Knee ligament injury: symptoms, treatment and recovery

Treatment depends on which ligament is injured, how badly, and whether other structures such as the meniscus are damaged. NHS Greater Glasgow and Clyde (GGC) says all injuries follow an early care plan (PEACE and LOVE) and then rehabilitation. Royal Cornwall Hospitals NHS Trust advises that for mild injuries such as sprains, PRICER (protect, rest, ice, compression, elevation and rehabilitation) plus time allows the injury to heal, while more severe injuries may need imaging such as an MRI scan, and you may or may not need an operation.

The aims of treatment, according to Royal Cornwall, are to manage pain, minimise swelling, maintain the range of movement in the knee joint, and keep the front thigh (quadriceps) muscles working while stopping the hamstrings taking over too much. Physiotherapy is an integral part of managing knee injuries, whether or not you have an operation.

Royal Cornwall advises that in the first 72 hours you rest your leg, elevate it above hip level, apply a cold pack regularly and use crutches or a support bandage for walking. Use ice packs or frozen peas wrapped in a wet thin towel for up to 15 minutes every few hours, and do not leave an ice pack on for more than 20 minutes at a time in one hour.

The NHS suggests PRICE therapy for the first 2 to 3 days after a sprain: protection, rest, ice for up to 20 minutes every 2 to 3 hours, compression with a bandage and elevation, avoiding heat, alcohol and massage in the first couple of days to help prevent swelling. When you can move the joint without pain stopping you, try to keep it moving so it does not become stiff. At first, try painkillers such as paracetamol and ibuprofen gel, mousse or spray, and ask a pharmacist for advice.

You can put weight through the injured knee, but be guided by your pain and swelling, says Royal Cornwall. Walk little and often.

The NHS lists, for a sprain, pain, tenderness or weakness, swelling or bruising, and being unable to put weight on the injury or use it normally. For the knee in particular, the NHS says unstable, gives way when you try to stand, unable to straighten, or a popping sound during injury can point to a torn ligament, tendon or meniscus, or cartilage damage.

NHS GGC describes each ligament:

• ACL: immediate pain and tense swelling after trauma, usually non-contact, such as landing from a jump, pivoting or decelerating suddenly, often with an audible pop or crack or a feeling of something going out. Instability and locking are common afterwards.

• MCL: pain over the inner side of the knee; heat, swelling and pain at the end of bending and straightening may be present. It usually follows a sideways strain on a fixed foot (GGC); Royal Cornwall says twisting the knee or a direct blow to the outside of the knee, often during sport.

• PCL: effusion (swelling), stiffness and mild to moderate pain at the back of the knee, with pain on deep bending such as squatting or kneeling; Royal Cornwall says you may have few or no symptoms and may be able to walk normally.

• Posterolateral corner and lateral ligament: usually combined with ACL or PCL tears, potentially disabling, and needing specialist assessment (GGC).

GGC describes the MCL as the most frequently injured ligament of the knee, while the ACL is the primary stabilising structure limiting forward movement of the shin on the thigh bone. Royal Cornwall says a PCL injury might happen from direct contact in sport, for example the shin falling on a bent knee, from twisting the knee, or from the knees hitting the dashboard in a car accident.

GGC says the diagnosis is made on clinical history and examination. Your clinician may find heat, swelling and deformity, with pain at the end of bending and straightening. In severe injuries, testing ligament stability may have to wait until the subacute phase, when swelling and bleeding are under control. They test stability by applying sideways stress to the knee for collateral ligaments and forward or backward pulling movements for the cruciate ligaments.

Royal Cornwall says more severe injuries may need further imaging such as an MRI, CT or X-ray, and that a specialist physiotherapist may follow up where a major ligament or cartilage injury is suspected. The diagnosis should be made by an orthopaedic consultant or a team member working under their supervision.

Recovery times vary widely. GGC lists simple ligament injuries as 6 to 8 weeks of rehabilitation and complex injuries as around 6 months. Royal Cornwall gives approximate healing times of 3 to 9 months for the MCL and 6 to 12 months for the PCL, and 9 to 12 months before returning to sport after ACL surgery.

The NHS says that after a sprain most will feel better after 2 weeks, but you should avoid strenuous exercise such as running for up to 8 weeks as there is a risk of further damage, and severe sprains can take months to get back to normal.

GGC says MCL injuries up to grade III usually heal without surgery, and that surgical repair followed by immobilisation of an isolated MCL tear does not enhance healing. Isolated PCL injuries can usually be managed without surgery; surgery is recommended for acute injuries with severe instability (more than 10 mm of backward movement of the shin) or when other ligaments are also torn.

For the ACL, Royal Cornwall says it is rare for it to heal completely by itself; depending on the injury and lifestyle you may manage with physiotherapy, while younger people and those with active lifestyles may be offered reconstructive surgery, which uses a graft from the hamstring or patella tendon and fully restores the functioning of the knee in more than 80% of cases. GGC notes there is ongoing debate about whether ACL tears can be managed successfully without surgery using neuromuscular rehabilitation.

If surgery is an option, a knee surgeon will discuss the risks and benefits, and prehabilitation exercises help you prepare for and recover from the operation (Royal Cornwall).

• Call 999 or go to A&E if you heard a crack when you had your injury, the knee has changed shape or is pointing at an odd angle, the leg or foot is numb, tingling or has pins and needles, or the skin has turned blue or grey or is cold to touch (NHS). You may have broken a bone.

• Get help from NHS 111 if the knee is very painful or getting worse, there is a large amount of swelling or bruising, you cannot put weight on it or walk more than a few steps, it is very stiff, or it has not improved after treating it yourself (NHS).

• Get advice from 111 if your knee locks, gives way or painfully clicks, or if you have a very high temperature with redness or heat around the knee, which can be a sign of infection (NHS knee pain advice).

• GGC says vascular compromise and altered sensory or motor function require urgent surgical intervention and immediate referral.

• See a GP if knee pain does not improve within a few weeks (NHS).

The UK sources used for this page focus on adults and sports injuries. Children and teenagers with a swollen, unstable or locked knee after a twist should be seen urgently, because growth plates and other structures can be involved. Ask your GP, NHS 111 or an urgent treatment centre.

None of the UK sources used here discusses knee ligament injury in pregnancy. If you are pregnant and injure your knee, seek an assessment at an urgent treatment centre or from your GP or midwife, and tell staff you are pregnant before any scans or medicines.

After an injury, you may be seen at an emergency department, a minor injuries unit or a fracture clinic. Royal Cornwall says its fracture clinic refers patients to a physiotherapist for rehabilitation or prehabilitation, and sometimes to a knee surgeon. In many areas you can refer yourself to NHS community musculoskeletal (MSK) services for physiotherapy without seeing a GP, the NHS says, though NHS physiotherapy may not be available everywhere and waiting times can be long; you can also get physiotherapy privately from a chartered physiotherapist.

Private MRI scans and orthopaedic consultations are also available. Whichever route you use, make sure the surgeon and physiotherapist agree a plan and ask for scan reports to be shared with your GP.