From the case:
Ossified subperiosteal hematoma - femur
{"current_user":null,"step_through_annotations":true,"access":{"can_edit":false,"can_download":true,"can_toggle_annotations":true,"can_feature":false,"can_examine_pipeline_reports":false,"can_pin":false},"extraPropsURL":"/studies/8301/annotated_viewer_json?lang=us"}
Along the anterior aspect of the distal femur is a linear region of ossification almost certainly representing an ossified subperiosteal hematoma following total knee replacement.
Unable to process the form. Check for errors and try again.