Meniscal tear and extrusion are strongly associated with progression of symptomatic knee osteoarthritis as assessed by quantitative magnetic resonance imaging

Abstract

Background: The relation between knee meniscal structural damage and cartilage degradation is plausible but not yet clearly proven.

Objectives: To quantitate the cartilage volume changes in knee osteoarthritis using magnetic resonance imaging (MRI), and determine whether meniscal alteration predicts cartilage volume loss over time.

Methods: 32 patients meeting ACR criteria for symptomatic knee osteoarthritis were studied. MRI knee acquisitions were done every six months for two years. The cartilage volumes of different knee regions were measured. Three indices of structural change in the medial and lateral menisci were evaluated--degeneration, tear, and extrusion--using a semiquantitative scale.

Results: 24 patients (75%) had mild to moderate or severe meniscal damage (tear or extrusion) at baseline. A highly significant difference in global cartilage volume loss was observed between severe medial meniscal tear and absence of tear (mean (SD), -10.1 (2.1)% v -5.1 (2.4)%, p = 0.002). An even greater difference was found between the medial meniscal changes and medial compartment cartilage volume loss (-14.3 (3.0)% in the presence of severe tear v -6.3 (2.7)% in the absence of tear; p<0.0001). Similarly, a major difference was found between the presence of a medial meniscal extrusion and loss of medial compartment cartilage volume (-15.4 (4.1)% in the presence of extrusion v -4.5 (1.7)% with no extrusion; p<0.001).

Conclusions: Meniscal tear and extrusion appear to be associated with progression of symptomatic knee osteoarthritis.

Figures

Figure 1

Different meniscal pathologies as seen by magnetic resonance imaging (MRI) contrasted to normal meniscus (top left panel). The MRI acquisitions are three dimensional fat suppressed FISP sequences as described in Methods.

Figure 2

Cartilage volume loss (%) at two years compared with baseline, divided by degree of meniscal tear, as described in the text. Non-parametric two sample tests showed significant differences in cartilage volume loss between the severe medial meniscal damage and no tear groups for both the cartilage global and medial compartment volume. No significant differences in cartilage volume losses were seen among the groups with lateral meniscal tear.

Figure 3

Cartilage volume loss (%) at two years divided by degree of meniscal extrusion, as described in the text. Non-parametric two sample tests showed significant differences in cartilage volume loss between the severe meniscal anterior horn extrusion and no extrusion for the medial compartment volume. No significant differences in cartilage volume loss were seen among the groups with middle horn extrusion.