Inter- and intra-observer variation of the Schatzker and AO/OTA classifications of tibial plateau fractures and a proposal of a new classification system.

Background: The aim of this study was to evaluate the intra- and inter-observer variation of the Schatzker and AO/OTA classifications in assessing tibial plateau fractures, using plain radiographs.

Methods: Fifty tibial plateau fractures were classified independently by six observers as per the Schatzker and AO/OTA classifications, using antero-posterior and lateral plain radiographs. Assessment was done on two occasions, 8 weeks apart.

Results: We found that both the Schatzker and AO/OTA classifications have a high intra-observer (kappa = 0.57 and 0.53, respectively), and inter-observer (kappa = 0.41 and 0.43, respectively) variation. Classification of tibial plateau fractures into unicondylar versus bicondylar and pure splits versus articular depression +/- split conferred improved inter- and intra-observer variation.

Conclusions: The high inter-observer variation found for the Schatzker and AO/OTA classifications must be taken into consideration when these are used as a guidance of treatment and when used in evaluating patients' outcome. Simply classifying tibial plateau fractures into unicondylar versus bicondylar and pure splits versus articular depression +/- split may be more reliable.