A Meniscus Tear on Your Knee MRI

The menisci. Each knee has two C-shaped pads of cartilage between the thigh bone and the shin bone: the medial meniscus on the inner side and the lateral meniscus on the outer side. They help spread load across the joint. Reports name the part involved: the anterior horn at the front, the body in the middle, the posterior horn at the back, and the root, where each end anchors to the bone.

Signal and grades. A healthy meniscus looks dark on MRI. Many reports grade brighter signal inside it from 1 to 3. Grades 1 and 2 stay inside the meniscus without reaching its surface, which radiologists read as wear within the tissue (intrasubstance or mucoid degeneration), not a tear. Grade 3 reaches the surface, and that is what a report calls a tear. Numbered grades are used inconsistently, and a 2026 radiology consensus panel favoured describing what is seen and where instead (Nguyen et al., 2026). A report written that way may say “intrasubstance signal” rather than grade 2, and “signal extending to the articular surface” rather than grade 3. After meniscus surgery these rules change: a repaired or trimmed meniscus can show signal that would mean a tear in an untreated one, so a report after surgery is read alongside the operation details and earlier scans (Fierstra and White, 2022).

The words that come with it. These are the terms you are most likely to see beside a tear.

Tears are common in knees that do not hurt. In a Framingham study of 991 adults aged 50 to 90 who were not chosen for knee problems, MRI showed a meniscus tear or a worn-away meniscus in 19 percent of women aged 50 to 59, ranging up to 56 percent of men aged 70 to 90. Sixty-one percent of the people with a tear had had no knee pain, aching or stiffness in the previous month (Englund et al., 2008).

With arthritis, a tear is part of the picture. Among people whose X-rays already showed knee osteoarthritis, a tear was found in 63 percent of those with knee pain, aching or stiffness on most days and in 60 percent of those without (Englund et al., 2008). A guideline panel writing in the BMJ described meniscus tears in degenerative knees as common, usually incidental and unlikely to be the cause of knee pain (Siemieniuk et al., 2017). That does not make the pain less real; it means the plan is built around the whole knee rather than the tear. The joint space narrowing guide explains the arthritis wording on an X-ray report.

Catching does not decide it. Catching, clicking and brief locking that frees itself were common among the people in the surgical trials. For degenerative knee problems, the guideline panel found no important lasting benefit from surgery in any group, and judged that this holds whatever the catching, with one possible exception: a knee that cannot be fully straightened, a true locked knee (Siemieniuk et al., 2017).

Degenerative or from an injury. European knee surgeons’ consensus statements define a degenerative tear as one that develops slowly, without a significant injury, in someone over 35, typically as a horizontal split (Beaufils et al., 2017), and a traumatic tear as one whose symptoms start suddenly with an injury forceful enough to cause it, such as a twist on a planted foot (Kopf et al., 2020). The two are managed differently, which is why your story matters as much as the scan.

The labels on a report vary. Words such as degenerative, traumatic, stable and repairable are used inconsistently between reports, and the 2026 radiology consensus favoured describing what is seen and where (Nguyen et al., 2026). Whether a tear came from wear or from an injury is worked out from your history and the examination, and whether it can be repaired is a surgeon’s decision, not something the scan can settle.

Randomised trials have compared keyhole surgery to trim a degenerative tear (arthroscopic partial meniscectomy) with a placebo operation and with exercise. People improved in both groups, and the operation did not add a lasting benefit.

