According to the American College of Rheumatology, doctors use the exam and X-rays to tell if you have arthritis. You must have knee pain along with at least one of the following:
Age over 50 years
Morning stiffness lasting less than 30 minutes
Crunching sounds called crepitus with active movement of the knee
Changes on X-ray
X-rays may show bone spurs, thinning of the cartilage or narrowing of the joint space.
Call the doctor's office and let them know about this. They can send additional records and results to support the doctor's diagnosis.