Because of the various industrial and scientific interests, a proliferation of roughness parameters, possibly running into hundreds, has been developed to describe the different kinds of surface morphology with regard to specific functions, properties or applications. In spite of this of roughness parameters, there is still no complete comprehensive account for the relevance of all these parameters. Hence, the selection of a roughness parameter for describing and/or modelling a surface morphology is very often subjective. Thanks to a methodology based on the Computer-Based Bootstrap Method (CBBM), the experimental results of this study exhibit the major influence of the order parameter as far as the relationships between the surface morphology of Ti6Al4V substrates and the in vitro cell adhesion of human osteoblasts are concerned. The lower is the value of this roughness parameter that characterises the surface texture, the better is the cell adhesion. Moreover, the cell adhesion seems to be rather affected by the surface morphology than by the surface chemistry in the experimental conditions of our work.