Why do my knees crack?

UAB’s Harsvardhan Singh, Ph.D., says typically, there is no concern if there is no pain associated with knee cracks.

UAB’s Harsvardhan Singh, Ph.D., says typically, there is no concern if there is no pain associated with knee cracks.You might have heard this sound before: the loud pop or crack of someone else’s or your own knees. Sometimes it can be an unpleasant experience, but one researcher at the University of Alabama at Birmingham says typically, there is no need for concern.

What does it mean that my knees crack?

“Knee cracking could mean lots of things,” said Harshvardhan Singh, Ph.D., assistant professor with UAB’s Department of Physical Therapy. “If it is painful, then you should see a health care provider.”

Singh adds that a painless knee crack could come from multiple sources:

• A large-sized kneecap that does not fit well into the groove, thus producing a cracking sound during activities such as running and jogging.
• If the thigh muscle (quadriceps) is too tight, it can pull the kneecap and affect its free gliding movement, generating a knee crack.
• If the various soft tissues such as cartilage or meniscus have degenerated, resulting in loss of smooth cover of the knee joint, and leading to knee cracks during various activities.

“The degenerative changes can also lead to pain and/or locking of the knee joint,” he said. “Typically, degenerative changes are common in older people, so a degenerative change-associated knee crack may be found commonly in older people.”

MRI studies have revealed that the displacement of the joint surfaces forming the knee joint can create a vacuum, and the compression of the joints can lead to flow of synovial fluid into the joint, which can lead to the collapse of gas bubbles formed in this process. This collapse of gas bubbles could also lead to knee cracking.

Should I be worried if my knees crack often or loudly?

“You should not be worried if your knees crack often as long as it is not associated with pain,” Singh said. “Typically, there is no concern if there is no pain associated with knee cracks.”

Singh says the intensity of the crack’s sound follows the same principle; if there is no pain associated with it, you should not be concerned. However, if you have had a recent trauma to your knee and your knee started to crack after that event, you should see a doctor even in the absence of pain.

“Do not allow these sounds to make you feel abnormal or mentally stressed, or limit your functional activities,” Singh said. “A knee crack by itself does not indicate presence of any disease.”

What if my knees only crack during certain kinds of physical activity like running, walking or squats? Should I stop?

“It is absolutely normal for knees to give a cracking sound when you are active,” Singh said. “If you have no pain during these activities, then you should not be worried about the cracking sound during the performance of these movements.”

A cracking sound during activities could simply mean your kneecap is mobile and moving. The kneecap moves in a groove located in the knee joint during activities such as walking, running or squatting.

“Interestingly, individuals who have a large-sized kneecap may produce a greater crack because the huge kneecap may not fit well into the groove and can lead to some popping noise,” Singh said.

Harshvardhan Singh, Ph.D.Does this mean I have arthritis?

“No, knee crack by itself does not mean you have arthritis,” he said. “Interestingly, in knee arthritis, knee joint becomes hypomobile and loses its movement to a certain degree, which may lead to no knee crack. A knee crack may mean your joint is mobile and lubricated.”

Are there ways to keep my knees from cracking so often?

Singh says if knee crack is due to any malalignment of the kneecap, then techniques such as taping or correcting the alignment of the kneecap with the help of exercises can be useful.

“A physical therapist may be able to help you determine if there are specific movement patterns or any biomechanical alignment which may be leading to knee crack and prescribe you certain exercises to help improve it,” he said.

Learn more about UAB’s Department of Physical Therapy here.

Source: https://www.uab.edu/news/youcanuse/item/11479-why-do-my-knees-crack