Reliability analysis of novel 3D classification of intertrochanteric fractures

Objective To verify the reliability of novel 3D classification of intertrochanteric fractures by comparing the consistency between conventional and novel classifications. Methods Included for the present study were the preoperative X-ray and CT images of 189 patients with intertrochanteric fracture who had been hospitalized at Department of Orthopaedics, Beijing Chao Yang Hospital, Capital Medical University from 1 January, 2017 to 1 January, 2019. The patients’ intertrochanteric fractures were classified by 6 orthopedic surgeons independently using Evans classification, Jensen classification, AO classification and novel 3D classification, respectively. One month later, the original images of the 189 patients were renumbered and classified again in the same way. The Kappa values between observers and within observers were calculated for the classifications of intertrochanteric fractures based on X-ray and CT images. Results In Evans classification, Jensen classification, AO classification and novel 3D classification, the interobserver Kappa values of X-ray films were 0.54±0.03, 0.53±0.03, 0.45±0.03 and 0.63±0.02, respectively, and the interobserver Kappa values of the CT images were 0.49±0.03, 0.49±0.03, 0.44±0.04 and 0.63±0.03. The intraobserver Kappa values of the X-ray films were 0.53±0.02, 0.54±0.03, 0.44±0.04 and 0.65±0.02, respectively, and the intraobserver Kappa values of the CT images were 0.52±0.03, 0.52±0.03, 0.41±0.02 and 0.64±0.03. In the novel classification based on X-ray and CT images, the interobserver and intraobserver Kappa values were both significantly higher than those in Evans, Jensen and AO classifications (P<0.05). Conclusion The novel 3D classification of intertrochanteric fractures is more reliable than the conventional ones. Key words: Femur; Fractures, bone; Reproducibility of results; Fracture classification