Aim: To describe a radiographic biomechanical classification of tibial plateau fractures which dictates treatment. To compare the intra- and interobserver reliability and reproducibility of this, the Chertsey (C1-3) classification, and the Schatzker (SK1-6) classification.

Method: This classification system has been used at this institution for 8 years by the orthopaedic trauma consultants and consists of C1 – valgus fractures, C2 – Varus fractures and C3 axial fractures. Our treatment regime is based on this classification and results presented in a sperate study. These consultants were excluded from the study on reliability and reproducibility. 2 Orthopaedic consultants, 2 orthopaedic registrars and 2 radiologists were selected randomly to classify 30 sets of AP and Lateral radiographs, of randomly selected patients treated in this institution with tibial plateau fractures, consisting of 9 SK1-3/C1, 8 SK4/C2 and 13 SK5,6/C3 fractures, and again with the same radiographs in a random order 1 month later. Radiographs of fractures treated conservatively were excluded. Statistical analysis included Kappa concordance according to Landis and Koch, and the Mann-Whitney U test.

Results: The Schatzker system was only moderately reliable (K=0.66), and the Chertsey classification system significantly more reliable (K=0.82) (p=0.03) with regards to interobserver reliability. Excellent reproducibility (intra-observer reliability) was seen amongst all observers. The consultant orthopaedic surgeons were significantly more reliable than the radiologists, but not the orthopaedic registrars. No particular fracture type in any classification proved to be significantly more difficult to classify.

Conclusion: We present a classification used in our institution based on plain radiographs, which depicts investigations and treatment. The Chertsey classification is significantly more reliable between observers than the Schatzker classification and is reproducible.