Thumb Trauma: Bennett Fractures, Rolando Fractures, and Ulnar Collateral Ligament Injuries

Abstract

Injuries to the thumb are predominated by fractures of the proximal phalanx, ligamentous injuries about the metacarpophalangeal joint, and metacarpal base fractures. This article will attempt to summarize recent advancements within the realm of thumb trauma, with particular attention to Bennett fractures, Rolando fractures, and ulnar collateral ligament injuries. (J Hand Surg 2009;34A:945-952. Copyright © 2009 T HE THUMB PROVIDES up to 40% of hand function. Total disability of the thumb is devastating and equilibrates to a loss of 22% of bodily function. 1 The thumb's uniqueness and versatility in man is primarily due to the position of the thumb axis. The thumb axis is based at the trapeziometacarpal (TM) joint and is pronated and flexed approximately 80°with respect to the other hand metacarpals. This position enables circumduction, which permits opposition and prehension; however this position also exposes the thumb to unique injury. INCIDENCE Recently, Stanton and colleagues examined the incidence of fractures within the tubular bones of the hand. Thumb fractures were found to occur most commonly in children and the elderly. In children (age 0 -16 years), 22% of all tubular bone hand fractures occurred somewhere within the first ray. In retirement age individuals (age Ͼ65 years), 20% of hand fractures occurred in the thumb, whereas only 12% of fractures in young adults (age 17-40 years) were found to occur in the thumb ray. First-ray fractures were half as common in the 17-to 40-year age group when compared with that for the elderly or the pediatric groups. In addition, in the elderly population, the thumb was the most common tubular bone fractured with fracture patterns tending to be oblique and intra-articular. RADIOGRAPHIC EVALUATION In addition to careful physical exam, radiographic imaging is an essential part of a complete evaluation after thumb trauma. Because the thumb sits out of plane from the rest of the hand and fingers, special radiographic views are necessary for appropriate evaluation. A true anteroposterior view of the thumb can be obtained with the Robert's view, which requires that the hand be hyperpronated so that the dorsum of the thumb lies against the radiographic plate. To obtain a true lateral of the TM joint, the palm of the hand must be placed flat on the cassette with the hand pronated 15°to 35°; the beam is then directed 15°distal to proximal. This imaging technique is referred to as the Bett's view of the thumb. This image allows one to evaluate the TM joint and the 3 additional articulations of the trapezium: the trapezoid, the scaphoid, and index metacarpal. Both views are helpful when evaluating fracture displacement and joint congruency. PHALANGEAL FRACTURES The management of extra-articular thumb phalangeal fractures differs from that of finger phalangeal fractures in that some angular displacement or malunion is ac