Validation of the AOSpine-DGOU Osteoporotic Fracture Classification - Effect of Surgical Experience, Surgical Specialty, Work-Setting and Trauma Center Level on Reliability and Reproducibility

STUDY DESIGN: Cross-sectional survey. OBJECTIVES: A cornerstone of classification systems is good reliability amongst different groups of classification users. Thus, the aim of this international validation study was to assess the reliability of the new AO Spine DGOU Osteoporotic Fracture Classification (OF classification) stratified by surgical specialty, work-setting, work-experience, and trauma center level. METHODS: 320 spine surgeons were asked to rate 27 cases according to the OF classification at 2 time points, 4 weeks apart (assessment 1 and 2) in this online-webinar based validation process. The kappa statistic (κ) was calculated to assess the inter-observer reliability and the intra-rater reproducibility. RESULTS: A total of 7798 (90.3%) ratings were recorded in assessment 1 and 6621 (76.6%) ratings in assessment 2. Global inter-rater reliability was moderate in both assessments (κ = 0.57; κ = 0.58). Participants with a work-experience of >20 years showed the highest inter-rater agreement in both assessments globally (κ = 0.65; κ = 0.67). Participants from a level-1 trauma center showed the highest agreement (κ = 0.58), whereas participants working at a tertiary trauma center showed higher grade of agreement in the second assessment (κ = 0.66). Participants working in academia showed the highest agreement in assessment 2 (κ = 0.6). Surgeons with academic background and surgeons employed by a hospital showed substantial intra-rater agreement in the second assessment. CONCLUSIONS: The AO Spine-DGOU Osteoporotic Fracture Classification showed moderate to substantial inter-rater agreement as well as intra-rater reproducibility regardless of work-setting, surgical experience, level of trauma center and surgical specialty.