Search

Category: Ankle Arthritis; Ankle Introduction/Purpose: Ankle fusion takedown with conversion to total ankle arthroplasty (TAA) shows promising results with regards to patient satisfaction and functional outcomes. The objective of this study is to present the results of tibiotalar fusion takedown via a lateral approach with conversion to TAA in complex patients with prior lateral approaches or compromised anterior tissues. Methods: A retrospective review was completed using the senior author’s total ankle replacement database. 16 patients underwent an ankle fusion takedown (TD) with conversion to transfibular TAA. 9/16 patients had prior tiobiotalar fusions; 7/16 patients had either a pantalar or tibiotalar calcaneal fusion. A matched cohort of patients who underwent primary transfibular TAA (TF TAA) was compared. Patient demographics, complication profiles, subjective pain questionnaires, and radiographic parameters were collected. Patient reported outcome measures (PROMs) were analyzed with Short Form-12 (SF-12), Visual Analog Scale (VAS), and the Ankle Osteoarthritis Scale (AOS). Radiographic parameters included plantarflexion and dorsiflexion range of motion (PF,DF) measured by tibiopedal excursion on standing flexion-extension radiographs. Radiographic indicators of implant subsidence (alpha, beta, and gamma angles) were measured. Results: Average age was 56.81 ± 13.11 years with 3.23 ± 1.46 years of follow-up. ASA was 2 or 3 in 15/16 TD and 16/16 TF TAA. Operative time was longer in TD due to additional procedures (6:04 ± 0.4 vs 4:55 ± 1.0, p=0.004). 6/16 per group underwent reoperation(s), most commonly fibular hardware removal (p=1). Radiographic parameters of TD revealed a 2°change in the beta angle (p=0.02) and increased plantarflexion 7.89 (5.65) to 13.51 (9.09) degrees (p=0.02). Compared to TD, TF TAA had greater PF 17.61 ± 6.52 vs 7.89 ± 5.65 (p = 0.002) and DF 18.95 ± 6.70 vs 12.48 ± 5.61 (p=0.011). Postoperative PROMs showed no significant difference between groups. There was no significant difference in cyst formation or lucency between groups. Conclusion: Tibiotalar fusion conversion to a lateral total ankle replacement in complex patients with prior lateral approaches or compromised anterior tissues appear to be a safe and effective surgery. When compared to primary lateral ankle replacements, ankle fusion takedown with conversion to total ankle arthroplasty yields similar patient reported outcomes, radiographic results, and complication rates at 3.2 years follow-up. Although technically challenging, transfibular total ankle replacement following ankle fusion takedown is a reasonable treatment option for symptomatic ankle, pantalar, or tibiotalar calcaneal fusion.

Category: Ankle Arthritis; Ankle Introduction/Purpose: The current fourth generation of total ankle arthroplasty (TAA) continues to build upon previous advances in implant design. In contrast to these implants, which utilize a traditional anterior approach for implantation, the Zimmer Trabecular Metal Total Ankle (Zimmer-Biomet, Warsaw, IN) is unique in that it utilizes a transfibular approach to the ankle. This allows for a shallow resection depth, and the insertion of a curved prosthesis design, mimicking the native tibiotalar joint. While previous case-series have reported on implant survivorship, a comprehensive midterm study of the clinical and radiographic outcomes of this system is limited. Here we present the largest midterm study to date by a single-surgeon, and analyze the survivorship, clinical, and radiographic outcomes of the transfibular TAA at a minimum of 5-years follow-up. Methods: Retrospective review was performed on prospectively followed patients who underwent primary transfibular TAA by a single surgeon from October 2012 to December 2018. Inclusion criteria included: minimum 5-years of follow-up. patient-reported outcomes measures (PROM), and radiographic follow-up. Patient demographics and perioperative data were collected. PROMs included: 12-item Short Form Health Survey (SF-12) physical (PCS) and mental (MCS) component scores, Ankle Osteoarthritis Scale (OAS), and Visual Analog Scale (VAS). Functional outcomes included range of motion (ROM) measured on weightbearing ROM radiographs. Radiographic outcomes included coronal and sagittal alignment, and evaluation of periprosthetic lucency utilizing a 12-zone system. Adverse events and reoperations were reported using the Canadian Orthopedic Foot and Ankle Society (COFAS) Reoperation Coding System (CROCS). A total of 130 ankles (122 patients) with average follow-up of 5.9 years (range, 5.0-10.1) were included in the study. The average age was 60.8 years-old, with 50.8% being females. Results: Postoperative PROMs included SF-12 PCS: 41.5; SF-12 MCS: 54.9; VAS: 2.3; AOS Pain: 19.1; AOS Disability: 28.5. Postoperative tibiopedal ROM was 17.7° dorsiflexion and 21.8° plantarflexion. Postoperative tibiotalar ROM was 7.4° dorsiflexion and 17.3° plantarflexion. A total of 26 (20%) ankles had a single zone of lucency, while 7 (5.4%) ankles had 6 or more; none had more than 7 zones. There were no cases of cysts, subsidence, septic/aseptic loosening, or fibular non-union. Reoperation rate was 36.2% (n=47) at average 26.7 months, most commonly removal of fibula hardware (n=28, 21.5%), medial gutter debridement (n=18, 13.8%). There were 5 (3.8%) cases of acute infection treated with I&D and metal component retention. Overall implant survival, defined by retention of the metal components, was 100%. Conclusion: Transfibular TAA is an effective durable treatment option for end-stage ankle arthritis with excellent implant survivorship, providing sustained improvements in clinical and radiographic outcomes at the midterm. Reoperations were mostly elective removal of fibular hardware or medial impingement. There was 100% retention of the metal components. Deformity correction was achieved and maintained. The majority of ankles had no radiographic lucencies and only 20% had a single zone out of 12 zones which did not correlate with clinical outcomes. There were no cysts, subsidence, or fibular non-unions.

