Knee meniscus surgery: trimming or repair, risks and recovery

Each knee has two menisci that act as shock absorbers between the thigh bone and shin bone. They tear with a twist on a bent knee, or gradually with age. Typical symptoms are catching, locking, sharp pain on turning and swelling that comes and goes.

Surgery is more clearly helpful when a torn fragment physically blocks the joint, causing true locking, or when a young person has a repairable tear. For a smaller degenerative tear in a knee that is also arthritic, a trust leaflet notes that diagnosis is often possible without surgery and that physiotherapy and injections are alternatives. Keyhole surgery does not treat the arthritis itself.

A good first step is a clear explanation from the surgeon of what the scan shows and which of your symptoms are likely to come from the tear.

Trimming (partial meniscectomy) removes the unstable torn edge and leaves the healthy rim. Recovery tends to be quicker because the knee can usually be used straight away, but less cushion is left.

Repair puts stitches or anchors through the tear so it can heal, aiming to preserve the cushion. It is considered mainly for tears in the better-supplied outer part of the meniscus. The price is a more protective rehabilitation, which commonly includes limits on bending and weight-bearing for a period; your surgeon will set out the exact rules.

Sometimes the decision is made during the operation, once the surgeon has looked inside, so it helps to know in advance that you may wake up with either procedure done.

You will be asked about medicines, allergies and previous anaesthetics. Fasting instructions apply if you are having a general anaesthetic; follow the leaflet from your hospital rather than general advice. The Hull leaflet describes local (awake) or general anaesthetic as options.

The surgeon makes small cuts at the front of the knee, inserts a camera and fine tools, inspects the cartilage, ligaments and menisci and then trims or repairs. Dressings and a bandage are applied and, in many units, you go home the same day with crutches or a brace if needed.

• Bring loose trousers that fit over a bandage.

• Arrange a lift home; you should not drive yourself.

• Tell the team if you take blood thinners.

Leaflets from two NHS trusts list infection, stiffness, nerve or blood vessel damage, blood clots, excessive swelling and anaesthetic complications. One adds complex regional pain syndrome, an uncommon chronic pain condition, and notes risk is higher in older people, people carrying extra weight, and people with heart conditions or diabetes. Neither leaflet gives percentages, so no figures are stated here.

Specific to the meniscus, a repair may fail to heal, and trimmed knees can feel less cushioned over time. These are reasonable matters to raise with your surgeon.

After trimming, leaflets describe walking on the leg straight away, or after a check before discharge, with gentle exercises to regain bend and strength. A Worcestershire leaflet suggests light work after about two weeks and heavier work later; the Hull leaflet says at least one week off work, longer for manual jobs.

Running and jogging are not expected for at least six months in the Worcestershire leaflet, and contact sports for at least nine months. Those figures cover arthroscopy generally, so a simple trim may be quicker and a repair slower; your surgeon's plan takes priority.

• Fever, chills, or persistent redness and warmth around the knee: contact the hospital or NHS 111 promptly.

• Pain that is rising despite your usual painkillers, or swelling that is growing.

• Calf pain with swelling, heat or redness: possible clot, seek urgent help.

• Discharge from a wound, or numbness near the joint.

• Chest pain or breathlessness: call 999.

• Is my tear one that can be repaired, and what happens if you cannot repair it?

• Would physiotherapy first be reasonable in my case?

• What can I put weight on, and for how long?

• When can I drive, work and exercise given my job and sport?

The operation itself does not differ by funding route. Waiting times, appointment flexibility and whether physiotherapy is included do. NHS pathways often expect a trial of physiotherapy before surgery for degenerative tears, while private care may offer an earlier date. Ask what review appointments are included.