Ultrasonographic evaluation of costal cartilage fractures unnoticed by the conventional radiographic study and multidetector computed tomography.

INTRODUCTION: Rib fractures are the most common injuries resulting from blunt chest trauma. However, costal cartilage fractures are almost invisible on chest X-rays unless they involve calcified cartilage. The sensitivity of conventional radiography and computed tomography for detecting rib fractures is limited, especially in cases where rib cartilage is involved. Therefore, this study was designed to evaluate the sensitivities of chest wall ultrasonography, clinical findings, and radiography in the detection of costal cartilage fractures.

MATERIALS AND METHODS: A total of 93 patients presenting with a high clinical suspicion of rib or sternal fractures were recruited for radiological workup with posterior-anterior (PA) chest radiographs, oblique rib views, sternal views, computed tomography, and chest ultrasound between April 2008 and May 2010. There were 47 men and 46 women, and the mean age of the patients was 51.8 ± 15.9 years (range 17-78 years). These patients with minor blunt chest trauma showed no evidence of rib fractures on conventional radiography and computed tomography, and no evidence of other major fractures. Chondral rib fractures were detected by using ultrasonography on a 7.5-MHz linear transducer.

RESULTS: Of the total 93 patients, 64 (68.8%) showed chondral rib fractures, whereas 29 (31.2%) did not. The mean number of chondral rib fracture sites detected in 64 patients was 1.8 ± 0.8 (range 1-5). Subperiosteal hematoma was the most common finding associated with costal cartilage fractures (n = 14, 15.0%), followed by sternal fracture (n = 9, 9.7%). However, subperiosteal hematoma was also noticed in 1 (1.1%) of the patients without costal cartilage fractures, and sternal fractures in 7 patients (7.5%).

DISCUSSION: The results of this study suggest that ultrasonography may be a useful imaging method for detecting costal cartilage fractures overlooked on conventional radiographs and computed tomography in patients with minor blunt chest trauma. Early ultrasonographic evaluation can give more accurate information than clinical and radiologic evaluation in detecting costal cartilage fractures and sternal fractures that are overlooked on conventional radiography and computed tomography after minor blunt chest trauma.