If you have unexplained knee pain, swelling or instability, you may be wondering if you have a meniscus tear. We’ll guide you through the common symptoms of a meniscus tear, what a meniscus tear MRI can show, and how it is carried out. We’ll also describe the different types of meniscus tears that can happen and what treatment your clinician will likely recommend if they find out you have a tear in the meniscus.
What is the meniscus?
The meniscus is a C-shaped piece of cartilage in your knee joint that acts like a cushion between your thighbone (femur) and your shinbone (tibia). You have two menisci in each knee - the lateral meniscus on the outer and the medial meniscus on the inner side.
These menisci are really important for proper knee function and joint health. They act like shock absorbers, taking on much of the pressure and force that goes through your knees when you walk, run or jump. They help to stabilise the joint and enable it to move smoothly.
What is a meniscus tear?
A torn meniscus is a common injury to the knee cartilage, especially if you’re very active or athletic. Meniscus tears can happen with sudden twisting or rotating of the knee joint, overuse from repetitive activities, or degenerative changes that come along with ageing.
There are six different types of meniscus tears, and each one gets its name from the pattern of damage experts can see on the meniscus itself:
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Radial meniscus tear: Develops along the curve of the meniscus.
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Intrasubstance meniscus tear: Develops within the meniscus without extending to the edges.
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Horizontal meniscus tear: Runs horizontally across the meniscus.
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Complex meniscus tear: Involves multiple tears, such as radial and horizontal tears.
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Bucket handle meniscus tear: A portion of the meniscus displaces into the joint, making it look like a bucket handle.
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Flap meniscus tear: A flap of the meniscus tissue detaches partially or entirely from the main body.
While younger people are more likely to experience acute meniscus tears through exercise or injury, older people are more likely to have a variety of tears and fragmentation due to the meniscus weakening with age.
When should I get a meniscus tear MRI?
It may be a good idea to have an MRI for a meniscus tear if you experience certain symptoms in the knee, including:
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Pain.
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Swelling.
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Tenderness.
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Stiffness.
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A sensation of the knee ‘catching’ or ‘locking’, which may feel a bit crunchy or clicky.
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A feeling of instability or ‘giving way’ in the knee.
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Difficulty bending, straightening or moving the knee.
If you tore your meniscus in an injury, you may also have felt a ‘pop’ in the knee.
Some small meniscus tears can heal on their own but many cannot, so it’s essential to get the correct diagnosis and treatment to help relieve your symptoms and prevent further damage.
What does a torn meniscus look like on the outside?
Some people notice swelling on either side of the knee. A torn meniscus can also bulge from the knee, causing a visible deformity. However, in many cases, there is no external evidence of a tear, so your doctor will recommend an MRI scan so they can take a closer look at the inside of your knee.
If you are unsure whether you need an MRI for a meniscus tear, Scan.com offers one-to-one consultations with an expert clinician who can recommend the next steps based on your symptoms. After your consultation, you are not obligated to book an MRI scan.
Torn meniscus knee MRI scan: What does it involve?
The MRI machine uses powerful magnetic fields and radio waves to create detailed cross-sectional images of your knee joint and surrounding soft tissues, including the menisci. It’s noninvasive and doesn’t involve radiation exposure. You'll need to remain perfectly still during the imaging process, which usually takes 20 to 40 minutes.
Before the MRI scan, your technician will ask you to remove any metal objects, jewellery, or clothing with metal zippers or fastenings. These can interfere with the magnetic field used in the MRI machine.
You'll lie flat on your back on the MRI table, with your knee positioned in a specialised device or coil that helps produce clear images of the knee joint.
In some cases, your technician may inject a contrast agent into a vein in your arm, which can help to enhance the visibility of the inside of the knee. This isn’t usually required, but we’ll let you know in advance of your scan if it is.
Meniscus tear MRI vs normal: What does a meniscus tear look like on an MRI?
