Knee clicking, especially when going up stairs, is common. This phenomenon, medically known as crepitus, is often harmless. Understanding its causes can help determine when medical attention is needed.
Common Reasons for Knee Clicking
A common, harmless cause of knee clicking is the formation and collapse of gas bubbles within the joint’s synovial fluid. This fluid lubricates the joint, reducing friction between cartilage surfaces. Changes in joint pressure, like bending or straightening the knee, can cause tiny nitrogen bubbles to form and burst, producing a pop or crack, similar to cracking knuckles. This process, known as cavitation, does not indicate damage or harm to the joint.
Another cause of knee sounds involves tendons and ligaments moving over bony structures or soft tissues. As the knee flexes and extends, these tissues can momentarily catch or rub against a prominence and then snap back, creating a click. This can occur with the iliotibial band (running along the outside of the thigh) or hamstring tendons at the back of the knee. Such occurrences are generally not a cause for concern unless accompanied by pain or swelling.
Minor irregularities in knee cartilage can also cause clicking. Cartilage provides a smooth, elastic covering for bone ends, allowing them to glide easily. If the cartilage surface becomes rough, movement can produce a crunching or grinding sensation as bones do not slide smoothly. The patellofemoral joint (where the kneecap meets the thigh bone) is a common source of this crepitus, especially when bending the knee for activities like squatting or going up stairs.
When to Consult a Doctor
While knee clicking is often harmless, certain accompanying symptoms warrant medical evaluation. Seek medical advice if clicking is consistently accompanied by pain, especially sharp or persistent discomfort. Painful clicking can be a sign of conditions like a meniscus tear or cartilage damage.
Noticeable swelling around the knee is another indicator that medical attention may be necessary. Swelling, especially if severe or worsening, can suggest inflammation, fluid buildup, or even infection. A sensation of the knee locking or catching (feeling stuck or unable to move freely) along with clicking, also warrants a doctor’s visit.
If the knee suddenly buckles or feels unstable (known as “giving way”), it could signal ligament damage or other structural problems. Additionally, if clicking began after an acute injury or trauma, or if symptoms persistently worsen, a medical professional should assess the knee.
Simple Steps for Relief and Prevention
Gentle exercise and stretching can help reduce knee clicking and promote overall knee health. Strengthening surrounding knee muscles (quadriceps, hamstrings, glutes) provides better joint support, alleviating pressure and strain. Low-impact activities like walking, cycling, or swimming build strength and flexibility without excessive knee stress. Incorporating exercises like wall squats, leg lifts, and hamstring curls can specifically target these muscle groups.
Maintaining proper body mechanics, especially when using stairs, can also reduce knee stress. Focusing on good posture and controlled movements helps distribute weight evenly and minimizes unnecessary strain. Paying attention to how the kneecap tracks during movement can also be helpful.
Supportive footwear is important for knee comfort. Shoes with adequate arch support and cushioning help maintain proper body alignment and absorb shock, reducing knee impact. Avoid worn-out shoes or high heels, which can misalign the body and increase knee stress.
Managing body weight significantly impacts knee health by reducing joint load. Each pound of weight lost can reduce the pressure on the knees by approximately four pounds. This stress reduction can decrease cartilage wear and tear and lower osteoarthritis risk. Additionally, weight loss can reduce systemic inflammation, which contributes to joint pain.
Always warm up before physical activity and cool down afterward to prepare knee joints and muscles. Warm-up routines like light cardio (walking or mini-squats) increase blood flow and muscle flexibility. Cool-down stretches, such as hamstring or quadriceps stretches, release muscle tension around the knee and improve flexibility, contributing to joint comfort.