What Causes a Meniscus Tear, and Do You Always Need Surgery?

You have two menisci in each knee. One sits on the inner side (medial meniscus) and one on the outer side (lateral meniscus). They are crescent-shaped pads of tough, rubbery cartilage between the thighbone and the shinbone. Think of them as shock absorbers. They spread the force of every step across a wider area, which protects the smooth cartilage on the bone surfaces.

When a meniscus tears, it can catch, swell and hurt. But the story rarely ends at the knee itself. The alignment of your whole leg, from hip to ankle, determines how much pressure the inner or outer compartment of the knee takes. That matters when deciding on treatment.

What does a torn meniscus feel like?

A torn meniscus typically causes pain along the joint line, which is the crease where the two bones meet. You may also notice swelling, stiffness, or a feeling that the knee catches or locks in certain positions. Some people describe a feeling that the knee gives way.

The symptoms of a meniscus tear can overlap with other conditions of the inner knee, such as pes anserine bursitis or an MCL injury. That is why accurate imaging matters.

What causes a meniscus tear?

A meniscus tear is caused either by a sudden force, usually twisting on a planted foot, or by gradual wear as the cartilage becomes less resilient with age. In many adults over 40, a degenerative meniscal tear can happen with a movement as simple as standing up from a low chair.

There is an important overlap between a degenerative meniscal tear and early arthritis. The meniscus protects the joint surface. As it wears thin, the cartilage gets less protection, and the two problems can feed into each other. Seeing the bigger picture, your full lower limb alignment, helps clinicians understand why one side of the knee is wearing faster than the other.

Can a meniscus tear heal without surgery?

Yes, many meniscus tears in adults settle without surgery. Research shows that for degenerative tears, a structured rehabilitation programme often gives results comparable to arthroscopy (keyhole surgery). The decision depends on the type of tear, your symptoms, and how your knee responds to physiotherapy over several weeks.

ScanAlign does not provide treatment. It provides the diagnostic imaging that helps you and your specialist make an informed decision about what to do next.

How does leg alignment affect a meniscus tear?

Leg alignment directly changes how load is shared across your knee. If your leg angles inward (knock-kneed), the outer compartment takes extra force. If it angles outward (bow-legged), the inner compartment is overloaded. Either pattern puts more stress on the meniscus on that side. This makes tears more likely and slower to settle.

This is the part that standard imaging often misses. An MRI of the knee is taken lying down. In that position, the muscles relax and body weight is taken off the joint. The result is a detailed picture of the tear itself, but no information about the mechanical forces acting on it when you stand and walk.

Your body is a connected chain from your feet to your head. A slight tilt at the hip, or an ankle that rolls inward, changes how force travels through the knee. Pain often shows up in a different place from the real cause. Seeing the whole chain under load reveals patterns that a lying-down scan of a single area cannot.

How does a standing EOS scan help with a meniscus tear?

A standing EOS scan captures your skeleton from head to toe while you carry your full body weight. It shows whether your leg alignment is putting one compartment of the knee under more stress than it should take. This gives your specialist context that lying-down imaging does not provide.

ScanAlign standing imaging uses about 90% less radiation than a standard X-ray, around ten times less. The scan takes just seconds and produces a full-length image of your skeletal alignment under real-life conditions.

An EOS scan does not replace MRI for confirming the tear itself. It adds the alignment layer. Together, MRI and standing imaging give a complete picture: the state of the soft tissue and the mechanical setting it works in. That combination helps surgeons and physiotherapists plan the most effective approach.

Before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in your pelvis, your legs or your spine changes what will actually help.

If you are thinking about whether to book a standing knee scan, the free video consultation is a good place to start. A specialist radiographer will review your situation and tell you whether a standing scan would add useful information.

Frequently asked questions about meniscus tears