Abstract: BACKGROUND: The anatomical morphology of the distal femur and proximal tibia has an important influence on the movement of the tibiofemoral joint, and its role in anterior cruciate ligament injury has been well described. However, the research on the anatomical risk factors of posterior cruciate ligament tibial avulsion fracture is still limited, and no unified consensus has been formed. 
OBJECTIVE: To investigate the anatomical risk factors for posterior cruciate ligament tibial avulsion fracture.
METHODS: The medical records of 53 patients who underwent surgical treatment for posterior cruciate ligament tibial avulsion fracture from March 2021 to September 2024 were retrospectively collected as the posterior cruciate ligament avulsion group (32 males and 21 females), and the data of 53 subjects without posterior cruciate ligament injury in the same period were included as the posterior cruciate ligament normal group (24 males and 29 females). The intercondylar notch width, femoral condyle width, intercondylar notch width index, intercondylar notch height, intercondylar notch shape index, intercondylar notch angle, Blumensaat's line inclination angle, medial tibial posterior slope, and lateral tibial posterior slope were measured and calculated in Magnetic Resonance Imaging to analyze the differences in the anatomical data of the two groups. Binary logistic regression analysis was used to determine the independent risk factors and to establish a risk factor model by receiver operating characteristic curve. 
RESULTS AND CONCLUSION: (1) The intercondylar notch width index, intercondylar notch shape index, intercondylar notch angle, and medial tibial posterior slope of the posterior cruciate ligament tibial avulsion group were smaller than those of the posterior cruciate ligament normal group, and the differences were statistically significant (P < 0.05). The data of the two groups were not statistically different in the intercondylar notch width, femoral condyle width, intercondylar notch height, Blumensaat's line inclination angle, and lateral tibial posterior slope (P > 0.05). (2) Binary logistic regression found that the intercondylar notch width index was associated with posterior cruciate ligament tibial avulsion fracture. (3) It is indicated that patients with posterior cruciate ligament tibial avulsion fracture had smaller intercondylar notch width index, intercondylar notch shape index, intercondylar notch angle, and medial tibial posterior slope compared with those with a normal posterior cruciate ligament. The intercondylar notch width index was an independent risk factor for tibial avulsion fracture of the posterior cruciate ligament.

Key words: posterior cruciate ligament tibial avulsion fracture, intercondylar notch, tibial plateau, anatomy, risk factor