TWO-DIMENSIONAL AND THREE- DIMENSIONAL COMPUTED TOMOGRAPHY FOR THE CLASSIFICATION AND CHARACTERIZATION OF TIBIAL PLATEAU FRACTURES

Abstract

Background: Complex fractures of the tibial plateau can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional computed tomography reconstructions improve the reliability of tibial plateau fracture characterization and classification.

Methods: Forty-five consecutive intra-articular fractures of the tibial plateau were evaluated by six independent observers for the presence of six fracture characteristics that are not specifically included in currently used classification schemes:

1. posteromedial shear fracture;

2. coronal plane fracture;

3. lateral condylar impaction;

4. medial condylar impaction;

5. tibial spine involvement;

6. separation of tibial tubercle necessitating anteroposterior lag screw fixation.

In addition, fractures were classified according to the AO/OTA Comprehensive Classification of Fractures, the Schatzker classification system and the Hohl and Moore system. Two rounds of evaluation were performed and then compared. First, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, four weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed.

Results: Interobserver agreement improved for all classification systems after the addition of three-dimensional reconstructions (AO/OTA κ2D = 0.536 versus κ3D = 0.545; Schatzker κ2D = 0.545 versus κ3D = 0.596; Hohl and Moore κ2D = 0.668 versus κ3D = 0.746).

Three-dimensional computed tomography reconstructions also improved the average intraobserver reliability for all fracture characteristics, from κ2D = 0.624 (substantial agreement) to κ3D = 0.687 (substantial agreement). The addition of three-dimensional images had limited infiuence on the average interobserver reliability for the recognition of specific fracture characteristics (κ2D = 0.488 versus κ3D = 0.485, both moderate agreement). Three-dimensional computed tomography images improved interobserver reliability for the recognition of coronal plane fractures from fair (κ2D = 0.398) to moderate (κ3D = 0.418) but this difference was not statistically significant.

Conclusions: Three-dimensional computed tomography is helpful for;

1. individual orthopaedic surgeons for preoperative planning (improves intraobserver reliability for the recognition of fracture characteristics), and for

2. comparison of clinical outcomes in the orthopaedic literature (improves interobserver reliability of classification systems).