Knee Osteoarthritis and Obesity

But what if I already have knee OA?

If you already have problems with your knees there is clear evidence that losing weight reduces the symptoms of pain and immobility and can delay or prevent surgical intervention. These findings are regardless of the level of structural damage caused by OA, improvement in symptoms is found in patients who lose weight no matter what their x-rays say.

There are benefits to losing weight if you need a knee replacement too. Performing a total knee replacement operation on an obese patient is technically more challenging for the surgeon, the surgery takes longer to perform and there is a higher risk of complications like infection. Over time implants used in total knee replacement fail more quickly in obese patients.

What is the best way to lose weight?

Studies show the most effective means of losing weight is following a lifestyle that gives you a ‘continuous energy deficit’. This essentially means that the amount of energy you put into your body as food and drink should be less than the amount of energy you use in your daily activities. Effective, long-lasting weight loss is achieved through adjusting your lifestyle, rather than crash dieting. Finding the best strategy that works for YOU is important and getting support from your family and friends can make a big difference. There are many weight loss plans and methods out there to chose from; here are some suggestions for effective weight loss programs.

Weight Loss Guide    |    How to Lose Weight

Exercise is an obvious way to lose weight but knee pain can make weight-bearing activities difficult. Running, football or squash may not be possible due to pain. With all types of exercise, be guided by what you can do comfortably and stop if it hurts too much. Cycling and swimming are excellent exercise alternatives that put minimal strain on the knees, but still get your heart rate up and burn calories.

If you can move about comfortably there is evidence that combining weight loss through diet and regular long-term exercise is effective at improving arthritis pain and mobility, in addition to the normal care you receive from your GP. Either weight loss or exercise is better than standard care alone, but combining both gets even better results.

If you are overweight or obese aim for losing 5% of your total current weight over 20 weeks to give symptom relief. Losing 10% within 12 weeks has been shown to have even more significant clinical effects.

What if I wait until after my surgery to lose weight?

The evidence says this is not the general rule! One study showed that after knee replacement 21% of patients gained further weight whilst only 14% lost weight. Don’t put off until tomorrow, what you can do today!

Weight loss reduces symptoms, delays surgery and, if surgery does become necessary, improves the outcomes you will experience.

Written by Rachel Milner (Medical Student) for the knee team UHCW NHS Trust 


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Gudbergsen, H. et al., 2012. Weight loss is effective for symptomatic relief in obese subjects with knee osteoarthritis independently of joint damage severity assessed by high-field MRI and radiography. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society, 20(6), pp.495–502.
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