When should you see a doctor for meniscus tear?

See a doctor if your knee locks or catches, gives way under your weight, will not fully straighten, or swelled up within a few hours of a twisting injury.

Those mechanical signs suggest a torn piece of cartilage is caught in the joint, which does not resolve on its own. Get care the same day if you cannot put weight on the leg at all, if the knee looks out of shape after a hard impact, or if it is hot and red with a fever. Many smaller tears calm down over a few weeks with rest, ice, compression, elevation, and gentle range-of-motion work, so make an appointment if pain, swelling, or stiffness is still limiting you at the three week mark. After about age 40 a meniscus can tear during ordinary movements like squatting, so persistent pain along the inner or outer edge of the joint is worth checking even without a clear injury. A clinician can examine the knee, order imaging if needed, and tell you whether physical therapy or a surgical opinion makes sense.