In 1903, Robert Bayley Osgood and Carl B Schlatter first described this entity as traction apophysitis of insertion of tibial tubercle leading initially to tendinitis (inflammation) and later on avulsion.
It’s usually at the ligament-bone junction of the patellar tendon and the tibial tuberosity.
The tibial tuberosity is a slight elevation of bone around the proximal and front portion of the tibia (lower bone of the leg).
The patellar tendon is an extension of the quadriceps (thigh) muscles to the tibia via the patella (knee cap)
This disease typically occurs in boys ages 12 to 14 and girls ages 10 to 13. The difference is because girls enter puberty earlier than do boys. The condition usually resolves on its own, once the child’s bones stop growing.
It’s usually one-sided but bilateral symptoms are seen in around 30% of cases.