Why Does My Knee Pop and Snap?

Overview

• Knee popping, clicking, crunching, or grinding may be due to harmless causes like air bubbles in joints but could also indicate underlying issues if accompanied by pain or loss of mobility.
• Crepitus: The medical term for popping sounds produced by friction between bone and cartilage.

Harmless Causes

Air Bubbles

• Often harmless; air can seep into synovial fluid, creating bubbles that collapse upon movement, causing popping sounds without pain.

Potential Causes of Concern

Cartilage Damage

• Cartilage cushions joints; damage may cause knee popping with pain, swelling, stiffness.
• Can lead to osteoarthritis.

Runner's Knee

• Caused by overuse or misalignment of knee joint bones, leading to softened cartilage.
• Associated with pain during specific activities (e.g., running, stair climbing).
• Treatment includes rest, ice, anti-inflammatory drugs, and physical therapy.

Kneecap Misalignment

• Incorrect kneecap position can hinder knee extension, cause pain, and instability.

Meniscus Tear

• Popping and pain may indicate a meniscus tear, a C-shaped cartilage in the knee.
• Can heal on its own or may require surgical intervention.

Knee Osteoarthritis

• Age-related condition where cartilage wears down, causing pain and loss of motion.
• Early sign may be popping without pain, worsening over time.
• Treatments: exercise, weight loss, heat/cold therapy, anti-inflammatory drugs.

Ligament Damage

• Damage to ligaments (MCL, LCL, ACL, PCL) can cause a popping sensation initially.
• Treatment may involve immobilization, pain management, physical therapy, and possibly surgery.

Patellar Tendon Tear

• Involves the tendon that helps straighten the leg; may be partial (conservative treatment) or complete (requires surgery).

Knee Tendonitis

• Swelling of tendons (e.g., iliotibial band) causing them to catch on joint edges, resulting in snapping.
• Treated with rest, ice, and, if necessary, surgery.

Osteonecrosis

• Occurs when blood supply to knee bones is disrupted; leads to arthritis and joint damage.
• May require surgical intervention.

Prevention

• Athletes should consider knee injury prevention programs and proper warming up.
• Warming up increases blood flow and muscle flexibility, reducing injury risk.

When to See a Healthcare Provider

• If knee popping is painful or persistent, it should be evaluated by a healthcare provider to prevent more severe injury.
• Even painless popping could signal early stages of an overuse injury or osteoarthritis.

Summary

• Knee popping can be benign or a sign of serious issues when accompanied by pain or mobility loss.
• Common causes include meniscus tears, runner’s knee, osteoarthritis, and tendonitis.