Background: Particulated autograft cartilage implantation is a surgical technique that has been previously described for the repair of osteochondral lesions of the talus (OLT). It uses cartilage fragments harvested from the OLT that are minced into 1-2-mm 3 fragments and then immediately reimplanted back into the chondral defect and sealed with fibrin glue during a single-stage surgery. The purpose of this study was to characterize the suitability of these minced cartilage fragments as immediate autograft for the treatment of OLTs. Methods: Thirty-one patients undergoing primary arthroscopic surgery for their OLT consented to have their loose or damaged cartilage fragments removed and analyzed in the laboratory. Harvested specimens were minced into 1- to 2-mm 3 fragments and cell count, cell density, and cell viability were determined. In addition, physical characteristics of the OLT lesion were recorded intraoperatively and analyzed including size, location, Outerbridge chondromalacia grade of the surrounding cartilage, density of underlying bone, and whether the surgeon thought the OLT was primarily hyaline or fibrocartilage. Results: An average of 419 000 cells was able to be obtained from the harvested OLT fragments. The cells were 71.2% viable after mincing. Specimens from younger patients and from lesions with worse chondromalacia adjacent to the OLT had significantly higher cell numbers. Those from lateral lesions and with worse neighboring chondromalacia had a significantly higher cell density. None of the remaining physical OLT characteristics studied seemed to significantly affect cell number or viability. Conclusion: A large number of viable cells are available for immediate autografting by removing the loose or damaged cartilage from an OLT and mincing it into 1- to 2-mm 3 fragments. These can be reimplanted into the chondral defect in a single-stage surgery. Future clinical studies are needed to determine if the addition of these live autologous cells either alone or in conjunction with other techniques significantly improves the quality of the repair tissue and clinical outcomes. Level of Evidence: Level IV, case series.

Category: Basic Sciences/Biologics; Arthroscopy Introduction/Purpose: Osteochondral lesions of the talus (OLT) are frequently treated with microfracture and may be augmented with decellularized extracellular matrix or particulated juvenile cartilage. The damaged OLT cartilage is often discarded. Infrequently it is used as a source for autologous chondrocyte expansion and implantation in a subsequent procedure. This resected cartilage has demonstrated variable chondrocyte viability. The influence of cartilage type on chondrocyte viability, whether frayed fibrocartilage from in vivo repair or delaminated hyaline cartilage, remains unknown. Also, little has been reported on the use of the OLT cartilage as a source for immediate cartilage autograft. The purpose of this study is to evaluate chondrocyte quantity and viability from the excised cartilage of OLTs at the time of arthroscopic debridement and microfracture. Methods: Patients aged 18 to 65 undergoing arthroscopic debridement and microfracture of talar OLTs were included. IRB approval of the study protocol was obtained. At the time of ankle arthroscopy, the cartilage from the OLT was collected either by GraftNet™ Autologous tissue collector (GraftNet™ Autologous Tissue Collector, Arthrex; Naples, FL) or manual collection and mincing of the specimen with a scalpel. Chondrocytes were isolated by overnight digestion with 2% collagenase in tissue culture medium at 37°C. The isolated cells were stained with Trypan Blue and counted for total cell number and viability (%), using an automated cell counter. Data collection included patient age, size and location of the OLT, intraoperative surgeon assessment of cartilage type (hyaline cartilage, fibrocartilage, or mixed fibro-hyaline cartilage), histologic determination of cartilage type, weight of the specimen, and chondrocyte cell count and viability. Results: Fourteen OLT specimens were collected. The average size was 0.831 (SD ± 1.10) cm 2 , and average weight 0.19 (SD ± 0.17) grams. Overall, the average number of chondrocytes was 1.12 x106 (SD ± 1.13 x106) cells/mm 2 and 3.99 x106 (SD ± 3.28 x106) cells/gram. The average viability was 72.36% (SD ± 12.25%). Using histologic determination of cartilage type, in hyaline specimens (n = 8, 57.14%) we found 1.08 x106 (SD ± 0.85 x106) chondrocytes/cm 2 , 70.73% (SD ± 11.73 %) viability. In fibrocartilage specimens (n = 2, 14.29%) we found 0.37 x106 (SD ± 0.10 x106) chondrocytes/cm 2 , 78.08% (SD ± 22.03%) viability. In mixed cartilage specimens (n = 4, 28.57%) we found 1.58 x106 (SD ± 1.80 x106) cells/cm 2 , 72.78% (SD ± 11.79%) viability. (Table 1) Conclusion: We found OLT chondrocyte viability of 72.36%, with a trend toward greater chondrocyte concentration and similar viability comparing hyaline and fibro cartilage, respectively. Cartilage type was consistent between intraoperative and histologic assessment in all but four specimens. OLT cartilage has the potential to serve as an immediate intraoperative chondrocyte autograft source for enhancement of talus cartilage repair procedures, eliminating the risk of donor site morbidity and additional surgeries as in culture-based methods. Further study with more patients may shed light on the accuracy of intraoperative cartilage classification, and differences in chondrocyte quantity and viability between cartilage types.

