Taperloc Hip System

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Taperloc Hip System

• 
  Pierre-François Köver, PhD
• European Product Management Team

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Taperloc

• Flat Tapered Wedge
• Metaphyseal Fit
• Porous Ti Plasma Spray
• Interloc
• Standard and Lateral Offset Options

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Bio-mechanical Principles

• Axial / Rotational Stability
• Gradual Stiffness Reduction
• Proximal Load Transfer
• Collarless to enhance
• self-seating

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Fixation

• Need both axial and rotational stability
• Square peg in a round hole

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Taperloc

• A gradual change in stiffness is less likely to
  cause end pain!
• Prosthesis / Bone stresses more evenly
  distributed - reducing stress shielding and
  subsequent bone loss

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Taperloc Sizing

• 7.5 x 135 mm
• 10.0 x 140 mm
• 12.5 x 145 mm
• 15.0 x 150 mm
• 17.5 x 155 mm
• 20.0 x 160 mm
• Cemented and
• Uncemented
• Single Instrumentation

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Taperloc Lateral Offset

• First stem available with this option
• 6mm horizontal offset without lengthening the
  leg (taper shift)

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TaperLoc Tapers 10/12-12/14

• PRIMARY
  REVISION
• Cemented
  Uncemen. Uncemen.
• TiAlVa CoCr
  TiAlVa TiAlVa
• 10/12 - 12/14 10/12 - 12/14 10/12 -
  12/14 10/12 - 12/14
• STD. YES YES YES YES YES
  YES YES YES
• LAT. YES YES YES YES YES
  YES YES NO

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OFF-SET CHOICE - THE
ADVANTAGES

• Increased moment arm of the abductor muscles
• reduction of abductor force required
  for normal
• gait reduction of forces across the
  hip joint
• soft tissue balance
• joint stability
• avoiding leg lengthening (vector)
• impingement reduction
• reduced polyethylene wear
• P.S. Durgadas - 67th
  AAOS 15-19/03 2000

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Why the Taperloc?

• Simple-Accurate-Reproduceble Technique
• Single Set of Instruments
• Cemented / Uncemented Option
• Circumferential Porous Plasma Coating
• Off-loading Stem Geometry
• ABOVE ALL CLINICAL RESULTS

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Taperloc Clinical Results

• Rothman Institute
• 4750 cases up to 12 years
• 16 femoral revisions
• 7 - pain and loosening
• 6 - late femur fracture
• 2 - infection
• 1 - stem fracture
• 99.6 Survivorship !!

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Taperloc Clinical Results

• Dr. Hozack - CORR, No 33-3, Dec. 1996
• 105 primary total hips
• Mean patient age 61.2 years
• No Revision for aseptic loosening
• Minimum 5 year follow up
• 4 thigh pain
• NO Distal Osteolysis

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Taperloc Clinical Results

• Dr. McLaughlin - JBJS, Vol. 79B, Nov. 1997
• 8-12.5 year follow-up
• 114 Hip Replacements
• No Patients were lost to follow-up- 100
• 1 Revision Rate
• No hip had severe pain - only 2 moderate
• Only 6 osteolysis
• All Radiographs reviewed by independent surgeon

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Taperloc Clinical Results

• Dr. McLaughlin-1997 AAOS San Francisco
• 100 consecutive primary Taperlocs
• No Patients lost to follow-up 100
• Average patient age 37 years old
• 10.2 year average follow-up (8 to 13 years)
• 98 of implants in place and rigidly fixed
• 0 revisions for aseptic loosening
• 0 implants were unstable
• 98 ingrowth

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Taperloc Clinical Results
What about the Elderly?

• Rothman Institute - THA in Octogenarians
• 114 Cementless THA in patients gt 80 years !!
• No Femoral Splits!
• No Dislocations!
• 93.5 demonstrated bone ingrowth!
• 4 mild thigh pain!
• 2 - 11 years follow up
• By Keisu et al. - JBJS (A) - March 2001

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Taperloc Clinical Results What about
Hydroxyapatite?

