前交叉韧带股骨止点高密度纤维分布区的三维磁共振定位研究

A Three-dimensional Magnetic Resonance Study on the Position of High Density Fibre Part of Femoral Insertion of Anterior Cruciate Ligament

目的通过三维磁共振(magnetic resonance,MR)对前交叉韧带(anterior cruciate ligament,ACL)股骨止点高密度纤维分布区的位置进行研究,指导关节镜下ACL股骨骨道的定位。方法对20名健康中青年志愿者的单膝进行三维MR扫描,使用Mimics重建得到ACL的股骨止点、股骨外侧髁以及股骨外髁软骨结构的三维模型,测量股骨止点高密度纤维分布区的位置及其与髁间窝高度、股骨外髁后软骨缘最高点的关系。结果在高分辨率三维MR中,ACL的股骨止点可分为高密度和低密度信号区域,分别代表直接和间接止点。直接止点的长轴长度为(15.8±2.4)mm,短轴长度为(6.2±1.3)mm。以髁间窝高度作为参照,直接止点位于此高度22%~43%。以股骨整体止点的高度作为参照,直接止点位于上方50%。直接止点中心均高于后软骨缘最高点,两者之间的距离为(5.68±1.97)mm。以性别分组,男女性志愿者直接止点相对位置(e、f、g)和直接止点中心点到后软骨缘最高点的距离(a)均无统计学差异(P>0.05)。以年龄段分组,除≤29岁组和≥40岁组g值有统计学差异(P<0.05)外,其余各组e、f、g和a值均无统计学差异(P>0.05)。结论ACL股骨止点的MR影像高密度和低密度信号区域分别代表直接和间接止点。髁间窝高度和后软骨缘最高点可作为解剖标志辅助关节镜下ACL股骨骨道的定位。

Objective To study the location of high-density fibers in the femoral insertion of anterior cruciate ligament(ACL)by three-dimensional magnetic resonance(MR),and to guide the location of femoral canal of ACL under arthroscopy.Methods A total of 20 healthy young volunteers’unilateral knees were imaged by using 3D MR scanning.In each set of MR image,the ACL femoral insertion were analyzed with different signal type,and the 3D models of the high density signal part,low density signal part,the lateral condyle of the femur and the cartilage of lateral condyle of femur were reconstructed with the Mimics.The position of the high density signal part of the ACL femoral insertion and its relationship with the height of intercondylar notch and high deep point were measured on 3D models.Results The femoral footprint of ACL could be divided into high density fibre part which represented direct insertion,and low density fibre part which represented indirect insertion.The length of long axis of direct femoral insertion was(15.8±2.4)mm,the length of short axis of direct femoral insertion was(6.2±1.3)mm.With the height of the femoral intercondylar notch as a reference,the direct footprint located between approximately 22%to 43%of the height.With the height of the whole footprint as a reference,the direct footprint located at approximately the upper 50%of the height.The direct insertion center was higher than the height of the high deep point of the cartilage border,and the distance was(5.68±1.97)mm.Grouping by gender,there was no significant difference in the relative position of direct insertion(e,f,g)and the distance from the center of direct insertion to the highest point of posterior cartilage margin(a)(P>0.05).Grouping by age,there were no significant differences in e,f,g and a values among the groups(P>0.05),except for the g values of≤29 years old group and≥40 years old group(P<0.05).Conclusions The high density fibre part and low density fibre part of ACL femoral footprint represented the direct and indirect insertion.The height of the intercondylar notch and high deep point of the cartilage border could be used as references for allocating the femoral tunnel.