Abstract
OBJECTIVE: To compare measures of resting cartilage structure and composition in experienced older runners with and without knee osteoarthritis. DESIGN: 47 runners (mean (sd) age = 58.0 (8.4) years) with knee osteoarthritis, as well as 27 runners (mean (sd) age = 52.2 (9.7) years) with no radiographic knee osteoarthritis or knee pain participated. Magnetic resonance imaging was used to measure cartilage structure and composition and calculate: volume and thickness, as well as T2 and T1ρ relaxation times, for eight regions of interest. Between-group comparisons were examined using analysis of covariance with body mass, years of self-reported running experience, and average weekly running volume over the three months prior to testing included as covariates. RESULTS: Few between-group differences were observed. Runners with knee osteoarthritis exhibited less patellar cartilage thickness (mean difference [95% confidence limits]: -0.3 [-0.4, -0.1] mm) and volume (-408 [-736, -79] mm(3)), but thicker lateral posterior femur cartilage (0.2 [0.0, 0.3] mm), than runners without knee osteoarthritis. Further, runners with knee osteoarthritis generally exhibited longer relaxation times in all regions of interest, though statistical significance was only observed in the lateral posterior femur (T2 relaxation time: 1.8 [0.2, 3.3] ms) and medial posterior femur (T1ρ relaxation time: 2.6 [0.8, 4.4] ms) regions. CONCLUSIONS: Our findings do not support the notion of widespread cartilage degeneration in the knees of experienced older runners with knee osteoarthritis. Longitudinal research is necessary to examine the longer-term impacts of running on general knee health in runners with and without knee osteoarthritis.