Exploring the differences between radiographic joint space width and MRI cartilage thickness changes using data from...

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Longitudinal joint space width (JSW) from radiographs and cartilage thickness from MRI show weak correlations in osteoarthritis (OA) studies.
• Understanding factors influencing these correlations is crucial for accurate OA progression assessment.

Purpose of the Study:

• To investigate correlations between longitudinal weight-bearing radiographic JSW and non-weight-bearing MRI cartilage thickness changes.
• To explore how cartilage quality, meniscal extrusion, pain, and BMI affect these correlations.

Main Methods:

• 178 participants with medial knee OA were analyzed over 2 years.
• Changes in medial JSW, minimum JSW, and medial femorotibial cartilage thickness were measured using radiographs and MRI.
• Correlations were assessed, and the influence of cartilage quality (T2 mapping), meniscal extrusion, pain, and BMI was analyzed.

Main Results:

• Correlations between cartilage thickness and JSW changes were statistically significant but weak (R < 0.35).
• Significant moderate correlations were observed only in participants with the lowest T2 values (higher cartilage quality) and with meniscal extrusion.
• Neither pain-induced unloading nor BMI-induced loading influenced the correlations.

Conclusions:

• Weight-bearing radiographic JSW changes are a better reflection of MRI cartilage thickness changes in knees with higher quality cartilage and meniscal extrusion.
• The amount of loading (pain or BMI) does not appear to influence the correlation between these two imaging methods.