Isolated first naviculocuneiform joint coalition

Clinical analysis was performed on 60 feet in 40 patients with isolated first naviculocuneiform coalitions. The most common symptom was a mild pain at the medioplantar site of the first naviculocuneiform joint. Fifteen feet (25%) were asymptomatic. Some cases had been treated erroneously as osteoarthritis or bony cyst before diagnosis. We divided coalitions morphologically into three patterns based on computed tomography findings: irregular, cystic, and combined pattern. Based on the mean age of each pattern, we hypothesized that initial irregular coalitions gradually develop into cystic and, finally, combined patterns. Considering the modest number of reported cases, this condition might easily be overlooked in many patients or may be related to ethnic characteristics. We suggest that the actual incidence of first naviculocuneiform coalitions should be investigated again.