Under general or regional anesthesia, the patient is placed in the supine position. We use a thigh tourniquet to maintain bloodless field. No traction is required.

Arthroscopic triple arthrodesis comprises arthroscopic subtalar arthrodesis and arthroscopic transverse tarsal arthrodesis.

The subtalar joint comprises anterior, middle, and posterior articulations. The middle and posterior facets are separated by the sinus tarsi and tarsal tunnel. The posterior subtalar joint has a separate joint capsule and does not communicate with other joints. The talocalcaneonavicular articulation includes the posterior articular facet of the navicular bone, the plantar calcaneonavicular (spring) ligament, as well as the anterior and middle calcaneal facets articulating with the talus.

The subtalar portals include the anterolateral, middle, posterolateral, posteromedial, medial tarsal canal, medial midtarsal and dorsomedial portals (Figs. 12-1 and 12-2). The anterolateral portal is located at the angle of Gissane. The middle portal is just anterior and plantar to the lateral malleolar tip. The posteromedial and posterolateral portals are at the medial and lateral side of the Achilles tendon respectively. They are close to the tendon insertion and just above the superoposterior calcaneal tubercle. The medial tarsal canal portal is at the medial opening of the tarsal canal and just posterior to the sustentaculum tali. The medial midtarsal portal is just proximal and dorsal to the navicular insertion of the posterior tibial tendon.³ The dorsolateral midtarsal portal is located at the junction between the calcaneocuboid and talonavicular joints.

Arthroscopic arthrodesis of the posterior subtalar joint can be performed by either the lateral approach (anteromedial and middle portals) or the posterior approach (posteromedial and posterolateral portals). The lateral approach is the preferred approach in case of arthroscopic triple arthrodesis because the patient should be put in supine position for the midtarsal arthrodesis. To avoid painful neuroma formation, we create portals by skin incision, followed by blunt dissection of underlying subcutaneous tissue with a hemostat. A 2.7-mm 30-degree arthroscope is used for this procedure. The arthroscope is inserted in the capsular gutter and the junctions between the articular cartilage and the subchondral bone can be identified. The articular cartilage is denuded from the subchondral bone with a small periosteal elevator or an arthroscopic osteotome. The deep part of the cartilage can be removed with an arthroscopic curette. It is important to preserve the subchondral bone as much as possible. Subchondral bone is then microfractured with an arthroscopic awl.

The fusion area can be extended into the anterior subtalar joint. The anterior subtalar joint is approached through the anterolateral and dorsolateral portals. The anterolateral portal is the visualization portal and the 2.7-mm arthroscope is introduced through the superficial and intermediate roots of the inferior extensor retinaculum to the anterior subtalar joint. The dorsolateral portal is the working portal and the lateral capsuloligamentous structures of the anterior subtalar joint are removed by an arthroscopic shaver. The anterior subtalar joint is then exposed and the articular cartilage can be denuded. The subchondral bone is microfractured to prepare the surfaces for triple arthrodesis.^{1, 4}

Four transverse tarsal portals are used for the arthroscopic arthrodesis of the talonavicular and calcaneocuboid joints. The dorsolateral and the medial portals
have been described above. The dorsomedial portal is at the midpoint between the medial and dorsolateral portals. The lateral portal is at plantar lateral corner of calcaneocuboid joint (Fig. 12-3). The calcaneocuboid joint is approached through the lateral and dorsolateral portals. The talonavicular joint is approached through the dorsolateral, dorsomedial, and medial portals. Most of the time, the portals can be located by the surface anatomic landmarks. In the presence of dorsal osteophytes of the talonavicular joint or the presence of severe deformity the dorsomedial portal may be difficult to localize. Fluoroscopy can be used if localization is difficult. The dorsal capsule of the talonavicular joint can be stripped with a small periosteal elevator and fibrous tissue of the dorsal capsular gutter can be debrided with an arthroscopic shaver to identify the joint line. If after this the joint line is still ill defined, overhanging dorsal osteophytes can be removed by an arthroscopic burr. The portals are interchangeable as the visualization and instrumentation portals. The arthroscope is introduced into the capsular gutter to identify the joint line and the junction between the articular cartilage and subchondral bone. The cartilage is then denuded from the subchondral bone (Fig. 12-4).

Because of the three-dimensional anatomy of the transverse tarsal joint, the talonavicular joint is anatomically dorsal to the calcaneocuboid joint. The dorsolateral portal allows one to reach the plantar lateral aspect of talonavicular and then completes debridement of cartilage of the deep part of the talonavicular joint without the need for excessive bone resection. The dorsolateral portal is the single most important portal of this procedure because the medial aspect of the calcaneocuboid joint, the lateral and plantar aspects of the talonavicular joint, and the potential space between the talonavicular and calcaneocuboid joints can be approached through this portal.^{4, 5, 6} It is important to recognize that the anterior subtalar joint and the talonavicular joint share the same capsule and form the talocalcaneonavicular joint anatomically. The lateral part of the joint including the spring ligament can be approached through the anterolateral subtalar and dorsolateral transverse tarsal portals.