Tomasz Cudejko, Martin van der Esch, Marike van der Leeden, Jasmijn Holla, Leo D. Roorda, Willem Lems, Joost Dekker
Rehabilitation Medicine, VU University Medical Center, Amsterdam, The Netherlands. E-mail: tomaszcudejko@gmail.com
DOI: 10.2340/16501977-2272

Objectives: To determine whether systemic inflammation is associated with poor proprioception; to confirm that systemic inflammation is associated with muscle weakness; and to determine whether poor proprioception mediates the association between systemic inflammation and muscle weakness in knee osteoarthritis.
Design: Cross-sectional study.
Subjects: A total of 689 participants with knee osteoarthritis from the Amsterdam Osteoarthritis (AMS-OA) cohort.
Methods: Systemic inflammation was assessed by erythrocyte sedimentation rate, knee proprioception by determining the joint motion detection threshold, and muscle strength with an isokinetic dynamometer. Linear regression models were used to estimate direct associations between systemic inflammation, proprioception and muscle strength, and the indirect association (mediation) between systemic inflammation and muscle strength via proprioception adjusted for potential confounders.
Results: Higher erythrocyte sedimentation rates were associated with poor proprioception (p = 0. 022). Poor proprioception (p < 0. 001) and higher erythrocyte sedimentation rates (p < 0. 001) were associated with muscle weakness. Poor proprio-ception mediated the association between systemic inflammation and muscle weakness (p = 0. 035).
Conclusion: Results suggest that systemic inflammation is associated with poor proprioception in knee osteoarthritis. Poor proprioception may be a path-way through which systemic inflammation is associated with muscle weakness in patients with knee osteoarthritis.

It is not known why higher level of systemic inflammation is related to muscle weakness in persons with knee osteoarthritis. We hypothesized that proprioception, one’s ability to detect joint movement and position, might be a factor explaining the relationship between systemic inflammation and muscle weakness. We analyzed the data from 689 participants from the Amsterdam Osteoarthritis cohort. As expected, higher levels of systemic inflammation were associated with muscle weakness, and this relation was partly explained by poor proprioception. These results suggest that poor proprioception is indeed one of the factors that explain the relationship between systemic inflammation and muscle weakness in persons with knee osteoarthritis.