Continuous Bone Fixation Interface

The Auxano™ surface morphology addresses bone ingrowth and the implant/tissue interface in a more comprehensive way than competing technologies.  Utilizing a macro surface topology that enables continuous bony growth with superior vascularization combined with an immediate reduction in micromotion, Auxano™ has the potential to enable rapid and robust interdigitated fixation.  Design flexibility in surface features allows for optimally matching the surface to anatomical differences for a variety of orthopedic applications.  Overlaying the macroscale surface geometry with micro and nano features can further encourage optimal cellular response.  Initial animal studies have validated Auxano’s ingrowth potential in common test methodologies.  AMO will continue to drive the scientific understanding of this technology forward and anticipates a variety of clinical applications in the near future.

Hard Tissue Development Study

An in vivo sheep study was performed at the University of New South Wales (W.R. Walsh, Ph.D.) utilizing 6mm diameter titanium dowel implants.  There were three different pillared patterns on the dowels along with a grit-blasted control.  A total of 80 specimens were placed in different cancellous and cortical sites of eight sheep.  The study was terminated at four and 12 week time points.


Mechanical Testing

  • Specimens had significantly stronger mechanical fixation (6-7.5X) than grit blasted controls.
  • No pillar deformation or fracture was observed during mechanical testing.
  • There was no significant difference in mechanical fixable strength between pillar variations.

Histomorphometry

Histomorphometry data was collected to determine the percent of bone ingrowth visible into the pillar region.  The average percent bone ingrowth improved significantly from 40% at four weeks to over 80% at the 12 week time point.


Histology

  • Bone formation progressed from four to 12 weeks resulting in intimate bony contact at the implant surface.
  • No inflammatory response was evident and little to no fibrous tissue at the implant interface was observed.
  • Extensive vascularity was visible within new bone tissue throughout Auxano™ morphology.

Distinguishing Features

Continuous Bony Interface

The Auxano™ surface enabled a seamless and continuous transition from bone to implant through novel surface features developed exclusively by AMO. Bone ingrowth, the “continous phase,” is beneficial for tissue integration and structural integrity. The positive features of the Auxano™ morphology “discontinuous phase” allows the growing bone to interdigitate within and around the implant surface. Contrast that to other “add on” surfaces which require bone to grow into negative features, such as irregular or discontinuous voids.

Auxano™ morphology allows bone volumes of 75-85% throughout the transition region.

Primary and Secondary Fixation

The Auxano™ morphology provides a high friction interface for initial implant stability.  This initial motion control supplies the strain limited environment necessary for new bone formation.

The Auxano™ morphology allows for mature bone formation throughout the inter-pillar region with intimate contact to the implant surface.

Bone Integration

Within Auxano™ topography, stress is transferred from the implant to the bone in the pillared transition region.  With incremental bone ingrowth, there is a gradual load transfer and no apparent stress shielding.

Surface Integral to the Implant

The Auxano™ morphology is formed from the substrate material of the implant which provides an innate shear strength.  It is not a coasting or add-on process that may delaminate.

Customizable Morphology

Auxano™ can be customized to meet local loading patterns or bone types.  The Auxano™ surface is also compatible with other surface technologies, such as HA coating nano surface modification.

** INVESTIGATIONAL – NOT AVAILABLE FOR COMMERCIAL SALE. ALL IMAGES ARE REPRESENTATIVE OF POSSIBLE APPLICATIONS OF THE AUXANO™ TECHNOLOGY AND NOT ACTUAL DEVICES OFFERED FOR SALE OR CLINICAL USE. THIS TECHNOLOGY IS NOT CLEARED BY THE FDA FOR DISTRIBUTION IN THE UNITED STATES.