Exploring the differences between radiographic joint space width and MRI cartilage thickness changes using data from the IMI-APPROACH cohort

Abstract

Objective Longitudinal weight-bearing radiographic joint space width (JSW) and non-weight-bearing MRI-based cartilage thickness changes often show weak correlations. The current objective was to investigate these correlations, and to explore the influence of different factors that could contribute to longitudinal differences between the two methods. Methods The current study included 178 participants with medial osteoarthritis (OA) out of the 297 knee OA participants enrolled in the IMI-APPROACH cohort. Changes over 2 years in medial JSW (ΔJSWmed), minimum JSW (ΔJSWmin), and medial femorotibial cartilage thickness (ΔMFTC) were assessed using linear regression, using measurements from radiographs and MRI acquired at baseline, 6 months, and 1 and 2 years. Pearson R correlations were calculated. The influence of cartilage quality (T2 mapping), meniscal extrusion (MOAKS scoring), potential pain-induced unloading (difference in kneespecific pain scores), and increased loading (BMI) on the correlations was analyzed by dividing participants in groups based on each factor separately, and comparing correlations (slope and strength) between groups using linear regression models. Result Correlations between ΔMFTC and ΔJSWmed and ΔJSWmin were statistically significant (p < 0.004) but weak (R < 0.35). Correlations were significantly different between groups based on cartilage quality and on meniscal extrusion: only patients with the lowest T2 values and with meniscal extrusion showed significant moderate correlations. Pain-induced unloading or BMI-induced loading did not influence correlations. Conclusions While the amount of loading does not seem to make a difference, weight-bearing radiographic JSW changes are a better reflection of non-weight-bearing MRI cartilage thickness changes in knees with higher quality cartilage and with meniscal extrusion.

Machine-learning predicted and actual 2-year structural progression in the IMI-APPROACH cohort

“…Also, the current study revealed that the different progressor definitions do not show a high agreement ( Tables S3-S5 ), which may explain why the s-score cannot be reused to predict other progression definitions as well. In the comparison between JSW and MRI cartilage thickness this could potentially be the result of differences in acquisition (such the difference in weight-bearing, or the fact that JSW progression is a composite result of cartilage loss and meniscal damage and extrusion) ( 27 ), but even progression on qMRI cartilage thickness and MOAKS cartilage scores showed only low agreement in this study. This means that, even if the progression in one parameter (in this case minimum JSW) could have been predicted perfectly, this would not necessarily have resulted in a similarly high number of progressors in the other structural parameters.…”

Relevance of Biomarkers in Serum vs. Synovial Fluid in Patients with Knee Osteoarthritis

“…However, the minJSW measurement reflects a one-dimensional thickness measured from one specific location of the joint, and it may also include other tissues such as the menisci [21]. A correlation analysis between cartilage thickness and minJSW from previous studies showed some variation between the two parameters, which was explained by variation in the cartilage thickness [22,23]. The C2M levels in serum were also found to be negatively correlated with KL grade.…”