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Alignment in total ankle replacement is important for success and implant survival. Recently there has been the introduction and adoption of patient specific instrumentation for implantation in total ankle replacement. Current literature does not evaluate the effect of preoperative deformity on accuracy of patient specific instrumentation. A retrospective radiographic analysis was performed on 97 consecutive patients receiving total ankle replacement with patient specific instrumentation to assess the accuracy and reproducibility of the instrumentation. Subgroup analysis evaluated the effect of preoperative deformity. All surgeries were performed by fellowship trained foot and ankle surgeons without industry ties to the implants used. Preoperative and postoperative films were compared to plans based on computerized tomography scans to assess how closely the plan would be implemented in patients. Overall postoperative coronal plane alignment was within 2° of predicted in 87.6% (85 patients). Similarly, overall postoperative sagittal plane alignment was within 2° of predicted in 88.7% (86 patients). Tibial implant size was accurately predicted in 81.4% (79 patients), and talus implant size was correct in 75.3% (73 patients). Patients with preoperative varus deformity had a higher difference between predicted and actual postoperative alignment compared to valgus deformity (1.1° compared to 0.3°, p = .02). A higher average procedure time was found in varus patients, and more adjunctive procedures were needed in patients with varus or valgus deformity, but these were not significant, p > .5. Surgeons can expect a high degree of accuracy when using patient specific instrumentation overall, but less accurate in varus deformity., (Copyright © 2024 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Total ankle replacement (TAR) is an effective operative treatment of end-stage ankle osteoarthritis (OA) in the appropriate patient, conferring improved kinematic function, decreased stress across adjacent joints, and offering equivalent pain relief in comparison to ankle arthrodesis (AA). It is important to consider patient age, weight, coronal tibiotalar deformity, joint line height, and adjacent joint OA to maximize clinical and patient outcomes. Both mobile-bearing and fixed-bearing implants have demonstrated favorable clinical outcomes, marked improvement in patient-reported outcomes, and good survivorship; however, implant survivorship decreases with longer term follow-up, necessitating constant improvement of primary and revision TAR options., Competing Interests: Disclosure E. Teehan: nothing to disclose; C. Demetracopoulos: American Orthopaedic Foot & Ankle Society (AOFAS) board or committee member; Artelon: Paid consultant; Enovis: Paid consultant; Exactech, Inc: Paid presenter or speaker, IP royalties; HS2, LLC: Stock or stock options; In2Bones: Paid consultant, IP royalties; Responsive Arthroscopy: Paid consultant; RTI Surgical: Paid consultant; Simulate Technologies: Paid consultant, paid presenter or speaker; Treace Medical: Paid consultant, paid presenter or speaker; Wolters Kluwer Health–Lippincott Williams & Wilkins: Publishing royalties, financial or material support., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: In the past decade, the transfibular approach to Total Ankle Replacement (TAR) has emerged as an alternative to anterior approach with reduced bone resection. The purpose of this systematic review is to report survival, complications, and reoperation rates of transfibular TAR., Methods: We conducted a systematic search of studies that evaluated complications, reoperations, and survival of transfibular TAR following PRISMA guidelines across PubMed, Scopus and Web of Science., Results: Our review included data from 12 cohorts, comprising 919 patients across 7 countries, with an average age of 62 years (59% posttraumatic). Over an average follow-up period of 3 years, adverse events occurred in 23% of cases, with 18% requiring surgical reintervention, mostly due to hardware removal. The survival rate of the transfibular TAR metal components was 97% at the final follow-up., Conclusion: Transfibular TAR demonstrates a 97% survival rate at a 3-year follow-up., Level of Evidence: Level II., Competing Interests: Declaration of Competing Interest Dr. Lew Schon: Zimmer (IP royalties, paid consultant, paid presenter or speaker and research support). These interests have not affected methodological procedures used to perform this systematic review., (Copyright © 2024 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this study is to reveal the morphometry of the distal tibia and posterior malleolus and to generate morphometric reference data for the tibial component of total ankle prosthesis., Methods: This study was performed on 121 human dry tibiae (47 right, 74 left). The morphometric measurements of distal tibial structures, tibial length and the distance between the medial and posterior malleolus were measured in this study. Measurements on 44 tibiae were repeated three times and averaged for minimizing intra-observer error., Results: The tibial length was found 34.19 ± 2.31 cm. Mean values of width of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 25.71 ± 2.44 mm and 17.81 ± 2.46 mm, respectively. Mean depth of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 3.60 ± 1.04 mm and 3.37 ± 1.24 mm, respectively. Mean height of fibular notch was found 48.21 ± 10.51 mm. Mean width and height of medial malleolus were 25.08 ± 2.13 mm and 14.73 ± 1.85 mm, respectively. Mean width and length of tibial plafond were 27.71 ± 2.74 mm and 26.96 ± 2.62 mm, respectively. Mean values of width and height of posterior malleolus were measured 21.41 ± 3.26 mm and 6.74 ± 1.56 mm, respectively. Mean distance between medial and posterior malleolus was found 37.17 ± 3.53 mm. Mean width and depth of malleolar groove were 10.26 ± 1.84 mm and 1.73 ± 0.75 mm, respectively. The mean intra-class correlation values were found between the 0.959 and 0.999., Conclusions: Knowing the distal tibial morphometry is crucial for designing convenient ankle replacement implants for Turkish population. To our knowledge, this study is the first in the literature that identifies posterior malleolar morphometry on dry tibiae. We believe that this study will make a significant contribution to the literature about distal tibial morphometry and especially the posterior malleolus and the data of our study can be used for designing total ankle prosthesis in Turkish population., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Background: The management of failed total ankle replacements, with significant loss of bone stock, is challenging with high rates of complications and associated morbidity. Recent technological advances have enabled the development of patient-customized 3D-printed titanium truss arthrodesis implants, which offer an alternative salvage option for failed total ankle replacements., Methods: A prospective observational study was performed of 6 cases of failed total ankle replacements that were managed using custom patient-specific 3D-printed titanium truss arthrodesis implants. Technical tips, classification, and a treatment algorithm were developed based on our initial experience., Results: Between November 2018 and March 2022, 6 patients underwent arthrodesis for failed total ankle replacements. Follow-up was available for all cases. The mean follow-up was 3.0 years (range 1-4.5). The mean MOXFQ Index improved from 73.1 to 32.3 ( P  < .05). The mean EQ-5D-5L Index improved from 0.366 to 0.743 ( P  < .05) and the EQ-VAS also improved from 53.0 to 63.3 ( P  = .36). The mean VAS-Pain score at final follow-up was 27.5. There were no cases of nonunion. None of the patients were smokers. The overall complication rate was 50%. Two patients returned to surgery: one for wound washout following TAR explantation and a second for removal of metalwork 2 years following surgery for a prosthetic joint infection secondary to hematogenous spread. No patients underwent revision fixation or amputation., Conclusion: Custom patient-specific 3D-printed titanium truss arthrodesis implants are a viable treatment option for failed total ankle replacements., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: To characterize the 3D geometry of the distal tibia resection area from healthy individuals using CT-based digital implantation for proper preoperative sizing of TAA tibia component placement., Methods: Standardized CT images of healthy ankle joints serving as intra-individual references for treatment of contralateral injuries were identified. The tibial cross section dedicated to virtually host the tibial component was digitally prepared, and the size of the virtual contact surface was calculated. Finally, out of five prototypes the one fitting best in terms of size and alignment was identified., Results: CT scans taken from 319 subjects were used for the virtual implantation procedure. Body height and size of the distal tibia contact area correlated (r = 0.49 and 0.42 in females and males, each p < 0.001). Prosthesis sizes 2 and 3 fit well for the vast majority of patients, while the smallest and largest sizes are rarely required., Conclusions: Digital implantation of the tibial component should be considered a valuable tool for preoperative planning as well as for the development of new implant types., (© 2024. The Author(s).)

