Osgood-Schlatter disease (OSD) is a common type of knee pain that usually occurs in teenagers who play a lot of sport. It may sound like a scary complicated disease, but it is a relatively simple condition that usually disappears on its own by the end of a growth spurt.
How does Osgood-Schlatter disease occur?
During a growth spurt, the bones, muscles and tendons all grow quickly, but not necessarily at the same time, and this can put stress on the growth plate - a layer of cartilage in which most of a bone's growth occurs. In the case of OSD, the growth plate affected is found at the top end of the shin bone, and pain is felt at the tibial tubercle (the bony end of the shin bone just below the kneecap) when the patella tendon from the kneecap pulls on it.
Certain exercises and sports activities can aggravate the condition, especially running and jumping. Squatting down, for example, which forces the quadriceps (the large muscles at the front of the thighs) to contract, can pull on the patella tendon and therefore the bone, causing pain. However, some inactive children can also have OSD.
What are the symptoms of Osgood-Schlatter disease?
Children usually experience the symptoms of OSD during their 2-year growth spurt between the ages of 10 and 15 years. Girls usually start their growth spurt at an earlier age than boys: growth spurts peak in girls between 10 and 12 years and in boys between 12 and 15 years. OSD is more common in boys, but with more girls participating in sports it is becoming more common in them too.
The main symptom is knee pain, and it can range from mild and only occurring when exercising to being severe and continuous. OSD can affect one or both knees, and the level of pain may be stronger in one knee than the other. The pain often worsens with exercise and lessens with rest.
Other symptoms include:
- Tenderness or swelling under the kneecap and at the top end of the shin bone, at the tibial tubercle
- Limping after the child has been exercising
- Tightness in the hamstring and quadriceps muscles - the front and back thigh muscles.
Sometimes a bony lump known as a callus can form at the top of the shin bone if there is repeated stress and trauma from the muscles and tendons pulling on it. The lump forms as flakes of bone are pulled off, leading to new bone forming. If the child continues to put stress on the bone, the lump can gradually get larger.
How is Osgood-Schlatter disease treated?
Treatment is only necessary until OSD disappears, which is usually by the time the child finishes their growth spurt. The symptoms can last from a few weeks or months to sometimes up to a couple of years.