The meniscus is the pair of crescent shaped cartilage pads inside each knee, sitting between thigh bone and shin bone, spreading load and steadying the joint.
Tear one and you join a very large club. What happens next should depend almost entirely on which of two quite different injuries you actually have, because they share a name and not much else.
Two injuries, one name
The traumatic tear happens to younger, active knees in a single moment: a twist on a planted foot in football, a deep loaded squat, a tackle. There is swelling within a day or two, often a specific painful spot along the joint line, and sometimes mechanical symptoms.
The degenerative tear happens to knees over about 40, frequently with no injury the person can name. The meniscus dries and frays with age the way a rubber washer does, and a routine movement is simply the moment it was noticed. This kind is extremely common: MRI studies of pain free adults in middle age find meniscal tears in roughly a third of knees, rising steeply with age.
That statistic carries the whole argument. If a third of comfortable knees contain a torn meniscus, then finding a tear on your scan does not prove the tear is what hurts. In an older knee it is usually one feature of the same gradual change described in our guide to knee osteoarthritis.
Does this sound like yours?
- Pain along the joint line, the seam between thigh and shin bone, inner side more often
- Worse twisting, pivoting, squatting deeply or rising from squatting
- Swelling after activity, sometimes delayed to the next day
- Catching or clicking sensations
- Occasionally a knee that locks
On locking, a distinction matters. A knee that catches momentarily and releases is common and not alarming. A knee that gets genuinely stuck, unable to fully straighten until it is wiggled free, suggests a displaced fragment blocking the joint, and that specific pattern is one of the few that pushes towards early surgical opinion.
What the evidence did to keyhole surgery
For decades the standard answer was arthroscopy: trim the torn piece away. It is quick, it looks logical, and it was one of the most performed operations in the world.
Then it was tested properly. A series of randomised trials compared arthroscopic surgery against structured exercise, and against sham surgery where patients received only skin incisions, for degenerative tears in middle aged knees. The results were consistent: surgery performed no better than exercise, and no better than the placebo operation, at one and two years. Removing meniscal tissue also leaves the joint less cushioned, which is associated with faster arthritis later.
Guidelines followed, and keyhole trimming for degenerative tears is now discouraged in most of the world. If it is offered as a first option for a non locking, middle aged knee, asking what exercise based treatment was tried first is a fair question.
The traumatic tear in a young knee is a different conversation. Tears in the outer, blood supplied rim can sometimes be stitched and genuinely repaired, and a repair that saves the meniscus is worth a great deal over the following decades. Young, injured, swollen knees deserve a surgical opinion, particularly alongside a ligament injury such as an ACL rupture.
What rehabilitation looks like
The programme is close to the one for a sore arthritic knee, because the goal is identical: muscles absorbing load before it reaches the joint.
- Sit to stands for the pattern daily life actually uses
- Wall squats for quadriceps strength at an angle the knee tolerates
- Step ups, controlled down as well as up
- Straight leg raises on the days the knee is irritable
- Calf raises for the shock absorption below the knee
The knee strength set sequences all of this with doses. Expect meaningful change over six to twelve weeks, use the four out of ten rule for discomfort that settles within a day, and avoid deep loaded squatting and pivoting sports early on while tolerance rebuilds.
Most degenerative tears become quiet with this approach. The tear itself may still be visible on a future scan; the knee simply stops caring, which is the outcome that matters.
Get it assessed if
The knee locks solid and cannot be straightened, which deserves prompt attention. Also if this was a real injury in a young active knee with early swelling, if the knee repeatedly gives way, if swelling keeps returning without cause, or if six to eight weeks of honest strength work has changed nothing.
Otherwise, treat the scan finding the way you would treat grey hair discovered in a photograph: real, common at your age, and very rarely the emergency it first appears.