Exercise can reduce symptoms in patients with knee osteoarthritis and may also benefit from reducing the elevated risk of cardiovascular diseases such as ischemic heart disease and congestive heart failure in these individuals. Yet, the uptake of exercise by patients with knee osteoarthritis is poor. One of the most common myths is that exercise will cause damage to an already worn joint (particularly weight-bearing exercise). To dispel the fears that weight-bearing exercise, such as walking, is detrimental to knee structure, new knowledge is required to show its safe and does no harm to the knee joint. Such knowledge would have major implications, as it would dispel the fears around weight-bearing exercise, providing clinicians with the evidence base to confidently prescribe walking and reassuring patients to follow this advice. Greater uptake of exercise in this patient group is likely to result in greater symptomatic benefits, leading to a reduced/prolonged need for knee replacement surgery. Furthermore, dispelling the fear that exercise is damaging to the knee structures is likely to encourage physical activity participation in individuals with knee osteoarthritis, thus reducing the elevated risk of cardiovascular diseases including ischemic heart disease and congestive heart failure among these individuals. To date, there have been limited studies examining the effect of exercise on MRI-assessed knee joint structure. My project is a pilot randomised controlled trial (RCT) aimed to test the feasibility of an aerobic outdoor community walking intervention. The secondary objective was to provide exploratory information on the magnitude and direction of effect sizes for pain, function, stiffness, and MRI knee structural change.
This study demonstrated the feasibility of enrolment, adherence, and safety of implementing an aerobic outdoor community walking intervention among patients with knee osteoarthritis.
Feasibility of enrolment: Over nine months, 49 individuals were screened for eligibility, with 40 enrolled (24 randomised to walking and 16 randomised to usual care). We could not achieve our target sample size of 48 due to budgetary constraints. Randomisation worked relatively well given the small study sample: The baseline characteristics of the two groups were generally well balanced, apart from the walking group having slightly more females (62.5% vs 56.3%), having a higher BMI (33.6 vs 31.8), and having a lower proportion of varus aligned knees compared to the usual care group (66.7% vs 87.5%).
Adherence: Over 24 weeks mean adherence was 70.0% (85.1% for the first 12 weeks and 54.9% for the second 12 weeks). All participants who withdrew (n=7) were from the walking group.
Safety of intervention: Walking was safe, and the adverse events related to the intervention were low. There were more adverse events in the walking group (26 vs 8), of which the majority were mild and classified as musculoskeletal. Some of the adverse events reported include increased knee pain, foot pain, upper body pain, plantar fasciitis, and calf strain.
Although a pilot study, this trial showed that a community walking intervention led to clinically and statistically significant improvements in pain, function and stiffness, and performance of the 30s Chair Stand Test. The changes seen in MRI joint structure over 24 weeks can be used to inform the development of a larger, more definitive study to determine structural changes related to walking.
The study’s abstract has been accepted for a poster/rapid-fire presentation at the 2021 OARSI Virtual World Congress on Osteoarthritis. In addition, the project also attracted an Honours student who has now submitted his honour’s thesis.