Summary The use of diagnostic technologies is imperative in today’s healthcare setting, aiding accurate diagnosis and correct treatment. This paper critically reviews the use of X-rays in assessing the need for a total knee replacement, by the confirmation of a diagnosis of degenerative joint disease. It provides a comprehensive potted history of the use of X-rays, from the discovery by Wilhelm Conrad Röntgen in 1895 through to the development of the technology by the military to the present day usage of computed radiography. By way of a case study this paper explores issues of patient safety and preparation considering professional and legal implications of consent and a student’s perspective of communication difficulties experienced in gaining this.