Intermetatarsal Coalition: Case Report, Literature Review, and Imaging Findings of an Underrecognized and Underdiagnosed Cause of Foot Pain

Figure 1

40-year-old female with dorsal forefoot pain following a change in activity. AP (a) and oblique (b) radiographs reveal bony prominence of the lateral border of the proximal third metatarsal shaft. Short axis PD (c) and PDFS (d) sequences reveal abnormal articulation between the base of the third and fourth metatarsals. Surrounding reactive bony hypertrophy and intramedullary marrow oedema signal. This is consistent with nonosseous intermetatarsal coalition. Coronal PDFS (e) sequence with nonosseous coalition between the base of the third and fourth metatarsals. Localized marrow oedema signal at the third metatarsal base. Coronal PDFS (f) sequence reveals a bursal-neuroma complex at the third intermetatarsal space corresponding to the location of the coalition. Sagittal PDFS sequences (g) with low-grade marrow oedema in the third metatarsal head. These are speculated to arise from the altered weight-bearing mechanics as a result of the coalition with increased load on the metatarsal head.

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