Case Report
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Jun 18, 2016; 7(6): 401-405
Published online Jun 18, 2016. doi: 10.5312/wjo.v7.i6.401
Posterolateral dislocation of the knee: Recognizing an uncommon entity
Colin YL Woon, Mark R Hutchinson
Colin YL Woon, Mark R Hutchinson, Department of Orthopaedic Surgery, University of Illinois at Chicago, Chicago, IL 60612, United States
Author contributions: Woon CYL designed the report and wrote the paper; Hutchinson MR co-wrote and reviewed the paper for critical content.
Institutional review board statement: None.
Informed consent statement: The involved subject provided written informed consent for the study.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Colin YL Woon, MD, Department of Orthopaedic Surgery, University of Illinois at Chicago, 835 S. Wolcott Avenue, M/C 844, Chicago, IL 60612, United States.
Telephone: +1-312-9969858 Fax: +1-312-9969025
Received: February 3, 2016
Peer-review started: February 3, 2016
First decision: March 21, 2016
Revised: March 23, 2016
Accepted: April 7, 2016
Article in press: April 11, 2016
Published online: June 18, 2016

Posterolateral dislocations of the knee are rare injuries. Early recognition and emergent open reduction is crucial. A 48-year-old Caucasian male presented with right knee pain and limb swelling 3 d after sustaining a twisting injury in the bathroom. Examination revealed the pathognomonic anteromedial “pucker” sign. Ankle-brachial indices were greater than 1.0 and symmetrical. Radiographs showed a posterolateral dislocation of the right knee. He underwent emergency open reduction without an attempt at closed reduction. Attempts at closed reduction of posterolateral dislocations of the knee are usually impossible because of incarceration of medial soft tissue in the intercondylar notch and may only to delay surgical management and increase the risk of skin necrosis. Magnetic resonance imaging is not crucial in the preoperative period and can lead to delays of up to 24 h. Instead, open reduction should be performed once vascular compromise is excluded.

Keywords: Knee dislocation, Irreducible dislocation, Medial patellofemoral ligament, Vastus medialis, Medial collateral ligament

Core tip: Posterolateral knee dislocations are uncommon injuries that are often missed or misdiagnosed. We believe that attempts at closed reduction and preoperative magnetic resonance imaging are unnecessary delays to open reduction. We advocate emergent open reduction once vascular integrity is confirmed on ankle-brachial index testing.