Osteoarthritis and Your Knee

Healthy Knee

The bones in your knee joint work like a hinge. They are covered by cartilageCartilage
A usually translucent somewhat elastic tissue that composes most of the skeleton to keep them from rubbing together.

The space between the bones is filled with a thick, slippery liquid (joint fluidJoint Fluid
A transparent, lubricating fluid secreted by a membrane of an articulation (place of union between two or more joints) or bursa (a saclike body cavity between a tendon and bone)). Joint fluid acts like a shock absorber to cushion and lubricate your knee while walking, working or playing sports.

Mild to Moderate Osteoarthritis of the Knee

Your body’s joint fluid becomes less healthy and the cartilage begins to break down, leading to irritation and discomfort in the knee. Without healthy joint fluid, your knees become sore and swollen.

Progression to Severe Osteoarthritis of the Knee

As time passes, larger pieces of bone and cartilage can break off and float in the joint, causing pain and swelling. Large areas of cartilage can be completely worn away. Growths (bone spursSpurs
A sharp, bony outgrowth located at the end of a bone) may appear on the bone, leading to more irritation. In severe cases of osteoarthritis, your cartilage can be completely worn away. Your bones may actually rub together, causing pain and swelling.