Osteolysis around Screw in Cementless Total Knee Replacement

Bae, Dae Kyung; Chung, Shun Wook; Lee, Chong Won; Yang, Hyoung Seop

Abstract

Screw fixation of the tibial component offers advantages in initial fixation in cementless total knee replacement. But the high incidence of screw related osteolysis was reported. The purpose of this study is to evaluate clinical results of cementless total knee replacement and to look for radiographic changes at the screw-bone interface. From January 1988 to December 1991, primary cementless total knee replacements with Miller Galante I (Zimmer, Warsaw. IN) were performed to 53 knees at Kyung Hee university hospital. Among them, 21 cases which could be followed-up for more than 4 years were studied retrospectively about the clinical and radiographic results. The mean follow-up period was 5.5 years(ranged from 4.2 years to 8 years). At the last follow-up period, knee scores of Hospital for Special Surgery were improved from mean 56 points to 90 points and the range of motion from 72 degrees to 110 degrees. In the last follow-up radiographs, osteolysis around screw was classified as linear(type I ), cystic(type II ) and cavitary(type III ) according to the width of the lucency around screws. Among 21 cases, radiographic findings of osteolysis around screw were detected in 10 cases but not in 11 cases. But clinical results were similar between these two groups. Among the total 84 screws(4 screws in each case), 21 screws(25%) showed screw related osteolysis typed as I in 13 screws(15.4%), II in 4 screws(4.8%) and III in 4 screws(4.8%). Among the 13 cases that followed-up more than 6 years, 20 screws(38%) showed screw related osteolysis typed as in 11 screws(21.2%), I in 5 screws(9.6%) and II in 4 screws(7.8%). The most frequently involved site of screw was anteromedial(33.3%). In conclusion, after mean 5.5 year follow-up, the clinical results were satisfactory but the development of osteolysis around screw might be an indicator of the implant failure.