First (thumb) metacarpal fractures
- Josh Bloom, MD, MPH
Josh Bloom, MD, MPH
- Clinical Instructor, Department of Family Medicine
- University of North Carolina at Chapel Hill
Metacarpal fractures are common . 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 .
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".)
PERTINENT ANATOMY AND CLASSIFICATION
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 .
- Ashkenaze DM, Ruby LK. Metacarpal fractures and dislocations. Orthop Clin North Am 1992; 23:19.
- Carlsen BT, Moran SL. Thumb trauma: Bennett fractures, Rolando fractures, and ulnar collateral ligament injuries. J Hand Surg Am 2009; 34:945.
- Foster RJ, Hastings H 2nd. Treatment of Bennett, Rolando, and vertical intraarticular trapezial fractures. Clin Orthop Relat Res 1987; :121.
- Soyer AD. Fractures of the base of the first metacarpal: current treatment options. J Am Acad Orthop Surg 1999; 7:403.
- Burkhalter WE. Closed treatment of hand fractures. J Hand Surg Am 1989; 14:390.
- PERTINENT ANATOMY AND CLASSIFICATION
- MECHANISM OF INJURY
- SYMPTOMS AND EXAM FINDINGS
- RADIOGRAPHIC FINDINGS
- INDICATIONS FOR REFERRAL
- INITIAL TREATMENT
- Intraarticular fractures
- Extraarticular fractures
- Closed reduction
- FOLLOW-UP CARE
- RECOMMENDATIONS FOR RETURN TO WORK OR SPORT
- SUMMARY AND RECOMMENDATIONS