Degenerative joint disease

Degenerative joint disease (Osteoarthritis [OA]) is the most common form of arthritis. It is a common progressive multifactorial joint disease that is characterized by chronic pain and functional disability. Although osteoarthritis can harm any joint, it most frequently affects the hands, knees, hips, and spine joints.

How Common Is It?

“> 500 million individuals (7% of the global population)
1990~2019: increased by 48% globally”

In China, osteoarthritis, especially knee osteoarthritis, has shown a younger trend of incidence recently. It was found that people under 35 years old suffering from knee osteoarthritis rose by 22.9% from 2008 to 2017, with the greatest increased trend among all age groups.

Causes

Do you know how your behaviours will put you at risk?

Osteoarthritis is usually classified as either primary, which results from a combination of factors, including age, sex, hormones and genetic predisposition., or secondary, which is initiated by different diseases, infection, trauma etc.

However, for the most part, degenerative joint disease causes are mechanical. One of the main symptoms of degenerative disease is the degeneration and loss of the articular cartilage, which is commonly referred to as "wear and tear". Cartilage is a firm, slippery tissue enabling frictionless joint motion nearly. If the cartilage is totally worn away, the bone will eventually rub on other bones in the human joint, causing pain. 

Risk Factors

  Aging  

All studies suggested that degenerative joint disease increases sharply with age as the resilience and reparative capacity of cartilage decrease with age. 

Obesity

During gait, body weight would transfer onto the knee with significant leverage. Therefore, each additional kilogram of body mass increases the compressive pressure over the knee by around 4 kg.

Severe joint injury

According to the Johns Hopkins Precursor Study, knee injury at a young age was highly related to an increased risk of degenerative disease in later life.

High intense physical activity

It would enhance the risk of knee and hip osteoarthritis twofold in men before the age of 50.

Check whether you encounter any of the factors

How serious is it?

The degenerative joint disease occurs when the protective cartilage cushioning the ends of the bones wears down over time.

  • Osteophytes (bone growth at the joint margins)

  • Loss of articular cartilage

  • Weakening of the periarticular muscles  (muscles around the joint weaken)

  • Inflammation

A phenomenon associated with degenerative joint disease is eburnation, the result of the subchondral bone (the bone tissue underlying the classified cartilage) being exposed because of the destruction of cartilage. Bone affected this way would have a polished, ivory-like appearance.

What should I do to prevent it?

Since degenerative joint disease is caused by the degeneration of the loss of the articular cartilage gradually, joint pain caused by age-related factors can be hard to prevent proactively. However, since the disease is also associated with obesity and joint injury, reducing weight loss and avoiding knee injury would help slow down the wearing of cartilage. Though high-intensity exercise may increase the risk of degenerative joint disease, moderate exercise is beneficial. For example, the increased aerobic exercise would increase proteoglycan content (one of the major components that help form cartilage), hence reinforcing cartilage.