOAT Porous Coating
is found on a range of contemporary DePuy Synthes
Joint Reconstruction products.
POROCOAT is made by sintering (high temperature
bonding) a random array of spherical beads of titanium
or cobalt chrome to an implant. The sintered beads
form a three-dimensional network of interconnecting
pores exhibiting optimal morphological properties
for bone in-growth. POROCOAT’s high coefficient of
friction of 0.810 provides a roughness that enables
“very good initial stability and facilitates the scratch fit
of the implant”. It is engineered to provide “a high and
clinically advantageous ~80% volume porosity at the
surface an average pore size of 250 microns”, which is
documented in a laboratory studies16 to be within the
beneficial size range for good bone in-growth.
The three-dimensional, gradient structure of
POROCOAT Porous Coating is designed to provide
a favourable mechanical loading environment for
bone formation.15 POROCOAT Porous Coating is
manufactured with a coating tensile strength >23 Mpa
to minimise coating delamination. The coating process
has an average thickness of 0.762 (± 0.254 mm).
This tolerance variance is intentional because it adds
to the overall roughness of the coating. Research20
has demonstrated that virtually all bone growth onto
and into an implant is at the outermost surface (only
about 1-1.5mm deep into the pore structure), which
reinforces the design characteristics of a sintered
bead coating.
DePuy Synthes GRIPTION Product Rationale4
Built on the Foundations of POROCOAT
Characteristic POROCOAT10 GRIPTION10,13,21,22
Pore Size (Gradient Pore Size) ~250 microns (average) ~300 microns (average)
Volume Porosity ~80% (surface),
45% (average)
~80% (surface),
63% (average)
Thickness 0.762 (average) 0.889 (average)
Coating Tensile Strength >23 Mpa* >32 Mpa*
Coefficient of Friction 0.8 1.2
GRIPTION Porous Coating builds on the characteristics of POROCOAT and hence
emulates some of its proven properties:
• GRIPTION has a pore size of 300 microns13,21 versus 250 microns for
POROCOAT. Both POROCOAT and GRIPTION are documented in laboratory
studies14,16 to be within the beneficial size range for good bone in-growth and
vascular reconstitution.
• GRIPTION features a favourable three-dimensional, gradient structure, which
is designed to provide a favorable mechanical loading environment for bone
reconstitution.15 The microtexture additionally enables greater cell adhesion and
proliferation due to its morphology.14
• GRIPTION’s manufacturing principles and mechanical attributes are virtually
identical to POROCOAT and therefore replicate many mechanical properties such
as the resistance to delamination with a coating tensile strength >32 Mpa.22
• The GRIPTION Porous Coating is applied by first preparing the surface of the cup
to accept a coat of the same spherical titanium beads as used for POROCOAT
Porous Coating. Once these spherical beads are applied to the surface, multiple
coats of irregularly shaped particles of titanium are applied directly over the top.
The result is a high porosity, high friction GRIPTION surface.10,13,21
• GRIPTION exhibits a high co-efficient of friction for initial ‘scratch fit’ designed to
increased primary stability based on one of the industry’s highest coefficients of
friction at 1.2.10-12
• GRIPTION is engineered to feature “a clinically advantageous gradient and very
high porosity (80-percent at the surface)”13
Comparison of the physical characteristics of POROCOAT and GRIPTION porous coatings
* Actual values associated with failure of the coating were not obtained. The highest strength result obtained with no coating failure is indicated, as cohesive failure occurred between the outer surface of the porous coating and the testing medium in all cases.
GRIPTION Product Rationale DePuy Synthes 5
Super Textured Asperity TopographyGRIPTION incorporates a proprietary Super-Textured
Asperity Topography (STAT). STAT is a random array
of irregularly shaped, commercially pure titanium (CP
Ti) sintered particles forming a three-dimensional
network of interconnecting pores. STAT is comprised
of two differentiated structures; a macrotexture and
a microtexture.
The microtexture comprises a series of peaks and
troughs on the irregularly shaped titanium particles.
This microtexture may improve the osteoblasts’ ability
to stick to the surface, increasing adhesion strength
and enabling cell proliferation on the coating surface.14
DePuy Synthes GRIPTION Product Rationale6
The proprietary Super-Textured Asperity Topography (STAT) of GRIPTION Porous Coating features initial ‘scratch fit’
stability due to one of the industry’s highest coefficients of friction of 1.2.10-12
Implant micromotion exceeding 150 microns results in fibrous attachment and poor bone formation onto and
around an implanted device.19 Bearing this in mind, a superior coefficient of friction and therefore enhances initial
‘scratch-fit’ stability may be crucial with regards to long-term fixation for a cementless implant. This may be
especially important with regard to cases with a smaller host bone contact area (this may include revision or unusual
primary cases), where the coefficient of friction may be an important factor for initial stability and long-term
fixation of the implant.
