The Utility of the Tinel Sign in the Diagnosis of High Tarsal Tunnel Syndrome.

Background: Tarsal tunnel syndrome (TTS) can be divided into distal and proximal components. The latter is referred to as high TTS (HTTS) in which the tibial nerve is compressed above the location of the laciniate ligament. Although diagnosis of TTS has been shown to be enhanced by elicitation of a positive Tinel sign, no research into the utility of this provocation test has been conducted in the diagnosis of HTTS. This study aims to investigate the usefulness of the Tinel sign in diagnosing HTTS.

Methods: Seventy patients with electrophysiologic confirmation of HTTS were evaluated for the presence of a positive Tinel sign over the posterior tibial nerve's course in the area of the proximal tarsal tunnel (above the laciniate ligament).

Results: Of the 70 patients, 17 had a positive Tinel sign. Thirty-eight patients (54.3%) had electrodiagnostic evidence of polyneuropathy, and 12 of them (31.6%) had a positive Tinel sign. Among the 26 patients with HTTS and polyneuropathy who did not have a Tinel sign, electrodiagnostic testing found severe axonal dysfunction in ten. Fifteen of the patients with polyneuropathy were diagnosed as having diabetes mellitus, and a Tinel sign was present in 11 of them (73.3%). The four diabetic patients without a Tinel sign had marked axonal dysfunction (motor evoked responses were absent or significantly reduced).

Conclusions: The utility of the Tinel sign in patients with HTTS was found to be low; however, in the subpopulation of patients with diabetic neuropathy, the Tinel sign may be more useful.