Knee Pain? I prescribe diet & exercise

The following was created for an email newsletter for physiotherapists & general practitioners. I thought it was very good information so I convinced Rob Russo to allow me to post it here for you. Hope you find it useful and please do give us some feedback. I'll use it to convince Rob to write some more! Regards, Irwin Lim

By Dr Roberto Russo, Rheumatologist

It is always a pleasure when you come across literature that supports and/or confirms your beliefs and understanding in your area of health care. This last month has seen just that in the field of Osteoarthritis.

The BMJ (British Medical Journal) and JAMA (Journal of the American Medical Association) both published articles on the effectiveness of exercise and diet in the treatment of OA affecting the lower limbs.

The first of these published in the BMJ (Uthman et al) is a systematic review and network meta-analysis focused upon the effectiveness of exercise (including all types) in relieving pain and improving function in patients with lower limb osteoarthritis.

The most interesting result I found from the sequential analysis was that by 2002, there had accumulated sufficient evidence to show a significant benefit from exercise interventions such that further trials are unlikely to overturn that conclusion.

Consequently, it seems that you can be definitive in your recommendation that patients with lower limb OA should exercise.

The question was then, which form of exercise was most beneficial?

• In terms of pain relief, the overall best exercise intervention was a combination of aquatic exercise plus aerobic flexibility exercise, closely followed by a combination of strengthening exercises alone.
• However, for improving function, the combination of strengthening, flexibility, and aerobic exercises performed as well as aquatic strengthening plus aerobic exercise, which were both better than other combinations of exercise.

In the article published by Messier et al, titled the IDEA study, the effect upon knee loading forces and inflammation (by measuring levels of IL-6, which is a marker of inflammation) by either dietary modification, exercise, or diet + exercise was evaluated. What they found was that:

• Diet and exercise combined led to the greatest loss of weight (about 10% of initial body weight) and was associated with the greatest reduction in knee compressive forces and inflammation.
• Exercise alone led to only a modest amount of weight loss (close to 2%)
• All interventions improved pain and function, but the greatest improvements were seen in the combination group.

Their conclusion was that diet modification was the most critical factor in achieving the desired outcome, with addition of exercise augmenting the results.

A large strength of the study was that the population studied, I believe, closely resembled the cohort of patients I see in the clinic.

They included people older than 55, with a BMI between 27-41, who had mild to moderate osteoarthritis of the knee and pain on most days as a result of their disease.

Interestingly and perhaps most importantly, adherence with the treatment prescribed was around 55-70%, highlighting the greatest challenge we face in implementing this form of intervention.

Our job in some ways is in convincing all these patients to fully embrace and engage with these interventions in order to achieve the outcomes we know/promise them will follow.

I would be extremely interested to know what strategies you use to motivate your patients to commit with this form of treatment.

References:
1. Uthman OA, van der Windt, et al. Exercise for lower limb Osteoarthritis: Systematic review incorporating trial sequential analysis and network meta-analysis. BMJ 2013; 347: f5555
2. Messier SP, Mihalko SL, et al. Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults with Knee Osteoarthritis. JAMA 2013; 310 (12):1263-1273.