Emergent care / stabilization: Immobilization with thumb spica splint.

Causes / typical injury mechanism: Trapezial fractures are carpal fractures occurring from an axial load across the wrist joint, such as a fall onto an outstretched hand.

Classic history and presentation:

• Typically presents as pain in the distal aspect of the anatomical snuffbox or thenar eminence after an acute fall.
• Delayed presentation includes thumb weakness, with limited and painful pinch and grasp with a remote history of a fall.

Prevalence: Trapezium fractures represent 4% of all carpal fractures and are the third-most-common carpal fracture.

• Age – More common in young adults.
• Sex / gender – Equal distribution between males and females.

Risk factors: Risk factors include increased propensity to falls.

Pathophysiology: The distal carpal row bone, which articulates with the first and second metacarpal, the scaphoid, and the trapezoid, can be fractured when it is compressed between the base of the metacarpal and radial styloid during axial overload, via direct impact to the ridge, or as a result of avulsion of attached ligaments.

Grade / classification system: The classification system used for trapezium fractures is the Walker classification.

• Type I: horizontal fracture
• Type IIa: radial tuberosity fracture through the carpometacarpal (CMC) joint (ie, medial distal avulsion)
• Type IIb: radial tuberosity fracture through the scaphotrapezial joint (ie, medial proximal avulsion)
• Type III: ulnar tuberosity fracture
• Type IV: vertical fracture
• Type V: comminuted fracture