Objective To explore whether there are gender differences in the characteristics of medial patellofemoral ligament (MPFL) injury after acute and chronic traumatic lateral dislocation of the patella. Methods The clinical data and MRI imaging data of 161 adolescent patients with medial patellofemoral ligament injury after acute and chronic traumatic lateral patellar dislocation in our hospital from January 2008 to January 2018 were retrospectively analyzed. 93 patients with acute MPFL injury and 68 patients with chronic MPFL injury. All patients were followed up for 1 year to evaluate the injury degree and injury site of the medial patellofemoral ligament. Results There was no statistical significance in the degree and incidence of acute MPFL injury in male and female subjects (P>0.05). In terms of the degree of chronic MPFL injury in males, Ⅲ ° lesion was predominant, and significantly higher than that in females (P<0.05), while in females, Ⅱ ° lesion was predominant, and significantly higher than that in males (P<0.05). However, there was no statistical significance between males and females in Ⅰ ° lesion (P>0.05). In terms of injury sites of chronic MPFL, there was no statistical significance in the incidence of injury between male and female patients (P>0.05). Conclusion There is no gender differences in the MRI characteristics of acute MPFL injury degree and injury sites in adolescents, and the chronic MPFL injury site, but there is a difference in the chronic MPFL injury degree. Male patients mainly have Ⅲ° injuries, while female patients have Ⅱ° injuries mainly.