Importance of Posterior Tibial Slope, Medial Tibial Plateau Slope and Lateral Tibial Plateau Slope in Anterior Cruciate Ligament Injury

Increased posterior tibial slope (PTS), medial tibial plateau slope (MTPS) and lateral tibial plateau slope (LTPS) have been proposed as potential risk factors for anterior cruciate ligament (ACL) tear. However, prior literature is inconclusive. The primary goal of the study was to investigate the relationship of MTPS, LTPS and PTS with ACL tears. The secondary goal was to determine whether injury mechanisms, age, gender, tobacco, obesity, extreme PTS (>12°) or previous injuries are risk factors in ACL tears. Three groups were identified: a study group of patients with ACL injury; a second group diagnosed with meniscal injury; and a third group of non-injured patients. Demographic data was collected. MTPS and LTPS were measured in MRI and PTS in lateral radiographs by two blinded observers. Data was analyzed using SPSS. 416 patients were included in the study. MTPS ranged from 0° to 14° (average value 5.66 ± 2.98), LTSA 0° to 16° (5.69 ± 3.5) and PTS 0° to 17° (6.75 ± 3.18). Neither MTPS, LTPS nor PTS revealed increased risk of ACL tears related with higher slopes, although high MTPS showed a decreased risk. However, when comparing traumatic groups, extreme PTS was associated with LCA tear, but no differences were found when comparing non-traumatic groups. This could mean that the importance of extreme angles in the LCA rupture may be restricted to traumatic mechanisms. Previous ACL tear was identified as a risk factor to ACL tear; increased age and a traumatic mechanism were associated with a lower risk.