Correlation Between Changes in Global Knee Structures Assessed by Magnetic Resonance Imaging and Radiographic Osteoarthritis Changes Over Ten Years in a Midlife Cohort.

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

METHODS: A total of 211 participants (mean age 45 years [range 26-61 years], 57% female) were studied at baseline, 2 years, and 10 years. Approximately one-half were adult offspring of subjects who had undergone knee replacement for OA and the remainders 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 10 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 2 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.