The conical stem tibial design of total ankle replacement (TAR) has high implant-bone micromotion. This may lead to aseptic loosening which can be avoided by improving the tibial design. The objective was to propose the best stem design parameters to reduce implant-bone micromotion along with minimizing stress shielding using an integrated Finite Element-Multi Criteria Decision Making (FE-MCDM) approach. FE models of implanted tibia bones were prepared by changing the height of the stem, the diameter of the stem, and the slant of the stem. Weighted Aggregated Sum Product Assessment (WASPAS), Technique for Order of Preference by Similarities to Ideal Solution (TOPSIS), Evaluation based on Distance from Average Solution (EDAS), and VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) MCDM techniques with equal weights for micromotion and stress shielding were considered. The micromotion and stress shielding were greater when the height of the stem was increased. Whereas, the increase in diameter and slant affected them marginally. The best-performing design was the Model with stem height 6 mm (diameter 6.4 mm and slant 4°) and after that was the Model with stem height 8 mm (diameter 6.4 mm and slant 4°), and then the Model with stem height 10 mm (diameter 6.4 mm and slant 4°). The height of the stem is the most important stem design parameter. Shorter height, moderate thickness, and moderate slanting stem designs are recommended., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Revision of failed total ankle replacement (TAR) is challenging and associated with increased morbidity. Given the increased popularity of TAR in treating end-stage ankle arthritis (ESAA), viable revision options are needed. The objective of this case series is to present a minimum 2-year clinical and radiographic outcomes of patient-specific custom 3D-printed total ankle total talus (TATR) prostheses in this unique subset of patients., Methods: 19 participants with ESAA and failed primary TAR who underwent TATR by a single surgeon at our institution from 2019 to 2021 were retrospectively identified. All participants were indicated for revision of primary STAR implant (Stryker, Kalamazoo, MI) and underwent replacement with 3D-printed titanium implants based on preoperative CT analysis (Additive Orthopaedics, Little Silver, NJ). Custom components included a mobile-bearing total talus and stemmed tibial system, performed through an anterior approach. Pre- and postoperative patient-reported outcomes were assessed using the Patient Reported Outcomes Measurement Information System (PROMIS). Pre- and postoperative implant alignment was assessed using medial distal tibial angle (MDTA) and tibiotalar angle (TTA) on anteroposterior, and sagittal tibial angle (STA) on lateral weight-bearing plain films., Results: The average patient age was 60.6 (range, 39-77) years, with an average follow-up of 37.9 (range, 25.3-57.5) months. There was statistically significant improvement in all PROMIS domains. Short-term survivorship was 100%, with two participants (11.0%) requiring reoperation for postoperative complications: one underwent open reduction internal fixation of the tibia for a periprosthetic fracture, and another underwent medial gutter debridement and tarsal tunnel release for recurrent pain. There were no significant differences in pre- versus postoperative radiographic alignment measured by MDTA (89.9 vs 86.4), TTA (89.7 vs 88.1), or STA (85.2 vs 85.3)., Conclusion: Custom 3D-printed TATR is a promising option for revision TAR. There was significant short-term improvement in pain and physical function, with excellent short-term survivorship and an acceptable postoperative complication rate., Competing Interests: Declaration of Competing Interest All authors have no competing interests to declare., (Copyright © 2024 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Background: This is a pilot study reviewing patients undergoing ankle replacement with the 3-D printed INFINITY™ with ADAPTIS™ total ankle arthroplasty (TAA) system., Methods: A retrospective review was conducted of patients with a minimum two-year follow-up who underwent TAA with the INFINITY™ with ADAPTIS™ implant system. Outcome measures include implant survivorship, complications with subsequent reoperations, patient reported outcomes, and radiologic subsidence or radiolucency., Results: Thirty patients were included with median follow-up of 26 months (range, 24-36). Implant survival rate was 90% (27/30). Two patients experienced linear radiolucency > 2 mm: one required a revision TAA secondary to tibial subsidence; the other patient was asymptomatic and nonprogressive on serial radiographs. No cystic radiolucencies > 5 mm were identified. VAS, PROMIS PF, and FADI scores improved significantly., Conclusion: TAA performed with the 3-D printed INFINITY™ with ADAPTIS™ implant technology led to ninety percent short term implant survivorship and improvement in patient reported outcomes with comparable results to other 4th generation arthroplasty systems as a treatment modality for end-stage ankle arthritis., Level of Evidence: Level III, Retrospective cohort study, Prognostic., Competing Interests: Declaration of Competing Interest Dr. Jesse Doty has been a consultant for Arthrex, Inc., Globus Medical Inc., GLW Inc., International Life Sciences, Wright Medical Group, Stryker Corp., Vilex Inc. in roles unrelated to this manuscript. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2024 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

The success of uncemented total ankle replacement (TAR) is linked to initial stability because bony ingrowth depends upon limited early micromotion. Tibial implant design fixation features resist micromotion aided by bony sidewall retention and interference fit. Our goal was to investigate factors influencing implant-bone micromotion in TAR. Two TAR tibial components were virtually inserted into CT-derived computer models of two distal tibias from patients with end-stage ankle arthritis. Density-based inhomogeneous material assignment was used to model bone compaction during press-fit. Finite element analysis (FEA) was used to simulate three fixation cases: (1) no sidewalls + line-to-line fit, (2) sidewalls + line-to-line fit, and (3) sidewalls + 50, 100, or 200 µm interference fit. Kinetic profiles from the stance phase of gait were simulated and micromotions computed from FEA output. Without sidewalls or interference fit, micromotions were largest in early and late stance, with largest micromotions (averaging ~150-250 µm) observed near heel strike. Micromotions decreased 39%-62% when sidewalls were retained. When interference fit was also modeled, micromotions decreased another 37%-61% to ~10 µm. Micromotion differences between patients persisted with sidewall retention but largely disappeared with interference fit. This study presents new insights into the effects of TAR fixation features on implant-bone micromotion. Stability appeared to be influenced by surrounding bone quality, but this influence was greatly diminished when interference fit was introduced. More complete understanding of TAR implant features and performance is needed, but our results show the importance of bone quality and interference fit in the stability of uncemented TAR., (© 2024 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

The long-term performance of porous coated tibial implants for total ankle replacement (TAR) primarily depends on the extent of bone ingrowth at the bone-implant interface. Although attempts were made for primary fixation for immediate post-operative stability, no investigation was conducted on secondary fixation. The aim of this study is to assess bone ingrowth around the porous beaded coated tibial implant for TAR using a mechanoregulatory algorithm. A realistic macroscale finite element (FE) model of the implanted tibia was developed based on computer tomography (CT) data to assess implant-bone micromotions and coupled with microscale FE models of the implant-bone interface to predict bone ingrowth around tibial implant for TAR. The macroscale FE model was subjected to three near physiological loading conditions to evaluate the site-specific implant-bone micromotion, which were then incorporated into the corresponding microscale model to mimic the near physiological loading conditions. Results of the study demonstrated that the implant experienced tangential micromotion ranged from 0 to 71 μm with a mean of 3.871 μm. Tissue differentiation results revealed that bone ingrowth across the implant ranged from 44 to 96 %, with a mean of around 70 %. The average Young's modulus of the inter-bead tissue layer varied from 1444 to 4180 MPa around the different regions of the implant. The analysis postulates that when peak micromotion touches 30 μm around different regions of the implant, it leads to pronounced fibrous tissues on the implant surface. The highest amount of bone ingrowth was observed in the central regions, and poor bone ingrowth was seen in the anterior parts of the implant, which indicate improper osseointegration around this region. This macro-micro mechanical FE framework can be extended to improve the implant design to enhance the bone ingrowth and in future to develop porous lattice-structured implants to predict and enhance osseointegration around the implant., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Main objective of this research is to know if there is a different survival rate between fixed bearing (FB) and mobile bearing (MB) total ankle replacement (TAR). We hypothesized that there are no differences between the survival rates of both implants., Methods: A systematic search was performed in PubMed, Cochrane, EMBASE and ClinicalTrials.gov databases‎ to identify published studies from August 2018 to September 2022 including results for FB and MB TAR survivorship. Inclusion criteria included 1) primary TAR in one or both feet in which implant could be identified‎, 2) a minimum of 20 procedures reported, 3) reported implant survivorship or calculable and 4) a minimum of 12 months follow-up for level 1-3 studies or 60 months for level 4 studies., Results: 3902 ankles in 28 studies were included. 719 were FB and 3104 MB with an overall survivorship of 94% (95% CI [0.89; 0.97]) and 89% (95% CI [0.86; 0.92]) respectively. After subgroup analysis, we did not find differences among both groups (p = ‎0.429‎). Meta-regression analysis showed that longer follow-up was associated with lower survival rates in MB group (p = 0.000) while no other relationships were found with other factors (age, level of evidence or conflict of interests)., Conclusions: No differences in survival rates between both groups were found. Age and other studied confounders were not found to be related with implant survivorship. However, longer follow-up was found to be related with lower survival rates. Studies with longer follow-up and higher level of evidence are needed to confirm results., Level of Evidence: IV, systematic review of level I to IV studies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Ankle arthritis is becoming more common and can be pain-ful and debilitating. As the disease progresses, degenera-tive cystic changes may be found in the distal fibula, distal tibia, and talus. After failure of non-operative modalities, arthrodesis is often considered the surgical intervention of choice, but this leaves the patient with reduced range of motion, altered gait, and can negatively impact adjacent joints of the foot. Total ankle arthroplasty has been found to be an effective surgical option for ankle arthritis but is contraindicated in patients with talar collapse. When this is the case, a more personalized approach for preserving ankle motion is necessary. We present the case of a 65-year-old male with severe right ankle arthritis and talar collapse treated with a custom three-dimensionally printed talus and concurrent total ankle replacement with 2-year follow-up.

