This paper focuses on the development and validation of a generic musculoskeletal model of an osseointegrated transfemoral amputee. The model has been developed using OpenSim with the final goal of obtaining a competent tool to study and better understand the biomechanics of osseointegrated transfemoral amputees. The model has been validated on the experimental data obtained on one osseointegrated transfemoral amputee during level ground walking.