ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

4. RESULTS
All of the MR images of the loaded and unloaded knee were achieved. Imaging the knee
while flexed to 25 degrees and internally rotating the foot under axial loading required 3
repeats before motion artifact could be eliminated from the MR images. No motion
artifact or other distortion was present on any of the final scans and no abnormal
pathology was identified upon inspection of the MR images.
Table 1: Meniscal translation during passive knee flexion relative to the menisci
position in the unloaded, fully extended knee.
Knee flexion/
degrees
Medial Meniscus Lateral Meniscus
Posterior
translation/
mm
Medial
translation/
mm
Posterior
translation/
mm
Medial
translation/
mm
25 3.2 0.4 1.0 -3.2
50 3.3 1.3 4.5 -3.6
130 10.6 1.3 9.2 -6.4
Table 1 shows the posterior motion of both menisci relative to the fully extended knee
during passive knee flexion. The medial meniscus remains stationary between 25 and 50
degrees knee flexion having initially translated 3.3mm posteriorly from the neutral
position before translating a further 7.3mm in deep knee flexion. The lateral meniscus is
more linear in its translation in the posterior direction during knee flexion up to a
maximum of 9.2 mm in deep knee flexion.
Figure 1: 2D representation of 3D meniscal displacement with 25° (left) 50° (middle)
and 130° (right) passive knee flexion. Blue represents the tibial plateau, black the
position of the menisci in the neutral position and red represents the menisci position
with flexion. The arrows represent the change in meniscus centroid location. Right on
the figure is the posterior direction while up is the lateral direction.