• Against a placebo operation. In 146 people aged 35 to 65 with symptoms of a degenerative tear of the inner meniscus and no arthritis, trimming the tear gave no better result at 12 months than a placebo (sham) operation (Sihvonen et al., 2013).
• Against exercise. In 140 adults aged 36 to 60 with a degenerative tear of the inner meniscus, almost all without arthritis on X-ray, there was no meaningful difference over two years between 12 weeks of supervised exercise and surgery. Thigh strength was better in the exercise group at three months, and 19 percent of that group later had surgery, with no additional benefit (Kise et al., 2016).
• The guideline. The BMJ guideline panel made a strong recommendation against keyhole surgery for nearly all people with degenerative knee disease, its term for knee pain, particularly after 35, with or without a meniscus tear, arthritis on imaging, catching or a sudden start. Most people improved without it, and any added benefit from surgery was small, uncommon and had faded by a year (Siemieniuk et al., 2017).
• The surgeons’ consensus. A consensus of 84 European surgeons and scientists agreed that trimming should not be offered as the first treatment for a degenerative tear, and kept it as an option after a proper assessment, when the knee has not responded well enough to non-surgical care (Beaufils et al., 2017).
• What that means. A degenerative tear on a report is not a reason to go straight to surgery, and exercise-based rehabilitation is the usual first step. The two documents differ on what comes after: the BMJ panel advises against the operation in nearly all cases, while the European consensus keeps it for a knee that still limits you after non-surgical care. A surgical opinion at that point is reasonable, and your family doctor can arrange it.

Many tears settle without surgery, but some knees and some reports call for an orthopaedic surgeon’s view early. Your family doctor can arrange the referral.

• A locked knee. The knee will not straighten fully and you cannot unlock it yourself, often after a twist. This is the one possible exception the guideline against keyhole surgery left open (Siemieniuk et al., 2017). Get it assessed the same day by your family doctor, urgent care or emergency for an urgent orthopaedic referral.
• A bucket-handle tear. A displaced bucket-handle tear on the report is worth an early surgical opinion, even if the knee has since unlocked, because when a tear from an injury needs repair, European knee surgeons advise repairing it as early as possible (Kopf et al., 2020).
• Some root tears. A root tear changes how load passes through the joint, so it is worth a surgeon’s view. In a review of 11 studies of recent root tears, all of low to moderate quality, function improved with every approach after a year. Repair may have given better function at 12 months, and arthritis progressed on X-ray in every group, possibly more slowly after repair. More extrusion, bow-legged alignment and existing wear went with poorer results, while age on its own did not (Eseonu et al., 2022). Whether a repair suits your knee is a question for a surgeon.
• A younger person with a clear injury. The guideline against keyhole surgery did not cover young people with sports injuries or anyone with major trauma (Siemieniuk et al., 2017). For tears from an injury, European knee surgeons favour keeping the meniscus, by repairing it or leaving a stable tear in place, over trimming it, because long-term results after trimming are worse; most of that consensus rested on low-quality evidence or surgeons’ opinion (Kopf et al., 2020). In a trial of 121 adults aged 18 to 40, both groups improved, and early surgery did not give a clearly better result at 12 months than 12 weeks of supervised exercise and education, though the trial could not rule out a meaningful advantage for surgery; about one in four of the exercise group went on to have surgery (Skou et al., 2022). An early opinion is about whether the tear can be repaired, not a commitment to surgery.
• A knee that gives way. Giving way with a twist can come from a ligament injury as well as the meniscus, and it needs checking. The ACL injury page covers that side.

I start with the story, because it sorts these reports faster than the scan does: your age, whether there was a twist or a fall, how soon the knee swelled, whether it catches or truly locks, whether it gives way, and what it stops you doing. A knee that will not straighten needs a medical assessment the same day, and a displaced bucket-handle tear on the report needs an orthopaedic referral through your family doctor before rehabilitation starts. I cannot order imaging; when further imaging would change the plan, I flag it and refer you.

On examination I check for swelling, measure how far the knee straightens and bends, press along the joint line, test the ligaments, and test the strength of the quadriceps and hip and your balance on one leg. I screen the hip and lower back, because both can send pain to the knee. I read the report alongside that, giving the cartilage, the ligaments and any arthritis as much attention as the meniscus.

For a tear from gradual wear, the plan is usually progressive strengthening for the quadriceps and hip, with walking or cycling, and a few weeks of easing off sharp twisting and deep loaded squats while strength builds, then a gradual return. The exercise program in the trial comparing exercise with surgery ran for 12 weeks (Kise et al., 2016), and progress is judged on what the knee can do rather than on a repeat scan. After a recent injury in a younger person, rehabilitation starts while the question of repair is settled with a surgeon; after surgery, the plan follows your surgeon’s protocol. The rehabilitation stages are set out on the meniscus tear page.