Gait Biomechanics and Balance Associate with Talar and Subtalar T1ρ Relaxation Times in Those with Chronic Ankle Instability

Purpose This study aimed to determine associations between T1 rho relaxation times of talar and subtalar articular cartilage and commonly altered gait biomechanics and postural control outcomes in those with chronic ankle instability (CAI). Methods Fifteen individuals with CAI (21.13 +/- 1.81 yr) completed a T1 rho magnetic resonance imaging as well as a postural control and an overground gait assessment. Talocrural and subtalar cartilage was segmented manually to calculate T1 rho relaxation times. Greater T1 rho relaxation times were interpreted as decreased proteoglycan content. Pearson product-moment bivariate correlations examined the relationships between T1 rho relaxation times and the gait biomechanics and postural control outcomes. Results Across multiple variables, worse postural control demonstrated moderate to strong associations (range, 0.433-0.642 and -0.713) with greater talar T1 rho relaxation times. At the subtalar joint, greater T1 rho relaxation times were associated with lower peak vertical ground reaction forces, lower average vertical ground reaction force loading rates, and lower peak loading rates (range, -0.438 to -0.622). At the talar dome, greater talar T1 rho relaxation times were associated with increased knee extensor moments (r = 0.457), as well as greater knee flexion (r = 0.482) and knee adduction (r = 0.407) at initial contact. Larger step spatiotemporal gait parameters also associated with greater talar and subtalar T1 rho relaxation times (range, 0.434-0.697). Conclusions In individuals with CAI, worse postural control and altered kinematic, kinetic, and spatiotemporal outcomes demonstrate moderate to strong associations with greater talar T1 rho and/or subtalar relaxation times (i.e., less proteoglycan content). Associations between modifiable neuromechanical variables and greater T1 rho relaxation times may represent potential therapeutic interventions to mitigate ankle joint degeneration in those with CAI.