What is osteoarthritis?

Osteoarthritis is a condition affecting the joints. The knee joints are protected by a layer of smooth, flexible cartilage that prevents the bones from being damaged as they meet and flex against each other during normal movement. When that cartilage wears away, however, the bones lose their natural protection and begin to rub against each other more directly. This is what happens in osteoarthritis, and it has a range of impact on the joints. The bones may compensate for the lost cartilage by growing outwards and producing bony spurs (known as osteophytes). The synovium (soft tissue) inside the joint capsule may thicken, causing the joint to swell. The ligaments may also thicken as they try to provide more stability to the knee. These developments can result in a range of symptoms, including pain (which usually increases during activity), stiffness (especially after rest), reduced mobility, and sometimes ‘creaking’ sounds, or a grating sensation, in the affected joint (known as crepitus).

Who does osteoarthritis affect?

Osteoarthritis is the most common type of arthritis, and a very common condition in general: more than eight million people are thought to be affected by it in the UK. The natural ageing process partly accounts of this prevalence; over time, wear and tear reduces the effectiveness of the cartilage, while the body’s ability to heal itself also decreases with age. The chances of contracting osteoarthritis increase from the mid 40s – indeed most people are likely to develop some form of it eventually. Other factors associated with the condition include gender (women in their mid 50s and upwards are more susceptible to knee osteoarthritis than men), previous injuries (particularly ones caused by repetitive stress through squatting, kneeling or lifting), and excess bodyweight, which increases the pressure on joints.

How is it diagnosed?

Osteoarthritis is usually diagnosed by a physical examination of the knee, though an x-ray can be used to confirm the condition in certain cases. During a physical examination we will look for signs of the above-mentioned symptoms, from bony spurs and evidence of grating to obvious swelling in the joint. You will also be asked whether the degree of pain and stiffness (if present) changes during and after rest or exercise. Short-lived joint stiffness in the mornings after waking up, for example, can be an indicator of osteoarthritis – whereas more prolonged stiffness could indicate rheumatoid arthritis.

What happens next?

While there is no cure for osteoarthritis, the condition doesn’t necessarily worsen with time – and in some cases may even improve. Mild osteoarthritis can be managed with lifestyle improvements, including regular exercise, improved footwear and weight loss if a patient is overweight. Where pain becomes an issue, it can also be treated with creams, anti-inflammatory medication and steroid injections. People suffering from severe osteoarthritis, however, may want to consider surgical intervention, including knee replacement surgery.