Modified posterior portals for hindfoot arthroscopy.

PURPOSE: The purpose of this study was to determine the course and safe distances achieved with modified coaxial portals for hindfoot arthroscopy and report the clinical results.

METHODS: We used 30 embalmed cadaveric ankle specimens and 10 fresh-frozen ankle specimens for anatomic measurements and trial operations. The posteromedial portal via the posterior tibial tendon sheath was first established. The posterolateral portal was subsequently created immediately behind the posterior border of the lateral malleolus and anterior to the peroneal tendons via an inside-out technique. The coaxial portals were finally established with cannulas left in place. In the clinical series, posterior ankle arthroscopy was performed on 18 ankles in 15 patients. All patients were evaluated for any complications with a mean follow-up of 38 months.

RESULTS: The posterior tibial nerve, posterior tibial artery, and peroneal artery were located a mean distance of 8.7 mm, 10.1 mm, and 12.9 mm, respectively, from the near edge of the Kirschner wire as a reference to the coaxial portals. The sural nerve and lesser saphenous vein were at greater distances of 27.6 mm and 28.3 mm, respectively. The mean West Point score at the time of the latest follow-up was 91.5 points (range, 76 to 100 points), and there were 9 excellent results, 3 good results, and 1 fair result. No patients showed any complications related to the modified coaxial portals.

CONCLUSIONS: The modified coaxial portals seemed to have large distances to the neurovascular structures in our anatomic study. Clinically, this technique was safe, effective, and reproducible.

LEVEL OF EVIDENCE: Level IV, therapeutic case series.