ARTHRITIS OF THE KNEE JOINT

To assist us in selecting the most appropriate method of treatment, additional studies may be required on an out-patient basis.

1. Knee Aspiration. This is performed if there is suspicion of infection in a knee replacement. A needle is inserted into the joint using local anesthetic. It is not particularly uncomfortable. Fluid obtained from the knee joint is sent to the laboratory for culture (results usually take 10 days to 2 weeks to be returned to Dr. Huddleston).

2. Bone Scans. There are several types of bone scan: (a) The most routine type is done utilizing Technetium Diphosphonaten (TDP). The radioactive material is injected intra-venously and the whole body is scanned a few hours later. This test is most useful in identifying hairline bone fractures which do not show up on x-ray, and bone tumors. It may be helpful in diagnosing loosening of a hip or knee implant. (b) A Gallium Scan is ordered if there is concern about infection. (c) Another test that may be performed if infection is suspected is an Indium-111 Radioisotope Scan. This requires removing some of your own blood, labeling it with an isotopic material (Indium-111) and re-injecting it. You return a day later, and the joint is scanned. This is a relatively new procedure, sometimes used in combination with other, more routine types of scans. The isotopic agents are relatively innocuous. The amount of radiation is generally not much more than that in a single x-ray.

3. Magnetic Resonance Imaging (MRI). MRI has been a diagnostic revolution. It is done using giant magnets. No radiation is involved. It is useful in diagnosing the early stages of osteonecrosis, or in searching for bone tumors, and in determining if the knee menisci are intact (see Meniscal Injuries - Diseases of the Knee Joint). It is important for you and your family physician to know that there is no contra-indication to having MRI if you have an artificial joint, even thought parts of the implant are made of metal.

   Major surgery is not without risk. There are risks in everything we do in life. Our medical staff will do everything we can to minimize the risks that you undertake. The worse your preoperative symptoms are, the more reasonable it is that you take the risk inherent in having a knee replacement. Please feel free to ask Dr. Huddleston any questions you might have. We look forward to taking care of you.

   On the whole total knee replacement has proven to be an extremely beneficial contribution to modern surgery. We are pleased to be able to present you with this manual, which we hope will help you to understand your problem and the possible treatments you can obtain.