Research on the Relationship between the Anterior Ridge and the Tibial Attachment of the Anterior Cruciate Ligament on Magnetic Resonance Imaging / 中国运动医学杂志

ABSTRACT

Objective To measure and determine the position of the tibial attachment of the anterior cruciate ligament (ACL)in relation to its anterior ridge on the magnetic resonance imaging (MRI)of normal knee joints,and to explore the clinical role of the anterior ridge in guiding tunnel positioning during ACL reconstruction as well as in facilitating postoperative radiographic evaluation.Methods The knee MRI of one hundred young adult patients with an intact ACL and normal knee joint (mean age25.1 years,range18-40 years)was retrospectively reviewed.All MR images were obtained at full extension of the knee on the same MRI machine.Using digital image software on MRI,the measurements in the sagittal view were taken,including the depth of the tibia,the distance from the anterior edge of the tibial plateau to the most anterior and posterior portions of the ACL insertion on the tibia and the anterior ridge according to Staubli and Rauschning's method.Results The center of the tibial insertion of the ACL is located between 28.43％ and 50.94％ of the total anterior-posterior depth of the tibia,which was less than 43.3％ in 58 patients.The average distance from the anterior edge of the tibial plateau to the anterior ridge was 13.61 ± 2.17 mm (ranging from 8.03 to 18.65 mm),26.80％ ±3.89％ (ranging from 17.74％ to 33.94％)across the tibial plateau.There were significant positive correlations between the distance from the anterior edge of the tibial plateau to the most anterior portion of the ACL insertion and that to the anterior ridge.The distance from the most anterior portion of the ACL insertion to the anterior ridge was averaged 0.56 ± 0.68 mm (ranging from-0.28 to 2.71 mm).During the ACL reconstruction,with the anterior edge of the tibial tunnel determined at posterior 0.5 mm to the anterior ridge,the graft size as 8 mm,and the tibial guider angle set as 55 degree,96of the patients (96％)would have the center of the tibial tunnel located before the center of their native ACL attachment.Conclusions On sagittal MR images,the location of the anterior ridge and the most anterior portion of the ACL insertion correlated well,with the average distance between them of 0.56 mm.The study indicates that during ACL reconstruction,tibial tunnel drilling with the anterior edge of the ACL graft positioned at the anterior ridge can achieve a more anterior position than the traditional methods to orientate according to the center of the bone tunnel.