Fig. 5

Sleeve fracture of the lower patellar pole in an 11-year-old boy after falling on his flexed knee during a football game, with a popping sound. The patient presented to the ER 5 days later. (a) Lateral knee radiograph and (b) sagittal fat-suppressed T2-weighted MR image 3 days after knee x-ray show small bony fragment fracture from the lower pole (arrow), extending anteriorly, with detachment of a thin shell of cortical bone (arrowheads), consistent with a sleeve fracture. Note the injury of the distal attachment of the patellar tendon (open arrow). Images courtesy of Arnold Carlson Merrow, Jr., MD - Cincinnati Children’s Hospital Medical Center, OH, USA