Definition of Coefficient of Friction
The Coefficient of Friction is defined by the ratio of the
force that maintains contact between an object and a
surface and the frictional force that resists the motion of
the object.
→ A Coefficient of Friction of 1.2 (GRIPTION Porous
Coating) implicates that for each 1 kilogram of weight
applied downward, it needs 1.2 kilograms of force to
dislodge it.
High Coefficient of Friction
Coefficient of Friction
GRIPTION10 TRITANIUM12 TRABECULAR
METAL11
1.2
1.0 1.0
GRIPTION Product Rationale DePuy Synthes 7
A property that is proprietary to DePuy Synthes porous
coatings is its gradient porosity13 (see chart right).
GRIPTION like POROCOAT was designed with a
gradient porosity.13 The intent of this gradient porosity
is to assist with load sharing. The gradient coating
design gives rise to highest density of metal at the
substrate or surface of the cup and the lowest density
of metal at the outer surface of the coating.13 This
provides a smooth transition in porosity and metal
density as bone grows through the coating from bone
to substrate. The outermost surface of the coating
being more porous results in more open space for
vascurlarisation and good bone in growth. This gives
a strong bone-to-implant interface, and might aid in
stress shielding with the transition to lower porosity
providing a favorable mechanical loading environment
for bone formation.15,23 The outermost pores are
typically filled with scraped bleeding bone upon
impaction of the component.
GRIPTION is engineered to maintain a high and
clinically advantageous 80-percent volume porosity13 at
the surface for good bone in-growth.14 This 80-percent
volume porosity is equal to or better when compared
to the volume porosity of other advanced coating
surfaces in the market.11-13
Definition of Volume Porosity
Porosity is a measure of the void spaces in a material and
is a fraction of the volume of voids over the total volume,
expressed as a percentage between 0–100%.
→ A surface volume porosity of 80%13 (GRIPTION Porous
Coating) indicates, that 80% of the area is void space at
the bone implant interface.
Gradient, High Volume Porosity
Gradient Volume Porosity13
The volume of porosity increases as the distance from
the cup surfaces increases.
Surface Volume Porosity
GRIPTION13 TRITANIUM12 TRABECULAR
METAL11
~80%
~72%
<80%
100
90
80
70
60
50
40
30
20
10
0
Vo
lum
e P
oro
sity
(%
)
Distance from the substrate (µm)
0 250 500 750 1000
DePuy Synthes GRIPTION Product Rationale8
Optimal Pore Size
GRIPTION has an average pore size of 300 microns,13,21 which is documented in laboratory studies to be within the
beneficial size range of 50-400 microns for good bone in-growth and vascular reconstitution.16
Pores below 50 microns may hinder uniform maturation of tissue: in larger pores, 400 microns and above,
in-growth may be slow, inconsistent and tends to be fibrous.16
Definition of Pore Size
Pore size is a measure of the average diameter of a
material’s pores (this usually includes a definition of the
range of pore sizes).
→ GRIPTION Porous Coating has an average pore size of
300 microns.13,21
Op
tim
al Po
re S
ize
50
-40
0 µ
m
Optimal Pore Size
GRIPTION13,21 TRITANIUM12 TRABECULAR
METAL11
~300 µm
~546 µm ~550 µm
GRIPTION Product Rationale DePuy Synthes 9
The manufacturing process for PINNACLE cups with GRIPTION Porous Coating is very similar to the
manufacturing process for coating with POROCOAT.
Raw Forging
The PINNACLE Shell forging is essentially a “blank” that can be
made into almost any PINNACLE cup design including the 100,
300, Sector, Multihole or Bantam series.
Outer Diameter Machined
The forging is machined at this stage to include the apical hole and
any screw holes.
GRIPTION Porous Coating Applied
The surface of the cup is prepared to accept a coat of the same
spherical titanium beads as used for POROCOAT Porous Coating.
Once these spherical beads are applied to the surface, multiple
coats of irregularly shaped particles of titanium are applied directly
over the top. The result is a high porosity, high friction GRIPTION
surface.10,13,23 (Were this a cup with POROCOAT Porous Coating,
only spherical beads would be applied.)
Inner Diameter Machined
Following the sintering process (sintering is the process of high
temperature bonding of the beads to the implant creating a strong
metallurgical bond between the implant and the fused beads), the
PINNACLE shell’s inner diameter is machined to accept the liners.26
Finished Pinnacle Cup
PINNACLE Cups with GRIPTION Coating are checked against
specification and are cleaned, boxed and sterilised.