Total ankle arthroplasty continues to gain popularity amongst surgeons and patients as an alternative to arthrodesis. Historically the designs of early implants were plagued with complications and frequently abandoned. Since that time the procedure and materials have undergone significant advancements in both surgical approach as well as design and function of the available implants. In this study, 40 consecutive patients who received a semiconstrained prosthesis with a unique fixed-bearing polyethylene insert were identified. Minimum follow-up was 2 y. Demographic, social, and past medical data was retrospectively reviewed. Concomitant procedures were also recorded. Radiographic analysis included lateral ankle radiograph postoperative range of motion (ROM) with maximum dorsiflexion and maximum plantarflexion weight bearing at the most recent clinic visit. Clinical outcomes included VAS, FFI, and AOFAS scores. Lateral radiographs taken in the office at a minimum 2-y follow-up showed mean maximum dorsiflexion of 11.8 degrees and plantarflexion of 13.9 degrees. VAS, FFI, and AOFAS scores improved from 8.1, 92.9, and 44.8 to 1.4, 15.3, and 90.1 postoperatively, respectively. A total of 2.5% (n = 1) required revision surgery for poly failure, and 5.0% (n = 2) underwent local wound care in the office setting postoperatively and healed without complications. Overall survivorship was 97.5% at the minimum follow-up of 2 y. In conclusion, similar studies have reported survivorship from 90% to 100% with modern ankle implants in short to mid-term follow-up. Although this is a small sample size, our data shows a 97.5% survivorship at 2 y postoperatively with favorable patient-reported statistically significant functional outcome scores, and ankle range of motion consistent with existing literature., (Copyright © 2024 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Total ankle replacements (TARs) have rapidly advanced in terms of volume, technique, design, and indications. However, TARs are still at risk for early mechanical failure and revision. Prior studies have investigated potential risk factors for failure, but have been limited to smaller series or older implants. This study sought to identify risk factors for early mechanical failure in modern TAR., Methods: This is a retrospective study of a single-institution registry. Five surgeons contributed cases involving patients who underwent a primary TAR with any implant. Implants were grouped on the basis of the type of fixation. The primary outcome was early mechanical failure (revision with component removal for a non-infectious etiology, that is, subsidence, aseptic loosening, and/or malalignment). Logistic regression determined the effects of age, weight, hindfoot arthrodesis, implant type, and radiographic deformity on failure., Results: The 731 included patients had a mean follow-up of 2.7 years. Ten percent (71 patients) had hindfoot arthrodesis. There were 33 mechanical failures (4.5%) at a mean of 1.7 years after the index surgical procedure. Our model demonstrated that hindfoot arthrodesis was associated with 2.7 times greater odds of failure (p = 0.045), every 10 kg of body weight increased the odds of tibial-sided failure by 1.29 times (p = 0.039), and implants with more extensive tibial fixation (stems or keels) lowered the odds of tibial failure by 95% (p = 0.031)., Conclusions: In patients with uncontrollable risk factors (hindfoot arthrodesis) or risk factors that may or may not be modifiable by the patient (weight), implants with more robust tibial fixation may be able to reduce the risk of early mechanical failure. Further research is warranted to support efforts to decrease early failure in TAR., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: No external funding was received for this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H911 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Prosthetic substitution of the talus presents a significant challenge to the foot and ankle surgeon. The shear and compressive forces on the talus and its tenuous blood supply lead to high rates of avascular necrosis and eventual talar collapse. The purpose of this systematic review is to evaluate whether total ankle total talus replacement (TATTR) leads to improved clinical and radiographic outcomes with appropriate safety metrics in patients with a history of avascular necrosis or significant trauma., Methods: We searched the concepts of talus, prosthesis, and arthroplasty in MEDLINE (PubMed), Embase (Elsevier), CINAHL Complete (EBSCOhost), and Scopus (Elsevier) from the database's inception through March 9, 2023. Inclusion Criteria were 1) previous trauma to the talus, 2) post-traumatic arthritis to the tibiotalar joint, 3) avascular necrosis of talus, 4) multiple failed prior interventions, 5) degenerative osteoarthritis to the tibiotalar joint, and 6) inflammatory arthropathy to tibiotalar joint. Patients less than 18 years of age and manuscripts in non-English languages were excluded., Results: Of the 7625 references, 16 studies met the inclusion criteria, yielding data from 136 patients (139 ankles). The studies varied in design, with case reports and retrospective case series being predominant. The overall weighted average modified Coleman Methodology Score (mCMS) was 70.4 out of 100, indicating moderate flaws in study design that may be subject to various forms of bias and possible confounders. Demographics showed a diverse range of etiologies, with alumina ceramic being the primary prosthesis material. Functional scores demonstrated improvements in dorsiflexion and plantarflexion, although patient-reported outcome measures (PROs) were inconsistently reported. Complications included fractures, heterotopic ossification, prolonged wound healing, and infections. Revision details were sparsely reported., Conclusion: TATTR is a promising treatment modality for improving short-term functional outcomes for patients with avascular necrosis or trauma-related issues. However, this systematic review underscores the need for standardized reporting, longer-term follow-ups, and further research to establish the procedure's efficacy and safety, particularly in comparison to other treatment modalities., Level of Evidence: III, Systematic Review of Level IV Studies., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Background: Currently, the implants utilized in total ankle arthroplasty (TAA) are divided between mobile-bearing 3-component and fixed-bearing 2-component designs. The literature evaluating the influence of this mobility difference on implant survival is sparse. The purpose of the present study was therefore to compare the short-term survival of 2 implants of similar design from the same manufacturer, surgically implanted by the same surgeons, in fixed-bearing or mobile-bearing versions., Methods: All patients were enrolled who underwent TAA with either the mobile-bearing Salto (Tornier and Integra) or the fixed-bearing Salto Talaris (Integra) in 3 centers by 2 surgeons between January 2004 and March 2018. All patients who underwent TAA from January 2004 to April 2013 received the Salto implant, and all patients who underwent TAA after November 2012 received the Salto Talaris implant. The primary outcome was time, within 3 years, to first all-cause reoperation, revision of any metal component, and revision of any component, including the polyethylene insert. Secondary outcomes included the frequency, cause, and type of reoperation., Results: A total of 302 consecutive patients were included, of whom 171 received the mobile-bearing and 131 received the fixed-bearing implant. The adjusted hazard ratio for all-cause reoperation was 1.42 (95% confidence interval [CI], 0.67 to 3.00; p = 0.36); for component revision, 3.31 (95% CI, 0.93 to 11.79; p = 0.06); and for metal component revision, 2.78 (95% CI, 0.58 to 13.33; p = 0.20). A total of 31 reoperations were performed in the mobile-bearing group compared with 14 in the fixed-bearing group (p = 0.07). More extensive reoperation procedures were performed in the mobile-bearing group., Conclusions: With the largest comparison of 2 implants of similar design from the same manufacturer, the present study supports the use of a fixed-bearing design in terms of short-term failure. We found a 3-times higher rate of revision among mobile-bearing implants compared with fixed-bearing implants at 3 years after TAA. Reoperations, including first and subsequent procedures, tended to be less common and the causes and types of reoperations less extensive among fixed-bearing implants., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G666)., (Copyright © 2021 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Background: Patient-specific instrument (PSI) may theoretically make total ankle arthroplasty (TAA) more accurate. Several studies have reported the outcomes of PSI TAA. The aim of this study is to systematically review the literature of PSI TAA., Methods: PubMed, Embase, Web of Science, and Cochrane Library databases were systematically reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines for PSI TAA. The quality of the included studies was evaluated according to Methodological Index for Non-Randomized Studies (MINORS)., Result: Nine articles were ultimately included in the systematic review. The implant position and function outcome of TAA was similar between PSI and SI. Prediction accuracy of implant size remained great difference. PSI can shorten the operative time and fluoroscopy time. The quality of current studies on PSI TAA is insufficient to produce high-level evidence., Conclusion: PSI can get similar implant position and clinical outcome in TAA compared to SI, but current evidence is not strong enough to evaluate PSI TAA., (© 2021. SICOT aisbl.)

