The interobserver reliability of the diagnosis and classification of scaphoid fractures using high-resolution peripheral quantitative CT

Aims

Besides conventional radiographs, the use of MRI, CT, and bone scintigraphy is frequent in the diagnosis of a fracture of the scaphoid. However, which techniques give the best results remain unknown. The investigation of a new imaging technique initially requires an analysis of its precision. The primary aim of this study was to investigate the interobserver agreement of high-resolution peripheral quantitative CT (HR-pQCT) in the diagnosis of a scaphoid fracture. A secondary aim was to investigate the interobserver agreement for the presence of other fractures and for the classification of scaphoid fracture.

Methods

Two radiologists and two orthopaedic trauma surgeons evaluated HR-pQCT scans of 31 patients with a clinically-suspected scaphoid fracture. The observers were asked to determine the presence of a scaphoid or other fracture and to classify the scaphoid fracture based on the Herbert classification system. Fleiss kappa statistics were used to calculate the interobserver agreement for the diagnosis of a fracture. Intraclass correlation coefficients (ICCs) were used to assess the agreement for the classification of scaphoid fracture.

Results

A total of nine (29%) scaphoid fractures and 12 (39%) other fractures were diagnosed in 20 patients (65%) using HR-pQCT across the four observers. The interobserver agreement was 91% for the identification of a scaphoid fracture (95% confidence interval (CI) 0.76 to 1.00) and 80% for other fractures (95% CI 0.72 to 0.87). The mean ICC for the classification of a scaphoid fracture in the seven patients diagnosed with scaphoid fracture by all four observers was 73% (95% CI 0.42 to 0.94).

Conclusion

We conclude that the diagnosis of scaphoid and other fractures is reliable when using HR-pQCT in patients with a clinically-suspected fracture.