Diet, Exercise, or Both for Knee Pain?

The musculoskeletal consequences of overweight and obesity are perhaps by far the most disabling and costly sequelae of excess weight. Although they may be less likely to kill you than heart disease or stroke (also consequences of obesity), obesity related pains in your muscle, bones and joints can reduce your quality of life to a level where having a heart attack may seem like taking the easy way out.

So what is the best conservative treatment for weight-related knee pain?

This question was addressed now in a randomised controlled trial published last month in the British Medical Journal. Specifically, Claire Jenkinson and colleagues from the University of Nottingham, UK examined the effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain.

The study was performed in five general practices in Nottingham and involved 389 men and women aged 45 and over with a body mass index equal or greater than 28.0 and self reported knee pain.

Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; or and advice leaflet only (control group).

Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 600 kcal a day. Interventions were delivered at home visits over a two year period.

In the 289 (74%) participants who completed the trial, patients in the knee exercise groups reported greater reduction in knee pain than in the non-exercise groups at 24 months, although the effect size was moderate (number needed to treat for a 30% improvement in knee pain was 9).

As expected the dietary intervention group lost some weight (around 3 Kg), but this degree of weight loss did not have any meaningful effect on knee pain or function but was associated with a reduction in depression.

The authors conclude that a home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain.

Although a moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression, it is not enough to influence pain or function.

As knee pain is a common problem in patients presenting with excess weight, which if not addressed, will ultimately result in immobility and increasing weight gain, exercise prescriptions should be routinely implemented in patients presenting with this problem.

Edmonton, Alberta