Objective: To describe early prosthesis implantations in a cohort of patients with juvenile idiopathic arthritis (JIA) followed in a tertiary referral hospital and to analyze possible factors influencing implant survival., Methods: This was a retrospective cohort study. Charts of all patients with JIA who underwent total joint replacement at Gaetano Pini Hospital, Milan, Italy from January 1992 to June 2019 were retrieved, and relevant data were analyzed., Results: Eighty-five patients met the inclusion criteria for this study, with a median follow-up period of 17.2 years. The median age at first prosthesis was 22.7 years. The total number of replaced joints was 198 over a period of 27 years. The hip was the most frequently replaced joint, accounting for almost two-thirds of the total number of implants; the other one-third refers mostly to knee implants. Polyarticular JIA and systemic JIA were the most represented JIA categories in the study cohort. A significant upward trend of the age at arthroplasty and of disease duration before arthroplasty over decades was found. The rates of implant survival at 5, 10, and 15 years were comparable (from 84% to 89%); 50% of implants lasted ≥20 years., Conclusion: We reported retrospective data on early joint replacement in a cohort of patients with JIA. We observed a progressive and significant upward trend of both age at arthroplasty and disease duration before the first arthroplasty over time. The JIA category, year of implant, and presence of complications significantly affected implant survivorship., (© 2020, American College of Rheumatology.)

The International Standard Organization, ISO 22622, specifies two options for joint wear simulator evaluation of total ankle replacements (TARs): load-controlled and displacement-controlled. In the present study, the load-controlled testing parameters were applied to cadaveric specimens to quantify and compare the observed sagittal translations and axial rotations to those specified under the displacement-controlled option. Twelve cadaveric specimens were stripped of extraneous tissues, keeping surrounding ankle ligaments. A halo was used to produce plantarflexion and dorsiflexion of the talus through two screws, while a baseplate resisted axial loads. The axial force and torque were applied to the tibia and fibula under force and torque feedback control. An anterior-posterior force was applied to the tibia. Plantarflexion-dorsiflexion were applied using rotation control. To protect the cadaveric specimens, loads were applied at 50% of the specified load profile while plantarflexion-dorsiflexion rotation was applied as specified. There was variation among specimens in magnitudes of anterior-posterior displacement with peaks ranging from 3.3 mm posteriorly to 3.0 mm anteriorly. Likewise, there was variation among specimens in magnitude of axial rotation, with peaks ranging from 11° external rotation to 4.5° internal rotation. However, the mean magnitudes of AP displacement and axial rotation did not exceed those specified by ISO 22622., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Background: The Salto Talaris is a fixed-bearing implant first approved in the US in 2006. While early surgical outcomes have been promising, mid- to long-term survivorship data are limited. The aim of this study was to present the survivorship and causes of failure of the Salto Talaris implant, with functional and radiographic outcomes., Methods: Eighty-seven prospectively followed patients who underwent total ankle arthroplasty with the Salto Talaris between 2007 and 2015 at our institution were retrospectively identified. Of these, 82 patients (85 ankles) had a minimum follow-up of 5 (mean, 7.1; range, 5-12) years. The mean age was 63.5 (range, 42-82) years and the mean body mass index was 28.1 (range, 17.9-41.2) kg/m 2 . Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Preoperative, immediate, and minimum 5-year postoperative AP and lateral weightbearing radiographs were reviewed; tibiotalar alignment (TTA) and the medial distal tibial angle (MDTA) were measured to assess coronal talar and tibial alignment, respectively. The sagittal tibial angle (STA) was measured; the talar inclination angle (TIA) was measured to evaluate for radiographic subsidence of the implant, defined as a change in TIA of 5 degrees or more from the immediately to the latest postoperative lateral radiograph. The locations of periprosthetic cysts were documented. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared., Results: Survivorship was 97.6% with 2 revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle; another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 21.2% ( n = 18), with the main reoperation being exostectomy with debridement for ankle impingement ( n = 12). At final follow-up, the average TTA improved 4.4 (± 3.8) degrees, the average MDTA improved 3.4 (± 2.6) degrees, and the average STA improved 5.3 (± 4.5) degrees. Periprosthetic cysts were observed in 18 patients, and there was no radiographic subsidence. All FAOS subscales demonstrated significant improvement at final follow-up., Conclusions: We found the Salto Talaris implant to be durable, consistent with previous studies of shorter follow-up lengths. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at a minimum 5-year follow-up., Level of Evidence: Level IV, retrospective case series.

Purpose: To study the anatomical features of the ankle joint in Chinese northeast healthy adults and provide accurate data for the design of the total ankle arthroplasty (TAA) prosthesis., Methods: Computer tomography (CT) images from 156 healthy subjects, 86 males and 70 females, were collected and reconstructed through Mimics software. The 3D morphology of the distal tibia/fibula section and the whole talar was analyzed by measuring 28 parameters including maximal tibial thickness (MTiTh), anterior-posterior inclination angle, trochlea tali width (TaW), distal tibial width (TiW) and trochlea tali arc chode length (TaAL) and calculating MTiTh/TiW, TaAL/TaW. Gender difference and accuracy of CT images were evaluated. The measurements were compared with previously reported data from Caucasian subjects and Asian subjects. Statistical analysis was conducted by independent-samples t test through SPSS software., Results: (1) Twenty two out of the 28 parameters were found significantly different between males and females. Most of the parameters in males were found larger than that in females (p < 0.05). (2) The difference was found larger in comparison with the Caucasian subject groups than that with Asian subject groups. (3) All the selected 11 parameters measured by CT images were found to be smaller than those by X-ray images (p < 0.05)., Conclusion: The morphological parameters were found different between the Caucasian and Chinese northeast populations. Precise data of the ankle joint morphology were provided for the design and clinical application of TAA in the Chinese population.

