Between 1968 and 1987 we carried out a total replacement arthroplasty on 22 hips which were either ankylosed or had previously undergone arthrodesis. The hips were revised because of pain due to pseudoarthrosis or malposition, pain in the other joints such as the lumbar spine, the ipsilateral knee or the contralateral hip, fractures about the hip, or professional disability. Significant functional and subjective improvement was obtained. The revised hips were painfree, stable and had an average range of flexion of 70 degrees. Pain in other joints was improved if their degenerative changes were moderate, but many required further procedures. Revision of a hip arthrodesis to a replacement arthroplasty is a worthwhile procedure in suitable cases.