Double plasma sprayed coating of porous Titanium and Hydroxyapatite

1. Effective press-fit thanks to friction due to high surface roughness.

2. Fast osseointegration n the short term.

3. Stable anchorage between bone and porous titanium coating in the long term.

HaX-Pore® is a double plasma sprayed coating of porous titanium and Hydroxyapatite.

The coating HaX-Pore® is sed on Permedica prosthetic devices intended for press-fit implantation for which direct anchoring with bone occurs through osseointegration. .

The HaX-Pore® coating has been developed to optimize prosthetic osseointegration.

The rationale of HaX-Pore® coating is to use a double coating consisting of:

First layer

Pure porous titanium coating, applied by plasma spray in air (APS), deposited with a high thickness (300 µm / 500 µm) in order to obtain a high degree of roughness and porosity.

This surface morphology with an open porosity three-dimensional structure increases the surface in contact with the bone, ensures adequate bone ingrowth and increases friction with the bone, improving resistance to shear stresses between the bone and the prosthesis.

Second layer

HA coating, always applied by plasma spray in air (APS), deposited with reduced thickness (50 µm) in order to maintain, or slightly reduce, the roughness and surface porosity of the titanium coating.

The outer layer of HA serves as a bioactive surface to increase bone ongrowth.

The HA acts in fact only as an osteoconductive means to accelerate and increase the osseointegration of the prosthesis, without providing any mechanical support. Once the HA layer is reabsorbed, the long-term mechanical anchoring of the prosthesis is ensured by direct contact between the bone and the porous titanium coating.

APS Coating

Before carrying out the APS coating process, the surface to be coated is blasted with an abrasive consisting of pure alumina (corundum) until a surface roughness is obtained such as to ensure mechanical adhesion (resistance to shear and tensile stress) of the coating to the substrate, exceeding certain requirements set by the FDA regulations and guides.
The thin layer of HA above the thicker layer of porous titanium, both deposited by plasma spray, determine a high porosity and roughness of the coating, thus allowing a high mechanical bond (resistance to cutting and traction) both at the coating interface / bone than at the coating / substrate interface.