Popping from joints
By Song Sang-ho
Probably everyone has had the experience of hearing the sudden “popping” sound in their knees when getting up from seats, walking or while exercising. People don’t pay much attention to their knees until they hear the sound and they start to worry, visiting a clinic.
The knees are making a sound: Is it okay? Generally, doctors don’t diagnose the cracking sound in the knees as a disorder. There is no clear evidence for the cause of the sounds, but the phenomenon is understood as a tendon or ligament surrounding joints having contact with the bony prominences during movement. The sound can also come from a tendon or ligament getting stuck in between joints, making sliding friction. When joints are moved in an abnormal way, negative pressure (a kind of vacuum state) is formed, which makes air bubbles inside the joint that will pop later. This makes the “popping” sound.
However, when the sound continues and is accompanied by pain and edema, you need to take a closer look. In the case of degenerative arthritis, the knees make a friction-like sound — this refers to a rattling or grinding sound that is heard while moving. This sound is caused by friction of the joint surface when it is irregular and uneven. The sound is usually accompanied by pain.
Chondromalacia and plica syndrome can also be the cause.
Chondromalacia is a disease where cartilage surrounding the knee is put under continuous pressure, thus getting soft and changing in color, eventually wearing out. Due to the frequent impact on the knees, bubbles are formed and then pop inside the cartilage, making a crack on the surface or making it tender. This causes pain in the front of the knee joint, and the pain is aggravated when trying to stand up after sitting for a long time, ascending the stairs, or kneeling. The popping sound can be heard and the pain only worsens. Women who wear high heels are more vulnerable.
Plica syndrome refers to a disease where “plica,” the thin membrane located between the patella and femur, swells up and thickens. Plica is formed in the fetal period and disappears at birth, but in one out of three people it remains for a long time. Repetitive and severe stimulation in this area can cause “plica syndrome.” Symptoms include popping or cracking sounds accompanied by pain, and a rattling feeling inside the knee. These symptoms are often seen in soldiers, athletes, and active young men in their 20s to 30s.
When the “popping” sound is heard in the knees during sports activities or sudden movement, a ruptured cruciate ligament or cartilaginous plate can be the cause. A ruptured cruciate ligament can occur following a rapid directional change or a sudden stop during exercise, severe impact, or overdoing certain movements, which can all twist the joint.
The menisci (cartilaginous plate) are the fibrous cartilage that are located in the medial and lateral sides of the knee joint, and have the role of providing nutrients to the cartilage and distributing body weight at the same time. An aged meniscus, however, has low elasticity and can easily be torn by light pressure, thus requiring special attention for prevention of damage. Pieces of ruptured meniscus can get into the inter-joint space and interrupt movement, which leads to pain, severe edema and popping sounds.
Knees making abnormal sounds may not be the sign of serious disease, but if the symptoms persist, consult a doctor for a professional diagnosis.
As the average life span is increasing, having healthy joints has become the key to lifetime health. Please don’t overlook the signs from your body. The popping sounds from the knees may be the alarm saying “try to keep your joints healthy.”
The writer is the president of Wellton Bone & Joint Hospital.