Greater medial tibial slope is associated with increased anterior tibial translation in females with an ACL-deficient knee

Abstract

Purpose The purpose of the study was to determine the correlation between medial tibial slope (MTS) and anterior tibial translation (ATT) in female patients with an ACL-deficient knee. It was hypothesized that female patients with a greater medial tibial slope had an increased anterior tibial translation compared to males. Methods MTS and ATT were analysed in 276 patients (138 females and 138 males) with a complete ACL rupture from 2012 to 2016. The mean age was 32\u2009±\u200912\xa0years. Previous surgery or additional ligament injury was excluded. CT scan was used for measuring MTS. Meniscal findings were reported. Anterior tibial translation and side to side difference (SSD) were measured by bilateral Telos™ stress radiography with knee flexion of 20°. Results There was no significant difference in ATT between females (5.4\u2009±\u20093.9) and males (5.8\u2009±\u20094.2), nor was there a difference in MTS between females (9.8\u2009±\u20092.8) and males (9.8\u2009±\u20092.7). A positive correlation was found between MTS and ATT absolute ( r \u2009=\u20090.35, p \u2009<\u20090.001) and side to side difference ( r \u2009=\u20090.12, p \u2009=\u20090.03). MTS greater or equal to 11° significantly increased the ATT ( p \u2009<\u20090.05). For each degree of increase of the MTS, increases in ATT absolute of 0.6\xa0mm and SSD of 0.18\xa0mm were observed. Greater MTS was identified as a risk factor for an increase of ATT in females ( r \u2009=\u20090.37, p \u2009<\u20090.001) but not in males ( r \u2009=\u2009−\xa00.1, n.s). Increases of 1° of MTS increased ATT 0.57\xa0mm in female patients ( p \u2009<\u20090.001). MTS was influential in ATT despite the presence ( r \u2009=\u20090.28 [0.11, 0.44], p \u2009=\u20090.001) or absence ( r \u2009=\u20090.48 [0.35, 0.6], p \u2009<\u20090.001) of meniscal lesions. Conclusions Greater medial tibial slope is associated with increased anterior tibial translation in females with ACL-deficient knees compared to males, despite the presence or absence of meniscal lesions. This could be due to a quadriceps/hamstring imbalance in females and the ability of the hamstring muscles to moderate ATT. Level of evidence III.