• Dr. Rothman - JBJS Vol.78A, No. 3, Mar 96
• 52 Matched pair analysis
• 1/2 patients received Taperloc with HA
• 1/2 patients received Taperloc without HA
• Age, weight, sex and diagnosis all equal
• Minimum two year follow-up
• No wear, lysis or revision in either group
• No statistical difference with regard to pain,
  function or motion

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Taperloc Clinical Results

• CORR - December 1996
• Summary
• Despite 25.5 incidence of acetabular lysis with
  Hex-Loc cup distal femoral lysis was not
  observed.
• The authors think that the circumferential
  porous coating serves as a barrier to migration
  of debris distal to the proximal area of bony
  ingrowth

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Plasma Spray

• High energy electric arc 450-900 A
• Plasma gas Argon, Helium
• Temperature 12,000 - 20,000 C
• Velocity 300 m/s
• Titanium powder particles partially melt, and
  stick to target

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Plasma Spray
Powder Injector
Substrate
Coating
Gas in

-
Electrode
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Plasma Spray
Prosthesis
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Plasma Spray

• Ti alloy powder
• Ti alloy or CoCr substrate
• Sprayed in vacuum/inert gas chamber
• Substrate is NOT heated

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Biological Performance

• Material
• Cobalt Chrome vs. Titanium Alloy
• Pore size
• Primary stability
• Debris seal

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Fatigue Strength

• The plasma spray process enables the titanium
  alloy implant to retain 90 of its fatigue
  strength, as opposed to less than 50 for
  sintered or diffusion-bonded cementless devices.
  
• Bourne RB Rorabeck CH Burkart BC Kirk PG
• Clin Orthop R-R 1994 Jan - 29837-46

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Adhesion

• Removal of loose particles
• Tensile testing of coupons

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Removal of loose particles

• Low pressure ceramic bead blast
• High pressure water jet

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Coating strength

• Tensile strength
• Typical 442 kg/cm² /- 105
• gtgt Cancellous bone appr. 14 kg/cm²
• Shear strength
• Typical 475 kg/cm² /- 63
• Transcortical implants app. 155-175 kg/cm²
• Intramedullary implants app. 62-103 kg/cm²
  
• Anderson et al. Clinical Orthopaedics 1984
  

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Coupons are taken to confirm bonding strength
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Materials

• Porous coated titanium acetabular components
  demonstrated a three-fold greater frequency of
  bone ingrowth than similar cobalt alloy
  controls.
• Williams IR Surprenant VA Lund DR
• Orthop. Trans 19(2) 1995

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Primary Stability

• Our study demonstrates that micromovements
  between bone and implant inhibit bone ingrowth
  and lead to the development of a fibrous
  membrane.
• Soballe K Brockstedt-Rasmussen H Hansen ES
  Bunger C
• Acta Orthop Scand 63(2)128-40 1992

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Clinical Experience

• Radically differing stem designs show
• Low level of thigh pain / Excellent survival
• Common factor
• CIRCUMFERENTIALLY APPLIED
• PLASMA SPRAYED
• TITANIUM POROUS COATING

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Thigh Pain

• Rothman Taperloc 2
• Bourne Mallory-Head 3
• Mallory Mallory-Head 2
• Evans Bi-Metric 3
• Bourne PCA 23
• Haddad AML 30
• Kim H/G 28

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Mechanical Performance

• Fatigue Strength
• Adhesion

• Only slight reduction in strength of implant as
  opposed to BEAD or MESH sintering processed (75)
• Greater than strength of cancellous bone

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Biological Performance

• Material titanium for biocompatibility
• Pore size sized for ingrowth 100/1000 micron
• Primary stability scratch fit
• Debris seal closed pore - circumferential

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Porous Titanium Plasma Spray Coating
Circumferentially applied Pore size
100 - 1000 micron
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Thank you for your attention