Background: Computer navigation and patient-specific instrumentation for total ankle arthroplasty have still to demonstrate their theoretical ability to improve implant positioning and functional outcomes. The purpose of this paper is to present a new and complete total ankle arthroplasty customization process for severe posttraumatic ankle joint arthritis, consisting of patient-specific 3D-printed implant and instrumentation, starting from a ligament-compatible design., Case Presentation: The new customization process was proposed in a 57-year-old male patient and involved image analysis, joint modeling, prosthesis design, patient-specific implant and instrumentation development, relevant prototyping, manufacturing, and implantation. Images obtained from a CT scan were processed for a 3D model of the ankle, and the BOX ankle prosthesis (MatOrtho, UK) geometries were customized to best fit the model. Virtual in silico, i.e., at the computer, implantation was performed to optimize positioning of these components. Corresponding patient-specific cutting guides for bone preparation were designed. The obtained models were printed in ABS by additive manufacturing for a final check. Once the planning procedure was approved, the models were sent to final state-of-the-art additive manufacturing (the metal components using cobalt-chromium-molybdenum powders, and the guides using polyamide). The custom-made prosthesis was then implanted using the cutting guides. The design, manufacturing, and implantation procedures were completed successfully and consistently, and final dimensions and location for the implant corresponded with the preoperative plan. Immediate post-op X-rays showed good implant positioning and alignment. After 4 months, clinical scores and functional abilities were excellent. Gait analysis showed satisfactory joint moment at the ankle complex and muscle activation timing within normality., Conclusions: The complete customization process for total ankle arthroplasty provided accurate and reliable implant positioning, with satisfactory short-term clinical outcomes. However, further studies are needed to confirm the potential benefits of this complete customization process., Level of Evidence: 5.

Background: The presence of an interface between the tibial component and the polyethylene insert (PI) in mobile-bearing total ankle arthroplasty (TAA) may allow the talus to adapt its axial position according to the patient's anatomy. However, little is known about differences of the axial talar rotation between patients following mobile-bearing TAA. Therefore, the aim of this study was to assess the relative axial rotation between the talar and tibial component intraoperatively and after a minimum follow-up of 3 years following mobile-bearing TAA., Methods: The relative axial rotation between the talar and the tibial component was measured intraoperatively in a cohort of 58 patients who underwent mobile-bearing TAA. In addition, it was measured on weightbearing computed tomography (CT) scans in 48 patients after a mean of 6.3 (3.0-16.3) years following mobile-bearing TAA. The pre- and postoperative alignment of the ankle joint/tibial component and hindfoot assessed on conventional radiographs was correlated with the intra- and postoperatively determined relative axial rotation of the talar and tibial component., Results: The mean intra- and postoperative axial talar component position was 1.7 (range, 14 internal to 14 external) and 1.4 (range, 12 internal to 20 external) degrees toward internal when compared to the tibial component ( P = .960). The preoperative sagittal alignment of the distal tibia correlated with the intraoperatively determined relative axial rotation between the talar and the tibial component ( P = .019)., Conclusion: The wide range of the relative axial rotation between the tibial and talar component suggests that it is crucial to allow the talus to intraoperatively find a position that corresponds to the patient's individual anatomy. The fact that the range of axial rotation was similar after a minimum of 3 years measured under weightbearing conditions suggests that structural changes of the osteoarthritic ankle may be the main determining factors for the axial rotational position of the talus. Our findings improve current understanding of proper implant position during TAA. In addition, the current study provides a reliable method to assess the postoperative axial position of the prosthesis components. The high interindividual variability of the relative rotation between the tibial and talar component in the axial plane suggests that axial malpositioning following TAA may be a more common issue than currently expected. Our findings may help to improve the assessment of patients with persistent pain following TAA., Level of Evidence: Level III, comparative series.

Background and purpose - We have previously reported on the prosthetic survival of total ankle replacements (TAR) in Sweden performed between 1993 and 2010. Few other reports have been published on 5- and 10-year survival rates. Furthermore, there is a lack of long-term outcome data on modern prosthetic designs. Therefore, we compared early and current prosthetic designs after a mean 7-year follow-up.Patients and methods - On December 31, 2016, 1,230 primary TARs had been reported to the Swedish Ankle Registry. We analyzed prosthetic survival, using exchange or permanent extraction of components as endpoint for 1,226 protheses with mean follow-up of 7 years (0-24). Differences between current (Hintegra, Mobility, CCI, Rebalance, and TM Ankle) and early prosthetic designs (STAR, BP, and AES) were examined by log rank test.Results - 267/1,226 prostheses (22%) had been revised by December 31, 2016. We found an overall prosthetic survival rate at 5 years of 0.85 (95% CI 0.83-0.87), at 10 years 0.74 (CI 0.70-0.77), at 15 years 0.63 (CI 0.58-0.67), and at 20 years 0.58 (CI 0.52-0.65). For early prosthetic designs the 5- and 10-year survival rates were 0.81 (CI 0.78-0.84) and 0.69 (CI 0.64-0.73) respectively, while the corresponding rates for current designs were 0.88 (CI 0.85-0.91) and 0.84 (CI 0.79-0.88). Current prosthetic designs had better survival (log rank test p < 0.001).Interpretation - Our results point to a positive time trend of prosthetic survival in Sweden; use of current prosthetic designs was associated with better prosthetic survival. Improved designs and instrumentation, more experienced surgeons, and improved patient selection may all have contributed to the better outcome.

Background: Total ankle arthroplasty is an alternative for arthrodesis. The objective of this study was to investigate the safety of trabecular-metal ankle prosthetic system with transfibular approach and external frame and its association with changes in clinical and functional scores., Methods: Between May 2013 and June 2017, a total of 104 consecutive patients underwent primary total ankle arthroplasty with a trabecular metal implant. The prospective clinical and radiographic data were collected. The mean follow-up time was 43.6 (14.6) months., Results: Of 104 patients, 88 (89%) reported improved functioning and 65 (66%) were very satisfied with the surgery. Of the patients, 51 (50%) did not report any pain at the end of follow-up at all. The average Kofoed score was 37.6 (SD 17.4) points at baseline and 74.8 (SD 20.6) points at the end of follow-up. There were 37 additional procedures, and the complication rate was nearly 20%., Conclusion: Trabecular-metal total ankle prosthesis showed promising clinical results concerning pain and function. At 5-year follow-up, osteolysis and component loosening were rare., Level of Evidence: Level IV, case series.

Background: End-stage ankle arthritis can involve malalignment of the ankle in both the coronal and sagittal planes. Up to 33% to 44% of patients who present for total ankle replacement (TAR) have greater than 10° of coronal plane deformity. Normalization of the sagittal and coronal alignment is key in improving survivorship and functional outcomes in TAR. In the present study, we analyzed how both the ankle and hindfoot alignment for both a fixed-bearing and mobile-bearing TAR system changed over time. Specifically, we measured coronal and sagittal alignment of both the ankle and hindfoot complex., Methods: A retrospective study was performed on 2 independent groups of patients undergoing 2 different systems for total ankle replacement: Zimmer (lateral approach, fixed-bearing) and Hintegra (anterior approach, mobile bearing). Specific demographic data and radiographic data were measured. Within-group comparisons were performed using 1-way repeated measures ANOVA, analyzing the temporal course of clinical data within the Hintegra and Zimmer groups., Results: At the ankle joint, as measured by the α and β angles ( P > .05), the position of the components remained relatively similar in both the fixed- and mobile-bearing TAR at 24-month follow-up. The sagittal alignment, as measured by the TT (tibiotalar) ratio, demonstrated a posterior shifting of the talus in the mobile bearing group ( P = .036). Although the fixed- and mobile-bearing TAR had both significant hindfoot alignment improvement between the preoperative radiographs and at 24 months, over time, the fixed-bearing ankle had a significant increase in both the hindfoot alignment view angle and hindfoot alignment distance ( P < .001), suggesting a possible dynamism of the hindfoot in the fixed-bearing TAR., Conclusion: The lateral-approach fixed and anterior approach mobile-bearing implants maintained coronal and sagittal alignment in the short term; the temporal course of the lateral approach fixed-bearing ankle showed an increase in the valgus positioning of the hindfoot. The anterior approach mobile-bearing implant maintained its hindfoot alignment over the course of the study., Level of Evidence: Level III, case-control study.

