An ageing population and lifestyle factors such as a poor diet leading to obesity are increasing demand for knee arthroplasty surgery as more people suffer from joint pain and stiffness.

By 2030 the number of total knee replacements is predicted to rise by nearly 700%.

The average age of knee replacement surgery is around 70 with women more likely than men to need treatment.

People in their fifties are the fastest growing demographic segment requiring knee replacement surgery which is due partly to obesity-related conditions, claim experts.

Early symptoms of knee arthritis are treated with anti-inflammatories and exercise, but debilitating pain and stiffness is most commonly treated by arthroplasty surgery,” says Chris Dodd, president of the European Knee Society (EKS).

He says people are not aware of how being overweight when they are younger puts them at a greater risk of arthritis in later life.

“The rising number of replacements will impact the NHS,” says Dodd. “We are already seeing funding for elective surgery being squeezed and restrictions being made. For example, being excessively overweight is being used as a bar to surgery.

 Knee replacement surgery is usually necessary when the joint becomes worn or damaged. This reduces a sufferer’s mobility and they experience pain even while resting.

When it comes to knee surgery there are two types of arthroplasty, a partial or complete replacement.

The arthritis usually begins on the inner side of the knee and if the ligaments remain intact then a partial joint replacement is usually sufficient to reduce the pain and improve mobility.

However, only around 10% of operations are partial replacements even though about half of patients are suitable for this surgery. The concern among surgeons is that arthritis might progress to other parts of the knee and require further operations.

“A partial knee replacement will feel more normal and patients will recover quicker, but the long-term results are similar whichever treatment is selected,” says Dodd.

One of the most serious concerns for surgeons is the risk of infection. This occurs in around 1% of total knee operations and less than 0.5% of partial procedures. Patients will usually feel pain and notice swelling in the first 12  months after surgery.

“Infection is the most feared complication,” says Dodd. “The knee is usually washed out quickly and hopefully the implant can be retained without the need for further surgery.”

In many cases antibiotics are added to the cement used to fix the implants to bone during  knee joint replacement surgery  but surgeons worry about future antibiotic resistance in some patients.

Meanwhile, new technology is improving  arthroplasty surgery with many operations already assisted by computers and robots that help with the positioning of implants in the body.