A revolutionary history

1
A revolutionary history

• David Kelman, P.E.
• Group Director Hip Development
• Smith Nephew

2
Changing Environment

• THA patients decreasing in average age
• Increasing patient activity levels
• Functional lifetime demands of young active
  patients is 10 fold greater, Fisher et al
• Increasing Obesity
• Greater risk of dislocation, Kim et al
• Changing protocols
• Surgical technique
• Reduced LOS and quicker return to function

3
Previous Acetabular Designs

• Shells designs have been limited by the locking
  system either polyethylene or ceramic
• Limited head size
• Limited ROM
• Little intra-operative bearing flexibility
• Ingrowth Surfaces
• Beaded coating provided 3-dimensional porosity
  but limited roughness
• Need for multiple styles of adjunct fixation
• Screws
• Spikes
• Fins

4
Optimization of Shell/Liner Design

• Multiple locking mechanisms design specifically
  for each bearing system
• Polyethylene,
• minimum 5 mm of thickness,
• microstable locking method
• Supported polyethylene
• Metal/Metal,
• utilizes proven BHR bearing technology
• Run in and steady wear are not statically
  different, Kamali et al
• Enhanced insertion and extraction methodology
• Ceramic/Ceramic,
• proven ceramic technology,
• 68 increased burst strength
• Elimination of rim chipping
• Enhanced insertion and extraction methodology

5
Bearing Options for the Changing Environment

• High performance bearings
• Significant reduction in wear volume
• Maximize head size per acetabular shell diameter
• Increased ROM
• Increased stability

6
Enhanced Acetabular Fixation

• Objectives for enhanced fixation
• Maintain the performance characteristics of
  porous beaded coatings
• Enhance initial stability of the acetabular shell
• Potential to reduce need of adjunct fixation
• No increase in coating thickness
• 3 dimensional coating
• Increased thickness would negatively impact
  femoral head/shell relationship

7
Comparison of Porous Coatings

• Optimum pore size 50-400m to obtain fixation as
  quickly as possible, Bobyn et al
• Stiktite has greater volume porosity for
  biological fixation
• Stiktite has a high coefficient of friction,
  Hiener et al

Trademark of Smith Nephew. Reg. US Pat. TM
Off.
8
Stiktite in a Load Bearing Animal Model

• Load bearing ovine model, Fennwick et al
• Compared spherical beaded coating to Stiktite
  coating
• Superior initial stability was confirmed, Moss et
  al

9
RSA Clinical Results of Stiktite Coating

• Stiktite demonstrated
• 64 decreased medial translation
• 81.1 decrease in proximal translation
• No difference in anterior to posterior
  translation
• Stiktite had demonstrated greater initial
  stability
• Bourne, et al

10
R3 Provides a Method to Re-Think Your Options

• Uncompromised bearing options
• XLPE and Oxinium,
• Ceramic/Ceramic,
• Metal on Metal
• Stiktite porous coating
• Proven enhanced initial fixation

Trademark of Smith Nephew. Reg. US Pat. TM
Off.
11
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