[Surface arthroplasty of the knee by marmor prosthesis. Study of 35 unicompartimental prosthesis seen with a follow-up of 1 to 5 years (author's transl)].

The Marmor prosthesis may be used for a surface arthroplasty of the knee by means of a system of unicompartmental modules including 4 sizes of condylar ramps and 6 thicknesses of tibial plateaux in two widths. It is thus possible to treat one or both compartments and correct any axial deviation. The operative technique must be careful and accurate with regard to the positioning of the prostheses and the choice of thickness of the plateau to be inserted. Preoperative radiological assessment must be very precise, and include in particular films with monopodal weight bearing and in forced position in order to study the joint surfaces and predict the correction which must be applied. Fifty operations have been performed (in 37 cases for osteoarthrosis), but the essential aim of the present study is to report the results of 35 unicompartmental prostheses with a follow-up of 1 to 5 years (mean : 2 years and 2 months). Thirty results were assessed as good or very good. The most spectacular features were freedom from pain and the rapidity with which the results were obtained. They would seem to be clinically stable. Nevertheless, the development of 3 deteriorations of the tibial plateau after Marmor would appear to contraindicate the use of 6 mm thickness plateaux. In contrast to widespread opinion, the remaining compartment does not degenerate, so long as it was normal preoperatively and there has not been any hypercorrection of the deviation after unicompartimental arthroplasty. Nevertheless, the latter has its limits and whilst it may play a role in the treatment of certain cases of osteoarthrosis of the knee, it cannot replace either tibial osteotomy for correction of the axis or bicompartimental prostheses or total prostheses anchored in the diaphysis, which also have their indications.