Charcot Neuroarthropathy of the Foot and Ankle in the Acute Setting: An Illustrative Case Report and Targeted Review

Charcot neuroarthropathy (CN) is a rare but serious sequela of diabetes and other diseases that cause peripheral neuropathy. It is most commonly characterized by degeneration of the foot and/or ankle joints leading to progressive deformity and altered weight-bearing. If left untreated, the deformities of CN lead to ulceration, infection, amputation, and even death. Because of the associated peripheral neuropathy and proprioception deficits that accompany CN, patients typically do not perceive the onset of joint destruction. Moreover, in the hands of the untrained clinician, the initial presentation of CN can easily be mistaken for infection, osteoarthritis, gout, or inflammatory arthropathy. Misdiagnosis can lead to the aforementioned serious sequelae of CN. Thus, an early accurate diagnosis and off-loading of the involved extremity, followed by prompt referral to a specialist trained in the care of CN are crucial to prevent the late-term sequelae of the disease. The purpose of this article was to create an opportunity for enhanced understanding between orthopedic surgeons and emergency physicians, to improve patient care through the optimization of diagnosis and early management of CN in the emergent setting. Keywords: Charcot neuroarthropathy; Charcot foot; diabetes mellitus; midfoot collapse; emergency

Evaluating Failure Mechanisms for Total Talus Replacement: A Case Series

Category: Ankle Arthritis Introduction/Purpose: Talar collapse can occur from a variety of etiologies and may pose a unique challenge to the foot and ankle surgeon due to the complexity of the deformity and associated adjacent joint degenerative change. Total talus replacement (TTR) has emerged as an attractive option to help patients return to activities sooner than with arthrodesis and improve pain and joint mechanics postoperatively. However, there is limited long-term data on the most recent generation of implants. In this multi- institution case series, we present the severe complications that can occur after TTR, including instability, infection, and adjacent joint osteoarthritis. Methods: We present three cases from Duke University Hospital in Durham, North Carolina, and the Hospital for Special Surgery In New York City, New York. All three patients were treated with a total talus replacement (TTR) during their clinical course and experienced subsequent complications. Clinical data and radiographs were collected from chart review under an IRB-exempt protocol. Results: Case 1 demonstrates the risk of ligamentous insufficiency leading to dislocation following placement of a TTR. This case highlights the posterior instability due to soft tissue mobilization and division. Case 2 highlights the risk for adjacent joint degeneration with TTR. Case 3 presents an instance of non-union following a total ankle and total talus replacement (TATTR) with subtalar arthrodesis. To our knowledge, this represents the first case of nonunion following TTR in the literature. Finally, we discuss our institution’s experience with infection following TTR and possible contributing factors to this specific procedural risk. Conclusion: TTR shows promise in the properly selected patient with end-stage talar collapse. However, heterogeneous surgical techniques, implant composition, indications, and patient demographic variables complicate the interpretation of the literature. Moreover, few studies report mid-to long-term outcomes after this procedure and the occurrence of adjacent joint OA is likely underreported in the literature. Thus, until further, high-quality studies with long-term follow-up validate the positive early outcomes of TTR, we urge extreme caution in patient selection, choice of implants, and surgical techniques

The Invision Talar Component as a Revision Total Ankle Arthroplasty Option: Analysis of Early Outcomes

Category: Ankle; Other Introduction/Purpose: The Invision talar component was launched in 2018 as a revision total ankle arthroplasty (TAA) specific option geared towards avoiding further subsidence when poor talar bone stock is present. Due to the recency of the market- availability of the Invision, studies evaluating the efficacy of the implant, even in the short-term, are lacking. Thus, the purpose of this study was to present the early-term outcomes of a series of patients undergoing revision TAA with the use of the Invision talar component. Methods: This was a single-center, retrospective review of 28 patients undergoing revision TAA with the Invision talar component and Inbone II tibial component (Wright Medical; Memphis, Tennessee) performed between 2007 and 2022. Mean follow-up was 1.3 ± 0.93 years. Data on patient preoperative characteristics, postoperative complications, and survivorship were collected. The primary outcome measures were time to major complication, reoperation, and infection. Results: The most common concurrent procedures performed with revision TAA with the Invision talar component were gastrocnemius recession (n=14, 50%), subtalar arthrodesis (n=3, 10.7%) and cotton osteotomy (n = 1, 3.6%). The mean preoperative coronal deformity off the tibia was 4.07 ± 3.06 degrees for varus and 3.67 ± 4.36 degrees for valgus deformities, respectively, and postoperatively, was 1.67 ± 2.16 degrees for varus and 2.00 ± 3.48 degrees for valgus. The mean preoperative coronal plane deformity off the talus was 4.83 ± 6.68 degrees for varus and 4.22 ± 4.21 degrees for valgus, respectively, and postoperatively, was 1.23 ± 2.45 degrees for varus and 2.32 ± 3.93 degrees for valgus. The survivorship from any complication, major complication, reoperation, and infection is shown in Table 2. Conclusion: In a series of 28 patients undergoing revision TAA with the Invision talar component and Inbone II tibial component, we demonstrate a survivorship of 92.7% at 1-year follow up. The Invision appears to have a reasonable safety profile in this non- designer series. The implant compares favorably with others utilized in the revision TAA setting at the early-term, but further studies evaluating mid-and long-term outcomes are required to fully assess the efficacy of the Invision

