The availability of a validated subject-specific model of the knee joint would be extremely useful for the orthopaedic surgeon in evaluating the biomechanics of the joint of a patient, especially when suspecting an injury of one or more components. The aim of this paper was to describe a procedure designed and developed to validate a subject-specific model of the human knee. The proposed approach considers the use of clinical images to create a multi-body finite element model of a healthy knee. The same joint must undergo an experimental test aimed at collecting the data necessary to validate the model predictions. Therefore, the experimental set-up must be designed to monitor all the degrees of freedom of the joint, allowing the replication of the loading conditions in silico with a finite element (FE) model. At the moment, an animal model is used to verify the accuracy and repeatability of the developed procedure.