Background: Mobile-bearing total ankle replacement (TAR) potentially enables motion at the tibial implant-polyethylene insert (PI) interface. Such additional freedom of movement may overload periarticular ligaments and subsequently result in coronal translation of the talus. The aim of this study was to assess whether syndesmotic overload affects clinical and radiographic outcomes following mobile-bearing TAR and whether tibiofibular fusion is an effective treatment option., Methods: Thirty-one patients who underwent revision surgery for syndesmotic overload after mobile-bearing TAR were retrospectively analyzed. Clinical and radiographic outcomes were assessed before and after index TAR, preoperatively to revision surgery, and at the last follow-up after revision surgery. Computed tomography scans were also analyzed., Results: Ankles with lateral talar translation prior to revision surgery were about 10 times more likely to have valgus tibial implant position ( P = .003). A wide tibiofibular distance at the level of the syndesmosis after index TAR was associated with an increased hindfoot moment arm at revision surgery ( P = .025). Decrease of PI height at revision surgery and a PI fracture were evident in 10 (32%) and 4 (13%) cases, respectively. Talar cyst formation at revision surgery was evident in 12 (39%) cases. Tibiofibular fusion was effective in restoring function of the replaced ankle and providing pain relief., Conclusion: Syndesmotic overload impaired clinical and radiographic outcomes after mobile-bearing TAR. Proper implant positioning and additional realignment procedures may prevent overload of periarticular soft tissue structures after mobile-bearing TAR., Level of Evidence: Level IV, retrospective case series.

Background: Numerous studies have reported the use of laboratory multistation joint simulators to successfully predict wear performance and functionality of hip and knee replacements. In contrast, few studies in the peer-reviewed literature have used joint simulation to quantify the wear performance and functionality of ankle replacements. We performed a systematic review of the literature on joint simulator studies that quantified polyethylene wear in total ankle arthroplasty. In addition to the quantified wear results, the load and motion parameters were identified and compared among the studies., Methods: A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify articles reporting total ankle replacement polyethylene wear using joint simulators., Results: Nine studies that used joint simulators and 1 study that used a computer simulation were found. Although all studies used physiological multidirectional motions (i.e., internal/external rotation, plantar flexion/dorsiflexion, anterior/posterior translation), there was large variability among the studies in the magnitudes of these motions. Among these studies, mean non-cross-linked polyethylene wear ranged from 3.3 ± 0.4 to 25.8 ± 3.1 mm per million cycles. In contrast, mean highly cross-linked polyethylene wear ranged from 2.1 ± 0.3 to 3.3 ± 0.4 mm per million cycles. The wide distribution in wear rates was attributable to the highly inconsistent kinematic parameters and loads applied as well as differences in implant design and materials., Conclusions: There is a severe lack of clinically applicable data on wear performance of total ankle replacements in the peer-reviewed literature. No universal set of kinematic load parameters has been established. Furthermore, only 2 of the published studies have validated their findings using independently derived data, such as retrieval analysis. These shortcomings make it difficult to compare findings as a function of design parameters and materials, or to draw clinically relevant conclusions from these simulations. More work is required to enhance the predictive capability of in vitro simulations of total ankle replacements., Clinical Relevance: The results of joint wear simulator studies may not accurately represent in vivo wear of total ankle replacements. Joint simulator studies should establish that they are accurately replicating in vivo wear, thus enabling use of their predictive capabilities for new materials and designs.

Introduction: Patient-specific instrumentation (PSI) has been developed for total ankle arthroplasty (TAA), with proven benefits. One concern regarding PSI is the need for more soft tissue dissection in order to accurately position the PSI guides, which has the theoretical disadvantage of increased osteolysis. The purpose of our study is to compare the incidence and magnitude of osteolysis for the INFINITY Total Ankle System between PSI and standard referencing (SR) techniques. Methods: Sixty-seven patients who underwent primary TAA using Prophecy (PSI) or SR technique between 2013 and 2015 were reviewed in a retrospective observational study. Osteolysis was assessed on radiographs at 2 years. The incidence was calculated by binomial distribution. The number of zones compromised and the magnitude of osteolysis was calculated using the median as a summary statistic and interquartile range as dispersion statistic. Fisher exact test was used to compare both groups, then a regression model was estimated to calculate the odds ratio for osteolysis. Results: Of the 67 TAAs, 51 were in the PSI group and 16 in the SR group. In the PSI group the incidence, number of compromised zones (CZ), and magnitude was 41% (25%-59%), 1 [1-2], and 2 [2-3], respectively. In the SR group these were 36% (13%-65%), 3 [2-3], and 3 [2-4], respectively. No significant differences were found ( P = .46, P = .12, P = .33). A slightly higher risk of osteolysis was found in the PSI group (odds ratio = 1.33 [0.36-4.83]) ( P = .46). The majority of lesions were in 1 zone with size of 2 to 5 mm (63% for all cohort, 64% PSI, 60% SR). Two cases underwent revision for aseptic loosening, 1 in the SR group and 1 in the PSI group. Conclusion: According to our data, there is no significant difference between PSI and SR in terms of risk, incidence, size and magnitude of osteolysis in the INFINITY Total Ankle System at 2 years. Levels of Evidence: Therapeutic, Level III, Retrospective cohort study.

Case: We present a case report documenting the retrieval and histological analysis of a porous tantalum (P-Ta) total ankle replacement (TAR) from a 50-year-old woman after a below-knee transtibial amputation. This rare opportunity to examine an intact TAR may help to better understand the implant-bone relationship because it would be in situ., Conclusion: In this case study, we demonstrate bone ingrowth to the first layer of the P-Ta and organized trabecular orientation, suggesting that equal bone load was achieved on the base and the rails in both components using a transfibular surgical approach.

Background: Fourier-transform infrared spectroscopy (FTIR) is one of the standard methods to analyze ultra-high molecular weight polyethylene (UHMWPE) in orthopedic implants. For retrieved components, lipid extraction using an organic solvent prior to the measurement is necessary to eliminate the influence of lipids absorbed in vivo. However, its influence on the measurement has not been substantially investigated., Objective: To investigate the influence of lipid extraction on the FTIR analysis of UHMWPE and to develop a novel method to obtain reliable results without inconvenient lipid extraction., Methods: FTIR analysis was repeatedly performed on UHMWPE specimens from retrieved components before and after lipid extraction under various conditions. A method to calculate the extent of influence of the absorbed lipids from the FTIR spectra was developed using a peak separation technique., Results: An elevated temperature was necessary for lipid extraction; however, it had the potential to influence the results if the conditions were not properly controlled. The results obtained using the peak separation technique coincided with those obtained after lipid extraction., Conclusion: The use of the peak separation technique enables the efficient acquisition of reliable results without the need for lipid extraction.

Total ankle arthroplasty has been increasing as a treatment for end-stage ankle arthritis. With this increase, the incidence of total ankle prosthetic infections will also increase. Treatment of these infections depends on the duration of symptoms and whether the infection is acute or chronic in presentation. The treatment of choice for chronic infections is a 2-stage procedure, the removal of implants and placement of a static cement spacer. We describe a technique for creating an articulating antibiotic cement spacer through an anterior approach in a patient with an infected total ankle arthroplasty. The articulating antibiotic cement spacer allows high doses of local antibiotics, decreases soft tissue contractures, and allows continued motion of the joint., (Copyright © 2019 the American College of Foot and Ankle Surgeons. All rights reserved.)

