RESUMO
Objective:To measure the anatomical parameters of the simulated low tibial tunnel of posterior cruciate ligament (PCL) based on knee CT images so as to provide clinical reference for accurate location of the tunnel.Methods:The CT images of 201 healthy knee joints collected at Department of Orthopedics, The Second Hospital of Lanzhou University from June 2016 to September 2021 were used for simulation of the PCL low tibial tunnel. The anatomical parameters of the tibial tunnel were measured using the RadiAnt DICOM Viewer. The primary measures included the angle between tibial plateau and tibial tunnel (ATPT) and the perpendicular distances from the tibial tunnel entrance and exit point to the tibial plateau (L1 and L2). The secondary measures included the angle between tibial plateau and posterior slope (PSA), the angle between tibial anatomical axis and central line of tibial tunnel (ATAA), the angle between posterior tibial slope line and the central line of tibial tunnel (APST), the anterior and posterior diameter of tibial plateau (APD), the length of posterior tibial slope (LPTS), and the length of tibial tunnel (LTT). The measurement results were analyzed according to the body height (divided into 3 groups: a 1.00 to 1.60 m group, a 1.61 to 1.70 m group, and a ≥1.71 m group) and gender using the software IBM SPSS 26.Results:The primary measures: ATPT was 37.0°±4.5°, and L1 and L2 were respectively (57.8±7.4) mm and (34.5±3.3) mm. The secondary measures: PSA 128.1°±5.4°, ATAA 52.7°±4.1°, APST 89.1°±5.9°, APD was (32.9±2.6) mm, LPTS (20.5±2.4) mm, and LTT (40.9±5.7) mm. After grouping by gender, there was no significant difference in PSA between men and women ( P>0.05) while there were significant differences in the other indexes between men and women ( P<0.05). After grouping by body height, there was no significant difference in ATPT, PSA, APST or ATAA between the 3 groups (1.00 to 1.60 m group, 1.61 to 1.70 m group and ≥1.71 m group) ( P>0.05) while there were significant differences in L1, L2, APD, LPTS and LTT between the 3 groups ( P<0.05). Conclusions:Based on the knee CT images, the primary measures of PCL low tibial tunnel are as follows: the angle between tibial plateau and tibial tunnel is 37.0°±4.5°, and the perpendicular distances from the tibial tunnel entrance and exit point to the tibial plateau are (57.8±7.4) mm and (34.5±3.3) mm, respectively. Gender and body height are the important factors influencing the above measurement outcomes.