Depending on your particular history and exam, the doctor may suggest X-rays of the knee. X-rays show fractures (broken bones) and dislocations of bones in the knee as well as arthritis and abnormally large or small joint spaces.
Rarely, the doctor may order a CT scan (a 3-dimensional X-ray) of the knee to precisely define a fracture or deformity.
Both X-rays and CT scans are excellent for diagnosing fractures. They both are also poor, however, at evaluating soft tissue structures of the knee such as ligaments, tendons, and the menisci.
Magnetic resonance imaging (MRI) uses large magnets to create a 3-dimensional image of the knee.
In contrast to CT scans, MRIs do not image bones and fractures as well.
Also in contrast to CT scans, MRIs are excellent for evaluating ligaments and tendons for injuries.
The knee and all bursae of the knee are filled with fluid.
If your symptoms suggest infection or crystalline arthritis, such as gout, your physician may remove fluid, with a needle, from the knee.
This fluid will then be analyzed to better clarify the diagnosis.
Crystals, which suggest crystalline arthritis, often can be seen under the microscope. Infection may also be detected under a microscope by finding bacteria and pus in the fluid.
Blood tests: The doctor may also elect to perform certain blood tests to evaluate for signs of infection or diseases such as rheumatoid arthritis, lupus, and diabetes.
The orthopedic surgeon may elect to perform arthroscopy if you have chronic knee pain.
This is a surgical procedure where the doctor will place a fiber optic telescope within the knee joint. The arthroscope is attached to a camera that relays real-time images to a video monitor.
By doing so, the surgeon may be able to see small particles in the knee or to look more closely at damaged menisci or cartilage.
The doctor may also be able to repair damage by shaving down torn cartilage or removing particles from the knee while looking at the inside of your knee on a video monitor.