Artroplastica totale di ginocchio: selezione, analisi e valutazione di parametri agenti all’interfaccia cemento - substrato metallico nella componente tibiale = Total knee arthroplasty: selection, analysis and evaluation of agent parameters at the cement interface - metallic substrate in tibial tray

urpose Loosening of the tibial component after total knee arthroplasty is a common indicator of revision. The aim of this thesis is to select and evaluate the parameters that can damage or reinforce the primary interaction between acrylic cement - tibial tray. Methods A prior analysis of the state of the art has allowed us to identify the most in¿uential parameters in the bond between cement and metal. The de¿nition of the parameters was based on the variables that modify the properties and surface conformation of the materials in use. Some parameters required preliminary tests to be quanti¿ed. The in¿uence of the parameters was evaluated by testing the interface of interest with a tensile test. The bone - cement - prosthesis system was reproduced using a CoCrMo metal specimen and a support in PA 2200. The two components were cemented following a protocol to make the tests reproducible. The system is examined with a pull-out test setting a traction speed of 0.005mm/s. To evaluate the in¿uence of the parameter, each test was compared with a test called Standard. Results The standard tests reported a force value of 1495 N. H2O contamination of the metal-cement interface reduced the interface strength to pratically zero: -93% (p = 0.001). Early use of cement increases by 125% the initial interaction between the components (p = 0.0008), while the presence of a pocket on the metal surface leads to an increase in strength of 92% (p = 0.005). Conclusion The present study provided a reliable and consistent evaluation of the parameters already analyzed in the current state of the art. The choice to test new parameters allowed us to de¿ne and quantify the deleterious e¿ect of the water present at cement-metal interface.