Meniscus tear: the knee cartilage that catches, locks, and aches
Last updated September 3, 2026.
A meniscus tear is damage to the C-shaped cartilage cushions inside the knee, from a twisting injury (the classic young, sporting tear) or simple degeneration (the common over-50 tear that arrives with no memorable injury at all). Typical symptoms: pain along the joint line, swelling over hours to a day, catching, and sometimes locking. Most tears, especially degenerative ones, are managed without surgery: physiotherapy is the default, with the knife reserved for specific patterns.
What does it feel like?
The story divides by age: the young sporting tear (a planted-twist moment, pain at once, swelling over the next hours, catching on bending) versus the degenerative tear (over 50, often no injury: a knee that starts aching at the joint line, swells after activity, catches, and protests deep bending, stairs, and squatting). The mechanical symptoms are the characteristic ones: catching, clicking with pain, giving way, and the true lock (the knee physically will not straighten: the displaced fragment is blocking it). Pain sits at the joint line, the inner side more often than the outer.
Why does it happen?
The menisci are the knee's shock-absorbing washers, and they fail two ways: traumatic tears in healthy cartilage (twisting on a planted foot, deep squatting under load, the football-and-skiing injuries, often alongside the ACL) and degenerative tears in worn cartilage (the same cartilage aging that produces osteoarthritis: the tear is often part of the arthritis, not a separate accident). Degenerative tears are common, frequently found incidentally on scans, and often not the main source of the knee's pain.
What actually helps?
- The acute phase: relative rest from the aggravating (squatting, twisting, impact), ice, elevation, and simple painkillers; most swelling and pain settle over weeks.
- Physiotherapy: the core treatment: restoring range, rebuilding quadriceps and hip strength, and retraining movement; trials show it matches surgery for degenerative tears.
- Time: many tears (especially small and peripheral ones, which have blood supply) heal or quiet over 6-12 weeks.
- Surgery for the specific cases: the locked knee (prompt arthroscopy), repairable tears in the young (repair beats removal), and persistent mechanical symptoms despite genuine rehab; routine arthroscopy for degenerative tears is discouraged by the evidence.
- The long view: weight management and strength protect the knee's future: meniscus loss accelerates arthritis, which is why removal is avoided where repair is possible.
When is it an emergency?
The knee emergencies: a locked knee (physically cannot straighten) needs prompt orthopaedic assessment; a hot, red, very swollen knee with fever is same-day (septic arthritis until excluded); inability to bear any weight, gross deformity, or a numb cold foot goes in urgently. The swollen, catching, aching knee after a twist is next-day clinic medicine. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Will I need surgery?
Probably not: the evidence has reshaped this field: trials comparing arthroscopy with physiotherapy for the common degenerative (wear-related) meniscus tear show equivalent outcomes, so guidelines now steer most tears, especially degenerative ones, to structured physiotherapy first, and the majority settle over 6-12 weeks. Surgery keeps clear roles: the truly locked knee (the stuck fragment needs freeing), repairable tears in younger patients (suturing preserves the cartilage: repair beats removal for your knee's future), large unstable flap tears with persistent mechanical symptoms, and traumatic tears failing a genuine rehab course. Routine arthroscopy for a degenerative tear is increasingly viewed as low-value medicine.
What is the difference between catching and locking?
Both are mechanical symptoms, but they carry different weight: catching is a momentary painful snag on bending (the torn edge flicking), annoying but manageable within rehab; locking is the knee physically stuck (unable to fully straighten, with a hard block), meaning a displaced fragment (the bucket-handle pattern) is jammed in the joint, and that is a prompt-surgery situation because it will not rehab free. The middle symptom (giving way, clicking with pain) is common to both tears and other knee problems. If your knee ever locks truly (not just painfully reluctant: mechanically blocked), that is the get-seen-this-week sign, not the wait-and-see one.
Why does my doctor say the scan tear may not be the problem?
Because of the most replicated finding in knee research: meniscus tears on MRI are extremely common in middle-aged knees without any pain (studies find them in a large share of over-50s who feel fine), so a scan finding a tear does not prove the tear is the pain's source: the tear may be incidental wear, and the pain may be the knee's arthritis, tendons, or other structures. This is why good clinicians treat the knee, not the scan: symptoms, examination, and response to physiotherapy guide decisions, and MRI findings alone never justify arthroscopy. It is also why a meniscus tear on a scan is not a catastrophe: it may be your knee's normal middle age.
What does the physiotherapy actually involve?
A progressive 6-12 week rebuild: first the range (getting the swelling down and the knee bending and straightening fully: heel slides, gentle flexion), then the strength (quadriceps first: straight-leg raises, sit-to-stands, step-ups; then hips and hamstrings, since hip weakness drives knee load), then the control (balance and single-leg work, the foundations of twist tolerance), and finally the return-to-activity ladder (walking, then hills, then impact, then pivoting, each earned by the previous stage being symptom-free). The aggravating trio (deep squatting, twisting on a planted foot, kneeling) stays avoided until the strength holds. The exercises are unglamorous; the results, in the trials, match the scalpel for most tears.
Does a meniscus tear mean arthritis later?
The honest answer has a lever in it: meniscus damage (and especially meniscus removal) does increase later osteoarthritis risk, because the cartilage cushion that distributed load is compromised; the degenerative tear is often itself the first sign of the knee's arthritic process rather than a separate injury. The controllable part: the risk scales with how much meniscus is lost (why surgeons repair instead of trim whenever possible), with weight (every kilo multiplies through the knee), and with strength (the quadriceps are the knee's other shock absorber). So the answer is: some increased risk, yes, and the size of it is substantially yours to manage through weight, strength, and protecting the cartilage you have.
What can I do while I wait for it to settle?
The active-recovery list: relative rest (drop the twisting, squatting, kneeling, and impact; keep walking within comfort), ice for the swelling (15-20 minutes through a cloth, after activity), elevation when resting, simple painkillers as needed (paracetamol, or anti-inflammatories if you tolerate them), and the gentle range exercises from day one (heel slides, sitting knee bends: motion feeds cartilage). Pool work and stationary cycling are the fitness-preservers of choice. The trap to avoid: total rest, which stiffens and weakens the knee the physio will then have to un-do. Relative rest with movement is the craft; the couch is not the treatment.