Twenty patients received the installation of contrast material into th
e peroneal tendons while local anesthetic was injected as a diagnostic
test. In three patients (15%), communication with the ankle joint and
subtalar joint was noted, as well as failure of the contrast to fill
the distal tendon. Injection of local anesthetic into the peroneal ten
dons as a diagnostic measure, therefore, may not have 100% sensitivity
or specificity. Simultaneous injection of contrast material can be us
ed to alert the clinician to a lack of specificity of the anesthetic t
est injection.