Inter- And Intra-Observer Reliability of Schatzker, Ao, and Luo Classifications for Tibial Plateau Fractures

Abstract

Objective: To verify inter- and intra-observer agreement of three classification systems for tibial plateau fractures - Schatzker, AO/ASIF, and Luo’s - among orthopedic surgery residents. Methods: This cross-sectional study was conducted with 29 observers. Radiographic and tomographic imaging of the knee of 15 patients presenting with fractures were evaluated. After six weeks, the test was reapplied. The level of agreement was calculated by the Kappa index. Results: In test 1, inter-observer agreement of all residents, according to the Kappa index, for Schatzker classification was 0.226, for AO 0.431, and Luo’s 0.319. In test 2, values were 0.316, 0.333, and 0.347, respectively (p < 0.001). Regarding intra-observer analysis, the mean Kappa indexes of 1st-year residents were: Schatzker, 0.20; AO, 0.32; and Luo’s, 0.3. For 2nd-year residents, means were: 0.51, 0.58, and 0.38, respectively. As for 3rd-year, results were 0.42, 0.42, and 0.41, respectively (p < 0.001). Conclusion: AO/ASIF showed a better reproducibility than other classifications, with substantial inter- and intra-observer agreement. We also found a stronger agreement among 2nd- and 3rd-year residents. Level of Evidence III, Diagnostic Studies - Investigating a Diagnostic Test.