Knee X-Ray: When To Get One and What It Can Show

If you’re experiencing knee pain, you’ve been told you need a knee scan, or you have an injury, a knee X-ray can help your clinician identify fractures, swelling, or damage to the tendons, ligaments and cartilage. It’s a non-invasive method of checking whether you need treatment. In our guide to knee X-rays, you’ll find everything you need to know, from why your clinician may recommend having one to what it can show about your knee health. Plus, find out how to book a private knee X-ray quickly and easily.

Why would a doctor order a knee X-ray scan?

There are lots of reasons why a clinician might recommend that you have a knee X-ray. Here are some of the most common situations in which a doctor will want to have a closer look at your knee:

You’ve had an injury or trauma to the knee.
You have a suspected or confirmed degenerative joint disorder, such as osteoarthritis.
You have unexplained pain, swelling or tenderness in or around your knee.
You’re experiencing decreased motion or stiffness in the joint.
Your clinician needs to look at your knee before offering treatment or to check that treatment has been successful.

Your clinician may also recommend an X-ray if there’s a reason you can’t have an MRI scan; for example, you have metal in your body that may be affected by the powerful magnets an MRI scan uses.

What type of knee scan do I need?

A knee scan, whether an X-ray, MRI, CT, or ultrasound scan, can help your clinician identify a wide range of potential problems or conditions in and around the joint. Sometimes, you’ll need a combination of scans for a complete diagnosis. If you’re unsure which knee scan you need, book a consultation with a clinician today and get expert advice based on your symptoms. There’s no obligation to book a scan after your consultation.

Knee X-ray anatomy

An X-ray is a type of imaging that uses electromagnetic radiation to create images of the inside of the body. It will produce clear images of the anatomy of your knee, which includes:

Bones: The three main bones of the knee are the femur (thighbone), tibia (shinbone), and patella (kneecap).
Cartilage: Tough, rubbery tissue that covers the end of the bones where they meet each other in the joints. The knee has two types of cartilage: articular cartilage and meniscus cartilage.
Ligaments: Strong bands of tissue that connect the bones and stabilise joints. The knee has four main ligaments: the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL).
Tendons: Tough cords of tissue that connect the bones to your muscles. Within the knee are two important tendons: the quadriceps tendon, which connects the quadriceps muscles to the patella, and the patellar tendon, which connects the patella to the tibia.
Muscles: Two sets of muscles within the thigh and knee, at the front and back. The quadriceps at the front straighten the knee, while the hamstrings at the back bend the knee.

Types of knee X-ray

There are two main types of knee X-rays - a knee cap X-ray and a knee replacement X-ray.

An X-ray of a knee cap will look carefully at the knee cap and all the surrounding muscles and tissues. Your clinician may recommend a knee cap X-ray if they think you have a fracture, a dislocation, or suspected or confirmed arthritis.

If you have knee replacement surgery, your clinician will want to see how well the surgery has gone with an X-ray. It will clearly show the metal or plastic implants that have replaced damaged bone and cartilage, and they can check how well the implant is positioned and if there are any signs of complications, such as infection.

What are the three views taken during a knee X-ray?

During your X-ray, the technician will take three views of your knee. This helps your clinician get a good look at your knee from all angles and see the bones, tissues, and muscles within the joint.

Anteroposterior (AP) view: This view is taken from the front to the back of the knee. It helps your clinician check for possible dislocations, breaks, foreign objects in the area, and signs of arthritis.
Lateral view: This is taken from the side of the knee and can help if your clinician suspects arthritis or a bone abnormality. A lateral knee X-ray provides a different angle from the AP view and shows the spaces within the knee joint.
Sunrise view (sometimes called the skyline or Merchant view): This is a clear view of the kneecap, bent at a 45-degree angle during the X-ray. It helps your clinician identify whether the kneecap is dislocated or whether a condition, such as patellofemoral joint disease, is affecting its alignment.

What can a knee X-ray show?

Clinicians often use X-rays to look for bone fractures and breaks, but they may also use them to identify joint abnormalities or damage to the soft tissues of the knee, such as a meniscal tear or patella tendonitis (jumper’s knee). X-rays can also sometimes reveal extra fluid build-up (joint effusion) in the knee caused by an underlying condition, such as arthritis.

What does a normal knee X-ray look like?

A healthy knee X-ray will show the bones intact, with no fractures or breaks. The joints between the bones will be clear and visible, and the cartilage will show no signs of damage. The kneecap will be aligned and not tilted to either side, and there will be no signs of arthritis, such as bone spurs, bone density changes, or narrowing of joint spaces.

What does a fractured or broken knee X-ray look like?

What the X-ray will show depends on the type of fracture you have, but there may be a visible break in the bone, showing up as a dark line or a gap. If the fracture or break is particularly severe, fragments of bone may be visible, or the joint spaces may widen between the bones. There may also be soft tissue swelling, which will appear white and hazy on the X-ray.

What other conditions can a knee X-ray show?

As well as arthritis, dislocations, fractures and breaks and joint disorders, knee X-rays can help identify several other conditions that affect the knee, such as:

Bursitis: Inflammation of small fluid-filled sacs (bursae) near joints, causing pain and swelling.
Bone spurs (osteophytes): Smooth bone growths often appearing near joints. They can be caused by arthritis or joint damage.
Bone infection (osteomyelitis): A painful bone infection caused by bacteria and fungi that can lead to bone loss.
Osteoporosis: A condition where bones become weak and brittle, increasing the risk of fractures.
Avascular necrosis (osteonecrosis): A bone condition that happens when blood flow to a bone is cut off. It can be more common in older women with osteoporosis.
Bone cancer: A type of cancer that starts in the bone tissue, causing tumours.

How much does a private knee X-ray cost in the UK?

If you're wondering: how much is a knee X-ray? it can be tricky to find the answer, depending on where you live in the UK. However, a knee X-ray normally costs between £120 and £220. By searching with Scan.com, you can compare prices clearly upfront, so you'll know what the cost will be near you.

How can I get a private knee X-ray near me?

With Scan.com, you can book a private knee X-ray scan, CT, MRI, ultrasound scan, and more near you today. Choose from over 150 centres nationwide, compare prices, and book online in minutes. You’ll also have a phone consultation with a clinician before and after your scan so you can be confident in your choices and healthcare outcomes.