Reliability and reproducibility of the new AO/OTA 2018 classification system for proximal humeral fractures: a comparison of three different classification systems

Journal of Orthopaedics and Traumatology

Official Journal of the Italian Society of Orthopaedics and Traumatology

Table 7 Comparison of k coefficient values for intraobserver agreement

Classification system	Difference in k	95% CI	p-Value
Neer versus AO/OTA 2007	0.277	0.446–0.991	< 0.05
AO/OTA 2018 versus Neer	0.103	0.627–0.991	> 0.05
AO/OTA 2018 versus AO/OTA 2007	0.171	0.446–0.858	< 0.05
AO/OTA 2018 versus AO/OTA 2018 (with universal modifiers)	–0.007	0.627–0.858	> 0.05

Data acquired from interobserver testing from mean k values of two readings (Tables 1, 2, 3, and 4)