Glossary

Crepitus

Quick answer

Crepitus is a grinding, crunching or crackling sound or feeling when the knee moves, often felt under the kneecap when squatting or climbing stairs. On its own and without pain it is common and usually harmless, explains Doha knee surgeon Dr. Pablo Gelber, who assesses noisy knees at Aman Hospital.

What it is

Crepitus comes from the Latin for rattling. In the knee it can come from tiny gas bubbles in the joint fluid, soft tissues moving over bone, or roughened cartilage surfaces rubbing together.

Doctors may note it on examination by placing a hand over the kneecap while you bend and straighten. Many people with healthy knees have some crepitus, and it tends to become more common with age.

When it matters

Painless crepitus without swelling is generally not a cause for concern, and it is not a reason to stop exercising. It becomes more relevant when it comes with pain, swelling, stiffness or a feeling of catching.

Painful grinding behind the kneecap can go with chondromalacia or patellofemoral osteoarthritis. Grinding across the main joint with pain on walking can be a sign of more general osteoarthritis.

How it is assessed and managed

An examination and, when needed, a standing X-ray or MRI show whether there is cartilage wear. Where crepitus comes with pain, strengthening the quadriceps and hip muscles, weight management and adjusting heavy squatting or kneeling usually help. Surgery is not done for crepitus alone.

Frequently asked questions

Does a grinding knee mean arthritis?

Not necessarily. Many people with crepitus have normal knees. Grinding with pain, swelling or stiffness is more likely to reflect cartilage wear.

Should I avoid exercise if my knee crunches?

No. Exercise, especially strengthening, is usually helpful. If a particular movement is painful, modify it and seek advice.