Ligament contribution to patterns of articular fractures of the distal radius.

PURPOSE: Intra-articular fractures of the distal radius are common injuries, but the correlation between ligament attachments and fracture location is poorly understood. The purpose of this study was to assess the location of intra-articular fractures compared to the known ligament attachments of the distal radius.

METHODS: The authors retrospectively reviewed computed tomography scans of acute intra-articular distal radius fractures performed at 1 institution between 2001 and 2008. Of 145 scans, 45 were deemed unsuitable due to poor quality or presence of internal fixation in the distal radius, leaving 100 fractures for review. Fracture line locations of the distal radius were plotted to a standardized distal radius template and statistically analyzed for their relationship to known ligament attachments.

RESULTS: Fracture lines were significantly more likely to occur at the intervals between the ligament attachments than at the ligament attachments. Common sites of fractures were the center of the sigmoid notch, between the short and long radiolunate ligaments, and the central and ulnar aspects of the scaphoid fossa dorsally. The sites of the ligament attachments to the distal radius were relatively protected. The likely site of the impaction of the carpus on the distal radius articular surface can often be construed from viewing the computed tomography scans, and the subsequent propagation of the fracture can be identified.

CONCLUSIONS: Articular fractures of the distal radius are statistically more likely to occur between the ligament attachments. The ligamentous attachments of the distal radius to the volar carpus in an intra-articular distal radius fracture are relatively well preserved.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.