Periprosthetic acetabular fractures can lead to very serious consequences and therefore have an impact on people's quality of life. Their incidence has increased significantly in recent years, due to epidemiological factors such as increased life expectancy and changes in age distribution. Periprosthetic acetabular defects are classified using the Paprosky classification, which identifies type IV defects as the most severe, with pelvic discontinuity and significant bone loss. In the case of such fractures, typical acetabular prostheses fail to stabilise the acetabulum and thus to lead to fracture healing. It is therefore necessary to develop custom-made prostheses. The aim of this study is to provide an analysis of the post-operative status of a patient to whom a custom-made revision prosthesis was implanted following a periprosthetic type IV fracture of the acetabulum according to Paprosky.