Previous research has demonstrated that women have a higher risk of anterior cruciate ligament (ACL) injury than men. Tibiofemoral articular geometry may play a role in the occurrence of ACL tears. The purpose of this study was to analyze the gender-specific geometric characteristics differences in tibiofemoral morphology in ACL-deficient patients.Medial tibial slope (MTS), lateral tibial slope (LTS), medial tibial plateau concavity, medial and lateral femoral condyle convexity, and lateral plateau convexity were analyzed in 276 patients with complete ACL injuries (138 females and 138 males). Two blinded observers measured the anatomical parameters of tibiofemoral geometry with use of multiplanar CT scans. Intra- and inter-rater reliabilities were assessed and comparisons between anatomic measures were made between male and female patients.The average ICC for all measurements was 0.90 (range 0.83-0.97) indicating good reliability. Male ACL injured patients demonstrated significantly greater LTS (10.5° ± 2.8) than female patients (9.6° ± 3.5°; p < 0.05). No gender difference in MTS was found (n.s.). Medial and lateral femoral condyle convexity and medial tibial plateau concavity were greater in males than females (all p < 0.05). Lateral tibial plateau convexity in females was higher than in males (p < 0.001). The medial and lateral compartments were found to be more incongruent in females than males (p < 0.01 and p < 0.001, respectively).Female patients were noted to have more incongruent medial and lateral compartments than male patients. These gender-specific differences in joint morphology may contribute to graft tear risk and outcomes of ACL reconstruction; however, comparative clinical studies are needed to confirm this possibility.3.