Meniscus tear

Also called Torn cartilage, Knee cartilage damage

A torn knee cartilage. In people over 40 it is usually wear rather than injury, and surgery for that has been shown not to work.

What it is

A tear in one of the two crescent-shaped cartilages that cushion the knee joint.

There are two quite different situations and conflating them is the source of a great deal of unnecessary surgery.

**Traumatic tears** in younger people follow a twisting injury, often in sport, frequently with a pop and swelling over hours. Some of these, particularly larger tears causing locking, benefit from surgical repair.

**Degenerative tears** in people over about 40 are part of the same process as osteoarthritis and often occur with no injury at all. They are extremely common on MRI in people with no knee pain whatsoever. Multiple high-quality trials have shown that arthroscopic surgery for degenerative meniscal tears is no better than physiotherapy, and it remains one of the most performed unnecessary operations in orthopaedics.

That is the single most useful thing in this entry: a scan showing a degenerative meniscal tear in a middle-aged knee usually explains very little and rarely justifies an operation. Exercise therapy is the treatment.

The exception is a true locked knee, where a torn fragment is physically blocking movement. That needs prompt surgical assessment.

Signs you might notice

Pain along the joint line, on the inside or outside of the knee.

Swelling, developing over hours rather than immediately.

Catching, clicking or a sensation of the knee giving way.

Difficulty fully straightening or bending the knee.

Pain on twisting, squatting or getting out of a car.

Urgent: a knee that is locked and cannot be straightened; a knee that swelled immediately within minutes of an injury, which suggests bleeding and possibly a cruciate ligament tear or fracture; inability to weight bear; or a hot, red, very painful swollen knee with fever, which may be septic arthritis and is an emergency.

How it can affect day-to-day life

The word torn does most of the damage. People hear it and stop using the knee, which weakens the thigh muscle, which is the main thing protecting the joint.

Quadriceps strength is the single best predictor of function, and it is what exercise therapy builds.

Because a scan almost always finds something in a knee over 40, imaging early tends to lead to surgery rather than to better outcomes.

For people who do have surgery, rehabilitation determines the result far more than the operation, and it is often skipped.

Weight, activity and general fitness matter here as much as anything specific to the knee.

Supporting someone well

Do not rush to a scan for gradual knee pain in someone over 40. Start with physiotherapy.

Ask for a structured exercise programme and do it for at least three months before considering surgery.

Build the quadriceps. This is the treatment.

Keep moving and keep weight bearing unless told otherwise.

Get a genuinely locked knee assessed promptly.

Ask directly, if surgery is proposed for a degenerative tear, what the evidence says compared with exercise therapy.

After any knee surgery, do the rehabilitation properly; it matters more than the procedure.

Treat a hot swollen knee with fever as an emergency.

Where to get help

A GP practice, or self-referral to physiotherapy in most areas.

Urgent care for a locked knee, immediate swelling, or inability to weight bear.

A and E for a hot, red, painful knee with fever.

Arthritis UK and the Chartered Society of Physiotherapy publish knee exercise programmes.