Changes in inter observer variation of Schatzker and AO/OTA classification of tibial plateau fractures on addition of CT scan.

Abstract

Objective: Schatzker and AO/OTA classification are commonly used to classify tibial plateau fractures, but they are defined using plain radiographs and may not capture fully the complexity of these fractures. CT scan offers better visualization of occult fractures, joint depression and overall fracture morphology, but its impact on these classifications in term of interobserver variation is unclear. There is paucity of literature on this aspect, hence this study.

Methods: A total of 38 cases of tibial plateau fractures were classified by five different observers (four senior residents and one consultant) on the basis of Schatzker and AO/OTA classification. Initially, the observers classified the cases using plain radiographs and then reclassified the cases after supplementing the radiographs with CT scan images. The interobserver reliability was calculated using kappa coefficient.

Results: The interobserver agreement for Schatzker classification was found to be moderate on plain radiographs (mean κ_X-ray = 0.593) and substantial after addition of CT scan images (mean κ_{(X-ray + CT scan)} = 0.630). The interobserver agreement for AO/OTA classification was found to be fair on plain radiographs as well as after addition of CT scan images (mean κ_X-ray = 0.313 and mean κ_{(X-ray + CT scan)} = 0.320).

Conclusion: After providing advanced imaging both the classification systems showed improvement in the interobserver reliability. However, the change was found to be non-significant. This highlights the weakness of the plain radiograph based classification systems and indicates adoption of classifications based on advanced imaging.