The objective of this study is to evaluate the availability of the new type of knee brace with moving rotation axis as a normal knee. The motion of the new type of brace was created by a pair of circular and noncircular gears to roll back femoral condyle on tibial plateu. We structed the motion of normal knee by sagittal 4-bar linkage and calculated the slippage during knee flexion/extension on the fixed positions on both thigh and shank. The new brace and conventional one with fixed rotation axis were compared. As a result, in case of the best fixed positions, the slippage was 2 mm on thigh and 6 mm on shank for the new brace, and was 12 mm on thigh and 30 mm on shank for the conventional one. The new brace could decrease the slippage on the fixed positions.

Key words:Knee Brace, Slippage, Biological Motion, Deep Knee Flexion, Simulation