A Reliability Study of Multiplanar Radiographs for the Evaluation of SNAC Wrist Arthritis

Background: Scaphoid nonunion advanced collapse (SNAC) is a common form of wrist arthritis, the treatment of which depends on the arthritic stage. The Vender classification serves to describe SNAC arthritis based on a single posteroanterior (PA) radiograph. The purpose of this study was to evaluate the intraobserver and interobserver agreement of the Vender classification, comparing multi versus single radiographic views. Methods: A retrospective review of patients with SNAC arthritis who underwent a proximal row carpectomy or a 4-corner fusion was performed. The included patients had 3 radiographic views of the pathologic wrist. Fifteen patients were analyzed by 5 blinded reviewers. Wrists were graded using the Vender classification first on the PA view and then using multiview radiographs. The intraobserver and interobserver agreement was determined using weighted kappa analysis. χ² tests were calculated comparing the evaluation between single- versus multiview radiographs and determining a higher Vender stage. Results: Multiview radiographs demonstrated a higher intraobserver κ_w compared with single-view radiographs (0.72 vs 0.66), both representing substantial agreement. The average interobserver agreement was moderate (κ_w of 0.48) for single view and slight (κ_w of 0.30) for multiview evaluation. Evaluating multiview radiographs was 6.37 times more likely to demonstrate Vender stage 3 arthritis compared with single view (odds ratio = 6.37 [confidence interval, 3.81-10.64], P < .0001). Conclusion: Reviewing multiview radiographs more commonly yielded Vender stage 3 osteoarthritis classification. The decreased interrater reliability in the multiview analysis is likely related to the increased number of articular surfaces evaluated. Using a single PA view may underestimate the severity of arthritis present.