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

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: The anterior and middle subtalar portals were both less likely to damage important structures than the posterior subtalar portal. CLINICAL RELEVANCE: The results of this study can be of value to the surgeon when planning arthroscopic procedures to the subtalar joint from the lateral approach.

Posterior ankle arthroscopy portal safety regarding proximity to the tibial and sural nerves.

The aim of this cadaveric study was to assess the relative safety of posterior ankle arthroscopy portal sites regarding their distance from the tibial and sural nerves. We dissected 20 embalmed cadaveric lower limbs, carefully exposed the nerves, preserving their original position, and established the entry points of five posterior ankle portals using pins. We measured distances with a digital calliper and used Friedman test and Wilcoxon Signed Ranks tests for statistical analyses. There was unequal safety between the five portals (p = 0.00001). There was no statistically significant difference between the two posterolateral or two posteromedial portals. The trans-Achilles tendon portal as expected was significantly further away from either nerve (p = 0.00001). In conclusion, the trans-Achilles portal is the safest portal in terms of its distance from the nerves but has the disadvantage of surgical injury to the Achilles tendon. The two medial and two lateral posterior portals are equivalent in terms of safety.