Correlation between changes in global knee structures assessed on Magnetic Resonance Imaging and radiographic osteoarthritis changes over 10 years in a mid-life cohort

Objectives: The aim of this study was to describe the correlation between changes in structural abnormalities assessed on MRI and change in radiographic osteoarthritis (OA) over 10 years in a midlife cohort.

Methods: 211 participants [mean-age 45 (26-61); 57% female] were studied at baseline, two and ten years. Approximately, half were adult offspring of subjects who had undergone knee replacement for OA and the remainder were randomly selected controls. Joint space narrowing (JSN) and osteophytes were assessed from radiographs while cartilage volume, cartilage defects and meniscal tears/extrusion were assessed from MRI. Spearman ranked correlation analysis was used to describe the correlation between structural changes assessed on MRI and radiographs. Only medial tibiofemoral compartment results are presented as the lateral compartment had limited change.

Results: Over ten years, change in meniscal tears showed a moderate independent correlation with change in both JSN (ρ = +0.37, p < 0.01) and osteophytes (ρ = +0.31, p < 0.01) in the adjusted analysis. Meniscal extrusion (ρ = +0.22, p < 0.01) and cartilage defects (ρ = +0.16, p = 0.04) showed a slightly weaker independent correlation with JSN in the adjusted analysis, whereas cartilage volume loss showed no significant correlation with either of the two radiographic outcomes.

Conclusion: Change in JSN is correlated with change in meniscal tears and, to a lesser extent, with meniscal extrusion and cartilage defects. In this sample, change in JSN is a composite measure that does not reflect cartilage volume loss prompting the review of the use of JSN as an outcome measure in chondro-protective drug trials.