For measurement of the contact pressures of the tibio-femoral joint,a fresh cadaveric knee specimen was studied.The femoral and tibial shafts were cut 10cm above and below the joint line respectively.The capsule,ligamem structures and patella were preserved intact until immediately prior to testing.Both of the tibial and femoral shafts were set in the holders respectively on a fixation device using gypsum.After drilling twelve small holes vertically at various points in the tibial plateaus,twelve pipes 1.5mm in diameter were inserted into the holes as far as 0.5 to 1.0mm depth of the cartilage from the bottom upward to avoid the stress concentration.The pipes were connected to both miniature transistor pressure transducer and Bourdon tube pressure gauges.The tibial component with the holder was set on the auto-alignment device.It allowed varus-valgus angulation,anteriorposterior motion and rotation of the tibia about its long axis enabling