Alternative Names radiographic examination of the joint
Definition A joint x-ray is a radiographic image of a place where bones in the body connect. Examples include the knee, elbow and ankle. X-rays consist of electromagnetic waves of energy. They penetrate the body to varying extents depending on the density of the structures being viewed. The result is back and white images of interior portions of the body.
Who is a candidate for the test? A person who has pain, swelling, redness, limited motion or deformity of any joint is a candidate for a joint x-ray. X-rays can also be used to check on a person's progress after an operation.
How is the test performed? The person having the x-ray will remove clothing to expose the affected joint. The x-rays may be taken sitting, standing or lying on an x-ray table. Sometimes, iodinated contrast material, or dye, will be injected into the joint. An x-ray taken after the dye is injected is called an arthrogram.
The joint is placed over the x-ray film. The x-ray tube is positioned over the joint and the film is exposed. The exposure lasts only a fraction of a second. Several x-rays will be taken. The technologist will examine the pictures. If they are adequate, the individual is free to leave. In recent years, CT, a special three-dimensional x-ray, and the MRI, a special three-dimensional image using magnets, Images have largely replaced x-rays for the examination of joints.
What is involved in preparation for the test? Before the examination, an individual needs to remove all jewellery or other metal objects that may interfere with the process. He or she will also remove splints or prosthetic devices. Women will be asked if they might be pregnant.
What do the test results mean? Joint x-rays can show:
bad alignment, or joints in which the parts do not match up as intended
increase or decrease in bone density
abnormal calcifications, or hardening of tissue because of calcium deposits
loose pieces in the joint
Author: James Compton, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 16/10/2004 Contributors Potential conflict of interest information for reviewers available on request
