Characteristics

• Most fractures involve the base of thumb and are classified as intra or extra articular fractures.

• Intra-articular injury is important as malunion preferentially impairs the important functions of key grip and opposition.

• The common types of intra-articular fracture have been described by Bennett and Rolando.

• Common secondary to forced abduction of the thumb.

Clinical features

• Pain, swelling and thenar bruising often evident.

• Thumb deformity/malalignment and reduced range of movement.

Radiological features

• AP and lateral views essential – oblique view may be beneficial.

• Bennett's fracture – a distinctive small ulnar-sided fragment is seen to maintain its alignment with the trapezium. The thumb metacarpal is dislocated dorsally and radially due to the action of abductor pollicis longus.

• Rolando fracture – a fracture of the base of thumb extending into the carpo-metacarpal joint. The fracture line has a V or a T configuration.

• Extra-articular fractures are basal (transverse or oblique fractures just distal to the CMC joint) or pure shaft injuries.

Management

• Assess soft tissues, neurovascular status and immobilise initially.

• Bennett's fracture – Reduce with traction while abducting the thumb and applying pressure to the radial aspect of the base. K-wiring will usually suffice, but occasionally ORIF with large ulnar-sided fragments.

• Maintain position in a thumb spica and watch carefully in the hand/fracture clinic with weekly radiographs.

• Rolando fracture – Reduce and immobilise if undisplaced. ORIF for displaced fractures to restore CMC joint congruity.

• Extra-articular fractures – usually managed non-operatively as the thumb can tolerate 20° to 30° of angulation without functional impairment, because of adjacent joint mobility.