Patients with knee OA can gain significant benefits and avoid physical function limitations by simply walking more.
"As clinicians, we should be promoting walking in our patients with knee OA. We should have them measure their physical activity with a pedometer, much like people measure their weight with a scale. Those starting on a walking program should get to a target of at least 3000 steps/day and ultimately try to reach 6000 steps/day. This is well below the popular anecdote of 10,000 steps/day, which may be good news to those starting out. It doesn't take much to get to 3000 steps/day," Dr. White told Medscape Medical News. He is research assistant professor, Department of Physical Therapy & Athletic Training, Boston University College of Health and Rehabilitation Sciences, Massachusetts.
Long-Term Study Documents Benefits of Walking in Patients With Knee OA
The researchers measured daily steps taken by 1788 people with or at risk for knee OA who were part of the Multicenter Osteoarthritis (MOST) Study, a large multicenter longitudinal cohort study of community-dwelling adults. Mean age was 67 years, mean body mass index (BMI) was 31 kg/m2, and 60% of participants were female.
The researchers measured the number of steps patients walked with an ankle monitor over 7 days. They measured functional limitation at baseline and again 2 years later. The researchers defined functional limitation as walking speed less than1.0 m/s
The authors reported, "Among study participants who did not develop slow walking at the two-year follow-up (<1.0 m/s), 80% walked at least 5300 steps/day." The minimum for preventing functional decline was between 3250 and 3700 steps/day. Walking an additional 1000 steps each day was associated with a 16% to 18% reduction in incident functional limitation 2 years later.
"Our findings add to the idea that walking is good for people with knee OA. Specifically, walking that occurs during unstructured activities, a few steps here and there, add up and do seem to make a difference in terms of prevention of functional limitation in this patient population. I hope that these findings will lead to clinicians encouraging their patients to use a pedometer to measure their physical activity and work towards the 3000 then 6000 steps/day goal," Dr. White said.
Physical activity stimulates the expression of lubricin, a lubricant molecule of synovial fluid that is important for cartilage growth and that contributes to the delay of OA development.
More Walking Might Reduce Healthcare Costs Associated With Knee OA
According to Dr. White, data from the National Health and Nutrition Examination Survey showed that 80% of patients with OA have some limitation in movement and that 11% of adults with knee OA need assistance with personal care.
"Our findings strongly suggest that walking does work to prevent the onset of problems with physical functioning in the future in people with knee osteoarthritis," Dr. White said.
Arthritis Care Res. Published online June 12, 2014. Abstract