OBJECTIVES: In recent years there has been an increase in interest surrounding the adaptation of traditional paper-based PRO measures to create ‘ePRO’ (electronic PRO) versions. Questionnaires in this format are intended to be administered to patients via a tablet or PDA device, website or other electronic media. In collaboration with Isis Outcomes, PharmaQuest Ltd. has managed a series of ePRO migration and translation studies. The aim of the study presented here was to produce versions of the Oxford Hip Score (OHS) and Oxford Knee Score (OKS) that can easily be completed by patients through electronic media, and that are conceptually equivalent to the original paper-based measures. METHODS: The adaptation process consisted of 3 main steps. Firstly a draft ePRO version was produced and discussed to resolve any formatting issues. The draft was then tested for conceptual equivalence with the paper-based measure via cognitive debriefing interviews with patients from the target population. Finally, a series of usability questions were used to assess the patients’ experience of completing the ePRO measure. RESULTS: Overall, no comprehension issues were reported during the cognitive debriefing step for these questionnaires, although the clarity of some instructions was questioned. The feedback from usability testing varied predominantly by age group, with older respondents generally reporting more difficulty in using the ePRO device. However, a large majority of respondents reported that the ePRO version was preferable to a paper questionnaire. CONCLUSIONS: Cognitive debriefing feedback confirmed that the ePRO versions presented here were conceptually equivalent to the paper questionnaires. The ePRO versions were generally well received by patients, although the usability testing highlighted the importance of clear instructions and intuitive software.