Scaphoid nonunion advanced collapse classifications: a reliability study.

Watson & Ballet and Vender staging systems are widely known for classifying SNAC wrist osteoarthritis. Despite of its day-to-day use, no assessment for its agreement was performed. To Evaluate the intra and interobserver agreement for these classification systems. Forty-eight posteroanterior wrist radiographs from patients with osteoarthritis due to scaphoid nonunion were evaluated at two occasions-in a 1 week interval-by five observers with different expertise-hand surgeons, hand surgery residents, orthopedic surgeons and orthopedic surgery residents. They rated osteoarthritis stages according to the above-cited systems. Kappa statistics were performed for measuring agreement. Unsatisfactory (Cohen's Kappa <0.5) agreement was found for all intra and inter observer measures for both systems. There was no clear correlation between expertise and kappa values. Unsatisfactory agreement was found for both classifications, despite the evaluator expertise. A rationale of a more reliable classification is needed.