Diurnal variations in articular cartilage thickness and strain in the human knee

Abstract

Due to the biphasic viscoelastic nature of cartilage, joint loading may result in deformations that require times on the order of hours to fully recover. Thus, cartilaginous tissues may exhibit cumulative strain over the course of each day. The goal of this study was to assess the magnitude and spatial distribution of strain in the articular cartilage of the knee with daily activity. Magnetic resonance (MR) images of ten asymptomatic subjects (six males, four females) with mean age of 29 years were obtained at 8:00AM and 4:00PM on the same day using a 3T magnet. These images were used to create 3D models of the femur, tibia, and patella from which cartilage thickness distributions were quantified. Cartilage thickness generally decreased from AM to PM in all areas except the patellofemoral groove and was associated with significant compressive strains in the medial condyle and tibial plateau. From AM to PM, cartilage of the medial tibial plateau exhibited a compressive strain of −5.1 ± 1.0% (mean ± SEM) averaged over all locations, while strains in the lateral plateau were slightly lower (−3.1 ± 0.6%). Femoral cartilage showed an average strain of −1.9 ± 0.6%. The findings of this study show that human knee cartilage undergoes diurnal changes in strain that vary with site in the joint. Since abnormal joint loading can be detrimental to cartilage homeostasis, these data provide a baseline for future studies investigating the effects of altered biomechanics on diurnal cartilage strains and cartilage physiology.

Kinematics of passive flexion following balanced and overstuffed fixed bearing unicondylar knee arthroplasty

“…A possible explanation could be the fact that UKA implantation replaces the native articular surface (cartilage five to 12 MPa) with a polyethylene insert (850 MPa) on a metallic femoral component (97 GPa). Cartilage can be compressed under pressure [13,14], while implants less so, which may add to a more inferior position of the tibia. Overstuffing via a thicker polyethylene will increase this effect.…”

In vivo cartilage strain increases following medial meniscal tear and correlates with synovial fluid matrix metalloproteinase activity

“…Next, the MR images were imported into solid modeling software (Rhinoceros, Robert McNeel and Associates, Seattle, WA) so that outlines of the bony cortices and articular cartilage surfaces could be traced. These line models were converted into point clouds and 3D meshes of the femur, tibia, and articular cartilage were created with Geomagic Studio software (3D Systems, Rock Hill, SC) (Figure 1) (Coleman et al, 2013). This method has been previously validated for measuring tibiofemoral cartilage thickness (Van de Velde et al, 2009).…”

“…This method has been previously validated for measuring tibiofemoral cartilage thickness (Van de Velde et al, 2009). Additionally, a recent study from our laboratory demonstrated a coefficient of repeatability of 0.03 mm in measuring tibial, femoral, and patellar cartilage thickness (Coleman et al, 2013), corresponding to a difference in cartilage thickness of 1% (Coleman et al, 2013; Widmyer et al, 2013). …”

The structure and function of the pericellular matrix of articular cartilage

“…The proteoglycan content of the PCM is generally higher than that of the surrounding ECM. Therefore, tissue deformation and the associated changes in interstitial water content that occur during loading (Coleman et al, 2013) will result in dynamic changes in the physicochemical and osmotic environment of the chondrocyte (Haider et al, 2006). Importantly, a growing body of evidence suggests that osmotic changes may provide critical signals for regulating the chondrocyte response to loading (Chao et al, 2006; O'Conor et al, 2014).…”