Total Talus Replacement with Subtalar Arthrodesis for End-Stage Talar Osteonecrosis and Adjacent Joint Arthritis

Abstract

Category: Ankle; Hindfoot; Trauma; Other Introduction/Purpose: Late stage talar avascular necrosis (AVN) results in devascularization of the talus with osteonecrosis, subchondral collapse, talus fracturing, loss of talar height and declination, and adjacent joint arthritis. This results in significant disability for patients with limited treatment options. Tibiotalocalcaneal arthrodesis with structural allograft has been the historic treatment option for this challenging clinical scenario, however, the outcomes are fair with reported nonunion rate up to 40%. Total talus replacement (TTR) is an emerging treatment option for patients with talar AVN. TTR with subtalar arthrodesis may be utilized for end-stage talar AVN with adjacent joint arthritis. The purpose of this study is to evaluate the short-term outcomes for TTR with subtalar arthrodesis including pain, ankle range of motion, union rates, and complications. Methods: Consecutive patients who underwent TTR with a subtalar arthrodesis from 2016-2020 were retrospectively reviewed. All surgeries were performed by one of two fellowship-trained foot and ankle orthopaedic surgeons at a single academic institution. All talus implants were custom 3D printed total tali (Additive Orthopaedics, Little Silver, NJ), composed of a cobalt chrome alloy. The implants were sized based on computed tomography scans of the contralateral talus. The plantar surface of the tali were prepared with an ingrowth surface and drill holes to accept screws and facilitate subtalar arthrodesis. Patient demographics, comorbidities, and surgical data were collected. Outcomes included the Visual Analog Scale (VAS) scores, range of motion, union rates, and complications. Data analysis was performed with paired t-tests and a significance level of p<0.05. Results: A total of 19 patients were included with an average of 11.4 months follow-up. There were 11 (57.9%) men, and the average age was 52.3 (range, 18-75) years-old. About half (n=9, 47.4%) of the cohort had a previous talus fracture, and 17 (89.5%) patients had previous ipsilateral ankle surgery. There were 5 (26.3%) patients who underwent concomitant talonavicular arthrodesis at the time of TTR and subtalar arthrodesis. Significant postoperative improvements were observed in VAS scores (2.4 vs. 8.6; p<0.0001), ankle dorsiflexion (10.7° vs. 1.8°; p=0.0131), and ankle plantarflexion (32.9° vs. 21.3°; p<0.0068). All patients achieved a successful union of their subtalar arthrodesis (n=19/19, 100%) and talonavicular arthrodesis (n=5/5, 100%). There were 2 (10.5%) complications including 1 (5.3%) delayed wound healing successfully treated nonoperatively and 1 (5.3%) reoperation in a patient with persistent varus ankle deformity requiring distal tibia and fibula osteotomies. There were no postoperative infections, explants, or amputations required. Conclusion: TTR with subtalar arthrodesis should be considered as a treatment option for patients with end-stage talar AVN and adjacent joint arthritis. Patients experienced significant improvement in pain and ankle range of motion. The complication rate was 10.5% with only 1 patient requiring a reoperation. A union rate of 100% was observed with no postoperative infections, explants, or amputations. This technique perves ankle motion while eliminating hindfoot pain in patients with loss of talar bony integrity and adjacent joint arthritis. Further studies are required including longer-term follow-up and prospective cohorts to ensure continued safety and efficacy.