Differences in Magnetic Resonance Imaging between the Surgical Side and Healthy Side of Knee Joint after Anterior Cruciate Ligament Reconstruction

Abstract

Abstract Objective The inclination angle of the graft and the femorotibial position relationship after anterior cruciate ligament (ACL) reconstruction surgery has been widely discussed for long. However, studies comparing the surgical side with the healthy side are rarely reported. This study aimed to quantitatively describe the changes in the inclination angle of the graft and the femorotibial position relationship of the knee joint after ACL reconstruction relative to the healthy side based on magnetic resonance imaging (MRI), so as to identify effective indicators for quantifying the femorotibial relationship.Methods A retrospective analysis was performed on 50 cases of ACL reconstruction operated in the Sports Medicine Department of Shenzhen Second People’s Hospital from June 2019 to June 2020. MRI of the surgical side and healthy side was obtained for each patient. Based on the MRI, the inclination angle of the graft/ACL on the coronal plane and sagittal plane, the medial and lateral anterior tibial translation (ATT), and the femoral rotation angle (FA) and tibial rotation angle (TA) of both knees were measured. Then, the femorotibial angle (FTA) and the rotational tibial subluxation (RTS) were calculated in order to evaluate the differences in MRI results between the surgical and healthy sides.Results After ACL reconstruction, the inclination angle of the graft on the coronal plane and sagittal plane, the medial and lateral ATT, and the FA and TA were all greater than those of the healthy knee joint (P < 0.05). There were no significant differences in the FTA and RTS between the surgical and healthy sides, but there was a significant correlation between these two indicators.Conclusions After ACL reconstruction, the inclination angle of the graft cannot be restored to the level of the healthy knee joint, and obvious medial and lateral ATT occurred on the surgical side compared to the healthy side of the knee joint. In addition, there is a significant correlation between FTA and RTS, which are expected to be used as combined clinical indicators for evaluating the stability of knee joint rotation.