Risks relating to posterior 2-portal arthroscopic subtalar arthrodesis and articular surfaces abrasion quality achievable with these approaches: a cadaver study.

INTRODUCTION: Many techniques for arthroscopic subtalar arthrodesis have been described since 1985. The procedure can be challenging because posterior and anterior portals are used conjointly with distraction. A posterior 2-portal approach was described in 2000.

HYPOTHESIS: The goal of this study was to evaluate the quality of the freshening that can be achieved in the posterior subtalar joint using this approach. Does a posterior 2-portal approach allow for a complete freshening of the posterior subtalar joint?

MATERIAL AND METHODS: Freshening was performed through an arthroscopic posterior 2-portal approach on 10 cadavers. The quality of bone freshening and proximity of the neurovascular structures to the posterior portals were subsequently evaluated by dissection.

RESULTS: There was one partial laceration of the sural nerve. The posteromedial portal was 6.8mm (95% CI: 4.4 to 9.2) away from the posterior tibial vascular pedicle. The entire talar and calcaneal articular surfaces of the posterior subtalar joint were freshened. In eight of 10 cases (95% CI: 48 to 95%), the posteromedial process of the talus prevented contact between fragments.

DISCUSSION: This study showed that the entire posterior subtalar joint can be freshened through an arthroscopic posterior 2-portal approach with little morbidity.

LEVEL OF EVIDENCE: Level IV.