What is the difference between true locking and pseudo-locking of the knee?

How each one feels

• True locking: the knee gets stuck, usually slightly bent; it cannot be straightened by you or anyone gently trying; the end point feels firm; it may release suddenly with a clunk or stay stuck for hours
• Pseudo-locking: a sudden hitch, stiffness or stab of pain makes you stop; the knee hesitates but moves fully once you push through or take a step; often worse after sitting, on stairs or with swelling

Usual causes of each

True locking is most often caused by a displaced meniscus tear, especially a bucket-handle tear, a loose body of cartilage or bone, a displaced cartilage flap, or in a reconstructed knee a cyclops lesion.

Pseudo-locking is commonly caused by patellofemoral pain or kneecap irritation, a plica, swelling from any cause, arthritis, hamstring spasm after an injury, and occasionally pain referred from the hip.

Why the difference matters

True locking usually means a structural problem that will not resolve with exercise, and some of these, such as a displaced meniscus tear in a younger patient, are more likely to be repairable if treated early. That is why a truly locked knee should be seen by a knee surgeon promptly, and keyhole surgery is often recommended.

Pseudo-locking, by contrast, usually responds to physiotherapy, strengthening, load management and treatment of swelling. Surgery is rarely the first step.

How a surgeon in Doha tells them apart

The history is the most useful tool: what position the knee stuck in, whether you could straighten it at all, and how it released. At Aman Hospital, Dr. Gelber also measures the range of movement, feels the end point, and checks the joint line, kneecap and ligaments. An MRI confirms or rules out a meniscus tear or loose body. Seek urgent care if the knee is locked and will not straighten after a few hours, you cannot bear weight, or it is hot and red with fever.