Knee X-ray

Definition

X-rays of the knee may be helpful in management of knee injuries.

Description

X-rays are a form of invisible electromagnetic energy of short wavelength that is produced when high-speed electrons strike a heavy metal. X-rays can be used to produce images of bones, organs, and internal tissues. Low doses of X-rays are passed through the tissues and cast images - essentially shadows- onto film or a fluorescent screen showing structural changes in the area being examined.

X-rays play a role in diagnosing certain traumatic conditions involving the knee joint. Although, the great incidence of cartilaginous and soft tissue injuries, occurring as isolated conditions or with fractures, requires the use of additional imaging techniques for adequate evaluation of the joint capsule, articular cartilage, menisci, and ligaments.

The knee MRI (magnetic resonance imaging) gives exquisite detail of the internal structures of the knee and has largely replaced the knee X-ray in management of knee disorders.

Procedure

When a patient arrives for an X-ray, the X-ray technician explains the procedure. The patient undresses to expose the area concerned; care is taken to remove any objects that might produce an image on the film, such as jewelry. The position of the patient when the X-ray is taken is carefully chosen to provide the clearest view of the part under examination.

An X-ray of the knee is possible in at least four different views: anteroposterior (top view), lateral (side view), tunnel (back view) and axial (front view).

X-ray Safety

Large doses of radiation can be extremely harmful. Modern X-ray film, equipment, and techniques are designed specifically to produce high-quality images at the lowest possible radiation dose (exposure) to the patient. The possible hazard of genetic damage can be minimized by using a lead shield to protect the patient.

Questions to Ask Your Doctor

What are the risks of X-rays?

How often can x-rays be taken?

When is a knee MRI necessary?