When to worry about knee locking with a knee cartilage injury

Stiffness may ease gradually as swelling settles or the joint warms up. True locking means the knee is mechanically blocked and cannot complete a normal bend or straightening movement. A cartilage fragment, swelling, or another injured structure may interfere with motion.

Knee locking does not identify one cause by itself. Note whether the knee catches during a particular movement, how long the block lasts, and whether there was a twist, impact, pop, or sudden swelling.

Stop the movement that triggered the block and sit down safely. Do not forcefully pull, twist, or repeatedly bend the knee to release it. Keep activity light, support the leg, and use cold wrapped in cloth if swelling is uncomfortable.

Arrange assessment if locking recurs, interferes with work or sleep, or limits walking. A clinician can examine movement and decide whether imaging or supervised rehabilitation is appropriate.

Seek urgent care when the knee remains locked, is visibly deformed, swells rapidly after injury, or cannot support your weight. A hot, red joint with fever, new numbness, or a cold or pale foot also requires immediate assessment.

Ask whether the block sounds mechanical, which activities are safe, whether you need imaging, and how to maintain strength without provoking the injury. Tell the clinician about every episode, swelling pattern, and limitation in straightening.