Multifunctional hydroxyapatite and hopeite coatings on SS254 by laser rapid manufacturing for improved osseointegration and antibacterial character: A comparative study

Orthopaedic metallic implant’s long-term success strongly depends upon the two main factors: osseointegration and antibacterial character. Bioceramic (hydroxyapatite and hopeite) coatings have been proven effective for getting strong osseointegration and antibacterial character. However, deterioration of bioceramic coatings during the implantation period can adversely affect its overall biological performance. To conquer this issue, this research work recommends an innovative process route of laser rapid manufacturing for depositing bioceramic (hydroxyapatite and hopeite) coatings with metallurgical bonding. Microstructure, phase composition, antibacterial efficacy and bioactivity were evaluated using scanning electron microscopy, X-ray diffraction, fluorescence-activated cell sorting technique and simulated body fluid immersion test. The promising results obtained from these characterizations and testing establish the new process route laser rapid manufacturing as an effective alternative to deposit multifunctional bioceramic (hydroxyapatite and hopeite) coatings on metallic prosthetic–orthopaedic implants.

Characterization of bone ingrowth and interface mechanics of a new porous 3D printed biomaterial

Aims The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. Materials and Methods A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA). Results Substantial bone ingrowth was observed in all LRM implants, with and without HA, at both time periods. Bone ingrowth increased from 42% to 52% at four weeks, to 60% to 65% at 12 weeks. Mechanical tests indicated a minimum shear fixation strength of 20 MPa to 24 MPa at four weeks, and 34 MPa to 40 MPa at 12 weeks. There was no significant difference in the amount of bone ingrowth or in the shear strength between the three implant types at either time period. Conclusion At four and 12 weeks, the 3D printed porous implants exhibited consistent bone ingrowth and high mechanical shear strength. Based on the results of this study, we confirmed the suitability of this novel new additive manufacturing porous material for biological fixation by bone ingrowth. Cite this article: Bone Joint J 2019;101-B(6 Supple B):62–67.