Osteoarthritis Overview and Pathophysiology

Osteoarthritis (OA) is a chronic joint disease characterized by the breakdown of cartilage, bone changes, and inflammation. It affects over 2.2 million Australians, with higher prevalence in females.

Primary osteoarthritis is when the cause is unknown, while secondary osteoarthritis occurs due to specific factors like injuries or underlying conditions.

Primary OA can be localized (affecting 1-2 joints) or generalized (affecting 3 or more joints).

Mechanical incongruity of a joint, congenital defects, and previous injuries can lead to secondary OA.

Conditions like rheumatoid arthritis, gout, or infections can also contribute to secondary osteoarthritis.

Metabolic disorders, endocrine problems, and neuropathic disorders can also cause secondary OA.

OA affects joints crucial for daily activities, causing significant limitations and financial burden.

OA is more prevalent in females than males, reported in 18% of women and 10% of men.

The breakdown of cartilage is a hallmark of OA, leading to pain, stiffness, and reduced mobility.

The prevalence of OA necessitates understanding its mechanisms, risk factors, and treatment options.

Osteoarthritis is a dynamic process affecting different tissues like cartilage, bone, synovium, ligaments, and muscles within a joint. It involves both breakdown and rebuilding, leading to gradual changes in joint structure and function.

Contrary to the 'wear and tear' notion, osteoarthritis involves inflammation, though it can be mild or moderate and may occur intermittently.

As osteoarthritis progresses, inflammation disrupts the cartilage rebuilding process. This leads to thinner and less synovial fluid, which normally lubricates the joint.

The thinning of synovial fluid in osteoarthritis reduces joint lubrication, making it more difficult to withstand weight. This exposes cartilage and bone, leading to damage.

Osteoarthritis primarily affects individuals over the age of 50.

Osteoarthritis symptoms vary widely, ranging from no symptoms to severe joint pain and stiffness that limits daily activities.

Osteoarthritis affects joints asymmetrically, meaning the affected joints don't mirror each other. For example, one knee might be affected but not the other.

Unlike other forms of arthritis like rheumatoid arthritis or gout, Osteoarthritis inflammation is usually mild, localized, and often absent.

The common symptoms of Osteoarthritis are joint pain, which is usually worse with use, and stiffness, lasting less than 30 minutes, that can make daily activities difficult.

Osteoarthritis pain can be acute, caused by active inflammation, or chronic resulting from persistent pain and sensitization of nerves.

Distal finger joints (Heberden's nodes), proximal finger joints (Bouchard's nodes), wrist, knees, hips, lower spine, big toe.

It refers to the fact that OA is not caused by a single event, meaning there are multiple factors contributing to it.

Goals encompass patient education, pain management, mobility preservation or improvement, minimizing disability, addressing disease progression, and enhancing quality of life.

Weight loss, exercise, physiotherapy, heat therapy, TENS, acupuncture, surgery, insoles, splints, and mobility aids.

It's a common pain reliever taken regularly in divided doses to manage OA pain effectively.

Non-steroidal anti-inflammatory drugs (NSAIDs) are considered the second-line treatment for OA.

It aims to minimize potential side effects from medications like GI upset, kidney problems, and cardiovascular issues.

NSAIDs can be applied directly to the affected areas (e.g., rubs) or taken orally.

Intermittent use of NSAIDs helps to avoid potential side effects while providing temporary pain relief.

Regular use of paracetamol as background therapy is more effective than only using it when pain flares up.