Knee pain can have a wide range of different causes. It could be something as simple as chondromalacia, a softening of the cartilage behind the knee. Or it could be the result of osteoarthritis (OA).
Your doctor will be able to give you a better idea of the problem. A more complete history and description of the symptoms are needed. This will help your doctor identify the specific problem.
For example, arthritis between the patella (kneecap) and the femur (thighbone) can present with pain anywhere around or under the patella. Any activity that loads the joint can increase the painful symptoms. Going up and down stairs or hills, squatting, or kneeling are common activities that bring on this type of knee pain.
Walking on level ground causes less severe pain. Sitting with the knee straight out is the most comfortable position. The physician will ask you about a history of patellar dislocations. This may point to a misalignment of the kneecap. Imbalances of the muscles and other soft tissues around the knee can contribute to this cause of pain from uneven wear on the joint.
A physical exam with specific tests will be done. The results of this tesing helps the doctor decide what kind of further studies to order. For example, standing X-rays help show the joint space, position of the patella, and the presence of any bone spurs.
CT scans and MRIs are not routinely ordered. CT scans can help show how the patella is moving or tracking up and down over the femur. In the future, MRIs may be able to show the quality of the cartilage.