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has surpassed arthrodesis as the gold standard for treatment of end-stage ankle arthritis. The Zimmer Trabecular Metal Total Ankle Implant (Zimmer-Biomet, Warsaw, IN) differs from other newer- generation implants in the transfibular approach, non-mobile-bearing prosthesis, high-molecular-weight polyethylene, curved surface at every interface in the sagittal plane, and shallow resection depth. There is limited mid-term follow-up for this system. Therefore, we sought to report mid-term clinical, functional, and radiographic results we well as complications and survival for patients treated with the transfibular TAA at a minimum of 5-years follow-up. Methods: A retrospective review was performed on patients who underwent primary transfibular TAA by a single surgeon from October 2012 to January 2018. Inclusion criteria was a minimum of 5-years of follow-up with a completed consent for participation in the study and patient-reported outcome measures (PROM). Patient demographics and perioperative data were collected. PROMS included: 12-item Short Form Health Survey (SF-12) physical (PCS) and mental (MCS) component scores; Ankle Osteoarthritis Scale (OAS); and Visual Analog Scale (VAS). Functional outcomes included range of motion (ROM) measured on weightbearing ROM radiographs. Radiographic outcomes included coronal and sagittal alignment. Adverse events and reoperations were reported using the Canadian Orthopedic Foot and Ankle Society (COFAS) Reoperation Coding System (CROCS). Of the consecutive 151 TAAs, 83 (55.0%) ankles are included in this study, evaluated at a mean of 5.8 years clinical and 6.3 years radiographic follow-up. Results: The average age was 60.6 years-old. Preoperative tibiotalar coronal deformity included 27 valgus (10°, range 2-20°) and 25 varus ankles (-9°, range -2--25°), successfully corrected to neutral postoperatively. The postoperative PROMs were: SF-12 PCS: 40.4, SF-12 MCS: 56.0, VAS: 2.3, AOS Pain: 17.0, and AOS Disability: 24.9. Radiographic postoperative tibiopedal ROM was 17.8° dorsiflexion and 21.8° degrees plantarflexion. The overall reoperation rate was 38.6%(n=32) at an average of 28.7 months postoperative. Most common were removal of the fibula hardware (n=21,25.3%) and medial gutter debridement (n=15, 18.1%). There were 3 (3.6%) cases of acute postoperative infection (< 3 months) treated with operative irrigation and debridement but retention of the metal components. There were no cases of septic or aseptic loosening or subsidence. The overall implant survival, defined by retention of the metal components, was 100%. Conclusion: Transfibular TAA is a safe and effective treatment for end-stage ankle arthritis at 5-year mid-term follow-up. This study confirms excellent clinical results including PROMs and ROM as well as radiographic alignment correction and maintenance. The survival rate was 100% for retention of the trabecular metal components. The survival rate to reoperation was 60.7% with patients commonly requiring removal of the fibula hardware or medial gutter debridement. Patients should be counseled on the risk of reoperation preoperatively for postoperative expectation management.

Category: Ankle; Other Introduction/Purpose: Periprosthetic joint infection (PJI) is a devastating complication of arthroplasty. The well known PJI risk factors are useful for identifying high-risk patients but would be even more helpful for clinical decision-making if they are converted to a risk assessment scores. The Mayo Prosthetic Joint Infection Risk Score was based on the data of total hip and knee arthroplasty and has not been validated for application for total ankle arthroplasty. Methods: A series of 398 consecutive cases of total ankle arthroplasty, with minimal follow-up of 6 months, was reviewed for Mayo Periprosthetic Joint Infection Risk Score (Mayo score) and PJI. The patients' Mayo scores and PJI was examined by logistic regression. T-test was performed to compare the Mayo score between the non-infected TAA cases and infected cases. Receiver Operating Characteristic (ROC) was used to identify the critical value of Mayo score for total ankle arthroplasty. Results: There were 12 cases of PJI or 3.0% in the series. Of the 398 patients, the Mayo scores were in the range from -4 to 13 (median 2; interquartile range (IQR) 0-4). Preliminary analysis showed that, by logistic regression, the probability of PJI was increased as increases of the Mayo scores (Fig A). The mean Mayo score of the PJI patients (8.6+-1.8) was significantly greater than the rest of the patients (mean Mayo score 1.9+-3.4; p < .0001). ROC analysis showed that, when a Mayo score was greater than 5, the patient has a high probability of PJI (sensitivity = 100%; specificity = 86.9%; Fig B). Conclusion: This study showed a high correlation between the Mayo score and PJI in total ankle arthroplasty, which is the same trend as in total knee and hip arthroplasty. The preliminary results suggest that strategically focusing on the patients, who have a Mayo score > 5, could be a more efficient approach to prevent PJI after total ankle arthroplasty.

