The rationale of cementless revision of cemented arthroplasty failures.

Patients with failed cemented total hip replacements develop minor to massive bone loss. In nearly all cases, the quality of the endosteal surface has been converted to a sclerotic tube. Because of the bone loss and the change in character of the remaining bone stock with which to form an interface with polymethylmethacrylate (PMMA), the microinterlock necessary for long-term interface stability cannot be achieved. Moreover, the first failure leads to the production of cement particles that incite a histiocytic osteolytic response. The difficulty in achieving interfacial stability in the revision setting is borne out in the published clinical results of cemented revision total hip arthroplasties showing failure rates ranging from 17% to 60.3%. Porous-surfaced prostheses have been introduced to permit biologic fixation as an alternative to cement fixation of each implant component. The good midterm clinical results and the lack of catastrophic bone loss when failure does occur have given impetus to the application of this technology to the revision situation. The preliminary clinical experience with cementless revision arthroplasty has yielded favorable results. The authors have fully developed the rationale against the use of PMMA in revision total hip replacements and for the cementless approach with porous-surfaced metal prostheses and bone grafts. The latter appear as a viable approach to a growing clinical problem.