Osgood-Schlatter disease is generally caused by small injuries brought on by repeated overuse of the knee before it has completely finished growing. Because of this, the disorder is seen most often in young, physically active adolescents between the age of 10 and 15. Symptoms include pain and swelling at the front surface of the lower leg bone. Symptoms will become intensified with running, jumping, or climbing stairs. For more information on Osgood-Schlatter Disease, visit American Academy of Orthopaedic Surgeons.