Normal knee MRI
A normal knee shows the meniscus as a smooth, crescent-shaped structure with no breaks or tears. It is dark grey or black, and the outer edge is sharp and clear.
Abnormal knee MRI
An abnormal knee MRI will identify any issues with the meniscus. On MRI pictures of meniscus tears, a torn meniscus will look disrupted or abnormal. You may see bright, white vertical or horizontal lines through the menicus, or multiple irregular lines if you have a complex meniscal tear. Radial tears may extend from the centre towards the edge of the meniscus.
There may also be a build-up of fluid within or around the meniscus, which appears bright white or light grey.
What are my next steps if my MRI scan shows a meniscus tear?
If your MRI identifies a meniscus tear, several treatments are available, depending on the type and size of the tear, your age, your overall health, and how severe the tear is (grade 1, 2 or 3). Your clinician may refer you to an acute knee clinic for further tests and treatment.
Grade 1 or 2 meniscus tears usually require painkillers and physiotherapy. Grade 3 meniscus tear MRI results usually require physiotherapy, painkillers and a surgical procedure.
Medicines
Your clinician may recommend over-the-counter painkillers, such as paracetamol or ibuprofen, to help relieve your knee pain. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that can help reduce inflammation and swelling. If you are experiencing severe knee pain, your doctor may prescribe stronger painkillers.
Physiotherapy
Your clinician will recommend physiotherapy to help strengthen the knee joint and improve the mobility of your knee. You’ll have a specific set of exercises to do every day, sometimes multiple times a day. It’s important to do these exercises as recommended alongside any other treatment, such as surgery, as they can help with the rehabilitation process. You can also swim, cycle, walk or try other low-impact exercises that help to improve knee stability without causing pain.
Surgery
Your clinician may recommend surgery if you have a complex or severe meniscal tear, or if physiotherapy has not resolved the problem. A surgeon will carry out an operation called a knee arthroscopy, which is a type of keyhole surgery. During the surgery, they may trim or repair the torn meniscus or remove the damaged section of the meniscus. In some cases, such as older people with complex tears, the meniscus may be removed completely. You’ll also need physiotherapy for at least six weeks after the surgery.
How long does a meniscus tear take to heal?
Recovering from a meniscus tear can take time and patience. How long it takes to heal depends on several key factors.
Minor, stable tears may only need rest, ice, compression, and elevation (RICE), physical therapy exercises and medication for pain and swelling. The knee may improve in four to eight weeks, but it can take up to three months or longer depending on your age and physical health.
If the tear is more serious and requires surgery, you may need crutches and physiotherapy for around four to six weeks. Getting back to normal activities could take up to six months as you regain strength and flexibility.
If you're older or you have a degenerative condition, part or all of the damaged meniscus may need to be removed. Recovery can take up to four weeks, but you’ll need to adapt to the loss of the meniscus. This can take several months as your knee joint gets used to not having that shock absorber in place.
Dealing with a meniscus tear can be painful and frustrating, but an MRI can help to diagnose the injury quicker so you can get the right treatment - whether that’s rehabilitation through physiotherapy, or surgery. You can skip the NHS waiting lists and book a knee MRI with Scan.com at a time and place that’s convenient to you, so you can start to regain your mobility and strength.
Sources:
Bhan, K. (2020). Meniscal Tears: Current Understanding, Diagnosis, and Management. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359983/
Kim, SH, et al. (2021). Diagnostic Accuracy of Magnetic Resonance Imaging in the Detection of Type and Location of Meniscus Tears: Comparison with Arthroscopic Findings. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7914628/
Medial and Lateral Meniscus Tears. (N.D.) https://www.cedars-sinai.org/health-library/diseases-and-conditions/m/medial-and-lateral-meniscus-tears.html
Meniscus tear. (2023). https://www.bupa.co.uk/health-information/knee-pain/meniscal-tear
Torn meniscus. (2022). https://www.mayoclinic.org/diseases-conditions/torn-meniscus/diagnosis-treatment/drc-20354823
