 [ Symptoms ] my nephew about 3 years old has an enlarged left knee cap his left knee bone cap is bigger than the right and he can not stretch his legs straight sometimes he complains pain and does not want to walk on his own he crawls when he feels the pain as far as we know he did not have any injury please advise [ Disease ] i am glad to help you out your nephew needs urgent and through evaluation from an orthopedician one possibility for his symptoms can be osgood schlatter disease in which there is tender swollen bump just under their knee cap on the tibial tuberosity although usually just on one knee both knees can also be affected this bump can appear as enlarged knee cap it can cause pain during certain activities such as running kneeling jumping etc he needs to get an x ray and mri knees done moreover other causes also need to be ruled out treatment includes nonsteroidal anti inflammatory drugs such as ibuprofen rest putting ice on the area knee braces and knee immobilizer i sincerely hope that helps take care