Knee arthroscopy may be the most common orthopedic procedure done today. It is a highly safe and reliable way to locate the source of knee pain. Researchers estimate that it is accurate over 90 percent of the time. Also, arthroscopy is more readily available to most patients than some other diagnostic procedures, such as MRI.

While MRI may be less invasive, it's also more costly and, in some cases, harder to get. Some doctors worry that MRI may be less accurate than arthroscopy.

If both kinds of procedures are available to you, you may want to ask your doctor whether he or she prefers one method over the other. It may be that, in your case, one of the procedures would do a better job of finding the source of your knee pain.