Disclosure of unnoticed rib fractures with the use of ultrasonography in minor blunt chest trauma.

OBJECTIVE Rib fractures are the most common injuries resulting from blunt chest trauma. The sensitivity of chest X-rays in showing the rib fractures is limited particularly in those involving the cartilage part of the rib. We investigated the possible rib fractures, those overlooked on chest X-rays, with the use of ultrasonography in minor blunt chest trauma. METHODS A total of 37 patients, with minor blunt chest trauma showing no evidence of a rib fracture on chest X-rays, were examined with ultrasonography performed with a 7.5-MHz linear transducer. Logistic regression analysis was done to outline the clinical predictors of these insidious rib fractures. RESULTS A total of 15 (40.5%) patients showed rib lesions, whereas 22 (59.5%) patients had no evidence of rib lesions. Fracture of the rib associated with a subperiosteal hematoma was the most common finding in ten (66.7%) patients followed by the fracture of the rib alone in four (26.7%) patients, and subperiosteal hematoma alone in one (6.7%) patient. A total of eight (53.3%) patients had bony rib fractures, whereas seven (46.7%) patients had chondral rib fractures. Age (P=0.617), gender (P=0.552), type of etiology (P=0.954), duration of pain (P=0.234) and site of trauma (P=0.740) did not appear as significant predictors for these rib fractures. However, the involved part of the rib showed a significant correlation with either age (P=0.042) or duration of pain (P=0.033). Bony rib fractures significantly occurred in elderly patients, and the duration of pain in patients with bony rib fractures was significantly longer than that of patients with chondral rib fractures. CONCLUSIONS Ultrasonography is a useful imaging method in showing the rib fractures those overlooked on chest X-rays in minor blunt chest trauma, and no significant clinical feature exists as a predictor for these insidious fractures. However, bony rib fractures significantly occur in elderly patients and result in a longer duration of pain.