Pain on left knee. To decide what to do?

Last year in Jan, my son fell while playing football repeatedly he got injured on left knee. he started getting severe pain in nights in left knee joint. Took him to orthopedic doctor. X ray and MRI was done prescribed Tab Naproxen 500 and D-shine for 2 months. While taking Naproxen there was no pain. But after completion of course, it started again. This time he was given Tab Espra XN for 2 months again. The pain started again after course. Then we went for Homeopathic medicines for 6 months. Then the intensity reduced to 5% of original pain and frequency increased from daily to once in two days. But it is continuing till date. In between we consulted different Orthopedics, Neurologists, Sports injury specialists, Rheumatologists , We repeated MRI again in June2016, but doctors say there is no problem. Even now every alternate day he is taking Tab Naproxen500 for pain. One orthopedic from Hyderabad advised that he may need Diagnostic Orthoscopy. We are unable to decide what to do