Client: MBA & Ingeniacity
R+D+i: Implementation of anti-friction microtextures by additive manufacturing in joint prostheses with metal-polyethylene friction pairs.
We have carried out this project in collaboration with MBA Surgical Empowerment to try to increase the life of the prostheses, thus reducing the number of surgeries throughout the patien’s life and the costs to the healthcare system.
The objective of this project is to design a geometric pattern in order to decrease friction and increase autolubrication efect; validate geometries by using simulation tools and mechanichal testing; materialize geometries by using aditive manufacturing technology (SLS) and validate the prostheses behavior.
Microtextures design and validation by using simulation and testing
The project was carried out in three stages. In the first one, the previous studies necessary to begin the project were carried out, with the objective of knowing the mechanisms of lubrication in synovial joints; the characteristics of synovial fluid as well as its rheology and the anatomy of the friction pair. Following the ISO 14242 standard, that indicates standardized tests to measure wear on hip prostheses, we define the conditions for both simulations and empirical tests.
An important stage was the fluidynamic simulation model obtaining that allows to simulate the behavior of the lubricant with each of the microtextures, as well as the process of deposition of polyethylene particles that are detached due to wear. Once this model was obtained, 11 geometries were studied from which the 4 that showed the best behavior were validated by testing.
These validation prototypes are manufactured using laser sintered additive technology in a powder bed. the material used is a Cr-Co allow.
The tests are disk-on-disk with the Stribeck curve and long-term test that allow the final characterization of the specimen.
The second stage of the project aims to validate the application of these microtextures to the morphology of the prosthesis and its validation through tests following the norm indicated above, for which it was necessary to design and ad-doc machine.
The final stage focuses on the study of the results and the technical-economic analysis of the application of microtesctures to the prostheses.