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BACKGROUND

Because of its form, size and position, the scaphoid is known to be the foundation stone of the carpus, with an exceptionally important biomechanical function. Therefore evaluation of fracture morphology is essential. Experts already agree that computed tomography (CT scan) in the long axis of the scaphoid is the best approach for diagnosing scaphoid fractures, but also for therapy planning. But this method is hardly a standard in most hospitals and studies showing superiority of this technique for therapy planning are non-existent.

HYPOTHESIS

The purpose of this retrospective study was to test if the interobserver reliability for the evaluation of scaphoid fracture morphology in CT scans in the long axis of the scaphoid is greater than in CT scans in the plane of the wrist, and thus more reliable.

METHOD

42 patients with scaphoid fractures had a CT scan in the long axis of the scaphoid (CT-scaphoid). CT reformations along planes relative to the wrist (CT -wrist) were made. Those 84 cases were anonymised and put in a random order. They were presented to 4 clinical observers (2 hand surgeons and 2 radiologists) for fracture evaluation with respect to: localisation, humpback deformity, offset (radial/ulnar and palmar/dorsal) and classification by Herbert. Surgeons have to select a palmar or dorsal approach as well as an open or percutaneous technique. Statistical analysis was made between 2 and 4 observers by an impartial statistician, using Cohen's kappa coefficient, Pearson coefficient, Fleiss' kappa, interclass correlation coefficient (Shrout and Fleiss) and Spearman rho coefficient.

RESULTS

In all evaluated parameters, the interobserver reliabilty was higher in the CT scan in the long axis of the scaphoid, although statistical significance was only found for the humpback deformity.

CONCLUSION

For evaluation and understanding scaphoid fractures, the CT scan along the long axis of the scaphoid is more significant and reliable than the scan in the plane of the wrist and is therefore preferable.