Radiological measurements

Preoperative radiographic examinations consisted of plain radiographs and multidetector computed tomography (MDCT) scans. MDCT was indicated for detailed evaluation of the fracture morphology which facilitated surgical plan development. MDCT This was performed on a 64 slice multi-detector CT scanner (Siemens Sensation 64, Erlangen, Germany) using the following scan parameters: detector collimation 64 × 0.6 mm, tube voltage 120 kV scanning in a caudo-cranial direction. All radiological information was independently assessed by two authors (Zheng. and Chang.), who assigned the Schatzker classification and made the CT measurements using the PACS (Picture Archiving and Communication Systems) Imaging System. The mean values of fracture displacement measured by the two authors were used in the analysis. For articular depression and widening displacement, measurements were assessed from the coronal reformatted plane which was tangent to the posterior edge of femoral condyles in the transverse view, and parallel to the longitudinal axis of the tibial shaft in the sagittal view. The maximum amount of articular depression was measured from the intact plateau line (parallel to the femoral condyles) to the lowest point of depressed subchondral bone (Fig. 1A). Using the femoral condyle as a reference, widening displacement was equal to the distance between the tangental line to the femoral epicondyle (perpendicular to the femoral condyles) and the most laterally displaced point of tibial plateau (Fig. 1B). The area of depressed region was calculated from the CT scan coronal reformatted plane which could manifest the anterior and posterior edge of the depression region, the appropriate section could be easily identified to calculate the depression area using the freehand ROI (region of interest) tool (Fig. 1C). All parameters were calculated in millimeters and independently measured for the medial and lateral plateau.

A 42-year-old male who sustained a type II fracture of tibial plateau. (A) Coronal reformatted CT image, a = the depth of lateral plateau depression, 18.08 mm; (B) Coronal reformatted CT image, b = lateral plateau widening, 5.73 mm; (C) Axial view of CT image, c = the area of lateral depression, 787.03 mm².