A new study evaluated two additive manufacturing methods for producing either fine or coarse textured titanium implants and compared the strength of bone integration, interlocking, and torque in rats given one or both types of the implants in the distal femurs. The ability to apply this technology to customize implant surface textures and geometries to match the specific anatomy of human amputees is increasingly important as the trend in prosthetic devices moves toward transcutaneous osseointegrated implants rather than socket-cup fitting devices, according to an article published in 3D Printing and Additive Manufacturing, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the 3D Printing and Additive Manufacturing website until July 20, 2017.
The article entitled “Osseointegration of Coarse and Fine Textured Implants Manufactured by Electron Beam Melting and Direct Metal Laser Sintering” is coauthored by David Ruppert, Ola Harrysson, PhD, Denis Marcellin-Little, DEDV, Sam Abumoussa, Laurence Dahners, MD, and Paul Weinhold, PhD, University of North Carolina (UNC), UNC School of Medicine, Chapel Hill; North Carolina State University (NCSU) and NCSU College of Veterinary Medicine, Raleigh.
Electron beam melting produces a coarse textured implant, whereas direct metal laser sintering can create either a fine or coarse textured surface. The researchers reported substantial differences between the two fine and coarse implants based on mechanical testing to assess osseointegration and torsional properties, and measures of bone volume fraction and bone-implant contact.
The study concluded that as the trend in amputee prosthetic devices moves toward transcutaneous osseointegrated implants instead of socket-cup fitting prosthetic devices, it is important to show that additive manufacturing can provide a means of producing well-fitted osseointegrated implants that can be easily customized. AM implants provide a means to produce customized geometries to match patient-specific anatomy as well as customized surface textures for optimizing implant stability.
This research indicated that coarse textured surfaces can provide a higher interface strength for titanium alloy implants than fine textured surfaces. Future studies should be conducted to determine the optimal roughness for implant fixation. Another question left unanswered is whether there is an optimum surface roughness interaction between cortical bone and an implant compared with trabecular bone and an implant.
3D Printing and Additive Manufacturing is the only peer-reviewed journal focused on the rapidly moving field of 3D printing and related technologies. Led by Editor-in-Chief Skylar Tibbits Director, Self-Assembly Lab, MIT, and Founder & Principal, SJET LLC., the Journal explores emerging challenges and opportunities ranging from new developments of processes and materials, to new simulation and design tools, and informative applications and case studies. Published quarterly online with open access options and in print, the Journal spans a broad array of disciplines to address the challenges and discover new breakthroughs and trends within this groundbreaking technology. Tables of content and a sample issue may be viewed on the 3D Printing and Additive Manufacturing website.