The advent of state-of-the-art additive manufacturing (AM) processes has facilitated the manufacturing of complex orthopedic metallic implants such as femoral stems with porous portions based on lattice structures. These struts often have rough and not smooth textured surfaces, for which the irregularities may influence mechanical properties. To make robust predictions about the behavior of this kind of system, the variability of the mechanical properties and its impact on the stem stiffness must be considered in the processes of modeling and design of porous femoral stems. Also, to improve the credibility of computational models used for hip implant analysis, which involves numerous uncertainties, there is a need for rigorous uncertainty quantification (UQ) framework for proper model assessment following a credible-modeling standard. In this sense, this work proposes a UQ framework for analyzing a femoral stem implant model, to clarify how uncertainties impact the key properties of a porous femoral stem. In this study, uncertainties in the strut thickness, pore size, Young modulus, and external forcing are considered. A robust UQ framework is proposed and validated using experimental results available from literature, following the guidelines set in an AMSE standard. This study has a contribution in assessing the effect of input parameter uncertainties on femoral stem stiffness and the surface-to-volume ratio of porous stems.