A meniscus tear is a rip in one of the two C-shaped pads of cartilage that sit between your thighbone and shinbone, cushioning and stabilizing your knee joint. It’s one of the most common knee injuries, affecting athletes and older adults alike. About 28% of middle-aged and older adults have a meniscus tear visible on MRI, and that number climbs with age, reaching over 50% in people older than 80.
What the Meniscus Does
Each knee has two menisci: one on the inner side (medial) and one on the outer side (lateral). They’re made of tough, rubbery cartilage shaped to fit snugly between the rounded end of the thighbone and the flat top of the shinbone. Their primary job is spreading your body weight across a larger area of the joint surface so no single spot takes too much force. Without them, the pressure on your knee cartilage would concentrate in a small area, accelerating wear.
Beyond shock absorption, the menisci help stabilize the knee during movement, keep the joint surfaces aligned, and prevent the soft tissue lining of the joint from getting pinched as the knee bends and straightens. They also play a role in the knee’s natural “screw home” mechanism, the slight rotation that locks your knee into a fully straight position when you stand.
How Meniscus Tears Happen
Meniscus tears fall into two broad categories: traumatic and degenerative.
Traumatic tears happen suddenly, usually when the knee twists while the foot stays planted on the ground. This is common in sports that involve cutting, pivoting, or sudden direction changes, like basketball, soccer, and football. A hard tackle, an awkward landing, or a deep squat under load can all do it. Many people hear or feel a distinct pop at the moment of injury.
Degenerative tears are a different story. As cartilage wears down with age or arthritis, the meniscus becomes brittle and frail. Something as minor as stepping off a curb or rising from a chair can cause a tear. Some degenerative tears develop gradually with no specific injury at all. These tears are extremely common regardless of activity level, which is why so many older adults show tears on imaging without ever having had a knee injury.
Types of Tears
Not all meniscus tears look the same, and the pattern matters for treatment. The most common types include:
- Horizontal tears run parallel to the top of the shinbone, splitting the meniscus into an upper and lower layer. These are the most common pattern overall.
- Radial tears cut perpendicular to the curved edge of the meniscus, slicing through its fibers. Because they disrupt the structure that distributes load, radial tears can significantly affect knee function.
- Bucket-handle tears are a type of lengthwise tear where the inner portion flips into the center of the joint, like the handle of a bucket swinging inward. These often cause the knee to lock in place.
- Flap tears occur when a section of the meniscus tears partly free and folds over, catching between the joint surfaces during movement.
Why Location Matters for Healing
The meniscus has an uneven blood supply, and this is one of the biggest factors in whether a tear can heal on its own or be surgically repaired. The outer edge, sometimes called the “red zone,” has a good blood supply and a reasonable chance of healing. The inner portion, the “white zone,” has almost no blood flow. Tears in this area don’t heal well because the tissue can’t deliver the nutrients and cells needed for repair. Most treatment decisions hinge on which zone the tear is in, along with the tear pattern and the patient’s age and activity level.
Symptoms to Recognize
A meniscus tear doesn’t always announce itself dramatically. After an acute tear, you might feel a pop followed by pain and swelling that builds over the first day or two. Many people can still walk on the knee initially, which leads them to assume it’s a minor sprain.
The more distinctive symptoms tend to show up in the days and weeks that follow. Your knee may catch or click during movement. It may lock, meaning you temporarily can’t fully straighten or bend it, which happens when a torn fragment wedges between the joint surfaces. Some people describe the knee giving way or feeling unstable, as though it can’t fully support their weight. Swelling can come and go, often flaring after activity. Pain typically concentrates along the joint line, the crease where the thighbone meets the shinbone on either the inner or outer side of the knee.
Degenerative tears tend to come on more gradually. You might notice increasing stiffness, intermittent swelling, or pain with squatting and twisting that worsens over weeks or months.
How It’s Diagnosed
A doctor can often identify a likely meniscus tear during a physical exam by moving your knee and leg into specific positions, watching you walk, and asking you to squat. Tenderness along the joint line and pain with certain twisting maneuvers are strong clues.
MRI is the gold standard for confirming the diagnosis. It produces detailed images of soft tissue and can show the tear’s location, size, and pattern. For medial (inner) meniscus tears, MRI picks up about 93% of tears correctly. It’s somewhat less sensitive for lateral (outer) tears, catching around 69%, though it’s very accurate at ruling them out when they’re not there. X-rays won’t show a meniscus tear since cartilage doesn’t appear on X-ray, but they’re sometimes ordered to rule out fractures or arthritis.
Treatment Without Surgery
Many meniscus tears, especially degenerative ones, respond well to physical therapy without surgery. A structured rehab program focuses on strengthening the muscles around the knee (particularly the quadriceps), restoring range of motion, and improving balance and joint control. Rest, ice, compression, and anti-inflammatory medications help manage pain and swelling in the early phase.
Research comparing physical therapy to surgery in adults aged 18 to 45 with traumatic tears found that about 59% of those assigned to physical therapy alone recovered well enough that they never needed surgery. The remaining 41% eventually opted for surgery because their symptoms persisted. This suggests that starting with physical therapy is a reasonable first step for many people, with surgery available as a backup if the knee doesn’t improve.
When Surgery Is Needed
Surgery is generally considered when the knee locks and can’t fully extend or bend, when symptoms persist despite several months of physical therapy, or when the tear is in a location and pattern that’s amenable to repair. There are two main surgical approaches.
Meniscus repair stitches the torn edges back together. This is the preferred option when possible because it preserves the meniscus and its protective function. It’s most successful for tears in the outer, blood-rich zone. Recovery is slower, though, because the repaired tissue needs time to heal. You’ll typically use crutches and a brace for the first six weeks, with partial weight bearing during that time. Full return to sport generally takes six months or longer.
Partial meniscectomy removes the damaged portion of the meniscus. Recovery is faster since there’s no tissue that needs to knit back together. Most people are walking without crutches within a week or two and return to normal activities in four to six weeks. The tradeoff is that removing meniscus tissue means less cushioning in the joint long term.
Long-Term Impact on the Knee
One of the most important things to understand about meniscus tears is their relationship with knee arthritis. Losing meniscus tissue, whether from the tear itself or from surgery to remove damaged portions, increases the stress on the remaining cartilage surfaces.
A large study tracking patients over time found that 17% of people who had a partial meniscectomy later developed symptomatic knee arthritis, compared to 10% after meniscus repair and just 2.3% in the general population. Put another way, partial meniscectomy roughly doubled the arthritis risk compared to repair, and repair still carried about twice the risk of someone who never had a tear at all. The rate of arthritis-related medical visits after partial meniscectomy was nearly six times higher than in the general population.
This is a key reason surgeons prefer repair over removal whenever the tear allows it, and why many doctors recommend trying physical therapy before jumping to surgery. Preserving as much meniscus tissue as possible gives the knee the best chance of staying healthy in the decades ahead.