Two completely different problems share the name “meniscal tear,” and confusing them is behind a great deal of unnecessary knee surgery. Almost everything that matters about your tear follows from which one you have.
- A traumatic tear — a healthy meniscus torn by a specific event, usually a twist on a planted foot, usually in a younger and more active knee. There is a date. Often there was a pop, and swelling over the following day.
- A degenerative tear — a meniscus that has become brittle over years and has split without a real injury, in a knee that generally has some arthritis alongside it. There is usually no date, or the date is something trivial like standing up from gardening.
The scan report can read almost identically for both. The right treatment is close to opposite.
What the meniscus actually does
Each knee has two — wedge-shaped rings of tough fibrocartilage sitting between the end of the thigh bone and the top of the shin bone. They are not spacers. They convert the load coming down a rounded femur onto a flat tibia into a spread-out pressure across a wide area, and they contribute to stability and to how the joint is lubricated.
The consequence is the important part: load-bearing area is everything. Remove meniscal tissue and the same body weight is carried through a smaller patch of cartilage, at higher pressure, for the rest of your life. That is why meniscus is preserved wherever it can be, and why a generation of routine meniscectomy produced knees that wore out early.
Blood supply explains what can heal. The outer third has a genuine blood supply and can knit together if it is repaired. The inner two-thirds is largely avascular, which is why a tear there usually cannot be stitched with any realistic expectation of healing. Where a tear sits therefore determines whether repair is even on the table.
The degenerative tear, and the evidence that changed the answer
This is where most people over about forty-five sit, and it is the part of this page most worth your time.
Over the last fifteen years a series of high-quality randomised trials — including trials in which patients were randomised to arthroscopy or to a sham operation and did not know which they had received — have tested arthroscopic partial meniscectomy for degenerative tears against structured physical therapy and against placebo surgery. The consistent finding is that the surgery does not produce better outcomes in this group. Major guideline bodies now recommend against it as a first-line treatment for degenerative meniscal tears with or without accompanying arthritis.
The reason is not that the tear is imaginary. It is that in a knee of that age the tear is usually a feature of the arthritis rather than a separate fixable problem sitting on top of it. Trim the tear and you have removed some meniscus from a knee that already had too little functioning cartilage, and left the actual pain generator untouched.
There is also a plain fact about scans that is worth knowing before you look at your report: degenerative meniscal tears are extremely common in people with no knee pain at all, and they become steadily more common with age. Finding one does not establish that it is your problem.
Root tears — the one that genuinely gets missed
A meniscal root tear is a detachment where the meniscus anchors to the bone at the front or back of the tibia. It deserves its own section because it is under-recognised and because it does not behave like other tears.
The root is what stops the meniscus being squeezed sideways out of the joint under load. Detach it and the meniscus extrudes — it slides out of position and stops carrying load at all. Biomechanically, an untreated posterior root tear is close to having no meniscus in that compartment, and the joint can deteriorate surprisingly quickly afterwards, sometimes with a painful stress reaction in the bone underneath.
The presentation is characteristic and easily dismissed: a sudden pop or tearing sensation at the back of the knee, often doing something entirely ordinary like standing from a deep squat, followed by pain that does not settle in the expected way. It is worth naming specifically because this is the degenerative-age tear where an operation may genuinely be indicated, in exactly the age group where the evidence says most tears should not be operated on.
When the knee actually locks
A true mechanical block is different again. A displaced fragment — classically a bucket handle tear, where a longitudinal split flips into the middle of the joint — physically prevents the knee straightening. The knee is stuck, not just sore.
That is a mechanical problem and no injection unblocks it. A genuinely locked knee is one of the clearest indications for arthroscopy there is, and in a younger knee with a peripheral tear the goal is repair rather than removal.
Worth distinguishing from what most people mean by locking, which is catching, clicking, or a momentary sharp pain that stops them moving. That is common, it is usually not a displaced fragment, and it does not carry the same urgency.
How this is assessed here
The examination decides what the scan means. Where the joint line is tender, whether the knee straightens fully, whether there is a bounce at the end of extension, how the knee behaves under rotation and load, and whether there is fluid.
X-rays are taken standing rather than lying down, because a knee that is not being loaded looks better than it is — and in a knee with a suspected degenerative tear, the amount of arthritis present is the single most important piece of information for deciding what to do next. Ultrasound is used in the room for the surrounding soft tissue, for fluid, and to place any injection under direct vision.
