An ultrasound elastography method for examining the anterior cruciate ligament

We introduce an ultrasound elastography method for examining the ACL. It consisted of imaging the distal ACL while applying a drawer test and analyzing the resulting displacement and strain maps, where a map refers to how a variable is distributed spatially throughout an image. Our method was applied to healthy knees of cadaveric sheep to determine whether 1) our method can consistently generate displacements and strain maps in healthy ACLs; 2) displacement and strain maps are repeatable; and 3) healthy ACLs experience similar maps. We found that our method could consistently provide displacements and strain maps of the distal ACL region. Moreover, these ACLs experienced displacement and strain maps that were positivelycorrelated between trials, knees, and specimens. This correlation was statistically significant between pairs of trials and between left and right knees (p < 0.05). These results suggest that the maps are indeed repeatable and similar for healthy ACLs.