Knee Cartilage Thickness, T1ρ and T2 Relaxation Time Are Related to Articular Cartilage Loading in Healthy Adults

Abstract

Cartilage is responsive to the loading imposed during cyclic routine activities. However, the local relation between cartilage in terms of thickness distribution and biochemical composition and the local contact pressure during walking has not been established. The objective of this study was to evaluate the relation between cartilage thickness, proteoglycan and collagen concentration in the knee joint and knee loading in terms of contact forces and pressure during walking. 3D gait analysis and MRI (3D-FSE, T1ρ relaxation time and T2 relaxation time sequence) of fifteen healthy subjects were acquired. Experimental gait data was processed using musculoskeletal modeling to calculate the contact forces, impulses and pressure distribution in the tibiofemoral joint. Correlates to local cartilage thickness and mean T1ρ and T2 relaxation times of the weight-bearing area of the femoral condyles were examined. Local thickness was significantly correlated with local pressure: medial thickness was correlated with medial condyle contact pressure and contact force, and lateral condyle thickness was correlated with lateral condyle contact pressure and contact force during stance. Furthermore, average T1ρ and T2 relaxation time correlated significantly with the peak contact forces and impulses. Increased T1ρ relaxation time correlated with increased shear loading, decreased T1ρ and T2 relaxation time correlated with increased compressive forces and pressures. Thicker cartilage was correlated with higher condylar loading during walking, suggesting that cartilage thickness is increased in those areas experiencing higher loading during a cyclic activity such as gait. Furthermore, the proteoglycan and collagen concentration and orientation derived from T1ρ and T2 relaxation measures were related to loading.

Non-invasive T1ρ mapping of the human cartilage response to loading and unloading

“…In porcine cartilage, Hamada et al found significant strain-related decreases in T1r 16 . These observations were confirmed by recent in vivo studies 23,24 .…”

Identification of locations susceptible to osteoarthritis in patients with anterior cruciate ligament reconstruction: Combining knee joint computational modelling with follow-up T1ρ and T2 imaging

“…The VOI was defined as the volume of cartilage with either T 2 or T 1ρ relaxation times above 60 ms. This value is above the literature reported value of 50 ms for healthy cartilage (Bolbos et al, 2008;Li et al, 2011;Stahl et al, 2009;Surowiec et al, 2014;Van Rossom et al, 2017). Similarly, if no relaxation time exceeded this limit, the VOI was defined as "0".…”

Achilles tendon stiffness minimizes the energy cost in simulations of walking in older but not in young adults

“…We captured the trajectories of 68 reflective markers using thirteen infrared cameras (Vicon, Oxford, UK) recording at 100 Hz. We used a full body plug in gait marker set extended with 4 upper limb clusters, 4 lower limb clusters and one pelvis cluster (Van Rossom et al, 2017). We collected ground reaction forces using two force plates built in the treadmill at 1000 Hz.…”