Short Term Outcomes Utilizing Custom Total Talus Replacement with Subtalar Arthrodesis for Revision and Complex Total Ankle Arthroplasty

Category: Ankle; Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) in the setting of talar avascular necrosis (AVN) is a challenging problem and is often a contraindication for revision or primary TAA. However, 3D custom talar replacements offer a potential solution to this problem and has been shown to re-establish the normal alignment of the foot, preserve motion (with some achieving almost physiologic motion), and allow for almost normal ambulation. We performed this study to assess the short-term outcomes of 3D printed total talus replacements (TTRs) for revision TAA in the setting of talus AVN or collapse of the talar implant, or primary TAA in the setting of pre-existing talar AVN. Our hypothesis is that custom 3D printed talar body replacements lead to good outcome scores and patient satisfaction scores. Methods: We performed a retrospective chart review on 8 patients (9 TTRs) who underwent a TTR at our institution between May 2019 and October 2023. Initial data query yielded 14 patients (15 TTRs), TTR for acute trauma were excluded (n=6). All TTRs (9/9; 100%) had an associated subtalar ingrowth stem and were performed in conjunction with a primary TAA (5/9) or implanted in the setting of a previous TAA (4/9). One TTR had a talonavicular ingrowth surface. Patients included in this study had at least 12-week follow-up. Patient reported outcome measures (PROMs) included AAOS Foot and Ankle Questionnaire and visual analog scale (VAS) pain scores. Range of motion and 10-meter walking speed were evaluated. Results: Mean length of follow-up was 1.4 years. All patients achieved subtalar arthrodesis. Mean VAS score was 3 (range: 2-4) post-operatively. Average Foot and Ankle Core Standardized Mean was 70.5 (range: 52.2 - 93.6). Mean Shoe Comfort Standardized Mean was 64.5 (range: 40 – 88). Mean time to walk 10 meters post-operatively was 8.75 seconds (range: 6.2 – 10.4). Mean ankle dorsiflexion was 4.4° and plantarflexion was 23°. Three (3/9; 33%) TTRs had unplanned return to the operating room. The TTR with the talonavicular ingrowth stem went onto symptomatic nonunion of the TN joint requiring revision talonavicular fusion. Two TTRs had surgical wound dehiscence, one of which necessitated a radial forearm free fasciocutaneous flap but none had positive synovial fluid cultures, both were smokers. Conclusion: TTR for primary or revision TAA offers good outcomes and should be considered for patients presenting with a failed TAA or talar AVN with associated tibiotalar arthritis. Patient selection is important, as is education. This study adds to the current limited data on the use of 3D custom talar implants for revision and complex TAA and is the only one to the authors knowledge presenting data concerning concurrent subtalar arthrodesis utilizing on growth surfaces.