A Case of Bilateral Permanent Subluxation of the Lateral Meniscus.

Jun Suganuma,Tadashi Sugiki,Yutaka Inoue

doi:10.1155/2016/5912841

Abstract

We report a case of bilateral, permanent subluxation of the lateral meniscus. To our knowledge, the present case is the first reported description of bilateral irreducible anterior dislocation of the posterior segment of the lateral meniscus. This disorder is characterized by a flipped meniscus sign of the lateral meniscus on sagittal magnetic resonance images of the knee joint, with no history of trauma or locking symptoms. A detailed examination of serial magnetic resonance images of the lateral meniscus can help differentiate this condition from malformation of the lateral meniscus, that is, a double-layered meniscus. We recommend two-stage treatment for this disorder. First, the knee joint is kept in straight position for 3 weeks after the lateral meniscus is reduced to the normal position. Second, if subluxation of the lateral meniscus recurs, meniscocapsular suture is then performed. Although subluxation of the lateral meniscus without locking symptoms is rare, it is important to be familiar with this condition to diagnose and treat it correctly.

Highlights

We present a case in which the bilateral posterior segments of the lateral menisci were dislocated anteriorly and irreducibly
In most cases of recurrent subluxation of the lateral meniscus (RSLM), the first locking symptoms occur with severe pain when patients extend their knee joint from deep flexion [4,5,6]; the youngest reported age at which the first locking symptoms have occurred is 6 years [4]
The only difference between RSLM and this case is that the lateral meniscus is subluxated repeatedly in the former [4, 6], while the subluxated lateral meniscus cannot be reduced in the latter

Summary

Introduction

We present a case in which the bilateral posterior segments of the lateral menisci were dislocated anteriorly and irreducibly. To our knowledge, this is the first reported description of permanent subluxation of the lateral menisci. In August 2010, she had been practicing a dance that involved hopping alternately on her right and left legs when she suddenly experienced severe pain in her right knee joint. She was unable to move her knee joint or walk. In December 2010, she started suffering from slight left knee pain during daily activity

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Discussion

Conclusion