Osgood-Schlatter disease is a common, temporary condition that causes knee pain in older children and teenagers, especially those who play sports.
During activities that include a lot of jumping and bending — hockey, basketball, volleyball, soccer, skating, gymnastics, or ballet — the quadriceps muscle (thigh muscle) pulls tightly against the kneecap and the kneecap's anchor, the patellar tendon. The fibers of the patellar tendon are attached to the shinbone (tibia). With repeated pulling against these fiber connections, the tendon can become inflamed at or near its bone attachment. The result is pain and swelling at the tibial tuberosity, which is a raised area at the top of the shinbone. The tibial tuberosity is where the patellar tendon attaches to the bone.
This connection between the tendon and tibia is particularly vulnerable to stress and injury during times when the bone is growing rapidly. For this reason, symptoms of Osgood-Schlatter disease usually appear during the teenage growth spurt. In girls, this growth spurt typically occurs between the ages of 10 and 16. In boys, it occurs a little later, between the ages of 11 and 18. Up to 20% of adolescent athletes experience Osgood-Schlatter disease. The problem is more common in boys.
In most cases, symptoms of Osgood-Schlatter disease develop gradually as a result of repeated stress on the patellar tendon. Less often, the condition is caused by a single trauma to the knee.