DePuy Synthes GRIPTION Product Rationale10
Manufacturing Process
GRIPTION Product Rationale DePuy Synthes 11
There are three groups of patients that may stand to gain the most from GRIPTION’s high coefficient of friction,
high gradient volume porosity and optimal pore size:
• Atypical Primary Patients (in the case of a diminished contact area of the implant with the host bone)
This may include DDH, rheumatoid protrusio, prior fusion, severe natural anteversion or retroversion deformity,
or tumour.
• Traditional Revision Patients
This may include revisions of failed cemented cups, minor to moderate protrusio, migrated shell, osteolytic
defects and false acetabulum, where a loss of host bone may compromise primary fixation.
• Primary Patients with an Additional Need for Initial Stability
Any other primary patients where surgeons feel an improved initial scratch fit is of benefit.
12 DePuy Synthes GRIPTION Product Rationale
Clinical Applications
References
1. Kim Y-H, Kim J-S and Park J-W. Is Hydroxyapatite Coating Necessary to
Improve Survivorship of Porous-Coated Titanium Femoral Stem?J Arthroplasty.
2012;27:559-563.
2. Grobler GP et al. Ten-year results of a press-fit, porous-coated acetabular
component. J Bone Joint Surg Br 2005;87:786-9.
3. Kindsfater K, Barrett WP, Dowd JE, Southworth CB and Cassell MJ. “99.9%
Midterm Survival of the Pinnacle Multi- Liner Acetabular Cup in a Prospective
Multi-Center Study.” Poster Presentation #P077, AAOS, San Diego, CA. February
14-18, 2007.
4. DePuy Orthopaedics, Inc. Internal Study Update. PINNACLE Multi-Liner
Acetabular Cup in a Prospective Multi-Center Study. May 2011.
5. Engh CA, et al. “Porous-Coated Total Hip Replacement.” Clin Orthop Rel Res.
1994;298:89-96
6. Onodera S, et al. Cementless total hip arthroplasty using the modular S-ROM
prosthesis combined with corrective proximal femoral osteotomy. J Arthroplasty.
2006;21(5):664-9.
7. Cameron HU, Keppler L and McTighe T. The Role of Modularity in Primary Total
Hip Arthroplasty. J Arthroplasty. 2006;21 Suppl 1:89-92.
8. Chiu KY, et al. Cementless total hip arthroplasty in young Chinese patients: a
comparison of 2 different prostheses. J Arthroplasty. 2001;16(7):863-70.
9. Burt CF, Garvin KL and Erik TA. Femoral Component Inserted Without Cement In
Total Hip Arthroplasty, A Study Of The Tri-Lock Component With an Average Ten-
Year Duration of Follow-Up. J Bone Joint Surg Am 1998;80-A:952-960
10. DePuy Internal Test Report: WR070146; 2007.
11. Published literature: No.97-7864-001-00 7.5ML, Zimmer Inc, 2005 and Zimmer
Inc, Trabecular Metal Technology. Website accessed February 17, 2014 at URL
http://www.zimmer.com/en-US/hcp/hip/our-science/tm-technology.jspx
12. Published data of the Stryker Orthopaedics Test Report RD-07-077. Website
accessed January 10, 2014 at URL http://www.stryker.com/en-us/products/
Orthopaedics/HipReplacement/PrimaryAcetabular/
TritaniumAcetabularShell/index .htm.
13. DePuy Internal Test Report: WR070125; 2007.
14. Karageorgiou V, et al. Porosity of 3D biomaterial scaffolds and osteogenesis.
Biomaterials 2005;26:5474-91
15. Simmons, et al. Differences in osseointegration rate due to implant surface
geometry can be explained by local tissue strains. J Orthop Res 2001;19:187-
194
16. Bobyn JD, Pilliar RM, Cameron HU, Weatherly GC. The optimum pore size for the
fixation of porous surfaced metal implants by the ingrowth of bone. Clin Orthop
Rel. Res. 1980;150:263-270.
17. Furnes O, et al. Prospective studies of hip and knee prostheses - the Norwegian
Arthroplasty Register 1987-2004. Scientific Exhibit presented at 72nd Annual
Meeting of the American Academy of Orthopaedic Surgeons, Washington, DC,
USA. Feb 2005.
18. National Joint Registry for England, Wales, Northern Ireland and the Isle of Man,
13th Annual Report, 2016. Table 3.9. Available from www.njrreports.org.uk
19. Ayers RA, et al. Quantification of bone ingrowth into porous block
hydroxyapatite in humans. J Biomed Mater Res.1999: 47(1):54-59.
20. DePuy Internal Test Report: Master File 60.
21. DePuy Synthes Data on File, Master File 1478.
22. DePuy Synthes Data on File, WR070087,070065.
23. DePuy Synthes Data on File: Strength of GRIPTION Porous Coating.
©Johnson & Johnson Medical Limited. 2017. All rights reserved.
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CA#DSEM/JRC/0317/0783 Issued: 07/17