Walking for exercise in patients with knee osteoarthritis is associated with a lower of odds of developing new frequent knee pain
Individuals aged 50 and older with knee osteoarthritis and who report walking for exercise are significantly less likely to develop new frequent knee pain, compared to those who do not walk for exercise, according to finding of a study by US researchers.
Osteoarthritis (OA) is a leading cause of disability and societal cost in older adults. Globally, the incidence of OA has increased since 1990 and in 2019, there were estimated to be 527.81 million cases. Moreover, knee osteoarthritis is the most common presentation, accounting for approximately 85% of the worldwide burden of OA. Although pharmacological interventions for OA are known to be effective, non-pharmacological interventions such as exercise, are also recommended for all patients. However, while there is evidence that supervised fitness walking can improve functional status without worsening pain or exacerbating arthritis-related symptoms in patients with knee OA, the study was short-term and only lasted for 8 weeks.
For the present study, the researchers wanted to examine the impact of walking over a much longer period of time. They used data collected as part of the Osteoarthritis initiative, a prospective longitudinal observational study that recruited patients both with and without symptomatic knee OA from 2004 – 2006. Individuals undertook annual evaluations, starting when they were first recruited and which continued until month 48 and then every two years to month 96. The researchers included participants aged over 50 with data on knee-specific pain and radiographs at baseline and at months 36 or 48, which provided evidence of OA. As part of their assessment, patients were asked about their level of walking, the time spent walking and for how many years. Individuals reporting walking for exercise at least 10 times (which was the question asked in assessment), were categorised as walkers and those who answered no, were deemed to be ‘non-walkers’. Three primary outcome measure were employed: new frequent knee pain, medial joint space narrowing (which is a marker for worsening OA) and the Kellgren-Lawrence grade, which assess OA severity.
Walking and OA outcomes
A total of 1212 participants with a mean age of 63.2 years (45% male) were included in the final analysis, of whom, 73% were defined as walkers.
Among those who reported walking for exercise, there was a 40% lower odds of new frequent knee pain compared to non-walkers (Odds ratio, OR = 0.60, 95% CI 0.40 – 0.80). There was also a significantly reduced odds of medial joint space narrowing among walkers compared to non-walkers (OR = 0.8, 95% CI 0.6 – 1.0). However, there was no significant difference in Kellgren-Lawrence score worsening between the two groups.
The authors concluded that their findings offered a glimmer of hope that walking might improve OA symptoms and provide a structural benefit (based on lower medial joint space narrowing).
Lo GH et al. Association Between Walking for Exercise and Symptomatic and Structural Progression in Individuals with Knee Osteoarthritis: Data from the Osteoarthritis Initiative Cohort Arthritis Rheumatol 2022