Is there difference and correlation between medial and lateral tibial plateau coronal obliquity in native knee? A radiographic study

Abstract

Background/Purpose: Knee joint line is commonly defined as a tangent to medial and lateral tibial plateaus in various radiographic measurements. We aim to investigate radiographic differences between medial and lateral knee joint line coronal obliquity. It has significant implication on radiographic analysis following unicompartmental knee arthroplasty. Methods: We analysed the knee radiographs of 48 young patients (mean age 25.1 + /-5.6 years) with 50 anterior cruciate ligament-deficient knees. Medial and lateral tibial plateau coronal obliquity were defined as angles between femoral knee joint line and the tangent to articular surface of each tibial plateau. Mediolateral differences and linear correlation were analysed. Results: Significant difference was found between medial (mean = -1.5, SD = 2.4 degrees) and lateral obliquity (mean = + 0.6, SD = 3.0 degrees) (p < 0.001). The mean mediolateral difference was 3.1 degrees (SD = 2.8, range 0–11.8 degrees), without significant correlation (r = 0.085, p = 0.56). Conclusion: Mediolateral differences exist in knee joint line obliquity. Each compartment should be considered separately when measuring knee joint line obliquity.