Over the last few years I've seen several kids that come in with knee pain that have been told they have Osgood Schlatters. Osgood's, classically, has been an enlargement of the tibial tubercle with inflammation of the tendon below the knee. This is attributed to because of extreme growth spurts with overuse activity.
To me this has become another catch all phrase Doctors give to parents when their kid complains of knee pain and there doesn't seem to be ligament/meniscal damage and they are 8-14 years old.
Often these kids have very tight peroneal muscles. These are the side of the calf. This can be accompanied by tibialis anterior tension, but not necessarily. After releasing the peroneal muscles, better tib/fib joint movement is created. Better alignment between femur and tibia is also achieved and well as dorsiflexion tends to improve. Kids this young are like plastic and when the right things are in place and the right things are no longer tight, it doesn't take long before proper biomechanical function is achieved.
Kids are pain free running around again. So the next time you hear of a kid with knee pain that has Osgood's, check the peroneal group and see if releasing the muscle and restoring tissue quality improves function and diminishes the knee pain.