Why Does My Knee Click or Crack?

Short Answer

Knee clicking or cracking sounds are common and often harmless. They may result from tendon movement, gas bubbles within joint fluid, or minor tracking changes. However, if clicking is accompanied by pain, swelling, locking, or instability, further assessment may be appropriate.

First: Is Knee Clicking Normal?

Yes.

Many people experience:

• Clicking when bending
• Cracking when squatting
• Popping during stairs
• No pain associated

Painless clicking is often a normal joint phenomenon.

Common Causes of Knee Clicking

1️⃣ Tendon or Ligament Movement

As the knee bends, tendons may shift slightly over bony surfaces, producing a clicking sound.

This is common and usually harmless.

2️⃣ Gas Bubbles in Joint Fluid

Joint fluid contains dissolved gases.

When pressure changes during movement, small bubbles may form or collapse, creating a popping sound.

This is similar to knuckle cracking.

3️⃣ Patella (Kneecap) Tracking Changes

If the kneecap moves slightly off optimal alignment, subtle clicking may occur.

This may be influenced by:

• Quadriceps weakness
• Glute weakness
• Muscle imbalance

Clicking without pain may not require treatment.

4️⃣ Meniscus Degeneration

In some cases, meniscus irritation or age-related degeneration may cause clicking.

If accompanied by:

• Locking
• Swelling
• Sharp pain

Further evaluation may be appropriate.

5️⃣ Cartilage Wear

Rough cartilage surfaces may produce grinding or crackling sensations (sometimes called crepitus).

This may occur with or without pain.

When Is Clicking a Concern?

Assessment may be helpful if clicking is associated with:

• Persistent swelling
• Locking (knee gets stuck)
• Instability
• Pain that limits activity
• Progressive worsening

Symptoms matter more than sound alone.

Does Clicking Mean Arthritis?

Not necessarily.

Many people with mild cartilage wear have minimal symptoms.

Many people with clicking have normal cartilage.

Sound alone does not confirm arthritis.

Why Knee Sounds Do Not Always Match MRI Findings

MRI may show:

• Mild meniscus changes
• Early cartilage thinning
• Degenerative findings

However:

• Some people with visible changes have no pain
• Some people with pain have minimal imaging findings

Imaging must be interpreted in context.

The Multi-Factor Nature of Knee Symptoms

If clicking is painful, contributors may include:

• Cartilage wear
• Meniscus irritation
• Joint inflammation
• Muscle weakness
• Patella tracking imbalance
• Load overload

Knee function is influenced by both structure and biomechanics.

The Four-Layer Integrated Knee Model™

Our clinic applies a coordinated outpatient framework.

Layer 1 — Medical Pathology Assessment

A doctor evaluates structural contributors such as cartilage and meniscus condition.

Layer 2 — Imaging Clarity (Where Appropriate)

MRI may be considered if mechanical symptoms persist.

Layer 3 — Biomechanical & Muscular Evaluation

A licensed physiotherapist assesses:

• Quadriceps strength
• Glute stability
• Patella tracking
• Movement control
• Load tolerance

Layer 4 — Targeted Non-Invasive Medical Technology

Where suitable, options may include:

• Shockwave for tendon-related contributors
• Heat-based radiofrequency therapies
• Structured muscle activation support

Doctor and physiotherapist discuss findings face-to-face within the same clinic to align planning.

Should I Stop Exercising If My Knee Clicks?

If clicking is painless, activity may often continue.

If clicking is painful or associated with swelling or instability, medical assessment may help clarify the cause.

Conclusion

Knee clicking or cracking is common and often harmless.

However, if accompanied by pain, swelling, or locking, it may reflect:

• Meniscus irritation
• Cartilage stress
• Inflammation
• Muscle imbalance
• Patella tracking changes

Sound alone does not determine severity.

Assessment should focus on symptoms, function, and structure together.