Hi, I have read your question, Osgood-Schlatter Disease (vern.knobby knees) generally shows a sign of outgrowth around the knee area/below the patella (=knee cap) , well as you didn t mention any such condition in the question and without physical medical check up its is difficult to come to a conclusion. Anyway i Appreciate your interest in doing research of you own. Treatment for O-S D is generally Rest, Ice, Compression, and Elevation, and if required acetaminophen (paracetamol), ibuprofen or stronger if in acute phase & (the pain is severe and continuous in nature). The condition usually resolves in a few months, with a study of young athletes revealing a requirement of complete training cessation for 1 week (on average) and gradual resumption of full training by 1 month. Often the Patients suffering with O-S D Don t show any swelling in the ankle region , Since you have said that you child is into sports one of the possible reasons could be Tear of meniscus , or sprain in the legs. In Such a condition i recommend you to consult a general physician and then a physiotherapist For further treatment. Wishing Your Child a Good Health and Bright future, Dr.G.Gayatri Devi (General Physician)