MRI is used to answer a defined question — is this a root tear, is this repairable, is there a discrete cartilage defect — rather than as a starting point. Ordered without a question, it reliably finds things that were always there.
What treatment actually looks like
Where the tear is degenerative and the knee has arthritis
The problem being treated is the arthritis, and the tear travels with it. Load management and proper rehabilitation come first and are the most under-done treatment in all of orthopedics. Where an injection is appropriate, platelet-rich plasma is the usual choice here, placed under ultrasound guidance, and the case for it is the case set out on the knee arthritis page — knee osteoarthritis is where the randomised evidence for PRP is strongest anywhere in orthopedics.
What PRP is not: a treatment that repairs a torn meniscus. No injection stitches a tear back together, and any practice implying otherwise is overselling. What it can do is address the inflamed, painful joint the tear is sitting in.
Where the tear is traumatic and repairable
The priority is preserving tissue. A peripheral tear in a vascular zone in a younger knee is repaired rather than trimmed, accepting a considerably longer rehabilitation in exchange for keeping the meniscus. Biologic augmentation of a repair is an area of genuine and active interest rather than an established standard, and it will be described to you as such.
Where a fragment is genuinely blocking the knee
Arthroscopy, promptly, with repair preferred where the tear pattern and the tissue allow it. See knee surgery in Dallas.
The honest summary
If you are over forty-five, your knee has been sore for months without a specific injury, and a scan has found a meniscal tear, the evidence says an operation is unlikely to be the answer and that treating the knee as an arthritic knee usually is. If you are thirty, your knee twisted, it swelled the next day and it now catches, that is a different conversation entirely. If your knee suddenly popped doing something ordinary and has not behaved since, a root tear should be specifically looked for.
Being able to say all three of those things is the point of seeing someone who both operates and injects.
Common questions
Do I need surgery for a meniscal tear?
Usually not, if the tear is degenerative and you are over about forty-five. Multiple randomised trials, including sham-controlled ones, have found that arthroscopic partial meniscectomy for degenerative tears does not produce better outcomes than structured rehabilitation, and major guideline bodies now recommend against it as a first-line treatment. Surgery keeps a clear role for a knee that is genuinely locked, for a repairable traumatic tear in a younger knee, and for a meniscal root tear.
Can a meniscal tear heal on its own?
It depends entirely on where it is. The outer third of the meniscus has a real blood supply and tears there can heal, particularly if they are repaired. The inner two-thirds is largely avascular and tears there do not knit together. That said, a tear that does not heal structurally can still stop hurting, which is why many people do well without anything being done to the tear itself.
Will PRP repair my torn meniscus?
No, and be careful with any clinic that suggests otherwise. No injection available today stitches a torn meniscus back together. What PRP can do is treat the painful, inflamed joint the tear is sitting in, which in a degenerative knee is usually where the pain is actually coming from. Biologic augmentation of a surgical meniscal repair is a separate and genuinely promising area, but it is described here as active interest rather than established standard.
What is a meniscal root tear and why does it matter?
It is a detachment of the meniscus from its bony anchor at the front or back of the tibia. It matters because the root is what stops the meniscus being squeezed out of the joint under load. Once detached, the meniscus extrudes and effectively stops working, so biomechanically the knee behaves much like one with no meniscus in that compartment, and it can deteriorate quickly. The classic story is a pop at the back of the knee while standing up from a deep squat. It is under-recognised and worth specifically asking about.
My MRI says I have a meniscal tear but my knee has hurt for a year with no injury. What does that mean?
Most likely that the tear is degenerative and part of a broader arthritic process rather than a separate fixable problem. Degenerative meniscal tears are very common in people with no knee pain at all, and they become more common with age. The useful next step is a standing X-ray to see how much arthritis is present, because that changes the plan far more than the tear itself does.
How long is recovery after meniscus surgery?
Very different depending on what is done. Trimming a fragment is a quick recovery measured in weeks, which is part of why it was done so freely for so long. A repair, which preserves the meniscus, involves protected weight-bearing and a restricted range for a period and a return to sport measured in months. That trade is usually worth making in a younger knee, because keeping meniscal tissue protects the joint surface for decades.