Category: Ankle; Ankle Arthritis Introduction/Purpose: The decision regarding total ankle replacement is challenging in inflammatory arthritis patients regarding more inferior bone quality, large bone cysts, and increased risk for infections. This systematic review aimed to compare the short and long-term results of total ankle replacement, including the revision rate and the patient-reported outcomes between inflammatory rheumatoid arthritis (RA) versus non-inflammatory ankle osteoarthritis (OA). Methods: All published clinical studies on total ankle arthroplasty were searched in the databases. We extracted the data, specifically the American Orthopaedic Foot & Ankle Society (AOFAS) improvement, complication rate, and the reoperation rate. The results were also analyzed based on the prosthesis type. Results: In total, 34 trials were included in our study. Out of 5,078 patients, the underlying condition was rheumatoid arthritis in 1,327 patients and was non-inflammatory osteoarthritis in 2,849 patients. There was statistically significant higher AOFAS improvement in the patients with RA vs. OA with a mean follow-up of 63 months (P=0.009). The rates of TAA removal or revision were estimated at 16% (95% CI, 10%-23%) in the OA and 13% (95% CI, 9%-18%) in the RA group. Overlapping confidence intervals showed no significant difference in the rate of failure between RA and OA. The survival rate was 66% in the OA group and 88% in the RA group during a 63-month follow-up. Conclusion: Total ankle replacement is a safe procedure in RA patients with fewer minor and major complications relative to other reasons for ankle osteoarthritis.

Category: Basic Sciences/Biologics; Diabetes Introduction/Purpose: Charcot neuroarthropathy (CNA) is a destructive joint condition secondary to neuropathic deficiency. For more than a century, the pathogenesis of CNA has been interpreted as unprotected injury and/or uncontrollable inflammation in a neuropathic joint, with little understanding its cellular and molecular pathology. Histologically, a hallmark of CNA is bone and cartilage fragments engulfed by hyperplastic synovium. Synovium is richly innervated. Neuropeptides, such as calcitonin gene- related peptide (CGRP), are secreted by neuronal and non-neuronal cells of the nervous, endocrine, and immune systems, and regulate inflammation. This study investigated the expression of CGRP in the synovial samples collected from CNA and non-CNA joint conditions, and the effects of CGRP on the proliferation and collagenolysis of fibroblast-like synoviocytes (FLS) isolated from CNA synovium in vitro. Methods: For this study, six CNA and 14 non-CNA synovial samples were collected during foot and ankle surgery. The donors included 10 male and 10 female, age from 14 to 79 years (mean 48). The non-CNA conditions consisted of osteoarthritis, ankle instability, Os Trigonum and osteochondritis dissecans. Western blot and immunohistochemistry of CGRP were performed to detect and localize CGRP expression in the CNA and non- CNA synovium. FLS was isolated from CNA synovium and cultured with, or without, human CGRP (10nM) in the culture media, for comparison of cell proliferation. Additionally, FLS were seeded on the collagen-coated 24-well plate and simulated with CGRP (10nM) and recombinant human tumor necrosis factor-alpha (TNF-α). After 7 days, the residual collagen on the bottom of the culture plate were stained and imaged for area measurements. Data were analyzed with t test or one-way Analysis of Variance, followed with post hoc Tukey's test. Results: By western blot, there was significant CGRP expression in the CNA synovium (5/6; Fig1). Except of an intense CGRP band in one of the osteoarthritis samples, only recognizable CGRP bands were shown in the samples of other non-CNA conditions. The average density of CGRP (in greyscale) in the CNA group was about 2-fold of that in the non-CNA group (10126 +- 5346 vs. 5377+-3734; p < 0.05). Immunohistochemistry demonstrated intense CGRP staining in the intimal layer of the CNA synovium (arrows) but not in the non-CNA synovium (Fig1). Treated with CGRP, the number of FLS in tissue culture increased. Cell number doubling time was 1.0 day (+-0.4) for the CGRP treated FLS and 2.2 days (+-0.5) for the control (p < 0.05). When the culture media were supplemented with CGRP and TNF-α, FLS eroded a larger area of collagen coating comparing with TNF-α alone in the media (p < 0.05). Conclusion: A knowledge gap in understanding the molecular and cellular pathology of CNA hampers the development of disease-modifying therapies. This study showed an increased CGRP, with a concentration in the intimal layer, in the CNA synovium as compared with the synovium in the non-CNA foot conditions. The increased CGRP expression in CNA synovium may be part of the unbalanced neuropeptide signaling in the neuropathic pathology. Functionally, CGRP stimulated FLS proliferation and degrading collagen in vitro. These effects suggest that CGRP may play a role in bone and joint destruction in the Charcot foot.

