Tachibana Yomei, Yamazaki Yuji, Ninomiya Setsuo
Division of Sports Medicine, Saitama Medical School, Iruma-gun, Saitama, Japan.
Arthroscopy. 2003 Sep;19(7):E12-8. doi: 10.1016/s0749-8063(03)00688-1.
A discoid medial meniscus is an extremely rare anomaly. We present 4 cases of symptomatic discoid medial meniscus. Furthermore, magnetic resonance imaging (MRI) of the unaffected knee was obtained in 3 cases, and 1 patient had bilateral discoid medial menisci as well as a unilateral discoid lateral meniscus proven by MRI. Another patient had bilateral discoid medial menisci. In one of the other 2 cases, an MRI of the unaffected knee was not obtained. However, in the involved knees of both cases, medial and lateral menisci were discoid. The incidence of bilateral discoid medial menisci is unknown. In the past, the diagnosis of a discoid meniscus was made with an arthrogram or at arthrotomy. Therefore, whether some of the unilateral cases reported in the literature might have been bilateral is unknown. The reported prevalence of bilateral discoid medial menisci will probably increase, because when a discoid medial meniscus is encountered currently, an MRI is used to find knee disorders, including in the contralateral knee. Axial multiplanar gradient-recalled-echo imaging could provide images of the discoid meniscus, depicted in its entirety in one section. This would make the recognition of a discoid meniscus simple.
盘状内侧半月板是一种极其罕见的异常情况。我们报告了4例有症状的盘状内侧半月板病例。此外，3例患者还对未受影响的膝关节进行了磁共振成像（MRI）检查，1例患者经MRI证实双侧内侧半月板为盘状，同时还有单侧盘状外侧半月板。另1例患者双侧内侧半月板为盘状。其余2例中的1例未对未受影响的膝关节进行MRI检查。然而，这2例患者患侧膝关节的内侧和外侧半月板均为盘状。双侧盘状内侧半月板的发病率尚不清楚。过去，盘状半月板的诊断是通过关节造影或在关节切开术中做出的。因此，文献中报道的一些单侧病例是否可能实际上是双侧的尚不清楚。由于目前遇到盘状内侧半月板时会使用MRI来查找膝关节疾病，包括对侧膝关节，所以报道的双侧盘状内侧半月板的患病率可能会增加。轴向多平面梯度回波成像可以提供盘状半月板的图像，在一个层面上完整显示。这将使盘状半月板的识别变得简单。
