Boxer's fracture

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Introduction

Metacarpal fractures occur frequently among the general population and report for 40% of all hand fractures. [1] The Fracture of the fifth metacarpal neck also known as Boxers Fracture, named after the classic mechanism of injury in which a direct trauma is applied to a clenched fist or fall directly onto the hand. Boxer's fracture account for 10% of the metacarpal fractures which particularly occur in contact sports. Nearly, one-fourth of cases occur during athletic events. This activity describes the pathophysiology, evaluation, and management of metacarpal hand fractures and highlights the role of the interprofessional team in the management of this condition.

Epidemiology/Etiology

Hand fractures constitute about 40% of all acute hand injuries, and they constitute about 20% of all fractures occurring below the elbow.[5][2] Metacarpal fractures typically occur in patients aged 10-40 years, and men are more likely to be affected than women.  Young men sustain metacarpal fractures secondary to a punching mechanism or a direct blow to the hand while geriatric females sustain these injuries secondary to a low energy fall.  The incidence rate of fracture seen in association with each digit's metacarpal bone increases from the radial to the ulnar side. The incidence rate of 2nd metacarpal fractures is lower than the incidence rate of 5th metacarpal fractures.[

Pathophysiology

Each metacarpal bone comprises of a head located distally, neck, body, and base which is located proximally. Fractures occur as a result of axial load to a clenched fist which causes direct trauma to the metacarpal bone, commonly resulting in apex dorsal angulation due in part to the forces exerted by the pull of the interosseous muscles. These interosseous muscles originate from the metacarpal shafts and insert onto proximal phalanges, responsible for adduction and abduction of the fingers. The collateral ligaments should be taken into consideration during splinting to minimize the risk of loss of motion due to shortening of the ligaments. The ligaments are taut in flexion, and more slack in extension, therefore the MCP joints should be splinted in flexion to prevent shortening (intrinsic plus positioning[4]. The arteries and nerves supplying the fingers are adjacent to the metacarpal bones and can be injured in severely displaced Boxer’s fractures, requiring surgical intervention.

Management

The treatment for a Boxer’s fracture differs based on whether the fracture is open or closed, characteristics of the fracture including the degree of angulation, shortening, and rotation, and other concomitant injuries. Immobilization with an ulnar gutter splint may be the definitive treatment for closed, non-displaced fractures without angulation or rotation, while open fractures, significantly angulated or malrotated fractures or those involving injury to neurovascular structures may require operative fixation.