Curve Inflection and Modification of the Anterior Knee Laxity Compliance Index: Specific Variables to Assess Anterior Cruciate Ligament Integrity

Variables assessed included (1) inflection point, (2) compliance index (CI), and (3) modified compliance index (MCI). These variables are illustrated in Figure 2. Inflection point was defined as the point of intersection of the linear portions. CI was defined as the difference in displacements at 67 and 89 N of anterior force [2]. MCI was defined as the compliance of post-inflection stiffness over 22 N. If no inflection point was identified, MCI was defined as the compliance over 22 N. Statistical interactions were evaluated using 3x2 repeated measures ANOVA. A least significant difference test was used for multiple comparisons.