Technique and early experience with posterior arthroscopic subtalar arthrodesis

Background: Subtalar arthrodesis is a reliable procedure for pain relief and improved function in patients with isolated subtalar arthritis. Arthroscopic subtalar arthrodesis (ASTA) was designed to improve upon traditional methods by using a minimally invasive technique. However, posterior arthroscopic subtalar arthrodesis (PASTA) has not been described. The purpose of the present study was to investigate the early results of PASTA. Methods: A retrospective review of 11 feet in 10 patients (one bilateral) that had PASTA was conducted. Inclusion criteria were isolated subtalar arthritis with no or minimal deformity and no significant bone loss. Exclusion criteria included patients requiring adjunctive open procedures or who had significant deformity. The technique involved prone positioning, two posterolateral portals and one posteromedial portal, posterior talocalcaneal facet debridement, percutaneous cancellous allografting and internal screw fixation. Outcome measures included patient satisfaction, the modified American Orthopaedic Foot and Ankle Society (AOFAS) score, union rate, time to union, and postoperative complications. Results: All patients were discharged the day of surgery or stayed one night in the hospital. Eight patients were very satisfied, one satisfied, and one patient not satisfied with the results of their surgery. The average modified AOFAS score (maximum 94 points) improved from 36 points preoperatively to 86 points postoperatively. Ten joints fused by 10 weeks postoperatively, and one patient developed a nonunion. No other postoperative complications occurred. Conclusions: For surgeons familiar with posterior ankle or subtalar arthroscopy, PASTA offers superior exposure of the posterior talocalcaneal facet, high patient satisfaction, an excellent fusion rate, and less postoperative morbidity for patients with subtalar arthritis.