Osgood-Schlatter disease is a common cause of knee pain in growing adolescents. It involves inflammation in the area just below the kneecap where the tendon attaches to the shinbone. It most commonly occurs during rapid growth spurts when bones, muscles, tendons, and other structures are changing rapidly. In most cases, simple treatment, such as rest, ice, stretching, and over-the-counter medication will be sufficient to treat the issue. However, a doctor will likely order an x-ray and potentially other imaging to confirm the diagnosis and rule out any other problems.