Risk of sural nerve injury during lateral distal Achilles tendinoscopy: a cadaver study.

BACKGROUND

The risk of damage to cutaneous sensory nerves located near portals has been evaluated for both conventional arthroscopy and extra-articular posterior ankle endoscopy. The objective of the anatomic study reported here was to assess the risk of injury to the sural nerve or lateral calcaneal nerve while using the distal lateral portal for the Achilles tendinoscopy procedure described by Vega et al. in 2008.

MATERIALS AND

METHODS

We dissected the sural nerve and its branch, the lateral calcaneal nerve, of 13 human cadaver ankles in the prone position. We defined P as the point where the Achilles peritendon was opened during the distal lateral approach used for the study technique. P was adjacent to the lateral edge of the Achilles tendon, 2 cm proximal to the postero-superior edge of the calcaneal tuberosity. T was defined as the attachment site of the most lateral fibres of the Achilles tendon to the postero-superior edge of the calcaneal tuberosity. We evaluated the origin of the lateral calcaneal nerve relative to T and we measured the shortest distances separating P from the sural nerve and lateral calcaneal nerve.

RESULTS

A lateral calcaneal nerve was identified in 10 (77%) ankles and originated a mean of 39.1mm (range, 25.0-65.0mm) proximal to T. P was at a mean distance from the sural nerve of 12.3mm (range, 5.0-18.0mm) and from the lateral calcaneal nerve of 6.8mm (range, 4.0-9.0mm). The median difference between these two distances was statistically significant (P=0.002).

DISCUSSION: While using the distal lateral portal for Achilles tendinoscopy, the lateral calcaneal nerve is at greater risk for injury than is the sural nerve.

LEVEL OF EVIDENCE: Level IV. Anatomic Study.