Category: Ankle Arthritis; Ankle Introduction/Purpose: Continued improvements in total ankle arthroplasty (TAA) implant design have led to promising clinical outcomes. The lateral transfibular approach TAA allows for excellent visualization of the center of rotation of the ankle and allows for correction of rotational and sagittal deformity by shortening or lengthening of the fibula. Furthermore, the curved implant design allows for minimal bony resection. The purpose of this study is to report the medium-term clinical and radiographic results for consecutive patients who underwent the lateral approach TAA. Methods: IRB approval was obtained for this study. Consecutive patients who underwent lateral approach TAA for tibiotalar arthritis by a single surgeon were enrolled on a prospective basis from January 2013 to June 2015. This time period represented the initial case series of TAA performed by the surgeon. Patient reported outcomes (PROs) were collected including the Ankle Osteoarthritis Scale (AOS), 12-item short-form survey (SF-12), and Visual Analogue Pain Scale (VAS). The need for subsequent procedures was recorded. Radiographs were evaluated for preoperative and postoperative alignment using the lateral distal tibial angle (LDTA), tibiotalar surface angle (TTS), anterior distal tibia angle (ADTA), and the lateral talar station (LTS). Radiographs were also evaluated for the development of peri-implant lucency and subsidence. Data was tested for normality. T-tests were used to determine differences between preoperative data and postoperative data. A p

Category: Ankle; Ankle Arthritis; Other Introduction/Purpose: Periprosthetic infection is a devastating complication in total ankle arthroplasty (TAA). Measures that can reduce or eliminate infection occurrence are warranted for further investigation, particularly if they also minimize added costs, operative time or potential adverse effects. There remains insufficient evidence to show definitive benefits or risks associated with use of local antibiotics such as vancomycin for infection prevention. The purpose of this study was to determine the effects of topical vancomycin powder application in TAA and whether it may decrease infection rate in the subacute postoperative period. To our knowledge, this is the first comparative study in a general population undergoing TAA. Methods: A retrospective study was conducted based on a consecutive series of patients who underwent TAA performed by a single senior surgeon. The control group without vancomycin powder was matched to the study group that received application over the implants prior to closure, which was based on when the surgeon transitioned to usage in all patients. Various demographic data for the patients was collected. Only patients with a minimal follow up of 80 days were included in order to capture the perioperative period of infection. Infection rate was based on a definition of deep infection necessitating inpatient hospitalization for IV antibiotics and/or surgical intervention. The associations of various demographic factors and vancomycin application with infection rate were calculated with chi square and odds ratio. Significance level was set to 0.05. Results: A total of 252 patients (n=103 without, and 149 with vancomycin powder) were included in the study. The overall infection rate was 3.2%, which was not correlated with a history of diabetes, BMI, additional concurrent surgery, or age, but was associated with current positive smoking status (p=0.03). The infection rates between the groups that received or did not receive vancomycin powder were not statistically significantly different (2.7% vs 3.9%, respectively, p=0.59). The odds ratio (OR) of infection with vancomycin powder was not statistically significant either, at OR=0.68 (95% CI 0.17-2.81). However, the vancomycin group did have a significantly higher number of patients with previous wound issues (12 vs. 2; p=0.04) and infection (7 vs. 0; p=0.04) as well as concomitant surgeries (81 vs. 41; p=.02). Conclusion: The consequences of periprosthetic TAA infection are substantial, and the risks should be mitigated. Although this study did not detect a statistically significant difference in infection rates between patients who received or did not receive vancomycin powder, there was a trend towards risk reduction by about 30%. In addition, current smoking was found to be significantly associated with higher rates of infection and smoking cessation can serve as another point of intervention. As the complexity of patient factors and indications for performing total ankle arthroplasty expand, vancomycin powder offers a relatively cost-effective, safe, and convenient option to potentially reduce infection.

