Diagnosis of elbow fracture patterns on radiographs: interobserver reliability and diagnostic accuracy

Studies of traumatic elbow instability suggest that recognition of a pattern in the combination and character of the fractures and joint displacements helps predict soft tissue injury and guide the treatment of traumatic elbow instability, but there is no evidence that patterns can be identified reliably. We therefore determined (1) the interobserver reliability of identifying specific patterns of traumatic elbow instability on radiographs for subgroups of orthopaedic surgeons; and (2) the diagnostic accuracy of radiographic diagnosis. Seventy-three orthopaedic surgeons evaluated 53 sets of radiographs and diagnosed one of five common patterns of traumatic elbow instability by using a web-based survey. The interobserver reliability was analyzed using Cohen's multirater kappa. Intraoperative diagnosis was the reference for fracture pattern in calculations of the sensitivity, specificity, accuracy, and positive predictive and negative predictive values of radiographic diagnosis. The overall interobserver reliability for patterns of traumatic elbow instability on radiographs was κ=0.41. Treatment of greater than five such injuries a year was associated with greater interobserver agreement, but years in practice were not. Diagnostic accuracy ranged from 76% to 93% and was lowest for the terrible triad pattern of injury. Specific patterns of traumatic elbow instability can be diagnosed with moderate interobserver reliability and reasonable accuracy on radiographs. Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidenc