Fig. 2
Examples of patellar contusions. (a) Axial fat-suppressed proton density-weighted MR image in a 20-year-old man shows hyperintense signal of the medial patellar bone marrow (solid arrow) and a fracture line through the adjacent cartilage (open arrow). Conventional radiographs were negative for fracture (not shown). (b) Axial and (c) sagittal fat-suppressed proton density MR images in another 20-year-old man following direct trauma, revealing bone marrow oedema (arrow) without cartilage damage. Conventional radiographs were also negative for fracture (not shown)