Adults aged 50 and older who walked for exercise were less likely to develop new frequent knee pain and medial joint space narrowing.
The study also showed that walking for exercise may be an effective therapy in slowing down damage occurring in the knee, although there was no relationship found between walking and improved frequent knee pain.
"Exercise is a physical intervention often touted as a treatment of os teoarthritis," the authors explained, adding that guidelines from the American College of Rheumatology "specifically mention walking as a reasonable means of obtaining such exercise."
The sample consisted of 1212 participants enrolled in the Osteoarthritis Initiative with radiographic evidence of osteoarthritis. Participants were aged 50 and older with a mean (SD) age of 63.2 (7.9) and body mass index of 29.4 (4.6) kg/m2. Most (73%) participants reported walked as a form of exercise.
Between baseline and 48 months, the authors measure participants’ new frequent knee pain, Kellgren-Lawrence grade worsening, medial joint space narrowing, and improved frequent knee pain. They also used a modified Historical Physical Activity Survey Instrument to ascertain walking for exercise after 50 years of age, administered at the 96-month visit.
Participants who reported at least 10 instances of walking for exercise were classified as “walkers,” while those who reported less were classified as “non-walkers.”
According to the authors, walkers had 40% decreased odds of new frequent knee pain (odds ratio [OR] 0.6; 95% CI, 0.4-0.8), and 20% decreased odds of medial joint space narrowing (OR 0.8; 95% CI, 0.6-1.0) compared with non-walkers.
Further, they found walking may be linked to less symptomatic and structural progression among knees with varus alignment (48%), less symptomatic progression among knees with neutral alignment (36%), and little benefit among knees with valgus alignment (16%).
No other findings were noted to be statistically significant.
“There is a wealth of data indicating that knee osteoarthritis is largely biomechanically driven, so it is not surprising that we found that static alignment could be an important effect measure modifier in evaluating the association between walking and knee osteoarthritis progression,” the authors wrote. “It will be important to replicate these analyses in other epidemiologic studies with larger groups of people who have neutral and valgus alignment to confirm these findings.”
The authors added that clinicians should encourage patients to walk and consider in-person or virtual walking programs.
“Our findings highlight the possibility that biomechanical interventions may hold the key to the elusive treatments in this disease that might provide benefit from both a structure and symptom perspective,” the authors concluded. “This is potentially an important paradigm shift in the field of osteoarthritis research.”
Lo GH, Vinod S, Richard MJ, 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. Published online June 8, 2022. doi:10.1002/art.42241