Characterization of the Dorsal Ulnar Corner in Distal Radius Fractures in Postmenopausal Females: Implications for Surgical Decision Making

Abstract

To characterize the dorsal ulnar corner fragment with regard to size and morphology using 3-dimensional software and computed tomography (CT) scans, as it presents in low-energy intra-articular distal radius fractures occurring in the female postmenopausal population. A multicenter retrospective review was conducted to identify postmenopausal females with low-energy distal radius fractures treated surgically at level-1 trauma centers. Patients with low-energy injuries with preoperative CT scans were included. The Digital Imaging and Communications in Medicine (DICOM) data from CT scans were used to reconstruct intra-articular fracture patterns. The dorsal ulnar fragment was isolated in each CT scan and measured, then normalized based on lunate depth. Eighty patients met the inclusion criteria. The mean dimension measurements of the dorsal ulnar corner were dorsal surface height, 9.82 ± 5.02 mm (95% confidence interval [95% CI], 8.72-10.92); dorsal surface width, 9.06 ± 3.72 mm (95% CI, 8.25-9.88); articular surface width, 7.44 ± 3.92 mm (95% CI, 6.58-8.30); articular surface depth, 4.14 ± 2.39 mm (95% CI, 3.62-4.67). The mean lunate depth measurement (17.52 ± 1.48 mm) was used to normalize articular surface depth demonstrating that, on average, the dorsal ulnar corner comprises 23.6% of the articular surface ± 13.6% (95% CI, 20.7-26.6). The mean articular surface depth of the dorsal ulnar corner fragment in this study was less than 5 mm, accounting for approximately 24% of the volar-dorsal width of the distal radius at the lunate facet. These data expand current understanding of the morphology and size of the dorsal ulnar corner fracture fragment. If fixation of this fragment is a goal, surgeons may need to use longer screws that penetrate closer to the dorsal cortex than those required for extra-articular fractures or to consider alternative methods of fragment-specific fixation for adequate capture of this fragment.