FNK femoral component and FNK tibial component. a: FNK femoral component. (A) The anterior chamber is thin to decrease pressure on the patellofemoral joint. (B) The standard size (size M) component is 7-mm thick at both the distal and posterior condyles, which is thinner than those in other Western company systems. b: FNK tibial component. The FNK tibial component has a 4-point locking mechanism (black arrows), a wide cross-shaped keel to soften the stress in various directions, and is 3.5 mm at the thinnest part to allow retention of original bone.