Relationship between knee kinetics during jumping tasks and knee articular cartilage MRI T1rho and T2 relaxation times

摘要

Background: Articular cartilage of young healthy individuals is dynamic and responsive to loading behaviors. The purpose of this study was to evaluate the relationship of cartilage T 1ρ and T 2 relaxation times with loading kinetics during jumping tasks in healthy young individuals. Methods: Fourteen healthy subjects underwent: 1) motion analysis while performing a unilateral hopping task and bilateral drop jumping task; and 2) quantitative imaging using a 3 Tesla MRI for T 1ρ and T 2 relaxation time analysis. Three dimensional net joint moments and angular impulse was calculated using standard inverse dynamics equations. Average T 1ρ and T 2 relaxation times and medial-lateral ratios for each were calculated. Multiple regression was used to identify predictors of cartilage relaxation times. Findings: Average knee flexion moment during hopping was observed to best predict overall T 1ρ (R 2 =.185) and T 2 (R 2 =.154) values. Peak knee adduction moment during a drop jump was the best predictor of the T 1ρ medial-lateral ratio (R 2 =.220). The T 2 medial-lateral ratio was best predicted by average internal rotation moment during the drop jump (R 2 =.174). Interpretation: These data suggest that loads across the knee may affect the biochemistry of the cartilage. In young healthy individuals, higher flexion moments were associated with decreased T 1ρ and T 2 values, suggesting a potentially beneficial effect. The medial-to-lateral ratio of T 1ρ and T 2 times appears to be related to the frontal and transverse plane joint mechanics. These data offer promising findings of potentially modifiable parameters associated with cartilage composition.