Which Clinical Features Best Predict Occult Scaphoid Fractures? Systematic Review of Diagnostic Test Accuracy Studies

BACKGROUND
Plain radiographs cannot identify all scaphoid fractures and so patients with a clinical suspicion of scaphoid injury often undergo immobilisation despite normal imaging in the Emergency Department. The aims of this study were to determine (1) the prevalence of scaphoid fracture amongst patients with normal radiographs despite a clinical suspicion of scaphoid injury and (2) whether clinical features can be used to identify patients that do not require immobilisation and further imaging.
METHODS:
A systematic review of diagnostic test accuracy studies was undertaken. All study designs were included if they evaluated predictors of scaphoid fracture amongst patients with normal initial radiographs. Quality assessment was undertaken using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool but study data meta-analysed regardless of these assessments.
RESULTS:
Eight studies reported data on 1,685 wrist injuries. The prevalence of scaphoid fracture despite normal radiographs was 9.0%. Most studies were at overall low risk of bias but two were at unclear risk and all eight were at low risk for applicability concerns. The most accurate clinical predictors of occult scaphoid fracture were pain on supination against resistance (sensitivity 100%, specificity 97.9%, LR 45.0 [95% CI 6.5-312.5], supination strength CONCLUSION:
No single feature can satisfactorily exclude the presence of an occult scaphoid fracture. Further work should explore whether a combination of clinical features, possibly in conjunction with injury characteristics such as mechanism, may be sufficient together with normal initial radiograph. Pain on supination against resistance would benefit from external validation.