The menisci are now recognised to be integral parts of the knee and not the vestigial and dispensable remains of evolution as once thought.
Because the meniscus was thus thought to be a trivial structure, tears in the meniscus often meant that the surgeon simply cut away the torn part or removed the meniscus altogether. But we now know that the meniscus is a very significant structure within the knee.
This page demonstrates the bones of the knee - femur, tibia, and patella. The shock-absorbing menisci fill the gap between the rounded ends of the femur bone and the flattened upper surface of the tibia bone. The cruciate ligaments act as a 'stay' to allow movement of the femur and tibia, without the movement being excessive.