Background: The Infinity total ankle replacement (Wright Medical Technology, Memphis, TN) is a low profile, fluoroscopically navigated, fixed-bearing device. We hypothesised that the fluoroscopic navigation would allow more accurate alignment of the prosthesis than conventional techniques. We present our minimum two year follow up data of Infinity ankle replacements., Methods: All total ankle replacements (TARs) performed at our institution were prospectively followed-up with EQ5-D and MOx-FQ scores as well as intra-operative radiation exposure and radiographic alignment data. Post-operative radiographs were used to measure the alignment of the prostheses. We identified 20 implants with minimum of two year follow up which were compared to a control group of 20 Zenith TAR's (Corin, Cirencester, UK)., Results: Intra-operative fluoroscopic navigation has allowed excellent alignment of all prostheses. Median deviations from 90° alignment to the anatomical axis of the tibia were 1.5° and 1.2° in the anterior-posterior (AP) and lateral planes respectively, compared to 2.8° and 3.1° in the Zenith group. This difference reached significance (p=<0.05) using the Mann-Whitney U test. At 2 years, MOx-FQ scores had fallen from pre-operative mean of 63.9∓17.1 to 15∓12.7. EQ-5D VAS scores had improved from 71.3∓17.3 to 81.4∓9.7 points. Radiation exposure had a mean screening time of 82∓29.4s and a decrease in exposure per patient was observed over time. No patients have undergone, or are awaiting, revision surgery. Complications include one intraoperative medial malleolar tip avulsion fracture, one medial malleolar stress fracture, and one patient who developed CRPS., Conclusions: We present evidence that this system achieves better anatomical alignment of the components when compared to techniques without fluoroscopic navigation. The implant survival and complication profile at a minimum of two years is satisfactory., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported long term for MB-TAR and at intermediate- to long-term follow-up for newer generation FB-TAR. Although comparisons between the 2 total ankle designs have been reported, to our knowledge, no investigation has compared the 2 designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes, and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis., Methods: Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65 years, range 35-85 years) were enrolled; a demographic comparison between the 2 cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees, or extensive talar dome wear pattern ("flat-top talus"). Prospective patient-reported outcomes, physical examination, and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score, Short Form 36, Foot and Ankle Disability Index, Short Musculoskeletal Functional Assessment, and American Orthopaedic Foot & Ankle Society ankle-hindfoot score. Surgeries were performed by a nondesign team of orthopedic foot and ankle specialists with total ankle replacement expertise. Statistical analysis was performed by a qualified statistician. At average follow-up of 4.5 years (range, 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, 1 had died, 4 were withdrawn after enrolling but prior to surgery, and 4 were lost to follow-up., Results: In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up with no statistically significant difference between the 2 groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FH-TAR, respectively. Reoperations were performed in 8 MB-TARs and 3 FH-TARs, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants., Conclusion: With a high level of evidence, our study found that patient-reported and clinical outcomes were favorable for both designs and that there was no significant difference in clinical improvement between the 2 implants. The incidence of lucency/cyst formation was similar for MB-TAR and FH-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not necessarily correlate with radiographic findings. Reoperations were more common for MB-TAR and, in most cases, were to relieve impingement or treat cysts rather than revise or remove metal implants., Level of Evidence: Level I, prospective randomized study.

End-stage ankle arthritis has a significant effect on function and quality of life. Total ankle arthroplasty continues to emerge as a safe and effective treatment of ankle arthritis. Ankle arthroplasty preserves motion at the ankle joint, while still achieving the primary goal of pain relief. With encouraging outcomes and improved implant longevity, there has been significant improvement on the results of first-generation implants. Further high-quality studies are required to clarify outcomes post ankle arthroplasty. This article reviews the latest data from national registries and the wider literature to evaluate the current status with outcomes of modern total ankle replacements., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Coronal plane deformity is common in patients who undergo total ankle arthroplasty. The correction of this deformity is paramount to the long-term survival of the implant. Coronal plane correction is achieved with soft tissue balancing and, in some part, is maintained through articular geometry constraint. The purpose of this study was to assess the influence of tibial component stem length on the coronal plane stability., Methods: A consecutive case series of stemmed implants that met inclusion criteria were reviewed to determine the correction and maintenance of the correction of coronal plane deformity with special emphasis on the effect of modular tibial stem lengths of 2 and >2 segments. Twenty patients received a tibial component with 2 stem segments, and 23 patients received a tibial component with >2 stem segments. At an average patient age of 62.1 years at implantation, there was no significant difference between the 2 cohorts with respect to preoperative deformity or demographics., Results: Our case series had a mean coronal deformity of 5.7 degrees, with valgus being more common than varus. At a mean final radiographic follow-up of 266.3 days after the first postoperative weightbearing radiography, coronal deformity increased by 0.4 degrees ( P = .031). From the first postoperative measurement to the last postoperative measurement, there was no difference in mean coronal plane ankle deformity change between patients who received 2 stem segments and patients who received >2 stem segments ( t = -1.14, df = 41, P = .259)., Conclusion: Coronal plane deformity had a tendency to recur, albeit at a much smaller angle than preoperatively. This recurrence of deformity did not occur because of tibial component movement. Tibial stem lengths of >2 segments did not influence the maintenance of correction of coronal plane deformity or the stability of the tibial component in the coronal plane., Level of Evidence: Level III, retrospective comparative series.

Total ankle arthroplasty has been in development for more than 40 years. Although early designs were experimental with high failure rates, current implants are significantly improved, showing promising functional results and clinical outcomes. Total ankle replacement designs are split into mobile-bearing and fixed-bearing designs. When deciding whether to perform ankle arthroplasty, many factors need to be considered to determine if the patient is suitable and which implant is the best fit for patient and surgeon. Many prostheses are available in the United States today and the purpose of this article is to outline options for foot and ankle surgeons., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Malaligned ankle arthroplasty components have been associated with increased postoperative pain and reduced ankle range of motion. With this study, we aimed to quantify how anterior and posterior malalignment of the talar component affects foot bone kinematics and plantar pressures in a dynamic, cadaveric gait simulation., Methods: Ten cadaveric foot specimens received a modified ankle prosthesis. Proper alignment was defined as the prosthesis being neutral to a plantigrade foot, where varus/valgus and internal/external rotation were determined using the tibial alignment guide from the prosthesis manufacturer. Axially loaded lateral radiographs were made to measure the tibiotalar ratio (TTR) preoperatively and postoperatively. Specimens were prepared for gait simulation and mounted into the robotic gait simulator. Foot bone kinematics and plantar pressures were measured for each alignment condition., Results: Posterior malalignment of the talar component decreased mean sagittal-plane range of motion (p ≤ 0.0005) in the tibiotalar joint (by up to 3.9°) and in the first metatarsophalangeal joint (by up to 7.7°) and increased sagittal-plane range of motion (p ≤ 0.0005) in the calcaneocuboid joint (by up to 2.0°). Posterior malalignment increased mean transverse-plane range of motion (p ≤ 0.0005 and p = 0.012) in the tibiotalar joint (by up to 2.3°) and in the calcaneocuboid joint (by 2.3°). Posterior malalignment decreased mean peak plantar pressures (p = 0.001 and p = 0.013) under the hallux and the first metatarsal (by up to 82.1 and 110.1 kPa, respectively) and increased (p = 0.012 and p = 0.0006) peak plantar pressures under the third metatarsal and the hindfoot (by 23.0 and 47.8 kPa, respectively). Anterior malalignment decreased (p = 0.0006) mean hindfoot peak plantar pressure (by 127.7 kPa). Anterior and posterior malalignments shifted center of pressure laterally during early and late stance. The TTR weakly to moderately correlated with range-of-motion changes in the tibiotalar, calcaneocuboid, and first metatarsophalangeal joints (r ≤ 0.39) and weakly correlated with plantar pressure changes under the hindfoot, the first metatarsal, and the hallux (r ≤ 0.15)., Conclusions: Anterior and posterior malalignments of the talar component altered foot bone kinematics and plantar pressures. Mild malalignments produced fewer significant differences than moderate and extreme malalignments. A greater number of significant differences were found for posterior malalignments than for anterior. The TTR weakly to moderately correlated with changes in range of motion and plantar pressures., Clinical Relevance: The observed changes in range of motion and plantar pressures may explain why malaligned ankle arthroplasties are associated with unfavorable clinical outcomes and poor prosthesis longevity. Posterior malalignments may produce worse clinical outcomes than anterior malalignments.

