Written by Christopher Thom
In a meta-analysis of 1,685 patients with suspected scaphoid fracture after negative plain radiographs, no clinical feature adequately rules out occult fracture.
Why does this matter?
Plain radiographs lack adequate sensitivity to rule out scaphoid fractures in patients with wrist injuries. Immobilization is often necessary due to concern for radiographically occult scaphoid fractures. Clinical features that can accurately predict the presence of fracture could have immense value in reducing unnecessary immobilization and follow up imaging.
We might be stuck with immobilization a while longer…..
This was a meta-analysis of eight studies encompassing patients with initial negative plain radiographs but ongoing clinical suspicion of scaphoid fracture. 1,685 patients were included, with 123 occult scaphoid fractures identified in the cohort (9.0% prevalence). The reference standard varied amongst the eight studies, with two using MRI, two using repeat plain radiographs at 10 or 14 days, and four using a combination of MRI, repeat radiographs, and/or bone scintigraphy.
The authors found that the most accurate clinical predictors of occult scaphoid fracture were pain on supination against resistance (sensitivity 100%, specificity 97.9%, LR+ 45), supination strength < 10% of contralateral side (sensitivity 84.6%, specificity 76.9%, LR+ 3.7), and pain on ulnar deviation (sensitivity 55.2%, specificity 76.4%, LR+ 2.3). The absence of anatomical snuffbox tenderness reduced the likelihood of occult scaphoid fracture (sensitivity 92.1%, specificity 48.4%, LR- 0.2). Importantly, while pain on supination against resistance had a sensitivity of 100%, this was only evaluated in one study of 53 patients, with 8 occult fractures. The sensitivity 95% confidence interval was 63.1% to 100%, indicating that this finding needs further study with a larger sample size. Conversely, the absence of anatomical snuffbox tenderness was evaluated in 1,309 patients, leading to a narrower sensitivity 95% confidence interval of 82.9% to 96.6%. Ultimately, no clinical exam characteristic, either individually or combined, was adequate for exclusion of occult scaphoid fracture.
Which clinical features best predict occult scaphoid fractures? A systematic review of diagnostic test accuracy studies. Emerg Med J. 2023 May 11;emermed-2023-213119. doi: 10.1136/emermed-2023-213119. Online ahead of print.