Abstract
Background
In suspected scaphoid fracture the initial scaphoid series plain radiographs are 84-94% sensitive for scaphoid fractures. Patients are immobilised awaiting diagnosis. Unnecessary lengthy immobilisation leads to lost productivity and may leave the wrist stiff. Early accurate diagnosis would improve patient management. Although Magnetic Resonance Imaging (MRI) has come to be regarded as the gold standard in identifying occult scaphoid injury, recent evidence suggests Computer Tomography (CT) to be more accurate in identifying scaphoid cortical fracture. Additionally CT and USS are frequently a more available resource than MRI.
We hypothesised that 16 slice CT is superior to high spatial resolution Ultrasonography (USS) in the diagnosis of radiograph negative suspected cortical scaphoid fracture and that a 5 point clinical examination will help to identify patients most likely to have sustained a fracture within this group.
Methods
100 patients with two negative scaphoid series and at least two out of five established clinical signs of scaphoid injury (anatomical snuffbox tenderness (AST), scaphoid tubercle tenderness (STT), effusion, pain on circumduction and pain on axial loading) were prospectively investigated with CT and USS. MRI was arranged for patient with persistent symptoms but negative CT/USS.
Results
CT demonstrated 8 scaphoid fractures. 17 other fractures (1st metacarpal, trapezium, trapezoid, distal radius, hook of hammate and triquetral) were also found. USS diagnosed 2/8 scaphoid fractures, raised suspicion in 5/8 and completely missed 1/8. Combining AST, STT with pain on circumduction improved accuracy (sensitivity 87.5% and Specificity 36%). No further fractures were identified on MRI.
Conclusions
- CT remains superior to USS for the exclusion of cortical scaphoid fracture. There remains a role for USS if resources are limited.
- Combining signs of ASB and tubercle tenderness with pain on circumduction assists in the identification of a ‘fracture likely’ subgroup.
