Almost all problems should be treated conservatively (no cortisone or surgery) first for a few weeks even if problems do show up on MRI as the body can heal itself and you can perform at 100% even with no ligaments (believe it or not) if your muscles are in top form! The techniques you will want your chiropractor to be versed in are Applied Kinesiology, TBM, Quantum Neurology and NET. On your own, make sure you are drinking a quart of water for every 50 lbs you weigh and add a cup for every caffeinated or alcoholic beverage you consume. If you work out a lot, you may need even more than that. Also, knee problems often correlate with gallbladder stress and adrenal stress so if this persists, consider having those issues checked. Good luck!
Some chiropractors do, some don't. Personally I choose not to x-ray everybody on intake because an x-ray will usually not change the treatment protocol, and I do everything I can to avoid radiation exposure for myself and patients. If there is a history of cancer, osteoporosis, or an injury which may have caused a fracture or some type of damage to the spine, or the patient is not responding to treatment as expected, then x-rays are indicated and I send patients off site to get them. I take a very detailed health history and do very gentle chiropractic adjustments, usually with an activator which has no history of injuring the spines of patients. Some chiropractors are more "rack and crack" docs who rush you in and out with a heavy handed adjustment and probably are wise to X-ray. Some do it to show the patient scoliosis or other problems in curvatures of the spine in order to show the patient why they need chiropractic care. The problem with using it to identify curvatures or educate their patient is that x-rays don't show everything. Also curvature can be changed dramatically depending on how a person stands during the x-ray. A disc herniation which is a very common problem seen in practice is not seen on x-ray, you must get an MRI for that. Also, osteophytes or arthritic changes may or may not affect the outcome of treatment. In my experience, function does not always follow structure, meaning that you can have a pretty "ugly" arthritic spine on x-ray and still have full range of motion and be pain-free, or you can have a very "clean" looking spine and be unable to move.. If X-rays did not subject the patient to radiation I would say it's ok to do them without cause if the patient wants to pay for them, but for me the risk of subjecting a patient to radiation outweighs the risk of missing a pre-existing condition. I hope that helps!