Decreased lateral posterior tibial slope and medial tibial depth are underlying anatomic risk factors for posterior cruciate ligament injury: a case–control study

OBJECTIVES: To research whether medial PTS, lateral PTS and MTD were different between the PCL injury group and the PCL intact group. DESIGN: Retrospective case–control study, level of evidence III. METHODS: Fifty patients with PCL rupture from 2015 to 2020 in our hospital, and 50 patients matched by age and sex with intact PCL were enrolled in our study. The intraclass correlation coefficient (ICC) was used to assess the reliability of each parameter. The independent t-test was conducted to identify the differences in tibial morphometric characteristics between the PCL-injured and PCL-intact individuals, including the posterior tibial slope (PTS), meniscal slope (MS), medial tibial depth (MTD). A binary logistic regression model was established to evaluate the roles of those anatomic parameters of interest play in PCL injuries. RESULTS: The interobserver reliability of each parameter showed excellent agreement. Significant differences in the medial (P = .023) and lateral (P = .009) PTS were found between the PCL-injured group (3.68 ± 2.70 and 4.55 ± 3.19, respectively) and the controls (5.00 ± 2.73 and 6.39 ± 3.29, respectively). And the MTD was 1.98 ± 0.64 mm in the PCL-injured group and 2.37 ± 0.55 mm in the control group (P = 0.007). Binary logistic regression analysis showed that smaller lateral PTS and MTD were directly associated with PCL injury, with an OR of 1.17 and OR of 3.14, respectively. The medial PTS was independent to PCL injures. CONCLUSION: Decreased lateral PTS and MTD were underlying anatomic risk factors for PCL injury.