Causes / typical injury mechanism: A boxer's fracture is defined specifically as a fracture to the subcapital or neck of the fifth metacarpal in the setting of direct trauma to a clenched fist. Trauma is typically distributed axially through the fifth metacarpal. Most commonly, there is apex-dorsal angulation secondary to the tension of the hand's interossei muscles. Additionally, a boxer's fracture can occur from direct trauma to the dorsum of the hand.
Classic history and presentation: History typically includes a report of punching with a clenched fist with force applied axially. This injury is commonly sustained while punching solid objects and/or at athletic events. This is not commonly associated with falling onto an outstretched hand (FOOSH), as is typical of most other hand fractures. Patients often report pain to the dorsum of the hand with associated swelling and/or deformity.
Prevalence: About 30%-40% of fractures of the hand involve the metacarpals. About 10% of all hand fractures are boxer's fractures. Boxer's fractures are observed 5 times more frequently in males between the ages of 10 and 29 years than in females.
S62.366A – Nondisplaced fracture of neck of fifth metacarpal bone, right hand, initial encounter for closed fracture
S62.367A – Nondisplaced fracture of neck of fifth metacarpal bone, left hand, initial encounter for closed fracture
263210007 – Fracture of neck of fifth metacarpal
Differential Diagnosis & Pitfalls
- Fight bites are often overlooked, especially if patients don't admit they were in an altercation. These injuries require immediate debridement and treatment with antibiotics to prevent infection due to penetrance of a human tooth through the extensor tendon and dorsal capsule into the MCP joint. Fight bites can be associated with extensor tendon lacerations and MCP joint infections. These injuries should not be sutured closed. If in doubt, treat with broad-spectrum antibiotics.
- Fracture of the metacarpal shaft (see metacarpal fracture)
- Fracture of the metacarpal base (see metacarpal fracture)