Figure 1. Anteroposterior radiograph of the left thumb.
Figure 2. Lateral radiograph of the left thumb.
A 17-year-old boy presents with pain and swelling in his left thumb following an injury sustained while playing football. Anteroposterior and lateral radiographs of the left thumb are obtained (Figures 1 and 2).
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Most (80%) fractures of the first metacarpal occur at the base and are described as either intra-articular or extra-articular.1Intra-articular fractures usually occur as a result of an axial force to a flexed thumb. These fractures are divided into 3 types: Bennett, Rolando, and severely comminuted. In Bennett fractures, the displaced fragment is found at the volar-ulnar portion of the metacarpal base. The strong volar oblique ligament holds the fragment in anatomic position, and the remainder of the metacarpal displaces radially and dorsally. Bennett fractures that are minimally displaced are treated with immobilization in a thumb spica cast for 6 weeks. Bennett fractures with >1 mm of intra-articular displacement are associated with increased risk for post-traumatic arthritis; this is an indication for surgical fixation, which is usually achieved by closed reduction and percutaneous pinning.2
Rolando fracture is a Y-shaped intra-articular injury that occurs at the base of the first metacarpal. Treatment usually requires open reduction and internal fixation due to fracture comminution. Intra-articular base fractures that are severely comminuted often require placement of an external fixator.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Soyer AD. Fractures of the base of the first metacarpal: current treatment options. J Am Acad Orthop Surg. 1999;7(6):403-412.
- Edgington J. Base of thumb fractures. OrthoBullets website. https://www.orthobullets.com/hand/6036/base-of-thumb-fractures. Updated October 6, 2018. Accessed February 25, 2019.