Knee giving way: why it happens and when to get it checked

People use "giving way" for several different experiences: a knee that suddenly buckles when you put weight on it, a feeling that it might collapse on stairs or when you turn, or a sense that it is wobbly and cannot be trusted. The NHS groups it with locking and painful clicking as features that need prompt attention, and says that if your knee locks, gives way or painfully clicks you should get advice from NHS 111. Painless clicking, it adds, is normal.

It helps to think about the structures that hold the knee steady. Arthritis UK explains that the knee is formed where the thigh bone, shin bone and kneecap meet, and that four main ligaments act like strong ropes to keep the bones in place. The collateral ligaments on either side control sideways movement and the cruciate ligaments inside the joint control backward and forward movement. Two wedge-shaped pieces of meniscal cartilage act as shock absorbers and, in its words, help to cushion and stabilise the joint.

The NHS says knee pain can be a symptom of many conditions and cautions against self-diagnosis. Its tables separate knee pain after an injury from knee pain with no obvious injury, and giving way features mainly in the first group.

If the first episode followed a twist, a fall or a sports injury, a ligament or meniscal problem is the main consideration, and it is worth mentioning exactly what happened, including any popping sound or swelling. Arthritis UK notes that sprains, strains and tears are all types of knee injury and that you do not need to be sporty to have one.

If it has built up slowly, with pain, stiffness and swelling, the NHS notes that osteoarthritis most often affects the knees, hips and small joints of the hands. It says a GP may suspect osteoarthritis when someone is 45 or older, has joint pain that worsens with use, and has morning stiffness that is absent or lasts less than 30 minutes, and that X-rays and blood tests are not usually needed unless something else is suspected.

The NHS says to get advice from 111 now if the knee is very painful, you cannot move it or put any weight on it, it is badly swollen or has changed shape, it locks, gives way or painfully clicks, or you have a very high temperature with redness or heat around the knee, which can be a sign of infection. For less dramatic pain it advises seeing a GP if knee pain does not improve within a few weeks.

Arthritis UK gives a similar list and adds that you may wish to see a physiotherapist first. Many areas allow self-referral to NHS community musculoskeletal services, and it is also possible to pay to see a physiotherapist privately without a doctor's referral.

Arthritis UK says a doctor will often be able to diagnose the problem from the symptoms and a physical examination of the knee, and may occasionally suggest tests or a scan, especially if more specialised treatment may be needed. The NHS says a doctor might prescribe medicine or physiotherapy, or refer you to hospital for a scan or specialist treatment such as surgery, depending on the cause.

Arthritis UK also notes that treatment may involve making the hip muscles stronger or helping with foot problems, because both can affect knee pain, and that a physiotherapist may use an exercise programme, taping of the kneecap or a knee brace. It says braces are not suitable for everyone or for all knee problems.

For short-term pain and swelling the NHS suggests putting as little weight on the knee as possible, avoiding standing for a long time, using an ice pack or bag of frozen peas wrapped in a tea towel for up to 20 minutes every 2 to 3 hours, and taking painkillers such as paracetamol or ibuprofen gel or tablets.

Arthritis UK suggests avoiding long periods of complete inactivity, moving the knee gently for 10 to 20 seconds every hour while awake in the first 24 to 48 hours, and using the leg more after 48 hours because exercise can help long-term pain. It also advises leading with the good leg when going upstairs and the sore leg when going downstairs. None of this replaces an assessment if the knee gives way repeatedly.