Category: Other; Ankle; Arthroscopy; Bunion; Hindfoot; Lesser Toes; Midfoot/Forefoot; Trauma Introduction/Purpose: The COVID-19 pandemic has brought a major increase in telemedicine utilization to conserve resources and maintain social distancing. The rapid transition over a short period of time has exposed challenges and limitations of virtual visits, especially with regards to performing an effective and efficient physical examination. Within months, orthopedic telemedicine guides were published for patient education and facilitating the musculoskeletal examination. These publications, however, included only a short video clip to explain to the patient how to participate in the examination during a telemedicine visit. In the foot and ankle subspecialty, the closely adjacent complex anatomy compared to other areas of the body presents unique challenges for physical exam. Methods: To optimize the efficiency and efficacy of the examination portion of the visit for both patients and providers, we designed and recorded an instructional video that is sent to all patients by email a minimum of 1 week prior to their appointment. This video consists of a step-by-step guide on how to take suitable photos and videos of their feet and ankles for the physical examination portion of their visit. These media files are then directly uploaded by the patients into their EMR or emailed to the physician's office to be uploaded for access by the provider before and during the virtual visit. Along with the video, patients are given a link to test their microphone and camera in advance of the visit to ensure adequate functionality and positioning. Results: Our pre-appointment instructional video has been effective to methodically replicate the most important aspects of an in-person foot and ankle evaluation. Both physicians and patients appear to benefit from the tutorial video by having more time during the telemedicine visit to focus on history, assessment, and plan. Patients are more actively involved in the clinical data collection process because they are educated on what to expect and how to best prepare and participate in telemedicine visits. Moreover, having a set of systematic and detailed photos and recordings of the patient's foot and ankle beforehand better focuses interaction and discussion with the patient during the telemedicine encounter. Additionally, these are saved into the patient's electronic medical record, available for reference and later review. Conclusion: Physical examination plays a critical role in diagnosis and treatment in the orthopedic foot and ankle subspecialty. More research is needed to discern how best to utilize virtual modalities as they become more commonplace, not just from the imposition from the COVID pandemic but also from the standpoint of patient convenience and time efficiency. Here we have described our creation of a pre-visit educational video to guide and engage patients on acquiring invaluable physical examination information for the orthopedic foot and ankle telemedicine encounter.

Category: Basic Sciences/Biologics; Hindfoot; Sports Introduction/Purpose: Different animal models of Achilles tendinopathy have been proposed in the literature. They usually involve the induction of tendinopathic findings by either chemical stress (most commonly with one or more injections of collagenase, mimicking intrinsic factors) or mechanical stress (by repetitive exercise-induced stress with treadmill running exercises, simulating extrinsic risk factors). To date, no study has evaluated the combination of a mechanical trigger followed by collagenase injections, replicating the logical and sequential steps involved in the development the human pathology. Our goal was to develop this novel animal model of Achilles tendinopathy and to compare histological and functional findings with animals subjected to isolated mechanical or chemical stress, as well as to controls. Methods: Sixty-four Sprague-Dawley rats were divided into four groups (n=16): isolated treadmill running protocol (15o uphill running, 20meters/minute, 1hour/day, 3 weeks duration, weeks 2-4); isolated injections of collagenase (0.1mg each, 3 injections total, weeks 5-7); treadmill protocol (weeks 2-4) followed by three consecutive collagenase injections (weeks 5-7); and controls, no running and three injections of normal saline (weeks 5-7). Five animals from each group were sacrificed at weeks 8 and 10. Six animals by group were sacrificed at week 12. Gait analysis was performed at weeks one (after acclimation), five (following running protocol), eight (following injection protocol) and twelve (just before latest sacrifice time-point). Histological findings were assessed by the Movin Tendinopathy Score (eight parameters, scored from 0-3, total score 0-24), assessing collagen arrangement, structure, and stainability, cellularity, vascularity, nuclear rounding, hyalinization and presence of glycosaminoglycans. Gait parameters included stand and swing times, stride length, duty cycle and swing length. Results: After 8 weeks, significantly increased tendinopathic scores (p

Category: Ankle; Hindfoot Introduction/Purpose: Multiple Lateral column lengthening procedures have been described for the correction of the abduction component of stage II flatfoot deformity. The Hintermann osteotomy, although technically difficult, offers powerful lengthening of the lateral column with low risk of violating the articular cartilage of the subtalar joint as compared to the more widely performed Evans osteotomy. This study reports on the radiographic and clinical outcomes of the Hintermann osteotomy performed by a single surgeon. Methods: Patients who underwent reconstruction for stage II flatfoot deformity with a Hintermann lateral column lengthening were restrospectively identified. The talus-1st metatarsal angle, percent talus uncoverage, calcaneal pitch, lateral column length, CC joint subluxation, and distance from CC joint to the osteotomy were measured on pre and postop radiographs. Radiographic union was also assessed. The Kellgren-Lawrence scale was used to assess degenerative changes at the ST, CC, and TN joints. Charts were reviewed for comorbidities, clinical evidence of union, time to protected weightbearing, time to unrestricted weightbearing, signs of peroneal irritation, clinical signs of osteoarthritis progression, and complications. A paired students t test was used to identify differences in radiographic parameters. Results: Twenty-six patients (30 feet) met inclusion criteria. All osteotomies achieved union with only 1 (1/30) instance of delayed union. Average duration before clinical and radiographic union was 12.6 weeks (9-37). The AP Talus-1st metatarsal angle decreased on average of 12.3 degrees (STD 9.1) (p

