Objective: To examine the associations of knee injury, radiographic osteoarthritis severity, and quadriceps strength with knee pain exacerbation during walking.
Design: Within-person knee-matched case-control study.
Methods: Participants from the Osteoarthritis Initiative who completed a 20-m walking test at the 24-month visit were included. Pain exacerbation was defined as an increase in pain intensity of 1 or more on a numeric rating scale (0 as no pain and 10 as the worst imaginable pain) while completing the 20-m walking test. We used conditional logistic regression to assess the relation of recent knee injury, Kellgren-Lawrence (KL) grade, and quadriceps strength to unilateral knee pain exacerbation during walking.
Results: We included 277 people who experienced unilateral knee pain exacerbation during the walking test. Recent knee injury was associated with pain exacerbation during walking, with an odds ratio of 3.4 (95% confidence interval [CI]: 1.3, 9.2). Compared with knees with a KL grade of 0, the odds ratios of pain exacerbation during walking were 1.3 (95% CI: 0.7, 2.7), 3.3 (95% CI: 1.5, 7.1), and 8.1 (95% CI: 3.1, 21.1) for knees with KL grades of 2, 3, and 4, respectively. Painful knees with a deficit in quadriceps strength of greater than or equal to 4% had a 1.4-fold (95% CI: 1.0, 1.9) higher risk of pain exacerbation during walking than their pain-free counterparts.
Conclusion: Recent knee injury, more severe radiographic osteoarthritis, and lower quadriceps strength were associated with an increased risk of knee pain exacerbation during walking. J Orthop Sports Phys Ther 2021;51(6):298-304. Epub 10 May 2021. doi:10.2519/jospt.2021.9735.
Keywords: disability; muscle strength; osteoarthritis; pain; risk factors.