About Knee Sprains and Strains

Knee Sprains and Strains

Your kneecap (patella) is a thick, round bone that covers and protects the front portion of your knee joint. It moves along a groove in your thighbone (femur) as part of the patellofemoral joint. A layer of cartilage surrounds the underside of your kneecap. This layer protects it from grinding against your femur.

When this cartilage softens and breaks down, it can cause knee pain. This is partly due to repetitive stress. The stress irritates the lining of the joint, and this causes pain in the underlying bone.

Knee pain is very common, especially in highly active people who put a lot of pressure on their knees, like runners. It affects women more often than men.


This type of knee pain is characterized by a dull, aching pain in the front of the knee in the area under and around the kneecap. This pain may start quickly or slowly. Your pain might be worse when you squat, run, or sit for a long time. You might also sometimes feel like your knee is giving out. You might have symptoms in one or both of your knees.

When to Call Your Doctor

If your symptoms do not start to improve after several weeks of treatment, see your doctor. You may have a different kind of problem with your knee.