Purpose: Dorsal comminution is widely accepted as a prognostic factor for reduction loss in the nonoperative treatment of distal radius fractures. However, the reliability of measuring dorsal comminution in simple radiographs has not been adequately studied. This study investigated the reliability of dorsal comminution measurements from simple radiographs, based on inter- and intra-rater reliability indices. Methods: We included 40 patients with distal radius fractures who underwent operative treatment from March 2016 to March 2017. We established three definitions for dorsal comminution: first, the rater’s subjective judgment; second, the presence of a free-floating piece of dorsal cortex; and third, the presence of a dorsal cortical defect of 5 mm or greater. Reliability was measured using Fleiss’ or Cohen’s kappa. Results: Based on Cohen’s kappa values, the intra-rater reliability of dorsal comminution assessment demonstrated fair to good agreement. In contrast, inter-rater reliability was generally poor to fair, and subgroup analysis by rater experience revealed poor agreement among less experienced surgeons. Conclusion The radiological predictors of dorsal comminution exhibited overall low reliability, limiting their usefulness in predicting reduction loss in distal radius fractures. A more precise definition of dorsal comminution is necessary, and additional methods, such as computed tomography and artificial intelligence, should be considered to increase reliability.

Purpose: Dorsal comminution is widely accepted as a prognostic factor for reduction loss in the nonoperative treatment of distal radius fractures. However, the reliability of measuring dorsal comminution in simple radiographs has not been adequately studied. This study investigated the reliability of dorsal comminution measurements from simple radiographs, based on inter- and intra-rater reliability indices. Methods: We included 40 patients with distal radius fractures who underwent operative treatment from March 2016 to March 2017. We established three definitions for dorsal comminution: first, the rater’s subjective judgment; second, the presence of a free-floating piece of dorsal cortex; and third, the presence of a dorsal cortical defect of 5 mm or greater. Reliability was measured using Fleiss’ or Cohen’s kappa. Results: Based on Cohen’s kappa values, the intra-rater reliability of dorsal comminution assessment demonstrated fair to good agreement. In contrast, inter-rater reliability was generally poor to fair, and subgroup analysis by rater experience revealed poor agreement among less experienced surgeons. Conclusion The radiological predictors of dorsal comminution exhibited overall low reliability, limiting their usefulness in predicting reduction loss in distal radius fractures. A more precise definition of dorsal comminution is necessary, and additional methods, such as computed tomography and artificial intelligence, should be considered to increase reliability.

Purpose: Dorsal comminution is widely accepted as a prognostic factor for reduction loss in the nonoperative treatment of distal radius fractures. However, the reliability of measuring dorsal comminution in simple radiographs has not been adequately studied. This study investigated the reliability of dorsal comminution measurements from simple radiographs, based on inter- and intra-rater reliability indices. Methods: We included 40 patients with distal radius fractures who underwent operative treatment from March 2016 to March 2017. We established three definitions for dorsal comminution: first, the rater’s subjective judgment; second, the presence of a free-floating piece of dorsal cortex; and third, the presence of a dorsal cortical defect of 5 mm or greater. Reliability was measured using Fleiss’ or Cohen’s kappa. Results: Based on Cohen’s kappa values, the intra-rater reliability of dorsal comminution assessment demonstrated fair to good agreement. In contrast, inter-rater reliability was generally poor to fair, and subgroup analysis by rater experience revealed poor agreement among less experienced surgeons. Conclusion The radiological predictors of dorsal comminution exhibited overall low reliability, limiting their usefulness in predicting reduction loss in distal radius fractures. A more precise definition of dorsal comminution is necessary, and additional methods, such as computed tomography and artificial intelligence, should be considered to increase reliability.

Background: Glenoid position and inclination are important factors in protecting against scapular notching, which is the most common complication that directly affects the longevity of reverse shoulder arthroplasty (RSA). This study aimed to investigate the biomechanical characteristics of glenosphere orientation, comparing neutral tilt, inferior overhang with an eccentric glenosphere at the same placement of baseplate, and inferior tilt after 10° inferior reaming in the lower part of the glenoid in RSA. Methods: Nine cadaveric shoulders were tested with 5 combinations of customized glenoid components: a centric glenosphere was combined with a standard baseplate (group A); an eccentric glenosphere to provide 4-mm inferior overhang than the centric glenosphere was combined with a standard baseplate (group B); a centric glenosphere was combined with a wedge-shaped baseplate tilted inferiorly by 10° with the same center of rotation (group C); an eccentric glenosphere was attached to a wedge-shaped baseplate (group D); and 10° inferior reaming was performed on the lower part of the glenoid to apply 10° inferior tilt, with a centric glenosphere secured to the standard baseplate for simulation of clinical tilt (group E). Impingement-free angles for adduction, abduction, forward flexion, external rotation, and internal rotation were measured. The capability of the deltoid moment arm for abduction and forward flexion, deltoid length, and geometric analysis for adduction engagement were evaluated. Results: Compared with neutral tilt, inferior tilt at the same position showed no significant difference in impingement-free angle, moment arm capability, and deltoid length. However, group D resulted in better biomechanical properties than a central position, regardless of inferior tilt. Group E demonstrated a greater range of adduction, internal and external rotation, and higher abduction and forward flexion capability with distalization, compared to corresponding parameters for inferior tilt with a customized wedgeshaped baseplate. Conclusions A 10° inferior tilt of the glenosphere, without changing the position of the baseplate, had no benefit in terms of the impingement-free angle and deltoid moment arm. However, an eccentric glenosphere had a significant advantage, regardless of inferior tilt. Inferior tilt through 10° inferior reaming showed better biomechanical results than neutral tilt due to the distalization effect.