A posterior 3-portal arthroscopic approach for isolated subtalar arthrodesis.

Arthroscopic subtalar arthrodesis was developed to improve on open methods of fusion. A posterior 3-portal arthroscopic approach with the patient in the prone position provides a new and optimal method for isolated subtalar arthrodesis. It facilitates safe access to the posterior talocalcaneal facet. The posterolateral portal was established using blunt dissection. The 3-mm, 30 degrees arthroscope was inserted, the posterolateral portal was made, and synovectomy carried out. A large 4-mm arthroscope was used to improve fluid flow. The third portal was then established approximately 1 cm proximal and 1 cm posterior to the tip of the lateral malleolus. This portal was used for distraction by inserting a large blunt trocar into the joint. Most of the procedure was performed with the arthroscope in the posterolateral portal and the instruments posteromedial. Allograft was inserted through the posterolateral portal. Fixation was achieved using 2 cannulated 6.5- or 7.3-mm cancellous screws, inserted under fluoroscopic control. Postoperatively, patients were assigned to non-weight bearing cast immobilization with crutch ambulation for 6 weeks, followed by gradual weight bearing until radiographs showed union. Preliminary results have shown high patient satisfaction, an excellent fusion rate, and less postoperative morbidity than with open subtalar arthrodesis.