Porous coatings have been used for many years for the cementless fixation of orthopedic implants. These surfaces were proposed in the late 60’s as a solution to problems encountered with methacrylate-based bone cement used for implant fixation. Since the mid-1970s, many studies provided evidences of the efficiency of cementless fixation and the use of porous coated implants expanded worldwide since then. In these procedures, the implants are press fitted into a bone cavity. These porous coating have a rough surfaces which provide friction with bone leading to the initial stability of the implants. The coating allows the bone to growth into the porosity which secures the long term fixation of the implant. One of the most common processes to produce porous titanium coating is vacuum plasma spray (VPS). In this process, vacuum is used to minimise the reaction of the melted titanium particles with oxygen, the ignition of the particles during the deposition, as well as the contamination of the coating.
A new process (shock wave induce spraying) has been recently adapted to produce porous coating at much lower temperature than those used during thermal spray. During the deposition, the particles remain solid and are much less reactive than in the molten state. Consequently, the deposition can be done in air, thus simplifying significantly the process and means to improve productivity. The process allows the deposition of coatings with excellent roughness and porosities ranging from 30 to 40%, similar to the range obtained using VPS. Shear (> 32 MPa) and tensile (> 69 MPa) strength higher than the minimal values required by the ASTM standards and the requirements of regulatory agencies (FDA, EU marking) can be obtained. This presentation reviews the advantages of the approach and presents the structure and properties of coating produced with this process.