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Possible Reasons Your Knee Keeps Locking

Possible Reasons Your Knee Keeps Locking

It’s hard to make a move without bending your knees. Forget running or jumping; even sitting in a chair or leaning over to tie your shoelaces is extremely difficult and often very painful when a knee locks up.

Unfortunately, knee locking is a common condition associated with various knee injuries and chronic conditions. 

One of Arizona’s top orthopedic specialists, Dr. Sumit Dewanjee, and our team at FXRX Inc. in Phoenix and Tempe are happy to answer questions about the conditions that cause knee locking.

What does knee locking mean?

Medically speaking, knee locking describes a condition in which you are unable to either fully straighten or bend a knee.

Some people experience pseudo-locking, which prevents the knee from bending due to pain or muscle spasms. In other cases (true locking), mechanical damage to joints or bone make it impossible to move the knee into a different position.

Locking may be related to a sudden knee injury sustained during a fall or sports activity. It can also be the result of chronic degenerative joint changes that develop over several years.

Depending on the underlying cause, symptoms that may accompany knee locking include:

Rather than locking up the knee, some injuries cause a catching sensation that may occur intermittently but tends to worsen over time without treatment.

What causes knee locking?

The conditions and injuries that may cause a knee to lock include:

Meniscus tear

The meniscus is a C-shaped piece of cartilage that cushions your knee joint. A meniscus tear, often from a twisting motion or overflexing of the knee joint, can cause the knee to lock.

Meniscus tears are a common injury in athletes who play contact sports but can also occur in nonathletes due to age-related wear-and-tear.

Loose bodies

Loose bodies in a knee joint, typically fragments of bone or cartilage, can obstruct normal movement, causing the knee to lock. These fragments can result from a traumatic injury or a chronic condition like osteoarthritis (wear-and-tear arthritis).

Anterior cruciate ligament (ACL) injury

The ACL is one of the knee's four main ligaments, stabilizing the joint. An ACL injury often happens during sports involving sudden stops and changes in direction, like basketball or soccer. If the ligament gets caught between the joint, it can cause the knee to lock.


Osteoarthritis is a degenerative joint disease that affects millions of people worldwide. As the protective cartilage at the ends of bones wears away, bone spurs can form, and loose bodies may develop, causing the knee to lock.

Kneecap dislocation

A dislocated kneecap happens when the triangular bone (patella) that covers the front of your knee slips out of place. When the kneecap moves out of position, it can cause the knee to lock. Notably, kneecaps can fracture during a fall or other trauma, which can also cause the knee to lock.

Treating knee locking

Seek medical care if you experience knee pain, swelling, or the sensation that your knee is locking. Early intervention can prevent further complications, and appropriate treatment can help you regain normal knee function.

Dr. Dewanjee develops treatment plans based on evaluation results. Your plan may include medication, physical therapy, knee injections, and other conservative therapies. Some injuries or conditions require knee surgery (arthroscopy) to recover full knee function and pain-free mobility.

For more information about knee locking or other services we offer, schedule a visit with Dr. Dewanjee at FXRX today. Call our office or request an appointment online.

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