Osgood Schlatter disease is a very common cause of knee pain in young athletes, affecting as many as one in five adolescents. It is characterized by pain and swelling just below the knee over the tibia (more commonly known as the shin bone). It can affect one or both knees. Osgood Schlatter disease is seen most often in adolescents who participate in sports which require running, jumping, and swift changes in direction such as basketball, soccer, figure skating, and gymnastics. It is more common in boys although the gender gap is closing as more young girls participate in sports.
However, the disease occurs during a growth spurt, usually during puberty, so in boys it is most commonly seen between the ages of 12 and 14 and in girls between the ages of 11 and 12. The disease usually resolves on its own once the child's bones stop growing. Due to this, it is very unlikely that you will experience this condition at the age of 20 as your bones are fully formed. There are multiple other causes of knee pain, however, so be sure to see your primary care doctor
if you have persistent knee pain or swelling.