Could be a torn miniscus, which can be identified by an MRI. Often, the cause is fluid in the joint, which is removed by a hypodermic syringe (not that painful, actually). PT would NOT help, and he has a torn miniscus would likely make him a cripple for life. You should go to a physician experienced in sports medicine.
Hello,
Three possibilities are there.First and foremost is chondromalacia patellae. This is a softening of the cartilage that lines the back of the kneecap.Diagnopsed by physical examination and MRI knee.Blood tests and x-rays are unhelpful since cartilage does not show up on x-rays.
Other possibilities are of tibial apophysitis, or Osgood-Schlatter lesion and Jumper's knee (irritation and inflammation of the patellar tendon).
Without clinical examination,diagnosis is tough.Pls discuss these possibilities with an orthopedcian as treatment is diagnosis specific.
Take care and do keep posting on how your son is doing.