Positioning

The procedure is carried out as outpatient surgery under general anaesthesia or spinal anaesthesia. The patient is placed in a prone position. The involved leg is marked with an arrow to avoid wrong side surgery. A tourniquet is inflated around the thigh for haemostasis. A small support is placed under the lower leg, making it possible to move the ankle freely.

Instruments

For irrigation normal saline is used, however ringers solution is also possible. Gravity inflow is adequate for irrigation. When needed a pressure bag is inflated up to 100 mmHg.
A 4.0 mm arthroscope with an inclination angle of 30 degrees is routinely used, permitting excellent visualization within the ankle and foot.
Furthermore, a blade, spinal needle, probes, graspers, basket forceps, a 5.0 mm bonecutter shaver, a large diameter blunt trocar, a small chisel (4/6 mm), a ring curette, two 6.5 mm lag screws, and fluoroscopy are used. 

Portals

For arthroscopic subtalar arthrodesis, we use the portals for the standard approach for posterior ankle arthroscopy plus a third portal in the sinus tarsi.

The anatomical landmarks on the ankle are the lateral malleolus, medial and lateral border of the Achilles tendon and the foot sole. A probe can be very useful to determine the exact location of the posterolateral portal. The probe is placed parallel to the foot sole with the foot in a 90 degree position and is "hooked" under the tip of the lateral malleolus. A straight line is drawn from the tip of the lateral malleolus to the Achilles tendon, parallel to the foot sole.
The posterolateral portal is made just above the line from the tip of the lateral malleolus and 1 cm anterior to the Achilles tendon. The posteromedial portal is made at the same level, just above the line of the tip of the lateral malleolus, but just anterior to the medial aspect of the Achilles tendon.

Via an accessory third working portal at the level of the sinus tarsi, a large diameter blunt trocar is introduced in order to provide subtalar joint opening. The sinus tarsi portal is also used for introduction of ring curettes in order to remove cartilage of the anterior part of the posterior talocalcaneal joint.