what is the cause of knee pain
Several other things can also cause knee pain, such as: 1  Bursitis: A bursa is a sac that holds a small amount of fluid thatâs under the skin above your joint. It helps prevent friction when the joint moves. 2  Dislocated kneecap: This means that your kneecap slides out of position, causing knee pain and swelling.
Arthritis of the Knee Arthritis of the Knee Arthritis is a common cause of severe knee pain and disability. Unfortunately, arthritis is a chronic degenerative condition that can eventually require surgery. The three most common types of arthritis are rheumatoid arthritis, post-traumatic arthritis, and osteoarthritis.
It's also possible that the problem is actually referred pain, when you have an injury elsewhere, and it's referred to the knee. Pain in the lower back or spine, or another part of the knee, can travel through nerves and be felt behind the knee. Less Common Causes of Behind-Knee Pain. -Popliteus tendonitis is an injury to or inflammation of a small muscle at the back of the knee called the popliteus. -Gastrocnemius tendonitis is an inflammation of a calf muscle tendon that originates at the back of the knee.