Posterior Fibula of Pes Cavus: Real or Artifact? Answer Based on Cross-Sectional Imaging

Cavus foot deformity is an often overlooked source of pathology. In the cavus foot, the fibula is often noted to be posterior on lateral radiographs. The objective of the study was to determine with threedimensional imaging if the fibula is truly posterior or just artifact. Using physical examination, patients with cavus were selected and compared to controls. An established technique to determine fibular position on computed tomography and magnetic resonance imaging was used to compare the study group to controls. Thirty-six cavus feet were compared to 36 controls. The average cavus fibula was noted to be 72% more posterior than the fibula of control patients and the difference in axial malleolar index was significant between the groups. This study shows that the cavus fibula is truly more posterior in patients with high arches. (Journal of Surgical Orthopaedic Advances 27(4):255–260, 2018)
Key words: axial malleolar index (AMI), fibula, peek-a-boo heel sign, pes cavus