Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

First (thumb) metacarpal fractures

Josh Bloom, MD, MPH
Section Editors
Patrice Eiff, MD
Chad A Asplund, MD, FACSM, MPH
Deputy Editor
Jonathan Grayzel, MD, FAAEM


Metacarpal fractures are common [1]. They account for 30 to 40 percent of all hand fractures. First metacarpal (thumb) fractures make up almost 25 percent of all metacarpal fractures, placing them second only to fifth metacarpal fractures in terms of frequency. Of these fractures, over 80 percent involve the base of the metacarpal. Thumb fractures occur most often in children (0 to 16 years) and in older patients (>65 years). The thumb provides approximately 40 percent of hand function so metacarpal fractures can have grave consequences [2].

This topic will review issues related to fractures of the first (thumb) metacarpal. A general overview of metacarpal fractures is presented separately. (See "Overview of metacarpal fractures".)


The thumb is distinct from the other fingers anatomically and biomechanically. Accordingly, fractures to the thumb are considered separately from other metacarpal fractures. Thumb anatomy is discussed in greater detail separately. (See "Finger and thumb anatomy".)

The majority of thumb metacarpal fractures occur at the base. Fractures of the thumb metacarpal are classified into four patterns (figure 1). Types I and II are intraarticular fractures and Types III and IV are extraarticular. Discerning whether the articular surface is involved in the fracture is critical as this dictates management.

Type I injury ("Bennett's fracture") is a fracture-dislocation of the base of the metacarpal (figure 2 and image 2C). In this injury, a proximal metacarpal fragment maintains its ulnar aspect attachment to the trapezium via the volar ligament. The distal aspect of the metacarpal is supinated and dislocated radially by the adductor pollicis. The proximal aspect of this fragment is pulled proximally by the abductor pollicis brevis and abductor pollicis longus [3].

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Oct 27, 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.