Fig. 2

Patient case 4. a, b Radiographs in the anteroposterior and internal oblique views. c The transverse ultrasound image showed the disrupted cartilage hinge and the stair sign in a large cartilage gap. d Radiographs of anteroposterior views of an arthrogram. The dye continued along the fracture line and passes through the articular surface, thus indicating an incongruity of the articular surface. Arrow, disrupted cartilage hinge; arrowhead, cartilage hinge; Asterisk, epiphyseal core of ossification of the capitellum; M, medial; L, lateral