Case Report
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Jul 18, 2016; 7(7): 448-451
Published online Jul 18, 2016. doi: 10.5312/wjo.v7.i7.448
Extensor pollicis brevis tendon can hyperextend thumb interphalangeal joint in absence of extensor pollicis longus: Case report and review of the literature
Robert J Strauch, Carolyn B Strauch
Robert J Strauch, Department of Orthopaedic Surgery, Columbia University, New York, NY 10032, United States
Carolyn B Strauch, Dartmouth College, Hanover, NY 03755, United States
Author contributions: All authors contributed to the acquisition of data, writing, and revision of this manuscript.
Institutional review board statement: Attached-no formal IRB approval needed for case report.
Informed consent statement: The patient involved in this study gave his verbal consent to inclusion in this case report.
Conflict-of-interest statement: The authors have no conflict of interests.
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: Robert J Strauch, MD, Professor of Orthopaedic Surgery, Department of Orthopaedic Surgery, Columbia University, 622 West 168th Street, PH11-1119, New York, NY 10032, United States.
Telephone: +1-212-3054272 Fax: +1-212-3054040
Received: January 30, 2016
Peer-review started: February 1, 2016
First decision: April 15, 2016
Revised: April 17, 2016
Accepted: May 7, 2016
Article in press: May 9, 2016
Published online: July 18, 2016

We are reporting a case of extensor pollicis longus tendon rupture which did not require tendon transfer owing to the ability of the intact extensor pollicis brevis (EPB) to fully hyperextend the thumb interphalangeal joint. The thumb metacarpophalangeal joint was also able to be fully actively extended by the EPB. Previous anatomical studies have demonstrated that the insertional anatomy of the EPB tendon is highly variable and sometimes inserts onto the extensor hood and distal phalanx, which is likely the mechanism by which our patient was able to fully extend the thumb interphalangeal joint. Despite the potential for the EPB to extend the IP joint of the thumb, virtually all previously reported cases of extensor pollicis longus (EPL) tendon rupture had deficits of thumb IP extension requiring tendon transfer. This case highlights the potential ability of the EPB tendon to completely substitute for the function of the EPL tendon in providing thumb IP joint extension.

Keywords: Extensor pollicis brevis, Extensor pollicis longus, Tendon rupture, Extensor pollicis longus tendon rupture

Core tip: The extensor pollicis brevis may be able to substitute for extensor pollicis longus (EPL) function in some patients when EPL has ruptured.