Radiographic difference and correlation between medial and lateral tibial plateau coronal obliquity in native knees

Abstract

Introduction: We aimed to investigate whether there is any radiographic difference or correlation between medial and lateral tibial plateau coronal obliquity in native knees. Methods: We recruited 48 (40 male, 8 female) young patients (mean age, 25.1 years) with 50 anterior cruciate ligament (ACL)–deficient knees. Standard anteroposterior non-weight-bearing radiographs of the 50 ACL-deficient knees were used for measurement. For reference purposes, knee joint line was defined as a line intersecting the most distal points of medial and lateral femoral condyles. We then measured the medial and lateral tibial plateau coronal obliquity, defined as the angle between the joint line and the line joining the most medial and lateral points of articular surface of each tibial plateau. For comparison, positive angles denoted lateral inclination while negative angles denoted medial inclination. Paired t test was performed to analyse the mean difference between medial and lateral tibial plateau coronal obliquity. We further assessed the association between medial and lateral obliquity using a Pearson correlation. Results: Significant difference was found between medial (mean -1.3 ± 2.5°) and lateral obliquity (+0.8 ± 2.9°) [p<0.001]. The mean difference was 3.3 ± 2.9° (range, 0-11.8°). On calculating the Pearson correlation coefficient, there was no significant correlation between medial and lateral obliquity (r=0.06, p=0.69). Conclusion: We found a significant difference without correlation between medial and lateral tibial plateau coronal obliquity in native knees. Our results highlight the importance of individualised assessment of mediolateral tibial plateau coronal obliquity in considering knee joint line obliquity.