Gaining just under a stone in weight could significantly increase the need for a total knee replacement, a new study has suggested.
Researchers found that women are more at risk of requiring knee surgery if they put on weight in midlife compared to men.
Women who gained 11lb (5kg) are 34 per cent more likely to need a total knee replacement, while men were 25 per cent more likely if they put on the same amount of weight.
The new study, which will be presented at the International Congress on Obesity in Melbourne, found that relatively small weight increases could heighten the chance of developing knee osteoarthritis and the need for a knee replacement.
Osteoarthritis, the most common type of arthritis in the UK, is a condition that causes joints to become painful and stiff.
There is no cure for osteoarthritis, but people can relieve uncomfortable and painful symptoms by making lifestyle changes and using pain relief medication.
In some cases, the condition can require joint replacement surgery.
The researchers from Monash University in Australia said that guidelines currently recommend weight loss to manage knee osteoarthritis, but do not recommend preventing weight gain in the first place.
Professor Anita Wluka, who led the research, said: “Weight loss can help ease the symptoms of knee osteoarthritis by reducing strain on the joint and lowering levels of harmful inflammation.
“However, the 10 per cent-plus reduction in total body weight that is required to have even a small effect on knee pain is difficult to achieve and even more difficult to maintain, particularly when osteoarthritis is present, reducing mobility.”
She added that there was evidence that preventing weight gain “is an easier and more achievable goal” than weight loss.
The research examines how weight gain was related to symptoms and progression of osteoarthritis.
The team reviewed existing research into the problem, analysing 20 previous studies which included hundreds of thousands of participants.
Overall weight gain appeared to have a significant detrimental effect on pain, stiffness, function, quality of life and on changes to the joint visible in X-rays.
It was also linked to further damage to cartilage and bone, as well as other parts of the joint.
Two studies involving more than 250,000 participants led the researchers to the conclusion that weight gain significantly increased the odds of having a total knee replacement surgery.
Dr Wluka added: “The prevention of osteoarthritis and the slowing of its progression would not only reduce the need for surgery, but it would also take pressure of the health service which, due to our ageing and increasingly obese population, is facing increasing demand for knee replacement.
“Given the challenges associated with weight loss, attention should also be paid to preventing weight gain, with individuals with osteoarthritis also given advice and support on how to maintain their current weight, something that can be particularly problematic as we get older.
“Weight maintenance in middle age would reduce the risk of knee osteoarthritis occurring and, in those with osteoarthritis, it would reduce worsening of pain, loss of function and the need for costly joint replacement.”
Additional reporting by PA