Boxer’s Fracture

Quiz

Treatment of the above fracture does not depend on which of the following?

1. Open or closed status
2. Degree of angulation of fracture fragments 
3. Mechanism of injury 
4. Neurovascular damage

Pathophysiology

Boxer’s fracture is term used for a fracture involving the neck of the fifth metacarpal and is the most common metacarpal fracture. The mechanism of the boxer’s fracture is direct trauma to the clenched fist transferring the energy through the fifth metacarpal axially which causes volar angulation of the distal fragment. Direct trauma to the dorsum of the hand can also cause a fracture of the fifth metacarpal neck. 

Here is an illustration depicting this:

Imaging Recommendation:

Radiograph with anteroposterior, lateral, and oblique views is the gold standard for detecting the 5th metacarpal fracture. In occult fractures, a CT scan would be useful.  

Key Imaging Features:

Radiographs are used to detect and describe the features of the fracture including location, comminution, intra-articular extension and degree of angulation. The lateral view is used to measure the degree of angulation. An angle is measured between the line drawn along the metacarpal shaft (medullary canal) and a line drawn from the center of the metacarpal head to the fracture site. Normal angulation of the metacarpal head to the neck is 15 degrees, so the angulation of the fracture should be measured as that more than the baseline of 15 degrees.

Clinical Features : 

• Commonly seen in young males
• Symptoms include: Pain, swelling, tenderness and decreased range of motion
• Loss of the normal knuckle contour due to depression of the MCP joint.

Classification System :

Metacarpal fractures can be categorized as neck, shaft, and base fractures, with neck fractures being the most common. 

Etymology and synonyms:

As the mechanism of this fracture is punching with a closed fist causing a direct blow to the knuckle, hence the name “Boxer fracture”. However, fifth metacarpal fractures are rarely seen in professional boxers who are well-trained and wear gloves. Boxer fracture is an example of Stigler’s Law of Eponymy, which states “No scientific discovery is named after its original discoverer”.

Dr. Indra Neil Mekala rightly commented on this in our radiology learning group:
Scrapper’s fracture, aka Street fighter’s fracture, aka Bar room fracture.
Boxer’s fracture applies to the 2nd or 3rd MC, whereas the 4th or 5th is Scrapper’s fracture. Trained professional strikes with fists in a neutral position, whereas inexperienced street fighters deliver a roundhouse blow exposing 4th and 5th metacarpals.

Treatment : 

Treatment of uncomplicated (closed and non-displaced) fifth metacarpal fractures include immobilization or splinting or strapping with adjacent fingers. Open fractures with significant angulation or involving injury to neurovascular structures need closed reduction and application of a splint.

References: 

Single best review article: Malik S, Herron T, Rosenberg N. Fifth Metacarpal Fractures. In: StatPearls. Treasure Island (FL): StatPearls Publishing; August 8, 2022.

Other references

Hussain MH, Ghaffar A, Choudry Q, Iqbal Z, Khan MN. Management of Fifth Metacarpal Neck Fracture (Boxer’s Fracture): A Literature Review. Cureus. 2020;12(7):e9442. Published 2020 Jul 28. doi:10.7759/cureus.9442. https://doi.org/10.7759/cureus.9442

Co-Authors: Dr. Mansi Sarmalkar and Dr. Gauri Parvathy.