Case Report
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. May 18, 2018; 9(5): 72-77
Published online May 18, 2018. doi: 10.5312/wjo.v9.i5.72
Periosteal pseudotumor in complex total knee arthroplasty resembling a neoplastic process
Madhav Chowdhry, Matthew V Dipane, Edward J McPherson
Madhav Chowdhry, Matthew V Dipane, Edward J McPherson, LA Orthopedic Institute, Los Angeles, CA 90057, United States
Author contributions: All authors contributed equally to this paper in regards to conception and structure of this case report, data collection, literature review, drafting, critical revisions, and final approval of the final version.
Informed consent statement: A written informed consent was taken by the participant before the beginning of the study.
Conflict-of-interest statement: The authors of the study have no potential conflict of interest to declare.
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: Edward J McPherson, MD, FACS, Director, LA Orthopedic Institute, 2200 West Third Street, Suite 400, Los Angeles, CA 90057, United States.
Telephone: +1-213-2075660
Received: January 5, 2018
Peer-review started: January 6, 2018
First decision: January 23, 2018
Revised: January 30, 2018
Accepted: February 28, 2018
Article in press: February 28, 2018
Published online: May 18, 2018
Core Tip

Core tip: Pseudotumor formation is a biologic response to microscopic metal particulate debris observed in metal-to-metal total hip bearings. It is considered non-existent in total knee arthroplasty (TKA), where the bearing surface articulates metal-to-ultrahigh molecular weight polyethylene. This report describes a rare case of pseudotumor formation in an endoprosthetic hinge TKA, as a result of femoral stem loosening with metallic debris exiting through a small crack in the distal femoral diaphysis. This case reveals that pseudotumor formation should always be considered when evaluating an expanding mass around a TKA.