The addition of Computed Tomography to X-ray imaging for diagnosing suspected scaphoid fractures

Introduction
Scaphoid fractures are common in early adulthood. For acute scaphoid fractures the sensitivity of X-ray imaging, after acquiring an additional 3-4 scaphoid specific projections (scaphoid series), is reported to be as low as 43-70%. Meanwhile, early and adequate treatment is important. For this reason CT-scans of the wrist have been acquired in early stage in patients with a clinically suspected scaphoid fracture. It is the aim of this study to investigate if the addition of CT-scan in the diagnostic process actually leads to additional diagnosis of scaphoid fractures.
Methods
The study was designed as a retrospective cohort study. Patients, aged 18 and older, who presented to the Emergency Department of our Level 1 trauma centre between October 1st 2015 and February 1st 2021, were screened for eligibility. Patients were included when there was a clinically suspected acute scaphoid fracture, and the patient had undergone X-ray and CT of the wrist within 14 days of one another. Data was extracted from the patient file and was processed anonymously through Castor EDC. Statistical analyses was performed using SPSS (version 26).
Results
A total of 277 patients were included in this study. 60 Of which had a scaphoid fracture on the CT. For X-ray, a sensitivity of 81,7% (49 out of 60) was found, along with a NPV of 94,1% (174 out of 185). In the simple FOOSH group, we found that the addition of CT to the diagnostic process, lead to 7 additional scaphoid fracture diagnoses within our sample. Two of which were incidental findings, as the CT-scan of the wrist was acquired for a different indication entirely. The scaphoid fractures which were not seen on X-rays are mostly non-displaced chip fractures, which were treated conservatively. Surprisingly it was found that a scaphoid series was only acquired as part of the X-rays in 2 out of these 7 patients.
Conclusion
This data indicates that X-ray imaging is much more reliable for ruling out scaphoid fractures than described in previously published literature. The found overall sensitivity is 81,7% along with a NPV of 94,1%. Surprisingly, it was also found that a scaphoid series is not performed in the vast majority of the false negative sets of X-rays. This may suggest that a complete set of X-rays, with the addition of a scaphoid series, is even more reliable than what is shown by the numbers in this study. However, if the level of clinical suspicion is very high, a negative set of X-rays doesn’t completely rule out a scaphoid fracture, even if the X-rays do include a scaphoid series. In addition to this it may be recommended to acquire a CT if X-ray results are inconclusive, as the prevalence of scaphoid fractures is relatively high amongst this group.