Arthroscopic Subtalar Arthrodesis Using a Posterior 2-Portal Approach in the Prone Position

Purpose: The purpose of this study was to evaluate the results of posterior arthroscopic subtalar arthrodesis (ASTA) by use of a posterior 2-portal approach in the prone position and to describe the surgical technique. Methods: Between September 2004 and December 2006, posterior ASTA was performed in 16 patients (all men) with post-traumatic subtalar arthritis after an intra-articular fracture of the calcaneus. The mean age was 44 years (range, 20 to 64 years). The mean follow-up period was 30 months (range, 20 to 46 months). According to the Sanders classification of calcaneal fractures, 2 patients had type IIA fractures, 3 had type IIIB fractures, 6 had type IIIAC fractures, and 5 had type IIIBC fractures. The technique involved using posteromedial and posterolateral portals in the prone position, posterior talocalcaneal facet debridement, and percutaneous posterior fixation with 2 cannulated screws. Clinical results were evaluated by use of the ankle-hindfoot scale of the American Orthopaedic Foot & Ankle Society (AOFAS), the Angus and Cowell scoring system, and postoperative complications. To assess union rate and time to union, radiographic evaluations were also performed. Results: The mean modified AOFAS score (maximum, 94 points) improved from 35 points (range, 24 to 45 points) preoperatively to 84 points (range, 71 to 94 points) at final follow-up. According to the Angus and Cowell criteria, 13 patients had a good rating, 2 had a fair rating, and 1 had a poor rating because of nonunion. The union rate was 94% at a mean of 11 weeks, and nonunion occurred in 1 case. No other postoperative complications occurred. Conclusions: ASTA in the prone position through a posterior 2-portal approach provided safe access and superior visualization of the posterior talocalcaneal facet and easy fixation of posterior screws. This technique also provided good clinical outcomes (good results in 81% of patients according to the Angus and Cowell scoring system and a mean modified AOFAS score of 84 points) and a 94% union rate at a mean of 11 weeks. Level of Evidence: Level IV, therapeutic study.