The distance between the sural nerve and ideal portal placements in lateral subtalar arthroscopy: a cadaveric study

There have been limited studies assessing the relative safety of lateral portals for subtalar arthroscopy in terms of their distance from the sural nerve and its branches. The aim of this cadaveric study was to assess and compare the distance of lateral subtalar arthroscopy portal sites to the sural nerve and its branches.

Twenty embalmed cadaveric lower limbs were dissected exposing the nerves and tendons and subtalar arthroscopy portals were replicated using pins. The anatomically important distances were measured with a digital caliper. Statistical analysis of the data was performed using SPSS for Windows 11.5 (SPSS Inc, Chicago, IL) using Friedman Tests and Wilcoxon Signed Ranks tests.

The median distance of the anterior and middle subtalar portals to the nearest nerve was 21.3 mm and 20.9 mm, respectively, and 11.4 mm for the posterior portal. There was no statistically significant difference between anterior and middle portals (p=0.87) but there was statistically significant difference between anterior versus posterior and middle versus posterior portals (p=0.001 in each comparison).

The anterior and middle subtalar portals were both less likely to damage important structures than the posterior subtalar portal.

The results of this study can be of value to the surgeon when planning arthroscopic procedures to the subtalar joint from the lateral approach.