盘状软骨弹跳征的实验观察及临床意义

目的通过MRI检查和关节镜直视下观察盘状软骨的弹跳征，探索弹跳征出现时半月板的运动轨迹及其临床意义。方法11例盘状软骨患者共12膝行MRI检查，在弹跳征出现前、后分别对外侧半月板的矢状位成像，其中对6膝进行了关节镜下观察和盘状软骨成形术。结果通过观察发现盘状软骨的反常运动与正常半月板的运动有明显区别。随着膝关节的屈曲，正常的半月板向关节的后方移动，而外侧盘状软骨却向关节的前方移动。膝关节由屈曲到伸直的过程中，在弹跳征出现时，盘状软骨会在瞬间出现明显的由前向后的较大距离的位移。盘状软骨成形术可以消除反常运动。结论盘状软骨的患者在半月板未损伤时，即应在关节镜下行半月板成形术，而伴有反常运动和弹跳征的患者，更应早期手术治疗。

Experimental observation and clinical signiifcance of the snapping sign of the discoid lateral meniscus

Objective To observe the snapping sign of the discoid lateral meniscus in the knee in MRI examination and under arthroscopy, and to explore the motion trail of the meniscus at the time of snapping knee syndrome and the clinical meaning.Methods A total of 12 discoid lateral menisci in 11 patients were examined. The knees were imaged in the sagittal plane before and after the appearance of snapping sign. The arthroscopic observation and meniscectomy were performed on 6 knees.Results Apparent differences between the abnormal motion of the discoid lateral meniscus and the motion of normal meniscus were noticed. During knee flexion, the discoid lateral meniscus moved anteriorly, but the normal meniscus moved posteriorly. Furthermore, with the knee extension, the discoid lateral meniscus instantly moved for a long distance from the posterior to the anterior at the time of snapping knee syndrome. The abnormal motion of the discoid meniscus could be eliminated in the arthroscopic meniscectomy. Conclusions For the patients with the discoid lateral meniscus but without meniscus injuries, arthroscopic meniscectomy should be performed. While the patients with the discoid lateral meniscus of abnormal motion and snapping sign should undergo surgical treatment in the early time.