Presentation
Twisted ankle.
Patient Data
Spiral fracture distal fibula, ankle mortise appears intact.
Three mortise views of the ankle are obtained, the first without and the second and third with stress. The view without stress shows normal alignment, the 2 stressed views show widening of the medial clear space indicating a deltoid ligament tear.
Case Discussion
Bones are held in anatomic position by ligaments, which cannot be seen directly on a plain radiograph. However, if the normal distance between 2 bones is increased, we can infer that the ligament(s) that normally hold the bones together has torn. Occasionally, putting stress on the injured ligaments is necessary to distract the bones and demonstrate that the ligament is torn.