In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred hydrophilic functional groups onto the surface, which lead to enhanced bioactivity of UHMWPE without affecting the biocompatibility of the polymer. The latter was checked by increased adhesion of fibroblast cells to the polymer. The effects of the He/2% O2 DBD plasma was compared for the first time to a rotating blown arc atmospheric pressure plasma jet (r-APPJ) in air. The results show a better functionalization as well as stability of the surface properties of the films treated with the DBD. The surface modified UHMWPE once immersed in a Simulated Body Fluid induced the formation of nucleus of hydroxyapatite (calcium phosphate) leading to the growth of a thick apatite coating which was followed up to 14 days, which can be expected to be highly bioactive. Surface characterization techniques also showed different chemical moieties in the case of the two different atmospheric discharges. DBD discharge in He/2% O2, leading to more stable polar functions grafted to a crosslinked polymer surface, proved to be more bioactive than UHMWPE treated by a r-APPJ in air. The latter treatment lead to grafting of less oxygen containing groups to the surface as well as to LMWOM created on r-APPJ treated UHMWPE which are unstable in aqueous media used both in SBF and fibroblasts in DMEM.