Slideshow
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Figure 1: Anteroposterior radiograph of right hand.
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Figure 2. Lateral radiograph of right hand.
A 26-year-old woman presents with right hand pain after punching a wall 2 days earlier. She describes immediate pain and swelling following the incident. The patient is having difficulty using the hand. On physical examination, the patient has loss of knuckle prominence of the fifth metacarpal head; the skin is intact. Radiographs taken of the hand show a displaced fifth metacarpal neck fracture with 60° of angulation (Figures 1 and 2).
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Metacarpal fractures comprise between 18% to 44% of all hand fractures.1 Fractures of the fifth metacarpal neck are common injuries, representing 10% of all hand fractures, and are commonly seen in the emergency department and orthopedic settings.2 Knowing which fractures require surgery and why is critical. Fifth metacarpal neck fracture is often called boxer’s fracture because direct trauma applied with a clenched fist is the most common mechanism of injury.2
These fractures often result in shortening and angulation of the fifth metacarpal. Significant shortening of the metacarpal head can create a tendon imbalance resulting in an extension lag of the fifth digit. Shortening and angulation of the metacarpal neck fracture can also result in loss of knuckle prominence and grip strength weakness.1,2
The fifth finger can tolerate more displacement than the other 4 fingers without functional impairment due to increased metacarpophalangeal joint flexibility of the fifth metacarpal compared with the others fingers. Nonoperative treatment is recommended for the fifth metacarpal neck injuries with up to 40 to 50° of angulation whereas 30°, 20°, and 15° of angulation are acceptable for the ring, middle, and index fingers, respectively.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 Orthopaedics for Physician Assistants.
References
1. Kollitz KM, Hammert WC, Vedder NB, Huang JI. Metacarpal fractures: treatment and complications. Hand (N Y). 2014;9(1):16-23. doi:10.1007/s11552-013-9562-1
2. Malik S, Herron T, Rosenberg N. Fifth metacarpal fractures. In: StatPearls. StatPearls Publishing; 2021 Aug 11.
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