Posterior Arthroscopic Subtalar Arthrodesis.

Introduction: Although subtalar joint arthrodesis may be achieved through open or arthroscopic approaches, we have found that posterior arthroscopic subtalar arthrodesis has technical advantages compared with other approaches.

Step 1 Preoperative Assessment And Planning: Clinically assess the foot and ankle with regard to remaining motion, previous scarring, and associated deformities, ensuring that no concomitant procedure will be needed in the supine position.

Step 2 Positioning Of The Patient: Use spinal or general anesthesia.

Step 3 Placement Of The Posterolateral Portal Lateral To The Achilles Tendon: Place the posterolateral portal lateral to the Achilles tendon at the level of the tip of the lateral malleolus, according to the original technique described by van Dijk et al.

Step 4 Placement Of The Posteromedial Portal Medial To The Achilles Tendon: Place the posteromedial portal medial to the Achilles tendon at the level of the tip of the lateral malleolus.

Step 5 Exposure Of The Subtalar Joint By Removing The Fatty Tissue And Part Of The Posterior Joint Capsule: With the help of the shaver, look for the landmarks of the posterior arthroscopy, going from the posterolateral part of the subtalar joint toward the flexor hallucis longus tendon, which is medially located, while exposing the tibiotalar joint.

Step 6 Debridement And Microfracturing Of The Posterior Facet Of The Subtalar Joint: Sometimes an accessory portal, just anterior to the tip of the external malleolus, may be needed to achieve a distraction of the anterior part of the subtalar posterior facet.

Step 7 Use Of Bone Graft: To perform this concomitant step, which generally is not necessary, use an arthroscopic forceps to insert a 5 by 20-mm autograft or allograft in the subtalar joint.

Step 8 Fixation Of The Subtalar Joint Using Two Cannulated Screws And Fluoroscopy: Use two cannulated screws with a 7.3-mm diameter; we prefer stabilization screws to compression screws.

Step 9 Additional Surgical Procedures: Always clean out the posterior compartment of the ankle during the PASTA procedure, as is done during surgical treatment for posterior impingement syndrome, and note that both posterior impingement syndrome and subtalar degenerative changes may thereby be easily addressed through this procedure.

Step 10 Postoperative Care: A short posterior leg splint is worn for three to ten days, followed by another non-weight-bearing cast for another three weeks.

Results: Since the appearance of the original article, a total of forty-one unilateral subtalar joints in twenty-five men and sixteen women, seen between May 2007 and December 2012, with isolated subtalar arthritis or talocalcaneal coalition without any other major hindfoot arthritis were treated by posterior arthroscopic subtalar arthrodesis, and all subtalar joints except for two were considered radiographically fused at the first attempt after an average of 6.7 weeks (range, six to ten weeks).IndicationsContraindicationsPitfalls & Challenges.