UC San Diego

Fixing palmar ulnar corner fragments of distal radial fractures can be challenging. We described the palmar ulnar corner fragment morphology in a retrospective cohort study of 40 patients who underwent preoperative wrist computed tomography scans. Palmar ulnar corner fractures were categorized based on articular cross-sectional area, sagittal angulation relative to the radius long axis, palmar cortical length, radioulnar width and associated palmar radiocarpal subluxation. Three types emerged: type 1 fragments involved 37% (SD 10) of the radiocarpal articular surface and were extended in the sagittal plane; type 2 fragments involved 28% (SD 10) of the articular surface and had a long palmar cortex, of which 57% had palmar carpal subluxation; and type 3 fragments involved 13% (SD 2) of the articular surface, had a short palmar cortex and all had palmar carpal subluxation. Understanding palmar ulnar corner fragment morphology may guide optimal reduction and fixation strategy and prevent palmar radiocarpal subluxation, especially in type 3 fractures.Level of evidence IV.