Mr assessment of movement and morphologic change in the menisci during knee flexion

Purpose. To examine movement and morphologic alteration in the menisci duri ng knee flexion. Material and Methods. Twenty healthy knees were imaged at 0 degrees, 45 deg rees, and 90 degrees of passive non-weight-bearing flexion in the sagittal plane with MR. In each meniscus, posterior movement distance during knee fl exion and the ratio of anteroposterior (a.p.) diameter at flexion to that a t extension were calculated. Results. Each meniscus moved posteriorly during knee flexion. Movement was greater in the anterior horn than in the posterior horn, and greater in the medial meniscus than in the lateral meniscus (p<0.05). The a.p. diameter o f each meniscus was reduced at flexion (p<0.05). Conclusion. Knee flexion normally leads to posterior movement and shortenin g of the a.p. diameter of the menisci, which may be related to the position ing and curvature of femoral condyles at the femorotibial contact point at knee flexion.