The posterior cruciate ligament angle in the setting of anterior cruciate ligament deficient knees: the effect of gender, age, time from injury and tibial slope

Purpose: This study aimed to assess the posterior cruciate ligament (PCL) angle in anterior cruciate ligament (ACL) deficient knees and correlate it with anatomical and demographic factors such as tibial slope, anterior tibial translation, age, gender, and time of injury. Material and methods: Patients were eligible for inclusion if they were clinically diagnosed with an ACL tear confirmed by MRI. For each patient, the following parameters were evaluated: PCL angle (PCLA), medial tibial slope (MTS), lateral tibial slope (LTS), medial anterior tibial translation (MATT), and lateral anterior tibial translation (LATT). Results: A total of 193 patients were included in the study, comprising 91 (47.2%) females and 102 (52.8%) males, with a mean age of 30.27 ± 12.54 years. The mean time from injury to MRI was 14.18 ± 55.77 days. In the overall population, the mean PCL angle was 128.72 ± 10.33°, the mean medial tibial slope was 3.57 ± 2.33°, and the mean lateral tibial slope was 6.07 ± 3.52°. The mean medial and lateral anterior tibial translations were 4.76 ± 2.02 mm and 7.01 ± 2.48 mm, respectively. In 190 cases (98.4%), the PCL angle was ≥ 105°. The PCL angle negatively correlated with medial and lateral anterior tibial translation (p < 0.05). Females exhibited a higher PCL angle compared to males (p = 0.019). Conclusion: In the context of ACL lesions, the PCL angle has a normal value in acute injuries (> 105°) and decreases over time. The PCL angle is negatively correlated with anterior tibial translation, and females have a higher PCL angle compared to males. Level of evidence iv: Retrospective Cohort.