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

Abstract

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. 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. 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. 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.