Knee cracking or popping when you bend it is usually called crepitus. In most cases it’s benign, but the cause can vary and occasionally signals an underlying issue. Here’s a concise guide to what it might mean and when to seek care. What often causes knee cracking
- Gas bubbles in the joint fluid: Tiny bubbles can form and pop as you move, creating a quick crack or pop.
- Tendons or ligaments snapping over a bony bump: As the knee flexes or extends, soft tissues can shift position and produce a snapping sound.
- Normal joint wear or stiffness: With aging or after periods of inactivity, changes in cartilage or surrounding tissues can make noises during movement.
When it might be a sign of something more serious
- Pain, swelling, warmth, or instability accompanying the sounds
- A history of injury (twisting knee, meniscal tear, ligament injury)
- Mechanical symptoms like a knee that locks or catches in the joint
If any of these apply, or if the sounds worsen or don’t improve with a few weeks of rest and gradual strengthening, a medical evaluation is wise.
Tips to manage and monitor
- Check for pain: If cracking occurs without pain, it’s often harmless; with pain, it needs assessment.
- Strengthen supporting muscles: Focus on quadriceps, hamstrings, and hip stabilizers to improve joint mechanics.
- Maintain joint-sparing activity: Low-impact activities (cycling, swimming) can keep the knee healthy without excessive stress.
- Gentle range-of-motion and stretching: Helps maintain flexibility and reduce stiffness.
- Proper footwear and technique: Use supportive shoes and correct form during exercises.
When to see a clinician urgently
- Severe knee swelling or deformity
- Inability to bear weight or move the knee
- A history of significant trauma followed by persistent pain or instability
If you’d like, share: your age, whether there’s pain or swelling, any recent injuries, and how long the cracking has been happening. With that context, more tailored guidance can be provided.