Category: Basic Sciences/Biologics; Ankle; Hindfoot Introduction/Purpose: The tall Controlled Ankle Motion (CAM) boot and the short CAM boot are commonly used devices to immobilize the foot and ankle. However, the effect of these devices on joint contact pressures is unknown. The objective of this study is to assess the effect of the tall CAM boot and short CAM boot on contact pressures of the ankle, subtalar, talonavicular, and calcaneocuboid joints. We hypothesize that both the tall CAM boot and short CAM boot will reduce contact pressures of the ankle and hindfoot joints, with the tall CAM boot having the greatest effect. Methods: Eight lower extremity cadaver specimens were mounted on a servohydraulic test frame. The specimens were loaded to 700 N at a cyclical frequency of 1 Hz with the posterior tibial, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and Achilles tendon physiologically tensioned. TekScan (TekScan, Boston, MA) pressure sensors were placed in the ankle, subtalar, talonavicular, and calcaneocuboid joints. In the sagittal plane, the specimens were loaded on a neutral surface, followed by 20o of dorsiflexion. Each specimen served as its own control, with contact pressures measured with no immobilization (control), followed by placement in a short CAM boot and tall CAM boot. In addition, contact pressures in the immobilized limbs were measured at muscle loads both equal to and half of the load applied to the control in order to account for decreased muscle activation during immobilization. Results: There was no difference in the average and peak contact pressures of the ankle, subtalar, talonavicular and calcaneocuboid joints when comparing the short CAM boot to no immobilization at equal tendon loads. The tall CAM boot significantly decreased average and peak contact pressures of the ankle, subtalar, and talonavicular joints when compared to no immobilization. The tall CAM decreased the contact pressures of the talonavicular and subtalar joint to a greater degree than the ankle joint. The reduction in contact pressures was accentuated when the load applied to the tendons was decreased in accordance with diminished muscle activation during immobilization. Neither immobilization device decreased the contact pressures of the calcaneocuboid joint at equal tendon loads. Neither CAM boot changed the center of pressure of any joint. Conclusion: Immobilization in a tall CAM boot decreases contact pressures of the ankle and hindfoot in both a neutral position and in dorsiflexion. A tall CAM boot should be used clinically if the goal of its use is to maximally reduce contact pressures of the ankle and hindfoot. The tall CAM boot is better at reducing the contact pressures of the subtalar and talonavicular joint than the ankle joint.

Purpose: Imaging is limited in the evaluation of bacterial infection. Direct imaging of in situ bacteria holds promise for noninvasive diagnosis. We investigated the ability of a bacterial thymidine kinase inhibitor ([ 124 I]FIAU) to image pulmonary and musculoskeletal infections. Methods: Thirty-three patients were prospectively accrued: 16 with suspected musculoskeletal infection, 14 with suspected pulmonary infection, and 3 with known rheumatoid arthritis without infection. Thirty-one patients were imaged with [ 124 I]FIAU PET/CT and 28 with [ 18 F]FDG PET/CT. Patient histories were reviewed by an experienced clinician with subspecialty training in infectious diseases and were determined to be positive, equivocal, or negative for infection. Results: Sensitivity, specificity, positive-predictive value, negative-predictive value, and accuracy of [ 124 I]FIAU PET/CT for diagnosing infection were estimated as 7.7% to 25.0%, 0.0%, 50%, 0.0%, and 20.0% to 71.4% for musculoskeletal infections and incalculable-100.0%, 51.7% to 72.7%, 0.0% to 50.0%, 100.0%, and 57.1% to 78.6% for pulmonary infections, respectively. The parameters for [ 18 F]FDG PET/CT were 75.0% to 92.3%, 0.0%, 23.1% to 92.3%, 0.0%, and 21.4% to 85.7%, respectively, for musculoskeletal infections and incalculable to 100.0%, 0.0%, 0.0% to 18.2%, incalculable, and 0.0% to 18.2% for pulmonary infections, respectively. Conclusions: The high number of patients with equivocal clinical findings prevented definitive conclusions from being made regarding the diagnostic efficacy of [ 124 I]FIAU. Future studies using microbiology to rigorously define infection in patients and PET radiotracers optimized for image quality are needed.

Category: Ankle, Hindfoot Introduction/Purpose: The tall Controlled Ankle Motion (CAM) boot and the short CAM boot are commonly used devices to immobilize the foot and ankle. These devices are preferably used instead of casts and splints as they are easily removed, allowing possible wound examination, personal hygiene, and therapeutic exercises. However, the effect of these devices on joint contact pressures is unknown. The aim of this study is to assess the effect of the tall CAM boot and short CAM boot on contact pressures of the ankle, subtalar, talonavicular, and calcaneocuboid joints. We hypothesize that both the tall CAM boot and short CAM boot will reduce contact pressures of the ankle and hindfoot joints, with the tall CAM boot having the greatest effect. Methods: Eight lower extremity cadaver specimens were mounted on a servohydraulic test frame. The specimens were loaded to 700 N at a cyclical frequency of 1 Hz with the posterior tibial, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and Achilles tendon physiologically tensioned. TekScan (TekScan, Boston, MA) pressure sensors were placed in the ankle, subtalar, talonavicular, and calcaneocuboid joints. In the sagittal plane, the specimens were loaded on a neutral surface, followed by 20o of dorsiflexion. Each specimen served as its own control, with contact pressures measured with no immobilization (control), followed by placement in a short CAM boot and tall CAM boot. In addition, contact pressures in the immobilized limbs were measured at muscle loads both equal to and half of the load applied to the control in order to account for decreased muscle activation during immobilization. Results: There was no difference in the average and peak contact pressures of the ankle, subtalar, talonavicular and calcaneocuboid joints when comparing the short CAM boot to no immobilization at equal tendon loads. The tall CAM boot significantly decreased average and peak contact pressures of the ankle, subtalar, and talonavicular joints when compared to no immobilization. The reduction in contact pressures was accentuated when the load applied to the tendons was decreased in accordance with diminished muscle activation during immobilization. Neither immobilization device decreased the contact pressures of the calcaneocuboid joint at equal tendon loads. Conclusion: Immobilization in a tall CAM boot decreases contact pressures of the ankle and hindfoot in both a neutral position and in dorsiflexion. A tall CAM boot should be used clinically if the goal of its use is to maximally reduce contact pressures of the ankle and hindfoot.

