CLINICAL-RESULTS AFTER TARSAL TUNNEL DECOMPRESSION

We reviewed the clinical results for thirty patients (thirty-two feet) who had had exploration and decompression of the posterior tibial nerve for the treatment of tarsal tunnel syndrome between 1982 and 1990. The average duration of follow-up was thirty-one months (range, twenty-four to 118 months). Most of the patients were female, and the average age was forty-seven years (range, thirteen to seventy-two years). Over-all, only fourteen (44 per cent) of the thirty-two feet benefited markedly from the operative procedure (a good or excellent result). Of the five patients (five feet) who were completely satisfied, three had another lesion (a ganglion cyst, an accessory navicular bone, or a medial talocalcaneal coalition) in or near the tarsal tunnel that had been treated at the same time. Eleven patients (twelve feet [38 per cent]) were clearly dissatisfied with the result and had no long-term relief of the pain (a poor result). The pain was decreased in six feet (19 per cent), but the patients still had some pain and disability (a fair result). There were four complications (13 per cent): three wound infections and one delay in wound-healing. Twenty-two feet had had preoperative electrodiagnostic studies; the results of eighteen studies were considered abnormal and supportive of a diagnosis of tarsal tunnel syndrome. However, there was no correlation between the clinical outcome at the latest follow-up visit and the results of these studies. Over-all, the patients in the current series had less improvement than those who have been reported on previously. This may be due to our more stringent postoperative rating system, to the longer duration of follow-up compared with that in most other reports, to the fact that many of our patients had had a previous operation on the foot to relieve the pain, or to the possibility that another lesion had been responsible for the pain. Our findings suggest that, unless there is an associated lesion near or within the tarsal tunnel preoperatively, decompression of the posterior tibial nerve should be considered with caution.