Localization of specific joint causing hindfoot pain: value of injecting local anesthetics into individual joints during arthrography.

OBJECTIVE: The purpose of this study was to evaluate the utility of selective injection of local anesthetic into hindfoot articulations for localizing the source of posttraumatic pain and to compare clinical response with the severity of degenerative change in the various articulations evident on plain radiographs or CT scans. SUBJECTS AND METHODS: Anesthetic arthrography was performed in 18 patients with posttraumatic hindfoot pain. In all, 32 joints were assessed: 15 talocalcaneonavicular, 11 subtalar, five ankle, and one calcaneocuboid. Following intraarticular injection of a mixture of equal amounts of meglumine diatrizoate 60%, lidocaine 1%, and bupivacaine 0.25%, patients were asked to grade the degree of pain relief they experienced on a scale from 0% to 100%. The degree of degenerative changes seen on preliminary radiographs and CT scans was graded blindly and retrospectively by an experienced musculoskeletal radiologist using a 3-point scale (grade 0 indicated a normal joint, grade 1 indicated mild to moderate degenerative change, and grade 2 indicated severe degenerative change). The value of findings on both routine radiographs and CT scans as predictors of the degree of symptomatic relief obtained from specific joint injections was determined. Arthrodesis was performed in nine patients on the basis of the results of anesthetic injections.
RESULTS: The degree of pain relief experienced after intraarticular injection of anesthetic correlated with the severity of degenerative change as assessed by routine radiography in 15 of 32 joints and as assessed by CT in eight of 18 joints. In 14 of 32 joints assessed by routine radiography and in seven of 18 joints assessed by CT, the amount of pain relief achieved by anesthetic arthrography was less than that predicted by imaging evidence of degenerative disease. In five of 32 joints judged normal on plain film radiographs, significant pain relief was experienced following anesthetic injection, resulting in a change in the proposed surgical procedure. Long-term follow-up indicated satisfactory results in eight of the nine patients in whom arthrodesis was performed.
CONCLUSION: Selective intraarticular anesthetic injections afford a direct method of confirming the site of hindfoot pain and may aid in surgical planning, because plain film radiography or CT may underestimate or poorly indicate the most symptomatic articulations.