Deep Knee Pain with Popping Sounds: Beware of Articular Cartilage Injury That Can Become Chronic if Untreated

Have you ever experienced deep knee pain accompanied by popping sounds when moving? Don't dismiss it as normal because it may be a warning sign of "articular cartilage injury" in the knee, which if left untreated can lead to chronic pain over time.

Understanding "articular cartilage": the unsung hero that absorbs shock in the knee.

"Cartilage" plays a crucial role in reducing friction during joint movement and absorbing impact from body weight. What many may not realize is that when this cartilage surface is injured, it not only causes pain but also leads to cartilage wear, affecting mobility in both the short and long term. Importantly, once cartilage is damaged, the body cannot regenerate the original cartilage to replace it.

Causes and risk factors leading to knee damage.

Articular cartilage injuries in the knee (Cartilage Injury) usually arise from two main factors:

• Severe trauma: such as direct impact, severe twisting of the knee, or injuries sustained during sports activities.
• Repetitive overuse: prolonged heavy use of the knee that gradually wears down the cartilage.

Check immediately! Which symptoms indicate risk of "articular cartilage injury"?

Patients with articular cartilage injury in the knee can watch for the following warning signs:

• Deep knee pain (distinct from general muscle pain).
• Popping or cracking sounds in the knee when moving.
• A feeling of catching or joint stiffness.
• In severe cases, inability to fully straighten or bend the knee compared to the other leg.
• Intermittent swelling of the knee.

Medical diagnosis.

Doctors will take a medical history, perform a physical exam, and order an MRI to closely examine cartilage wear and knee structures. In cases where surgery is indicated, arthroscopic techniques allow for more precise diagnosis.

Treatment approaches: surgical versus non-surgical.

Treatment for articular cartilage injury is personalized and divided mainly into two approaches.

1. Non-surgical treatment.

Behavioral modification and weight control: For overweight patients, weight loss is recommended alongside strengthening exercises for muscles around the knee, such as the hip abductors and thigh muscles, to reduce impact and cartilage damage.

• Physical therapy: to relieve pain and reduce swelling.
• Knee injections: such as hyaluronic acid for joint lubrication, platelet-rich plasma (PRP) injections, or stem cell therapy.

2. Surgical treatment.

When necessary, doctors consider surgical options tailored to each patient, such as:

• Microfracture surgery: creating small holes in the bone to stimulate new cartilage growth.
• Osteochondral autograft transfer: transplanting cartilage from another area of the patient's body to replace damaged sections.

Prevention before it’s too late for long-term knee health.

Although articular cartilage injury is not life-threatening, neglecting treatment can lead to chronic pain and impair knee function in the future. Simple preventive measures include:

• Maintaining a healthy weight to reduce pressure on the knees.
• Avoiding overly strenuous exercise when the body is not yet prepared or strong enough.
• Choosing appropriate footwear that matches the type of sport or exercise.
• Resting fully after injury and avoiding pushing through exercise, which may cause chronic damage.

Source: Dr. Peeraphat Lertwiram, Sports Medicine Specialist, Orthopedics Department, Faculty of Medicine Ramathibodi Hospital, Mahidol University.