Tomori Y, et al. - This study was undertaken to evaluate the relationship between ulnar styloid fracture (USF) associated with distal radius fracture (DRF) and triangular fibrocartilage complex (TFCC) injuries and to elucidate whether the presence or location of a USF in a patient with DRF predicts the presence of traumatic TFCC injuries. Between 2005 to 2018, researchers conducted an arthroscopic evaluation to detect TFCC injuries correlated with DRF. The computed tomography was applied to analyze the presence and location of USFs. They categorized TFCC injuries in accordance with Palmer’s classification. They classified all wrists into group A (DRF without USF) and group B (DRF with USF). This study recruited a total of 138 patients. In 42 patients, group A enrolled 42 wrists, whereas group B included 96 wrists in 96 patients. It was shown that the presence of USF correlated with DRF prognosticated the presence of frequently occurring traumatic TFCC injury and TFCC 1B injury. Furthermore, for TFCC 1B injury, the location of USFs was a predictive factor in adults with DRF. On the other hand, in adults with DRF, traumatic TFCC injury had occurred, regardless of the presence of USF.