Assessment of Recent Occult Scaphoid Fractures by High Resolution Sonography
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- Category: Vol. 77, December 2009
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Assessment of Recent Occult Scaphoid Fractures by High Resolution Sonography,MOSTAFA SAYED, MOHAMAD R. HABBA, MOHAMAD A.K. EL-BEBLAWY and AZZA A.M. GAD
Abstract
Objective: To evaluate the diagnostic values of high-resolution sonography in the diagnosis of occult fractures of the scaphoid bone.
Subjects and Methods: Sonography of the scaphoid bone with a 10-MHz transducer was performed in 35 patients with clinically suspected scaphoid fracture and normal findings on initial radiographs, including specific scaphoid images. Three levels of clinical suspicion were considered: High (25%), moderate (32%) and low (43%). Attention was paid to the continuity of the scaphoid cortex and to the surrounding soft tissues (i.e., hemarthrosis or hematoma). Data from early sonograms were then compared with the results of radiography repeated 10–14 days after the initial trauma.
Results: Follow-up examinations (either radiographs, CT or MRI) proved fracture of the scaphoid in nine patients. In all patients, diagnosis of fracture was suspected on initial sonograms showing cortical disruption associated with soft-tissue abnormalities. There was no false-negative results. Overall accuracy of high resolution sonography for detection of scaphoid fractures was 92% with 100% sensitivity and 88% specificity. Using cortical disruption as a diagnostic criterion, we found the sensitivity, specificity, positive pre-dictive value and negative predictive value of high-resolution sonography for the depiction of scaphoid fracture to be 100%. Using soft-tissue abnormalities alone as a criterion, we found the sensitivity, specificity, positive predictive value and negative predictive value of high-resolution sonography to be 77%, 88%, 70% and 92%, respectively. The overall prev-alence of occult fracture was 26%, ranging from 8.6% for moderate suspicion to 17.4% for high suspicion of fracture and no for low suspicion.
Conclusion: High-resolution sonography is a reliable and accurate method of evaluating occult fractures of the scaphoid. Cortical disruption is the diagnostic key. Soft-tissue abnor-malities alone lack sensitivity.