Pearls & Pitfalls
The addition of an accessory portal at the level of the sinus tarsi provides safe access for introduction of a large diameter blunt trocar in order to open up the subtalar joint.
The direction of the blunt trocar in the sinus tarsi is almost parallel to the subtalar joint space. Therefore, it can be forced in a sidewards direction into the joint from laterally. The sideward movement prevents the trocar of making a false route into the subchondral bone.
Removal of all articular cartilage of the posterior subtalar joint using ring curettes can be performed by changing portals whenever needed.
Before insertion of the two screws it is important to check the alignment of the hindfoot.
Co-aptation of the posterior subtalar joint surfaces can be checked arthroscopically when tightening the screws.