Femur X-Ray Exam

Overview

What’s a Femur X-Ray and What Does It Show?

A femur (FEE-mer) X-ray is a safe and painless test that uses a small amount of radiation to make an image of the bone inside the upper leg (the area between the hip and knee), called the femur or thighbone.

An X-ray of the femur can help with:

• Injuries and healing. The test can help find the cause of limping or upper leg pain, swelling, or tenderness. A femur X-ray can show broken bones and deformities (changes in shape or size). After a bone is set, an X-ray of a broken femur can show if the bone is lined up and healing properly.
• Planning and diagnosing. Doctors use femur X-rays to plan surgery — when needed — and check how well it worked after. The tests can sometimes also help find cysts (sacs filled with liquid), infections, tumors, and other bone diseases.

Top Things to Know

• A femur X-ray is a quick and pain-free test that makes pictures of the inside of the femur (thighbone).
• The X-ray can show if there’s a femur fracture (break), swelling, or other problem.
• The test uses a very small amount of radiation, which is safe for kids.
• Your child will need to stay still for a few seconds so that the images come out clear.

What to Expect

How Does a Femur X-Ray Work?

In a femur X-ray, an X-ray machine sends a beam of radiation through the femur, and an image is recorded on special X-ray film or a computer screen.

The X-ray image is black and white. Dense body parts, like bones, block the passage of the X-ray beam through the body. These look white on the X-ray image. Softer body tissues, like the skin and muscles, let the X-ray beams pass through them. They look darker on the image.

What Happens Before a Femur X-Ray?

To get ready for a femur X-ray, kids may be asked to remove clothing from the waist down and change into a hospital gown because buttons, zippers, and clasps might affect the image. The test often happens in a special room that has a table and an X-ray machine. A parent can usually stay in the room. Tell the X-ray technician if you’re pregnant because developing babies are more sensitive to radiation.

If your child is in the hospital, sometimes a portable X-ray machine can be brought to the bedside.

You can help your child prepare by explaining the test in simple terms. Say that it’s important to hold still to get the best images.

What Happens During a Femur X-Ray?

Femur X-rays take just a few minutes. They may be done while your child lies on the table or stands. After getting your child into the right position, an X-ray technician goes into the next room to take the images. Kids should stay still for 2–3 seconds while each X-ray is taken so the pictures are clear. If an image is blurred, the technician might take another one. Older kids may be asked to hold their breath for a few seconds to help keep them from moving.

The X-ray technician will take pictures of the femur from the front and side. If your child has an injury and can't stay in the right position, the technician can help find a position that feels better. Sometimes doctors also want an X-ray of the other “normal” femur to compare.

What Happens After a Femur X-Ray?

A radiologist (a doctor trained in reading and understanding X-rays) will look at the images and help figure out what the results mean. This person will send a report to your doctor, who will explain what the X-rays show.

X-rays can be read quickly, especially in an emergency. The doctor seeing your child can sometimes look at the X-ray before getting the official read from the radiologist. But in most cases, results can't be given directly to the patient or family at the time of the test.

What Else Should I Know?

In general, femur X-rays are very safe. There can be some risk to the body with radiation, but the amount in femur X-rays so small that it’s not thought to be dangerous. X-ray technicians use the least radiation needed to get the best images.

Based on the results of the femur X-ray, your child may need a follow-up appointment with the doctor or get more X-rays or other imaging tests.

If you have questions about the femur X-ray or what the results mean, speak with your doctor. You can also talk to the X-ray technician before the test.