Correlation analysis between femoral trochlear dysplasia and anterior cruciate ligament injury based on CT measurement.

Abstract

Anterior cruciate ligament (ACL) injury is the most common knee ligament injury. Femoral trochlear dysplasia (FTD) is an anatomic deformity characterized by a shallow trochlear angle and depth. There is limited research on the correlation between ACL injury and trochlear dysplasia. A total of 423 patients with an ACL injury who underwent ACL reconstruction and plain computed tomography (CT) follow-up scan one week after the operation in our hospital between January 2017 and March 2019 were enrolled in this study. A total of 352 patients (369 knees) without ACL injury served as a control group. The sulcus angle, trochlear facet asymmetry, trochlear depth, and lateral trochlear inclination were measured at 3 cm above the tibiofemoral joint. The notch width index (NWI) was measured on the CT axis, and the FTD was divided into four types according to the Dejour classification. The prevalence of FTD was significantly higher in the ACL injury group than in the control group (30.7% vs. 14.4%, χ2=30.834, P<0.001). The trochlear sulcus angle was higher, while the trochlear facet asymmetry and lateral trochlear inclination were significantly lower in the ACL injury group than in the control group (P<0.01). The NWI was 0.232 in the ACL injury group and 0.245 in the control group (P<0.01). In the ACL injury group, the NWI of patients with FTD was slightly smaller than that of the patients without FTD (P<0.01). Our findings indicate that FTD might be a significant risk factor for ACL injury. Whether FTD is related to ACL injury caused by smaller intercondylar notch needs further study.