Your knees are a critical piece of machinery. For runners, the amount of stress continually placed on this largest joint in the body can lead to injury. Pain in the back of the knee can mean a host of possible problems. Your ability to identify the source of injury quickly can mean a faster return to training through more timely treatment.
Baker's Cyst
A common cause of pain in the back of the knee, Baker's cyst often affects runners and tennis players. Caused by an excessive build-up of synovial fluid due to inflammation or knee joint injury, symptoms include localized pain at the back of the knee, rigidity of the knee joint and swelling that sometimes extends to the leg. Sometimes, however, no symptoms appear. In some cases, the cyst may burst and send fluid into the calf region, causing more pain and swelling, as well as a feeling of water dripping down the leg. You should see a doctor and expect an MRI or ultrasound to verify the injury. Treatment may involve exercising less, medication to reduce swelling, fluid drainage and physical therapy.
Meniscal Injury
The meniscus is composed of two pieces of cartilage that work to alleviate friction between the upper and lower leg. Injury to this cartilage often results when the knee of the weight-bearing leg is twisted. Osteoarthritis also can lead to a meniscus injury. Symptoms may include a popping sound or sensation at the point of injury, pain when walking or squatting, swelling and rigidity. Visit your doctor to determine the extent of the injury and an X-ray or MRI may be necessary. Treatment may involve surgery but usually starts with greatly reduced activity, icing the affected area, medication, physical therapy and shoe inserts.
Popliteus Injury
The popliteus is a muscle that runs diagonally across the back of the knee and is responsible for knee rotation and stability. This muscle is especially important during downhill running. Injury to this muscle often results in pain at the back of the knee and is commonly caused by overuse or running on poor surfaces or improper running mechanics. Symptoms include an inability to straighten the leg and pain along the back of the knee. Treatment often involves massage, ice, anti-imflammatory medication, gentle stretching and rest.
