Loading and knee alignment have significant influence on cartilage MRI T2 in porcine knee joints

Abstract

The response of T2 to change in static loading or alignment varied between the medial and lateral cartilages, and among the deep, intermediate, and superficial zones. These T2 changes were significantly related to the contact pressure measurements. Our results indicate that T2 mapping under loading allows non-invasive, biomechanical assessment of site-specific stress distribution in the cartilage.

Probing articular cartilage damage and disease by quantitative magnetic resonance imaging

“…There may also be little distinction in T 2 values within the spectrum of pre-radiographic to radiographic cartilage damage [34,90]. In addition to being affected by the angle at which cartilage is positioned with respect to the main magnetic field [55], T 2 values are sensitive to the type of radiofrequency coil [91], the choice of pulse sequence and sequence parameters [92], the joint position during imaging [93] and the type of equation used to fit data [94].…”

“…Values for T 2 , T 1,Gd and T 1r , even in normal cartilage, differ in the literature and can be dependent on pulse sequence [92], the strength of the static magnetic field [32,119] and the radiofrequency coil [91]. A number of studies have shown that loading history [93,120 -122] and joint alignment [93,123] can also affect some of these qMRI measures. Additionally, despite correlations that show a difference in these qMRI measures between normal and damaged cartilage, there may be a lack of sensitivity in distinguishing the levels of clinical damage [37,90,124,125].…”

Influence of medial meniscectomy on stress distribution of the femoral cartilage in porcine knees: a 3D reconstructed T2 mapping study

“…After conducting the following imaging and mechanical experiments, macroscopic inspection of the joint surfaces did not reveal any signs of joint disease or cartilage degeneration in the specimens. The porcine knee joints were mounted in a custom-made nonmetallic compression device, which has been described in detail in the report of a previous loading experiment 18 . In brief, the femoral and tibial shafts were firmly fixed to the nonmobile base and the opposing side of the mobile plate respectively, and under static loading conditions at neutral or varus/valgus alignments, longitudinal compression force was transmitted to the knee joint through a sliding plate bounded by a viscoelastic foam material (Fig.…”

“…1). When the foam material was compressed by 20 mm with a screw compression driver, the compression force was applied to the knee joint to achieve 300 N across the tibiofemoral cartilages 18 , which corresponded to approximately one-third of the body weight of the specimen.…”

“…In experimental studies using MRI and excised cartilageebone plugs 13e16 , significant changes in cartilage thickness and signal intensity were observed in response to increased loading. The change in cartilage T2 values on MRI significantly correlated with the applied pressure, and the T2 value on loading MRI may thus be a potent nondestructive index of transmission of applied load onto the cartilage 15,17,18 .…”