Knee Pain: When Do You Need an MRI?

Why an examination comes first

How the injury happened, where the pain is and what the knee does when it is moved and tested often point clearly to the diagnosis. A knee specialist checks the ligaments for looseness, looks for tenderness along the joint line, tests for clicking or locking and assesses the kneecap, the hip and the way you walk.

This examination decides which scan, if any, is needed, and it puts the scan result in context. An MRI report on its own, without a matching examination, can be misleading. That is why Dr. Gelber examines every knee at Aman Hospital in Doha before deciding on imaging.

When an X-ray is the right test

X-rays show bone, not soft tissue, but they answer several important questions quickly.

• Suspected fracture after a fall, twist or direct blow.
• Knee pain in people over about 40, where wear of the joint (osteoarthritis) is a common cause.
• Planning surgery such as knee replacement or osteotomy, often with standing X-rays that show how much joint space is left and how the leg is aligned.
• Checking the position of the kneecap or looking for loose fragments of bone.

For many older patients with gradual knee pain, a standing X-ray tells the surgeon more than an MRI.

When an MRI is useful

MRI uses a strong magnet, not radiation, and shows soft tissues in detail. It is often helpful when:

• An anterior cruciate ligament (ACL) or other ligament tear is suspected, for example after a pivoting injury in football or padel with swelling soon afterwards.
• The knee locks, catches or gives way, suggesting a meniscus tear or a loose fragment that may need treatment.
• Cartilage damage or bone bruising is suspected after an injury.
• Pain persists despite a sensible period of treatment and the cause is still unclear.
• Surgery is being planned and the surgeon needs a detailed map of the injury.

What MRI shows, and its limits

A good-quality knee MRI can show ligaments, the menisci, cartilage surfaces, tendons, fluid in the joint and bone bruising, which is swelling inside the bone after an impact or twist.

MRI is very sensitive, and that cuts both ways. Studies have found that many adults with no knee pain at all have abnormalities on MRI, especially degenerative meniscus tears and cartilage wear that become more common with age. Finding a meniscus tear on a scan does not necessarily mean it is the cause of your pain, or that it needs surgery.

MRI also cannot measure how stable a knee feels or how well it works. Those questions are answered by examination and, sometimes, by how the knee responds to physiotherapy.

What to bring to your knee consultation in Doha

If you have already had scans at another hospital or clinic in Qatar or abroad, bringing them saves time and can avoid repeating tests.

• The MRI or X-ray images themselves, on a disc, USB or as an online viewing link, not only the printed pictures.
• The written radiology report.
• Any previous operation notes, and a list of your medicines and allergies.
• Comfortable clothing, such as shorts, so both knees can be examined.

The surgeon will look at the images directly, as well as the report, and compare them with the examination findings.