Osteoarthritis: this type of arthritis is age related, caused by the normal wear and tear of the knee joint. It mostly affects patients aged over 50 years, but younger people may have it.

Osteoarthritis is caused by inflammation, breakdown, and the gradual and eventual loss of cartilage in the joints. Over time, the cartilage wears down and the bones rub together. To compensate, the bones often grow thicker, but this results in more friction and more pain.

Rheumatoid arthritis: also called inflammatory arthritis, the membrane around the knee joint to become thick and inflamed. Chronic inflammation damages the cartilage, causing soreness and stiffness.

Post-traumatic arthritis: this type of arthritis is due to a severe knee injury. When the bones around the knee break or the ligaments tear, this will affect the knee cartilage.

Knee surgery may be suitable for patients who experience:

• Severe knee pain or stiffness that prevents them from carrying out everyday tasks and activities, such as walking, going upstairs, getting in and out of cars, getting up from a chair
• Moderate but continuous knee pain that continues while sleeping or resting
• Chronic knee inflammation and swelling that does not improve after taking medications or resting
• Knee deformity, where there is a noticeable arch on the inside or outside of the knee
• Depression, resulting from an inability to carry out daily or social activities

Total knee replacement (TKR): Surgery involves the replacement of both sides of the knee joint. It is the most common procedure.

Surgery lasts between 1 and 3 hours. The individual will have less pain and better mobility, but there will be scar tissue, which can make it difficult to move and bend the knees.

Partial knee replacement (PKR): Partial replacement replaces only one side of the knee joint. Less bone is removed, so the incision is smaller, but it does not last as long as a total replacement.

PKR is suitable for people with damage to only one part of the knee. Post-operative rehabilitation is more straightforward, there is less blood loss and a lower risk of infection and blood clots.

The hospital stay and recovery period are normally shorter, and there is a higher chance of more natural movement.

A patient who has knee replacement surgery will be hospitalized for 1 to 3 days, depending on how well they follow and respond to rehabilitation.

There will be pain, but a day after the procedure medical staff will encourage patients to get up and try to walk about, usually with some kind of walking aid. It is important to follow the instructions for rehabilitation.

Physical therapy sessions aim to strengthen the knee. These may be painful, but they significantly reduce the risk of future complications.

Patients who do not have help at home may need to stay in the hospital for longer.