Volar Marginal Rim Fractures of the Distal Radius Have a Higher Rate of Associated Carpal Injuries-A Comparative Cohort Study

Background Volar marginal rim distal radius fractures can be challenging due to volar instability of the carpus. The associated carpal injuries, however, have not previously been reported. Purpose The aim of this study was to compare volar marginal rim fractures to other distal radius fractures to determine if there is any association with other carpal injuries. If so, do these injuries lead to further instability and fixation failure? Materials and Methods A retrospective radiological review of 25 volar marginal rim fractures was conducted. This was compared with a comparison cohort of 25 consecutive intra-articular distal radius fractures not involving the volar marginal rim. All radiographs were reviewed for associated carpal injuries, including carpal and ulnar styloid fractures, scapholunate instability, and carpal translocation. Results Volar marginal rim fractures had a significantly higher incidence of associated carpal injuries per patient (2.52 vs. 1.64), scapholunate diastasis (36 vs. 12%), and carpal dislocation (80 vs. 48%). The fixation chosen was more likely to involve a volar rim-specific plate (44 vs. 0%). Following surgical fixation, the volar marginal rim fractures had a significantly higher incidence of carpal instability (56 vs. 24%), failure of fixation (24 vs. 0%), and revision surgery (12 vs. 0%). Conclusions Volar marginal rim fractures have significantly more carpal injuries, scapholunate instability, and volar carpal instability, compared with other distal radius fractures. Despite the use of volar rim-specific plating, volar marginal rim fractures have a significantly higher incidence of persistent carpal instability, including scapholunate instability, ulnar translocation, volar subluxation, failure of fixation ,and revision surgery.