RADIOLUCENCY AT THE BONE-CEMENT INTERFACE IN TOTAL KNEE REPLACEMENT -THE EFFECTS OF BONE-SURFACE PREPARATION AND CEMENT TECHNIQUE

Three hundred and sixty-three knees (221 patients) that had been treat ed with total arthroplasty between 1975 and 1985 were divided into thr ee groups on the basis of the preparation of the surface of the bone a nd the technique of the cement application. Group 1 (155 knees) was tr eated with irrigation of the bone surfaces with a syringe and manual p acking of the bone cement. Group 2 (sixty-one knees) had high-volume, high-pressure lavage of the bone surfaces and manual packing of the ce ment. Group 3 (147 knees) had high-volume, high-pressure lavage and pr essure injection of low-viscosity methylmethacrylate cement. Radioluce ncy was evaluated at each followup interval, and the findings were sub jected to chi-square analysis and Kaplan-Meier survival analysis. Chi- square analysis of the data at one and three years indicated a signifi cantly higher frequency of lines at the bone-cement interface in the f emur and tibia in Group-1 knees compared with those in Groups 2 and 3. The survival curves showed increasing rates of radiolucency adjacent to the tibial components of the knees that had been prepared with lava ge that was not high-volume and high-pressure and that had been prepar ed with finger-packing of cement (Group 1). This may partially explain the clinical problem of loosening of tibial components despite accept able alignment. This study demonstrates that proper preparation of the cancellous bone and pressurization of the cement reduce the initial o ccurrence of a radiolucent line, which may have a positive effect on t he ultimate failure of at least the tibial component.