Short-Term Efficacy and Safety of Combined Total Talus and Total Ankle Replacement

CATEGORY: Ankle; Ankle Arthritis INTRODUCTION/PURPOSE: The indications for both total talus replacement (TTR) and total ankle replacement (TAR) are expanding. Combined total ankle-total talus (combined TAR) is a novel treatment option for patients with end-stage ankle arthritis and talar avascular necrosis (AVN) and patients with a prior TAR and talar component collapse. End-stage talar AVN with subchondral collapse is a challenging entity to treat. Historically, an alternative treatment option was tibiotalocalcaneal arthrodesis with structural allograft which results in fair outcomes including nonunion rates up to 40%. Combined TAR is a treatment option that theoretically maintains joint range of motion and restores anatomic alignment. The purpose of this study is to evaluate the short-term outcomes for combined TAR including pain, functional outcomes, radiographic outcomes, and complications. METHODS: Consecutive patients who underwent combined TAR from 2016-2020 were retrospectively reviewed. All surgeries were performed by one of four 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 an alloy primarily made of cobalt chrome. The implants were sized based on computed tomography scans of the contralateral talus and created to articulate with multiple TAR systems. Patient demographics, comorbidities, and surgical data were collected. Outcomes included the Visual Analog Scale (VAS) scores, radiographic alignment, range of motion, and complications. Data analysis was performed with paired t- tests and a significance level of p<0.05. RESULTS: A total of 66 patients (67 ankles) were included with an average 12-month follow-up. There were 35 (52.2%) men, and the average age was 56.4 years old. The majority of patients (n=42, 62.7%) underwent combined TAR for talar AVN and tibiotalar arthritis while 21 (31.3%) patients were converted from an isolated TAR and 4 patients (6.0%) from an isolated TTR to combined TAR. A total of 23 (34.3%) patients had a previous talus fracture. Significant postoperative improvements compared to preoperative included: VAS (2.8 vs. 8.2; p<0.0001), ankle dorsiflexion (11.0° vs. 4.7°; p=0.0007), ankle plantarflexion (31.9° vs. 23.7°; p<0.0001), talar declination angle (20.7° vs. 11.6°; p=0.0007), Meary’s angle (2.2° vs. 10.4°; p=0.0043), and talocalcaneal height (79.6mm vs. 74.2mm; p <0.0001). There was a total of 10 (14.9%) complications, 7 (10.4%) of which required repeat surgery. There were 3 (4.5%) failures requiring explant, revision, or amputation (Table 1). CONCLUSION: Combined TAR is an efficacious and safe procedure. Patients experienced improvement in pain, ankle range of motion, and radiographic parameters postoperatively. This technique provides an anatomic treatment with preservation of ankle motion for patients with severely deficient bone stock due to talar AVN with ankle arthritis or failed TAR. To confirm these preliminary positive results, further studies are required including continued longer-term follow-up, prospective cohorts, and comparative analyses to other treatment options.