X-rays can be helpful when looking at bones and joints, but don't show problems with the soft tissue structures. Joint spaces are seen on X-ray and can show the thickness or thinning of the cartilage.
Doctors and therapists don't rely on X-ray findings. Studies show patients can have severe symptoms without any changes seen on X-rays. And the opposite is also true: many patients with severe changes on X-rays have no symptoms at all.
During the patient exam, a history of what happened and information about the current symptoms are taken. Tests of motion, strength, and flexibility give the physical therapist (PT much of the information needed to start treatment. A postural assessment can also be very helpful.
Experts agree that even if the exact problem (pathology) can be found, it may not change the treatment. Efforts are being made to classify or group patients based on who is likely to get better with each type of treatment. X-rays may be of limited value in this decision.