Radiology, Vol 197, 447-449, Copyright © 1995 by Radiological Society of North America
Cortical defect of the distal fibula: variant of ossification
S Ehara, Y Tamakawa, J Nishida, M Abe, M Horiguchi and GY el-Khoury
Center for Radiological Sciences, Iwate Medical University, Morioka, Japan.
PURPOSE: To elucidate the nature of a normally occurring cortical defect of
the distal fibula. MATERIALS AND METHODS: In patients with sprain and
nonspecific ankle pain during a 2-year period, the authors reviewed ankle
radiographs, computed tomographic (CT) scans, and magnetic resonance (MR)
images. Cases were added from our file. Dried skeletons and cadavers were
evaluated with radiography for the presence of this cortical defect.
RESULTS: Fifteen (1.8%) of 847 radiographs in 739 patients (male, 377;
female, 362; age range, 15-84 years) showed a small cortical defect in the
anterior aspect at the level of the distal tibiofibular joint. The age
range of the subjects with the defect (male, four; female, 11) was 16-66
years. MR imaging in two patients showed a small low-signal-intensity area
at the insertion site of the anterior tibiofibular ligament. Evaluation of
148 skeletons (75 subjects) revealed similar cortical defect in two cases
(1.4%). CONCLUSION: The cortical defect of the distal fibula, at the
insertion site of the anterior tibiofibular ligament, has no clinical
significance and should not be confused with neoplasm.
