Excessive wear and destruction of cartilage leads to loss of its cushion effect. As a result bone gets exposed in the
joint area causing damage to other structures in the knee
joint. This causes arthritis and its symptoms.
The undersurface of the knee cap (patella) is also covered
with such a cartilage. Loss of this cartilage here also leads
to symptoms of arthritis under the knee cap.
Various Stages of Arthritis
Wear can be incomplete, in which case the cartilage is still
present, but thin and irregular. X-rays demonstrate a narrowing of the space between the bones. The wear can
be complete, in which case cartilage has essentially
disappeared. We are now dealing with a “bone on bone”
situation, i.e. bone rubs against bone. This is quite
painful. On x-ray, the space has essentially disappeared
between the bones, and the bone itself may start to wear
The arthritis can lead to wear and tear of the soft
meniscus which is present between the bone. The arthritis
is often accompanied by bone spurs (osteophytes), which
are quite apparent on x-rays.