ABSTRACT
Objective:To evaluate whether posterior cruciate ligament (PCL) avulsion fracture was correlated with intercondylar notch and tibial slope.Methods:A total of 48 patients with PCL avulsion fracture were compared with 48 age- and sex-matched healthy controls without PCL avulsion fracture from January 2012 to October 2018 in our hospital. There were 25 males and 23 females with an average age of 54.35±14.06 years (range 27-82 years) in PCL avulsion fracture group. MRI of the knee joint were acquired in the sagittal, coronal, and axial sequences. The measurements included intercondylar notch's angle, width, and height, medial/lateral condylar widths, condylar width, medial/lateral posterior tibial slopes and coronal tibial slope. Notch shape index and notch width index were also calculated to adjust for size variations. The predictive accuracy of Risk factors were analyzed using the area under the receiver operating characteristic curve (AUC). The differences of morphological measurements between the two groups were compared. The morphological measurements with statistical significance were included for further multivariate analysis. Risk factors of PCL avulsion fracture were determined by binary logistic regression analysis. The inter- and intra-observer reproducibility of the measurements was determined by the intraclass correlation coefficients (ICC).Results:Except for coronal intercondylar notch height (0.709), medial posterior tibial slope (0.699) and lateral posterior tibial slope (0.705), the other intra-observer ICC ranged from 0.802 to 0.980, which indicated that the parameters had desirable reproducibility. Similarly, except for coronal intercondylar notch height (0.700), the other intra-observer ICC ranged from 0.778 to 0.971. Parameters of patients with PCL avulsion fracture, including the axial notch angle (52.56°±6.56°), coronal notch angle (54.81°±7.29°), axial intercondylar notch width (19.62±2.32 mm), axial notch shape index (0.68±0.08) and medial posterior tibial slope (8.27°±3.53°), were all significantly larger than those of the control group. The binary logistic regression analysis showed that the coronal notch angle ( β=0.102, OR=1.108, P=0.030) and medial posterior tibial slope ( β=0.151, OR=1.163, P=0.046) were the risk factors or PCL avulsion fracture. The AUC for coronal notch angle (0.678) and medial posterior tibial slope (0.631) exhibited good predictive power for the occurrence of PCL avulsion fracture. Conclusion:The larger coronal notch angle and medial posterior tibial slope were positively correlated with the incidence of PCL avulsion fracture.