Introduction
A knee X-ray is a diagnostic test that produces an image of the anatomy of the knee, which helps in identifying any knee condition. In various situations, knee X-rays can be used to find the cause of pain, tenderness, or swelling. Knee X-rays are quick, easy, and painless procedures. The X-rays are best at showing bone and other surrounding structures, such as soft tissues and signs of arthritis. The X-rays help the doctor determine a treatment for the knee condition or may advise further tests to confirm the diagnosis.
What Is an X-Ray?
An X-ray is a quick, painless, and safe test that uses a small amount of radiation to show images of the inner structures of the body, such as bones, organs, and other parts. The image obtained from an X-ray is black and white, and when the X-ray beam is passed through the body, it gets absorbed in different amounts depending upon the density of the material through which it is passed. These dense structures, such as bones, appear white on X-rays and empty areas like the air in the lungs appear black, and soft tissues will appear gray.
What Are Knee X-Rays?
During a knee X-ray, the X-ray machine sends a beam of radiation through the knee, and the image is produced on a special film. In this film, various parts of the knee, such as the femur (thigh bone), tibia and fibula (lower leg bones), patella (kneecap), and the surrounding soft tissues, can be seen. The knee X-ray can be taken from different angles, which include:
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From the front (anteroposterior view or AP).
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From the side (lateral view).
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When the knee is bent (sunrise view of the kneecap).
In some cases, the doctor may advise getting an x-ray of the opposite knee for comparison. In the case of children, the X-ray can be taken with the child standing or lying down on the table. The child needs to stay still so that the image obtained on the X-ray is clear.
Why Are Knee X-Rays Needed?
A knee X-ray is required to diagnose the possible health and medical conditions of the knee or knees. The knee X-ray may help find the cause of symptoms in the knee, such as:
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Pain.
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Stiffness.
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Tenderness.
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Deformity.
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Swelling.
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Pain with walking or inability to walk.
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Weakness or instability in the knee.
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Grinding in the knee.
A knee X-ray may also help in diagnosing the following:
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Broken knee bones (fractures).
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Joint dislocation.
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Bone spurs (osteophytes).
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Excess fluid.
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Bone infections (osteomyelitis).
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Loose pieces of bone.
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Abnormal alignment of the knee joint.
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Osteoarthritis (a type of arthritis causing the wearing down of the protective tissue at the ends of bones (cartilage) that occurs slowly and worsens over time).
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Thinning of bone (osteopenia).
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Bone cancer.
Knee X-rays are also done as follow-ups in the case of fractured bones to ensure healing of the bones or joints is proper.
What Is the Procedure for a Knee X-Ray?
The procedure for the knee X-ray is as follows:
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The patient is asked to remove any jewelry or metal objects that may interfere with the result of the test.
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The procedure will take place in a room with a large X-ray machine, and the patient may be provided with a lead apron to protect them from radiation exposure.
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The patient is positioned appropriately either on an X-ray table or the X-ray might be taken while standing. The patient is advised to stay still so the image will be clear.
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The technician operates the machine behind a wall or adjoining room to avoid exposure to radiation.
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The leg may be repositioned to take multiple images, and this process usually takes around 10 to 15 minutes.
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Usually, the knee X-ray is taken from three angles which include:
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The front.
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The side.
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With the knee bent.
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What Are the Benefits of Knee X-Rays?
The are multiple benefits of knee X-rays, which include:
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These are quick and easy ways of diagnosing bone injuries and joint abnormalities.
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Readily available in almost every healthcare facility.
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Useful for emergency diagnosis.
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Does not cause any side effects when used in the safe diagnostic range.
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The retention of radiation in the body is minimum after the procedure is done.
What Are the Risks Associated With Knee X-Rays?
A single knee or chest X-ray exposes the patient to about 0.1 mSv (millisievert - a measure of radiation exposure). This amount of radiation exposure is the same as the natural exposure from the environment over the course of 10 days. Some risk factors associated with knee X-rays include:
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X-rays usually do not cause any side effects and do not harm the body as the amount of radiation exposure is very minimal. However, in the case of pregnant female patients, there may be a risk of exposure to radiation for the unborn child. Therefore, the patient should inform the technician before the X-ray whether they are pregnant or trying to get pregnant. In that case, the lead apron is used and worn around the belly to protect the baby from unwanted radiation exposure.
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In the case of children, the risk of radiation exposure is high; therefore, lower amounts of radiation should be used.
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The higher amount of radiation exposure may carry a risk of cancer. However, this is rare, and radiation exposure can be altered or reduced, and the benefit of diagnosis always has the upper hand in any case.
What Happens After the Knee X-Ray?
After the knee X-ray, the images of the X-ray are interpreted by the radiologists, and the reports are sent to the doctor, who formulates a treatment plan according to the condition. In case the X-ray image is blurred, the X-ray might have to be taken again.
What Other Tests May Be Required With the Knee X-Ray?
This usually depends upon the type of condition, which may include:
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Magnetic Resonance Imaging (MRI) - In this technique, magnetic fields and computer-generated radio waves are used to create detailed images of the organs and tissues of the body.
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Ultrasound Imaging - In this, high-frequency sound waves are used to view inside the body.
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Computed Tomography (CT) Scan - Special X-ray equipment is used to create detailed or high-quality multidimensional pictures, or scans, of areas inside the body.
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Bone Scan - In this, nuclear imaging is used to help detect several types of bone disease.
Conclusion
An X-ray is a quick and painless test that provides information to the healthcare professional that can be used to make a diagnosis for any knee condition. This is less costly as compared to other imaging tests and can show signs of fractures, infections, or arthritis. Knee X-rays help diagnosing conditions ranging from fractures to arthritis. The X-ray can help diagnose the later stages of infections, and it can also help in providing the information while the bones are healing properly after the treatment.
