Radionuclide bone scanning in subtalar coalitions: differential considerations.

The radionuclide bone scan is a noninvasive screening procedure which can help in identifying or confirming subtalar coalitions in patients with foot and/or ankle pain of unknown origin in whom routine plain film studies are inconclusive. Five patients (seven symptomatic feet) with clinical and plain film findings suggesting a subtalar coalition are presented. The radionuclide bone scans in four patients (six feet) with documented subtalar coalitions demonstrated augmented uptake in the subtalar joint in all six feet and a secondary area of augmented concentration in the superior aspect of the talus or talonavicular joint in five feet. The radionuclide bone scan was normal in the one patient who was later proved not to have a coalition. The scans of 100 patients with foot pain of other etiologies were reviewed, and in no instance did the scan demonstrate the combination of subtalar and talus or talonavicular uptake observed in the patients with coalitions.