This study presents an improvement of an existing tribocorrosion model developed for passive CoCrMo alloys. This model is based on an empirical formalism established by Duncan Dowson in his pioneering works on the relation between wear and elasto-hydrodynamic lubrication. The improvement consists in introducing surface topography features allowing for a mechanistic relation between lubrication and wear. The effective normal force accounting for the plastic deformation of passive metals during lubricated tribocorrosion was described through the real contact area, which in turn was related to the worn surface topography (roughness) and the elasto-hydrodynamic film thickness. The modified model was applied to results from dedicated tribocorrosion experiments obtained by varying the lubricant viscosity and the contacting surface roughness. Good correlations were found between the mechanical and chemical wear rates and corresponding variables, which validated the model. Further development of the model should include boundary film effects, third bodies build-up and time dependent evolution of the worn surface.