Knees Make a Cracking Sound When Moved, Is It Dangerous? Even Though It Doesn't Hurt, Recognize the Symptoms of a Serious Problem

Illustration of a knee making a sound when moved, is it dangerous (Freepik)

YOGYAKARTA – The knee is made up of three main bones, namely the femur or thigh bone, the tibia or shin bone, and the patella or kneecap. The femur supports the body's mass during activities. Such as when standing, walking, and running. When standing up from a sitting position, is it dangerous if the knee makes a cracking or clicking sound?

The sound of the cracking joint bones, around 83 decibels. The sound can be loud, or sometimes the sound is not realized. Knees making a sound when moved, according to chiropractor Andrew Bang, DC., reported by the Cleveland Clinic, Wednesday, August 28, can be normal and common. Bang explained, the sound of the joint bones in the form of a pop seems to occur often with age. Added orthopedic surgeon Kim Stearns, MD., although the sound of the knees cracking, may not be a cause for concern. This incident is common and normal, but be aware of the accompanying symptoms.

Illustration of the knee making a sound when moved (Freepik)

If the knee makes a noise when moved accompanied by pain or aches and swelling, it is important to immediately check with an orthopedic doctor. But if it makes a noise and is not accompanied by pain, it is useful to restore range of motion. Doctors Bang and Stearns explain, there are four reasons why the knee makes a noise when moved. Here is the explanation.

1. Gas escapes from the synovial joint

The first reason why the knee makes noise when moved is because of the synovial joint. Synovial joints consist of two bones connected by a capsule and membrane. Inside the capsule is synovial fluid.

“Synovial fluid is like motor oil for our joints. It provides a lot of lubrication, so everything is slippery and moves well. It also contains oxygen, nitrogen, and carbon dioxide. A creaking joint stretches the capsule. The crunching sound occurs because you are creating negative pressure inside the synovial joint space,” explained Dr. Bang.

Illustration of the reason why the knee makes a noise when moved even though it doesn't hurt (Freepik/stefamerpik)

2. Ligaments and tendons move

Ligaments are bands of connective tissue that connect our bones to each other. Tendons are also made of connective tissue, and their movement helps reduce the impact on our muscles. Sometimes, your knees make noises when you move them because the ligaments and tendons rub against each other.

3. Skin and muscle are separated

The third reason why the knee makes a noise when moved sounds terrible. But the skin and muscles are separated, which is normal. Anatomically, Dr. Bang explained that we have several layers of tissue. Under the skin, there is a layer of fascia. This layer is in between, which separates the skin and muscles. This layer, in addition to being a protector, also needs to be lubricated. For example, when the skin on the back is pulled quickly, a popping sound will be heard. This is not from the joints or ligaments, but the skin separating from the fascia, which is connected to the muscle layer.

4. Crepitus

As you age, your joints will start to sound “noisy.” It turns out that this isn’t a bad thing, there’s actually a good reason for it. According to Dr. Stearns, the older you get, the more cartilage wears away. This is a normal part of the aging process. The surface of the cartilage becomes a little rougher, making it sound “noisier” when it rubs against each other.

Those are the four reasons why knees make noises when moved even though they don't hurt. The sound in the knee is like when you crack your knuckles. This sound comes from the compression of nitrogen, oxygen, and carbon dioxide bubbles. The sound of gas released from the joints is called cavitation.

Well, knees that make noises when moved actually need to be watched out for. Feeling the need to crack joints that often occurs can indicate a problem. It could be because the urge is caused by a jammed or tight joint so that you feel the need to crack it and make a cracking sound.

It may feel relieving as if the pressure is released when you deliberately crack the joint. However, if it becomes a habit, it can affect the condition of the ligaments and tendons so that they become too loose. As a result, both will not function properly to protect you from injury. Dr. Stearns' suggestion, moving or exercising is lotion. By moving and exercising regularly, the body will produce lubricant for the joints and bones. This is also one way to deal with knees that make noises when moved.