Irreducible open posterolateral knee dislocation due to medial meniscus interposition.

Posterolateral knee dislocations are generally irreducible due to the interposition of the medial capsule and retinaculum. These injuries have a 'dimple sign' which shows the invagination of the tissues in the medial joint line. We present an unusual case of an open posterolateral traumatic knee dislocation (KD-4 [ACL/PCL/MCL/LCL-PLC torn] open knee dislocation) without a 'dimple sign'. Closed reduction attempts were unsuccessful. In surgery, it was found that the medial meniscus was detached from the meniscocapsular junction and entrapped in the joint. The medial meniscus was extracted from the joint, and the joint was reduced. The medial meniscus was sutured to the meniscocapsular junction with anchors. This is the first study reporting medial meniscus interposition in an open posterolateral knee dislocation. Moreover, the presented case is peculiar because although it was a posterolateral knee dislocation, the posterolateral ligament complex was also torn.