Figure 13 Osteochondral sleeve fracture in a paediatric patient. (A) Lateral plain film of a patellar avulsion fracture of the inferior pole of the patella demonstrating a superiorly displaced patella and a small bone fragment (arrow). Sagittal T1-weighted (B) and sagittal gradient recalled echo (C) MR images demonstrating an osteochondral fracture of high signal intensity with a small bone fragment (arrow).