Muscle function, quality and relative mass are associated with knee pain trajectory over 10.7 years
Pan, F and Tian, J and Scott, D and Cicuttini, F and Jones, G, Muscle function, quality and relative mass are associated with knee pain trajectory over 10.7 years, Pain ISSN 0304-3959 (2021) [Refereed Article]
Copyright 2021 by the International Association for the Study of Pain.
Periarticular muscle plays an important role in the pathogenesis of musculoskeletal pain. We
recently reported that pain population consists of distinct subgroups of which the causes and
mechanisms may differ. This study aimed to examine the association of lean mass, muscle
strength and quality with 10.7-year pain trajectory. 947 participants from a population-based
cohort study were analysed. Dual-energy X-ray absorptiometry was used to assess lean and
fat mass. Leg, knee extensor strength and lower-limb muscle quality were
measured/calculated. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index pain questionnaire. Radiographic knee osteoarthritis (ROA)
was assessed by X-ray. Three distinct pain trajectories were identified: "Minimal pain" (53%),
"Mild pain" (34%) and "Moderate pain" (13%). Higher total and lower-limb lean mass were
associated with an increased risk of "Mild pain" and "Moderate pain" trajectories relative to
the "Minimal pain" trajectory group, but these associations became non-significant after
further adjustment for fat mass. Total lean mass percentage was associated with a lower risk
of "Mild pain" [relative risk ratio (RRR): 0.95, 95%CI 0.92-0.98] and "Moderate pain"
trajectory (RRR:0.92, 95%CI 0.87-0.96). Greater leg and knee extensor strength and muscle
quality were associated with "Mild pain" and "Moderate pain" trajectories (RRR:0.52-0.65,all P<0.05). Similar results were found in those with ROA. Higher lower-limb muscle
strength and quality, and relative lean mass, are associated with a reduced risk of severe knee
pain trajectories, suggesting that improving muscle function and composition may protect
against persistent unfavourable knee pain courses.
muscle strength, lean mass, knee pain, trajectory, cohort study