BackgroundCognitive overload can impair learning, and different factors might affect cognitive load during simulation-based training. In this study, we investigate the role of failure in repeated practice of virtual reality (VR) simulation of hip fracture surgery on cognitive load (CL) estimated by secondary-task reaction time test and two questionnaires.MethodsThe VR simulation training program consisted of three competency levels of increasing complexity starting with the placement of a Kirschner wire in a fractured hip of one patient, adding clinical variability at the intermediate level, and performing the entire dynamic hip screw procedure in 24 different patients at the highest level. Thirteen consecutive passed simulations were required to advance to the next level. Performance was measured as passing/failing a procedure and the number of failed procedures within the latest three and five simulations. CL was measured objectively using reaction time testing during simulation and subjectively using the NASA-TLX and PAAS questionnaires. The study was carried out at a simulation center from November 2016 to March 2019. Forty-two first-year orthopedic surgery residents from the Central Denmark Region and the North Denmark Region participated in the training program.ResultsA failing performance in the simulated procedure was associated with a higher CL than passing a procedure. The subjective CL estimates were affected by the number of failures during last three and five procedures with a higher number of failures being associated with a higher CL. In contrast, relative reaction time estimates of CL were not affected by previous failures.ConclusionsQuestionnaires for estimation of CL seem to be affected by participant frustration after failure—a meta-cognitive “carry-over” effect. This could be a general limitation of the subjective questionnaire approach to estimate CL. Reducing CL through instructional design and handling of participant frustration might improve the learning outcome of simulation training programs.