Jordy van Sambeeck

Chapter 1 18 Figure 6. The three findings identifying trochlear dysplasia on lateral X-ray views: crossing sign, double-contour sign, and supratrochlear spur. Saggin PRF, Saggin JI, Dejour D; Imaging in Patellofemoral Instability: An Abnormality-based Approach. Sports Med Arthrosc Rev 2012;20:145-151. Crossing sign Type A Type B Crossing sign Shallow trochlea Flat trochlea Supratrochlear spur Crossing sign Supratrochlear spur Lateral convexity Medial hypoplasia Cliff Double contour (ending below the crossing sign) Double contour (ending below the crossing sign) Crossing sign Type C Type D Figure 7. Trochlear dysplasia classification according to D. Dejour. This figure was published in Insall & Scott Surgery of the Knee, Sixth Edition, 2018, Chapter 65 Disorders of the Patellofemoral Joint, Figure 65.14, Page 851, Copyright Elsevier (2018). (Insall Scott Ch. 65, Imaging)