Intraarticular foot and ankle injections to identify source of pain before arthrodesis.

OBJECTIVE: The purpose of our study was to evaluate the usefulness of diagnostic joint injections in patients with foot and ankle pain when the radiologist attempts to identify the source of pain. This study also correlated the results of injection with outcome after arthrodesis. MATERIAL AND METHODS: We retrospectively reviewed the records of 22 patients who had a foot or ankle joint injected to identify a source of pain and who later underwent arthrodesis of the painful joint. All patients had long-term foot and ankle symptoms of variable causes. Twenty-four joints were assessed: 13 subtalar, five talonavicular, four ankle, one calcaneocuboid, and one metatarsocuneiform. All patients had plain radiographs, 11 had CT studies, and five had bone scans. Contrast material was used to assess adequate positioning of the needle inside the joint before injection. All joints were injected under fluoroscopic control. Steroid was added in eight joints. After injection, patients were assessed for relief of symptoms. Patients subsequently underwent arthrodesis on the basis of the results of the injection. RESULTS: In 20 patients (22 joints), long-term follow-up showed that injections allowed us to correctly identify the source of pain and successfully guide arthrodesis. Of these 20 patients, 17 had significant pain relief after injection and fusion, whereas three patients had mild or no response. With one of these patients, we injected other joints and changed surgical plans. One of the two remaining patients had more pain relief after injection than after arthrodesis. The other patient had no relief after injection, but subsequent fusion because of persistent pain was successful. We found imaging studies to be less useful than diagnostic injections when we were attempting to identify the source of pain. CONCLUSION: Intraarticular injection of anesthetic in painful foot and ankle joints helped us confirm the source of pain in 20 of 22 patients, which in turn led to successful arthrodesis and good outcomes for these patients.