Knee makes a popping sound when the leg bends and straightens

Knee popping during leg flexion and extension may be caused by physiological crepitus, osteoporosis, gouty arthritis, meniscus injury, or degenerative joint disease. It is necessary to visit a hospital for examination to determine the exact underlying cause.

1. Physiological Crepitus

The joint cavity contains multiple spaces. During leg flexion and extension, air within these joint spaces can become compressed and rub against the joint structures, creating vibrations that result in audible knee sounds. This is a normal physiological phenomenon and does not require specific treatment.

2. Degenerative Joint Disease

Degeneration and damage of articular cartilage, along with reactive bone proliferation at joint margins and subchondral bone, lead to degenerative joint disease, causing knee popping. This condition may be accompanied by pain, swelling, and other discomforts. Treatments such as percutaneous electrical nerve stimulation (PENS) or heat therapy, performed under professional medical guidance, can improve blood circulation and reduce inflammatory responses.

3. Osteoporosis

Osteoporosis, resulting from abnormal calcium metabolism, leads to decreased bone density, increased bone brittleness, and reduced elasticity. These changes may cause joint popping during movement and are often associated with back or lumbar aching. Medications such as alendronate sodium tablets, risedronate sodium tablets, or clodronate disodium capsules may be used under medical supervision to inhibit osteoclast activity and prevent fractures.

4. Gouty Arthritis

In gouty arthritis, joint inflammation alters the quality and quantity of synovial fluid, leading to audible joint sounds during movement. Symptoms may include fever, redness, swelling, and pain in the affected joint. Under medical guidance, medications such as diclofenac sodium sustained-release tablets, celecoxib capsules, or meloxicam tablets can be used to relieve inflammation and pain.

5. Meniscus Injury

Sudden twisting of the knee joint or prolonged weight-bearing stress can easily cause meniscus injury, leading to movement limitations and knee popping—particularly noticeable during leg flexion and extension. It is recommended that a cast or brace be applied under the supervision of a specialist to immobilize the knee joint externally, promoting recovery of joint function.

Prompt medical consultation is advised. Complete relevant examinations, confirm the diagnosis, and actively pursue treatment under medical supervision to prevent disease progression. Adequate rest is essential during treatment to avoid excessive leg loading, which could impair recovery.