Prior to a knee replacement surgery or a knee revision surgery, candidates can expect to undergo a variety of tests. A bone scan may be one of them and will show the surgeon the condition of the knee. Or, if a knee replacement candidate had previous knee replacement surgery, a bone scan provides doctors with information on the current condition of the prosthesis.
What is a Nuclear Medicine Bone Scan?
Nuclear medicine bone scans, also known as scintigraphy, use a minute amount of radioactive material, called radiopharmaceuticals, for diagnostic and assessment purposes. Doctors can see issues on bone scans that are not as easily detected by other forms of diagnostic testing, such as radiographs. Nuclear medicine bone scans may indicate that the implant loosened from the bone.
The amount of radioactive material used during this bone scan is small and patients do not have to avoid contact with other people after the procedure, unlike some other tests or therapies involving nuclear medicine. A bone scan is non-invasive, generally painless, and does not require anesthesia or sedation.
There is one caveat to undergoing a bone scan, however. Knee or other joint pain may be exacerbated temporarily while the patient is undergoing the scan because of the lack of movement allowed.
Who is Eligible for a Bone Scan?
Because radioactive material is involved, pregnant women or those who are breastfeeding are not candidates for bone scans. There are few risk factors with a bone scan of the knee, other than a possible allergic reaction to the material. Patients who have undergone previous nuclear medicine testing and experienced side effects must tell their doctor beforehand. Patients may experience mild pain and redness at the injection site.
Bone Scan Procedure
In order to conduct a bone scan of the knee, the patient lies down on an examination table and an intravenous catheter is installed in an arm. Patients receive an injection of the radiopharmaceutical material via the catheter, which passes into the bloodstream. It can take a few hours for the material to circulate throughout the body so the doctor can take a scan. During the procedure, patients are expected to drink several glasses of water to hasten removal of excess radioactive material through urination.
During the scan of the knee, the scanner takes a series of pictures and the patient may need to move into various positions during the process. Patients must remain completely still while the images are taken. After the bone scan is complete, a technician observes the images. It is possible that additional images are necessary for a better view of the area. After the bone scan is complete, most patients have no limitations on activities. If a patient must avoid certain activities, their doctor will inform them.
Bone Scans for Knee Replacement
Bone scans can help diagnose whether someone needs a knee replacement or knee replacement revision. However, they are not the only diagnostic option for someone in need of knee replacement surgery.
Consult with your doctor to learn more about bone scans and knee replacement surgery to learn the correct diagnostic option for you.