A hip X-ray is a safe and painless test that uses a small amount of radiation to
make images of the hip joints (where the legs attach to the pelvis). During the examination,
an X-ray machine sends a beam of radiation through the pelvic bones and hip joints,
and an image is recorded on a computer or special film. This image shows the soft
tissues and the bones of the pelvis and hip joints.
The X-ray image is black and white. Dense body parts that block the passage of
the X-ray beam through the body, such as bones, appear white on the X-ray image. Softer
body tissues, such as the skin and muscles, allow the X-ray beams to pass through
them and appear darker. An X-ray technician takes the X-rays.
An X-ray technician in the radiology department of a hospital or a health care
provider's office takes the X-rays. Two different pictures are usually taken of the
hip: one from the front (anteroposterior view or AP), and one from the side (lateral
view, also known as the frog leg lateral view). Typically, X-rays of both hips are
taken for comparison, even if only one hip is causing symptoms.
Why It's Done
A hip X-ray can help find the cause of common signs and symptoms, such as limping,
pain, tenderness, swelling, or deformity in the hip area. It can detect broken bones
or a dislocated joint. If hip surgery is required, an X-ray may be taken to plan for
the surgery and, later, to see the results of the operation.
Also, a hip X-ray can help to detect bone cysts, tumors, infection of the hip joint,
or other diseases in the bones of the hips.
A hip X-ray doesn't require any special preparation. Your child may be asked to
remove some clothing, jewelry, or any metal objects that might interfere with the
If your daughter is pregnant, it's important to tell the X-ray technician or her
doctor. X-rays are usually avoided during pregnancy because there's a small chance
the radiation may harm the developing baby. But if the X-ray is necessary, precautions
can be taken to protect the fetus.
Although the procedure may take about 10 minutes or longer, actual exposure to
radiation is usually less than a second.
Your child will be asked to enter a special room that will most likely contain
a table and a large X-ray machine hanging from the ceiling. Parents usually can accompany
their child to provide reassurance. If you stay in the room while the X-ray is being
done, you'll be asked to wear a lead apron to protect certain parts of your body.
Your child's reproductive organs also will be protected with a lead shield.
The technician or radiologist will position your child on the table, then step
behind a wall or into an adjoining room to operate the machine. Two X-rays are usually
taken, one with the legs straight (AP view) and one with the knees apart and feet
together (frog leg view), which is how the lateral view usually is done. The technician
will return to reposition your child for each X-ray.
Older children will be asked to stay still for a couple of seconds while the X-ray
is taken; infants may require gentle restraint. Staying still is important to prevent
blurring of the X-ray image.
If your child is in the hospital and can't easily be brought to the radiology department,
a portable X-ray machine can be brought to the bedside. Portable X-rays are sometimes
used in emergency departments, intensive care units (ICUs), and operating rooms.
What to Expect
Your child won't feel anything as the X-rays are taken. The X-ray room may feel
cool due to air conditioning used to maintain the equipment.
The positions required for the X-rays may feel uncomfortable, but they need to
be held for only a few seconds. If your child has an injury or is in pain and can't
stay in the required position, the technician might be able to find another position
that's more comfortable. Babies often cry in the X-ray room, especially if they're
restrained, but this won't interfere with the procedure.
After the X-rays are taken, you and your child will be asked to wait a few minutes
while the images are processed. If they are blurred or unclear, the X-rays may need
to be redone.
Getting the Results
The X-rays will be looked at by a radiologist (a doctor who's specially trained
in reading and interpreting X-ray images). The radiologist will send a report to your
doctor, who will discuss the results with you and explain what they mean.
In an emergency, the results of an X-ray can be available quickly. Otherwise, results
are usually ready in 1-2 days. In most cases, results can't be given directly to the
patient or family at the time of the test.
In general, X-rays are very safe. Although there's some minor risk to the body
with any exposure to radiation, the amount used in a hip X-ray is small and not considered
dangerous. It's important to know that radiologists use the minimum amount of radiation
required to get the best results.
Developing babies are more sensitive to radiation and are at more risk for harm,
so if your daughter is pregnant, be sure to tell her doctor and the X-ray technician.
Helping Your Child
You can help your young child prepare for a hip X-ray by explaining the test in
simple terms before the procedure. It may help to explain that getting an X-ray is
much like posing for a picture.
You can describe the room and the equipment that will be used, and reassure your
child that you'll be right there for support. For older kids, be sure to explain the
importance of keeping still while the X-ray is taken so it won't have to be repeated.
If You Have Questions
If you have questions about why the hip X-ray is needed, speak with your doctor.
You can also talk to the X-ray technician before the procedure.