BACKGROUND:Anterior cruciate ligament avulsion fracture at tibial insertion is a special type of intra-articular fracture,which is mostly seen in sports injuries.At present,there are relatively few anatomical studies on this disease,but a large number of studies focus on the injury of the anterior cruciate ligament.It is generally believed that the increase in the posterior slope of the tibial plateau,the decrease of the depth of the medial tibial plateau,and the decrease in the width index of the femoral intercondylar notch are the risk factors for the injury of the anterior cruciate ligament.It is unclear whether avulsion fractures of the anterior cruciate ligament at the tibial insertion point are also related to it. OBJECTIVE:To investigate the correlation between the avulsion fracture of the anterior cruciate ligament at the tibial insertion and the posterior tibial slope,the medial tibial depth,the notch width index of the femoral intercondylar fossa,and the coronal slope angle of the tibial plateau. METHODS:A retrospective analysis was made on 101 patients who were admitted to the Department of Orthopedics of Affiliated Hospital of Xuzhou Medical University due to anterior knee pain from January 2019 to December 2022.Totally 51 patients with tibial insertion avulsion fracture of anterior cruciate ligament who received arthroscopy treatment were taken as the observation group,and 50 patients with anterior knee pain but no knee joint injury confirmed by physical examination and imaging examination were taken as the control group in the same period.The posterior tibial slope,anatomical parameters such as the medial tibial depth,and the notch width index of the femoral intercondylar fossa,were statistically analyzed for the anatomical risk factors leading to the tibial insertion avulsion fracture of the anterior cruciate ligament. RESULTS AND CONCLUSION:(1)There was no significant difference between the two groups in the comparison of the lateral posterior tibial slope,the posterior slope ratio of the lateral/medial tibial plateau,the notch width index of the femoral intercondylar fossa,and the coronary slope angle of the tibial plateau(P>0.05).The medial posterior tibial slope in the observation group was significantly higher than that in the control group(P<0.05).The medial tibial depth in the observation group was significantly lower than that in the control group(P<0.05).(2)Multifactor logistic regression analysis showed that the medial posterior tibial slope and the medial tibial depth were independent risk factors for tibial insertion avulsion fracture of anterior cruciate ligament(P<0.05).(3)The receiver operating characteristic curve shows that the medial posterior tibial slope and the medial tibial depth had certain predictive values for the tibial insertion avulsion fracture of the anterior cruciate ligament.(4)It is indicated that the increased medial posterior tibial slope and the shallower medial tibial depth are the anatomical risk factors for the avulsion fracture of the tibial insertion of the anterior cruciate ligament.