1997 年 46 巻 3 号 p. 657-661
We clinically evaluated the result of 41 knees in 28 OA patients treated by MG I with MG II total knee systems. MG I were used in 11 knees (MG I group) and MG II were used in 30 knees (MG II group). The mean post-operative JOA score was 80.9 points for MG I and 80.8 points for MG II. There were two cases with patella component failure in MG I group. We found tibial component subsidence in 9.0% of MG I group and in 3.3% of MG II group. Femoral and tibial component placement in the two groups was good. Patella component placement of MG II group was good but that of MG I group was not good according to measurement of the tilting angle and lateral shift. Patella ligament-tibial shaft angle (a) of MG I group was significantly greater than that of the MG II group. It was supposed that PF joint pressure of MG I group was higher than that of MG II group by calculating sin 1/2(a+knee flexion angle).
The reasons of patella component malalignment and PF joint high pressure were due to designs of femoral and patella components.