what causes the back side of the knee to swell
Dislocated kneecap: The kneecap slides out of position, causing knee pain and swelling. IT (iliotibial) band syndrome: The iliotibial (IT) band is a piece of tough tissue that runs from your hip down to the outer part of your knee. When you overdo activity, it can become inflamed over time. That causes pain on the outer side of the knee and is common in runners when going downhill. Loose cartilage: Sometimes, a knee injury can break loose cartilage. These pieces can get stuck in the joint, which causes pain and swelling.