Postoperative Outcomes Between Positive and Negative Electrodiagnosis in Patients With Tarsal Tunnel Syndrome: A Retrospective Comparative Study

Abstract

Background: The sensitivity of diagnosing tarsal tunnel syndrome with an electrodiagnostic study is just over 50%. Given this low reliability, many surgeons prefer to make a diagnosis solely from a physical examination, despite reported electrodiagnostic findings. Thus, to understand the clinical ramifications between these 2 methods of diagnosis, this investigation compared the postoperative outcomes following a tarsal tunnel release between patients with positive and negative preoperative electrodiagnosis (EDx). Methods: This study retrospectively reviewed 53 consecutive patients who underwent tarsal tunnel release by a single surgeon between 2015 and 2022. The primary outcome was pain level using visual analog scale (VAS) whereas the secondary outcomes were 36-Item Short Form Health Survey questionnaire, Foot and Ankle Ability Measure, recovery times (time to return to activities of daily living, work, and sports), and complications. Pre- and postoperative functional outcomes were compared within each EDx group using a paired sample t test. Postoperative outcomes between groups were compared using a generalized linear model adjusted for potential confounders. Results: Both EDx groups (positive studies = 31 patients and negative studies = 22 patients) demonstrated significant improvement of all functional outcomes ( P < .001). We found no significant difference in recovery time or postoperative outcomes between the 2 groups ( P > .05). Multivariable analysis showed diabetes (risk ratio [RR] = 1.79, 95% CI 1.11-2.90) and longer duration of symptoms before surgery (RR = 1.02, 95% CI 1.00-1.04) as prognostic factors for residual pain following tarsal tunnel release. Conclusion: In our series, we found that preoperative electrodiagnostic results did not prognosticate postoperative functional outcomes or recovery times after tarsal tunnel release. Level of Evidence: Level III, retrospective cohort study.