Pain behind the knee can be caused by several conditions, including a Baker's cyst, arthritis, an injury to leg muscles, tendinitis, and even bone fractures. A visit to a doctor may be necessary to determine the exact cause or causes of pain behind the knee, especially if the pain is recurring or chronic. In many cases, pain behind the knee will go away on its own given enough rest, proper exercise and stretching, but more severe instances of knee pain may require surgery. This is not a common option, however, and it is reserved for degenerative conditions or especially traumatic injuries.
A strained or torn hamstring can lead to pain behind the knee. The hamstring is a long muscle that connects to tendons secured behind the knee, so when this muscle becomes injured, the pain may be felt anywhere along its length, including behind the knee. A hamstring strain occurs when the tiny fibers that make up the muscle begin to tear due to overstretching or undue stress on the muscle. A muscle tear or rupture occurs when the hamstring separates entirely from itself or the tendons. This is an extremely painful condition that may need to be repaired surgically, so if one experiences pain behind the knee as a result of a muscle rupture, he or she should seek medical attention immediately.
Arthritis can cause pain behind the knee as well as the sides and front of the knee. It is a degenerative condition in which the ligaments and cartilage of the knee begin to break down or wear out, leading to excess joint movement, inflammation, and other joint problems. There is no cure for arthritis, but pain management techniques can be used to alleviate discomfort, and regular exercise and stretching can help slow the degenerative process.
A Baker's cyst occurs when a bursa, or fluid-filled sac, in the knee becomes inflamed, leading to pain behind the knee. Such a cyst often occurs simultaneously with arthritis or cartilage damage that results from injury or other conditions. Treatment for such a cyst usually consists of the RICE treatment, or rest, ice, compression, and elevation. Most Baker's cysts heal on their own, but if they are chronic or are causing significant pain, a doctor may aspirate the cyst or prescribe anti-inflammatory medications. In rarer cases, the cyst may be addressed surgically, though this is usually reserved for cysts that are extremely limiting mobility or causing excessive pain.