Measurements of knee morphometrics using MRI and arthroscopy: a comparative study between ACL-injured and non-injured subjects

Purpose The primary purpose of this study was as follows: (1) to compare bony morphology in subjects with and without ACL injury. The secondary purposes were the following: (2) to compare bony morphology between men and women and (3) to determine whether MRI measurements of the notch correlate with intra-operative measurements. Methods MRI measurements of NW, bicondylar width, medial condyle size and lateral condyle size, and medial-to-lateral condyle ratio (M:L) were taken from 45 subjects with ACL injury and 44 subjects without ACL injury, by two independent observers. In addition, notch width measurements were taken arthroscopically in the 45 injured subjects. Knee morphometrics were compared between men and women. Additionally, values of ACL-injured and non-injured subjects were compared for male and female subjects separately. Correlations between notch measurements taken from MRI and measured arthroscopically were determined. Reliability of the MRI measurements was calculated. Results Significant differences were found for bicondylar width (P = 0.001), medial condyle width (P = 0.002), and lateral condyle width (P = 0.002) between male and female subjects. When bony morphology was compared between ACL-injured and non-injured subjects, the male subjects showed significant differences for bicondylar width (P = 0.002) and medial condyle width (P = 0.008). For the female subjects, significant differences were found for bicondylar width (P = 0.009) and lateral condyle width (P = 0.002). There was no correlation between notch width measured on the MRI's and NW measured intra-operatively. The intra- and inter-observer reliability of the MRI measurements was satisfactory. Conclusions There were differences in bony morphology between men and women and between subjects with and without ACL injury. The bony morphology that was different between ACL-injured and non-injured subjects varied between male and female subjects.