We present the outcome of a mould arthroplasty implanted for a congenital hip dysplasia in 1955 to revise a previous cup arthroplasty. This type of prosthesis, which has been developed on the basis of the concept of Smith-Peterson, by Prof. Marino-Zuco in Rome in the early 1940s, showed excellent results and was widely used until the advent of Charnley low-friction arthroplasty.