Revision Total Ankle Arthroplasty Outcomes in a Large Single-Center Series: Evaluation of Coronal Plane Deformity Correction and Patient Reported Measures

Category: Ankle Arthritis Introduction/Purpose: As total ankle arthroplasty (TAA) rises in popularity nationwide, the incidence of major complications and need for revision TAA will continue to increase. A better understanding of the ability to durably correct deformity and improve patient reported outcomes (PROs) in the TAA revision setting is paramount for surgeons facing the impending wave of failed TAA. Thus, the purpose of this study was to present the largest single-center case series of revision TAA to date and to evaluate improvement in PROs and maintenance of correction of coronal plane deformity in patients undergoing this procedure. Methods: This was a single-center, retrospective review of 87 revision TAAs performed between 2007 and 2022. Reoperations for cyst formations only or without metallic component exchange were excluded. The two most common implants used for revision TAA were Inbone II (n=65) and Inbone I (n=14). Mean follow-up was 2.8 ± 2.9 years. Data on patient preoperative characteristics, concurrent procedures, and postoperative complications were collected. The primary outcome measures were time to major complication, reoperation, and infection. Secondary outcomes included PROs and correction of coronal plane deformity measured from both the tibial plafond and talar articulating surface from pre- to post-operatively. Cox regression analyses were performed to compute survivorship. Results: The most common concurrent procedures performed concomitantly with revision TAA were gastrocnemius recession (n=31, 35.6%), subtalar arthrodesis (n=18, 20.7%), and talonavicular arthrodesis (n=5, 5.7%). Mean preoperative coronal plane deformity measured off both the tibial plafond and talar articular surface improved after revision TAA. 1- and 5-year survivorship from major complication, reoperation, and infection is shown in Table 2. Fourteen patients underwent subsequent revision, including TAA (n= 6, 6.9%), arthrodesis (n= 4, 4.6%), below-the-knee amputation (n= 2, 2.3%), or implantation of an antibiotic spacer (n= 2, 2.3%). At one-year postoperatively, mean VAS pain score, SF36, and AOFAS Hindfoot score was 18.2 ± 16.0, 73.0 ± 13.3, and 68.8 ±:9.3, respectively, representing an improvement in PROs after revision TAA. Conclusion: In the largest single-center series of patients undergoing single or double component exchange revision TAA, we demonstrate durable improvements in coronal plane deformity measured off both the tibial plafond and talar articular surface. We also noted 63.0% survivorship with regards to reoperation and improvements in average PROs across the cohort. Overall, revision TAA is a successful procedure, but is associated with higher failure rates at 5 years than primary TAA

Association of Radiographic Soft Tissue Thickness With Revision Total Ankle Arthroplasty Following Primary Total Ankle Arthroplasty: A Minimum of 5-year Follow-up

Background: The incidence of primary total ankle arthroplasty (TAA) is rising, with a corresponding increase in revision surgeries. Despite this, research on risk factors for revision TAA following primary TAA remains limited. Radiographic soft tissue thickness has been explored as a potential predictor for outcomes in hip, knee, and shoulder arthroplasty, but its role in TAA has not been assessed. This study aimed to assess the predictive value of radiographic soft tissue thickness for identifying patients at risk of requiring revision surgery following primary TAA. Methods: A retrospective study was conducted on 323 patients who underwent primary TAA between 2003 and 2019. Radiographic measurements of soft tissue thickness were obtained from preoperative radiographs. Two novel radiographic measures of soft tissue thickness were developed and assessed (tibial tissue thickness and talus tissue thickness). Clinical variables including age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, diabetes, smoking status, primary diagnosis, and implant type were recorded. Logistic regression analysis was used to assess the predictive value of soft tissue thickness and BMI for revision TAA. Results: The rate of revision surgery was 4.3% (14 of 323 patients). Patients requiring revision had significantly greater tibial tissue (3.54 vs 2.48 cm; P  = .02) and talus tissue (2.79 vs 2.42 cm; P  = .02) thickness compared with those not requiring revision. Both the tibial tissue thickness (odds ratio 1.16 [1.12-1.20]; P  < .01) and the talus tissue thickness (odds ratio: 1.10 [1.05-1.15]; P  < .01) measurements were significant predictors of revision TAA in multivariable logistic regression models. However, BMI was not a significant predictor of revision TAA. The two metrics demonstrated excellent interrater reliability. Conclusion: Greater soft tissue thickness was a better predictor of revision TAA compared with BMI. These findings suggest that radiographic soft tissue thickness may be a valuable tool for assessing the risk of the need for revision TAA following primary TAA. Further research is needed to validate and explore the potential impact on clinical practice. Level of Evidence: Level III, comparative study