Protective hard films on soft inorganic/organic substrates are appealing for several technological applications like solar cells, organic electronics, fuel cells, etc. The main concern is still related to the bad quality of the interface and to the weak mechanical properties of the film as a consequence of the low working temperatures mandatory to prevent substrate softening/melting. Our research activity at Rizzoli Orthopaedic Institute is mainly directed toward the deposition of functional ceramic thin films to improve the mechanical properties (and thus the clinical performances) of the load-bearing plastic component of the prosthetic implant. To this aim, we use a novel sputter-based electron deposition technique named Pulsed Plasma Deposition (PPD) able to provide nanostructured ceramic thin films highly adhered to the plastic substrate and with optimum mechanical performances even if working at room temperature and using very-soft substrates.