An innovative technique is presented for salvage of a failed total ankle replacement resulting from talar subsidence with the use of a custom 3-dimensional printed articulating talar component with a titanium truss cage. This introduces a better alternative to an ankle arthrodesis with which ankle joint function and range of motion may be preserved., (Copyright © 2018 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Total ankle arthroplasty is a useful surgical procedure for osteoarthritis of the ankle, but aseptic loosening of components is an issue. We report here a case of aseptic implant loosening with metallosis after total ankle arthroplasty using the TNK ankle (Kyocera, Kyoto, Japan), which occurred despite the components being ceramic. We also report favorable results from our method of treatment using a total talar prosthesis in the revision surgery. During the revision surgery, synovial metallosis was found, probably related to superficial damage to the screw affixing the tibial component to the bone. Because both the tibial and talar components were loose, all the components and the remaining talar bone were removed. A new tibial component and a custom-made alumina-ceramic total talar prosthesis was inserted. Pain relief was achieved and maintained through the latest follow-up visit at 42 months after revision surgery. Dorsiflexion of the ankle improved from 0° to 5° and plantarflexion remained unchanged from its preoperative range of 20°. The American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 38 to 80 points. To the best of our knowledge, this is the first reported case of an alumina-ceramic total ankle prosthesis loosening caused by metallosis resulting from screw abrasion. Favorable treatment results were obtained by using a total talar prosthesis in the revision surgery., (Copyright © 2019. Published by Elsevier Inc.)

Background: Ankle disorders in patients with rheumatoid arthritis (RA) reduce their quality of life and activities of daily living. The aim of this study was to evaluate the midterm clinical and radiographic outcomes of TAA in patients with RA., Methods: This retrospective study included patients with a minimum follow-up of 2 years. A total of 37 RA patients (39 ankles) were enrolled in this study from August 2006 to March 2016. All the patients had undergone primary cemented mobile-bearing total ankle arthroplasty (TAA). Nine ankles received arthrodesis of the subtalar joint simultaneously. Patient-reported outcomes were measured preoperatively and at the latest follow-up by Self-Administered Foot-Evaluation Questionnaire (SAFE-Q). Radiographs of the ankle were analyzed preoperatively and at all follow-up visits to measure the periprosthetic radiolucent line, migration of the tibial component, and the subsidence of the talar component. Intraoperative and postoperative complications were recorded. The average duration of follow-up for the entire cohort was 5.0 ± 2.0 years (range 2.1-10.1 years)., Results: All subscales of the SAFE-Q had improved significantly at the latest follow-up. No significant difference was found between the range of motion of the ankle before and after the surgery. Radiolucent lines were observed in 28 (73.7%) ankles. Migration of the tibial component and subsidence of the talar component were found in 8 (21.1%) and 11 (28.9%) ankles, respectively. Intraoperative malleolus fractures occurred in 3 (7.7%) ankles and delayed wound healing in 10 (25.6%) ankles. Four ankles were removed because of deep infection or noninfective loosening, resulting in an implant survival rate of 88.4% (95% CI, 0.76-1.0) at 10 years., Conclusion: The midterm patient-reported outcomes and implant retention rate after cemented mobile-bearing TAA for RA patients were satisfactory. However, a low radiographic implant success rate was observed., Level of Evidence: Level IV, retrospective case series.

Background: Highly crosslinked polyethylene (HXLPE) was developed for its superior wear properties in comparison to conventional polyethylene (CPE). Concern over fatigue resistance has prevented widespread adoption of HXLPE for use in total ankle arthroplasty (TAA). The aim of this study was to determine whether HXLPE has sufficient fatigue strength for total ankle arthroplasty under simulated physiologically relevant motion profiles and loading in the ankle., Methods: Physiologic load and motion profiles representative of walking gait were incorporated into a computational model of a semiconstrained, fixed-bearing TAA to determine the loading state with highest stresses in the HXLPE bearing. Subsequent fatigue testing to 10 million cycles (Mc) at 5600 N was performed to assess bearing strength., Results: Peak stresses in the bearing were predicted at peak axial load and peak dorsiflexion during gait, occurring near heel off. All samples withstood 10 Mc of fatigue loading at that orientation without polyethylene bearing fracture., Conclusion: HXLPE had sufficient fatigue strength to withstand 10 Mc of loading at more than 5 times body weight at the point of peak stresses during simulated gait in total ankle arthroplasty., Clinical Relevance: HXLPE may be mechanically strong enough to withstand the in vivo demands of the ankle. Improvements in wear afforded by HXLPE can be obtained without compromising sufficient polyethylene strength properties in total ankle arthroplasty.

Background: Total ankle arthroplasty (TAA) has been developed to treat patients with end-stage ankle osteoarthritis (OA). However, there is often difficulty in treating complicated pathologies such as ankle OA with subtalar joint OA and severe talar collapse. Therefore, this study aimed to explore the short-term results and complications of TAA with total talar prosthesis, known as combined TAA, as the new techniques to treat such complicated pathology., Methods: We examined postoperative results including ankle range of motion, Japanese Society for Surgery of the Foot (JSSF) scale, and complications. There were 22 patients (15 women), with mean follow-up of 34.9 (range, 24-53 months), and the mean age was 72 (range, 62-80) years. The main indications for combined TAA included osteoarthritis (18 patients), rheumatoid arthritis (3 patients), and talar osteonecrosis with osteoarthritis (one patient)., Results: The mean range of motion improved from 4.0 to 14.4 degrees in dorsiflexion and from 23.8 to 32.0 degrees in plantarflexion. The JSSF scale improved from 50.5 to 91.5 points. Prolonged wound healing occurred in 3 patients, and medial malleolus fracture occurred in 4 patients., Conclusion: Combined TAA was a reliable procedure for the treatment of not only ankle OA following avascular necrosis of talus but also of degeneration of both ankle and subtalar joints., Level of Evidence: Level IV, case series.

Recommendation: Though literature specific to total ankle arthroplasty (TAA) is lacking, based on recommendations for the management of hip and knee arthroplasties, the choice of antibiotic should be made based on the identification and sensitivities of the infecting organism(s). Dosing, frequency, and route of administration of antibiotics may be determined in consultation with an infectious disease specialist and by taking into account the patient's weight and comorbidities, such as renal impairment and the antibiogram., Level of Evidence: Consensus., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Recommendation: Debridement, antibiotics, and implant retention (DAIR) in acute total ankle arthroplasty (TAA) infections may be an acceptable treatment option. If performed, DAIR should be done meticulously, ensuring that all necrotic or infected tissues are removed and modular parts of the prosthesis, if any, exchanged. The infected joint should also be irrigated with antiseptic solutions., Level of Evidence: Consensus., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Recommendation: We recommend tailoring the antibiotic in cement spacers to the infecting organism if it has been identified, as is typically done in total knee and hip arthroplasty. Otherwise, broad-spectrum antibiotics may be utilized. Medical comorbidities should always be considered, especially with regard to renal function and allergy profile. A thermostable antibiotic should be added to cement., Level of Evidence: Consensus., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Recommendation: Debridement, antibiotics, and implant retention (DAIR) with polyethylene exchange may be indicated in early postoperative infection (<4 weeks) or acute hematogenous infection (<4 weeks of symptoms) in patients with infected total ankle arthroplasty (TAA), although recurrent infection has been seen. Suffcient clinical evidence is lacking., Level of Evidence: Consensus., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Recommendation: Predictors for treatment failure in patients undergoing 2-stage exchange for infected total ankle arthroplasty (TAA) include compromised soft tissues (eg, sinus tract and exposed hardware), significant bone involvement/osteomyelitis, and insufficient timing of antibiotic course before reimplantation., Level of Evidence: Moderate., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

Recommendation: The treatment of an infected total ankle arthroplasty (TAA) is largely dictated by the acuity of the infection. The following treatment algorithm modified for TAA is recommended. 19 ., Level of Evidence: Limited., Delegate Vote: Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).