My knee got stuck bent and I can't straighten it. What should I do?

What true locking means

With a true lock, the knee bends but stops short of straight, often 10 to 40 degrees off, and pushing it straight meets a firm, painful block rather than just stiffness. It typically starts with a twist, a deep squat or getting up from kneeling, sometimes with a pop. Many people can still limp on the bent knee.

The usual cause in young and active adults is a bucket-handle meniscus tear, where a long strip of meniscus flips into the centre of the joint. Loose bodies, a displaced cartilage fragment, or a torn ACL stump can do the same. A knee that is simply too swollen or painful to straighten can mimic locking, which is one reason examination matters.

What to do right now

• Stop the activity and sit or lie down with the knee supported in its comfortable position
• Do not let anyone yank or force the knee straight
• Ice wrapped in a cloth for 15 to 20 minutes can ease pain and spasm
• Use crutches or avoid putting full weight on it
• Gently try small, relaxed movements; sometimes a fragment slips free on its own
• Arrange to be seen by a knee surgeon within days, or the same day if pain is severe

Red flags: go to emergency

• You cannot bear any weight on the leg
• The knee looks deformed, or the kneecap is out of place
• The foot is cold, pale or numb
• The knee is hot, red and swollen and you have a fever
• Pain is severe and rising despite rest

Why prompt surgical review matters

A displaced meniscus tear that is put back and repaired early has a better chance of healing than one left flipped over for weeks, as the torn strip can become damaged and no longer repairable. A locked knee also rubs on cartilage with every step.

At Aman Hospital in Doha, Dr. Gelber examines the knee and usually arranges an MRI quickly. When a tear is confirmed, keyhole surgery (knee arthroscopy) is typically recommended soon, to free the knee and, where the tissue allows, repair the meniscus rather than remove it. Loose bodies can usually be removed during the same procedure.