Femur : the medial condyle is larger and it projects further than does the lat condyle.
The relative tibiofemoral incongruence is improved by the addition of medial and lateral menisci, which act to convert the convex tibial plateau into concavities for the femoral condyles.
If the femoral condyles sat directly on the relatively flat tibial plateau, there would be a small contact area between the bony surfaces.
The anterior cruciate ligament may also be considered to consist of two separate bundles that wrap around each other as the knee flexes.