Category: Ankle, Ankle Arthritis Introduction/Purpose: A major complication of total ankle replacement (TAR) is a periprosthetic joint infection (PJI). The reported rate of this complication ranges between 2.4 – 8.9%. Identifying preoperative patient characteristics that correlate with an increased risk of PJI is of great interest to orthopaedic surgeons, as this may assist with appropriate patient selection. The purpose of this study is to systematically review the literature to identify risk factors that are associated with PJI following TAR. Methods: Utilizing the terms “(risk factor OR risk OR risks) AND (infection OR infected) AND (ankle replacement OR ankle arthroplasty)” we searched the PubMed/MEDLINE electronic databases. Using the PRISMA guidelines, studies were selected for inclusion if they assessed clinical risk factors for developing a PJI following TAR. In addition, the reference lists of included studies were also reviewed and compared to the collected studies to ensure that no pertinent papers were omitted. The quality of the included studies was then assessed using the American Academy of Orthopaedic Surgeons Clinical Practice Guideline and Systematic Review Methodology. Recommendations were made using the overall strength of evidence. Results: Eight studies met the inclusion criteria, totaling 12,704 patients who underwent a TAR. A limited strength of recommendation can be made that the following preoperative patient characteristics correlate with an increased risk of PJI following TAR: inflammatory arthritis, prior ankle surgery, age greater than 65 years, body mass index less than 19, peripheral vascular disease, chronic lung disease, hypothyroidism, and low preoperative AOFAS hindfoot scores. There is conflicting evidence in the literature regarding the effect of obesity, tobacco use, diabetes, and duration of surgery. Conclusion: Several risk factors were identified as having an association with PJI following TAR. These factors may alert surgeons that a higher rate of PJI is possible. However, because of the low level of evidence of reported studies, only a limited strength of recommendation can be ascribed to regard these as risk factors for PJI at this time.

Category: Sports Introduction/Purpose: Flexor digitorum longus (FDL) transfer to the lateral foot for concomitant irreparable rupture of the peroneal tendons has been reported in few clinical series. The purpose of this study is to provide midterm outcomes including subjective outcome scores, clinical examination data, and objective power after single-stage FDL tendon transfer. Methods: Twenty-five consecutive patients over a 7 year period (2008-2015) underwent FDL to fifth metatarsal transfer for irreparable peroneal tendon tears. Fifteen patients with a mean follow-up of 53.7 months completed the pain visual analog score (VAS), Foot Function Index (FFI), Short Musculoskeletal Functional Assessment (SMFA), and Foot and Ankle Ability Measure (FAAM) scores and participated in range of motion, peak force, and peak power testing. Results: All 15 patients were satisfied with their surgery and reported a reduction in their pain level with the average decrease in VAS of 5.59 +/- 2.5 (range: 1 - 9). The mean FAAM was 86.4 +/- 9.7 (range: 52.4 - 100). The mean FFI was 12.8 +/- 9.2 (range: 0 - 21.4). The mean SMFA Function index was 12.4 +/- 8 and the mean SMFA Bothersome Index was 11.5 +/- 11. Patients had on average 58% less eversion and 28% less inversion compared to the nonoperative side. Both isometric peak torque and isotonic peak velocity were decreased by 38.4% and 28.8%, respectively. On average, power in the operative limb was diminished by 56% compared to the nonoperative limb. Conclusion: FDL transfer to the lateral foot for significant, non-reconstructable peroneal tendinopathy is an effective, and durable treatment option.

Category: Midfoot/Forefoot Introduction/Purpose: Surgical treatment for osteoarthritis of the first metatarsophalangeal joint (MTPJ) includes cheilectomy or fusion for advanced arthritis. In addition, procedures to preserve or restore motion have demonstrated promising short-term results. Currently, no studies have described long-term results following interpositional arthroplasty. Our institution has performed interpositional arthroplasty with autograft (joint capsule/extensor hallucis brevis) or allograft (dermal matrix) with anecdotal success for over 15 years. The purpose of this study is to report long-term outcomes following interpositional arthroplasty. Methods: All patients undergoing interpositional arthroplasty at our institution from 2000-2015 were identified and a retrospective chart review was performed. Long-term follow-up was conducted through a telephone survey to obtain survivorship, satisfaction, and functional scores. Average follow-up was 89.1 months (range, 6 to 179 months). Survivorship of the interpositional arthroplasty procedure was defined as no subsequent surgery on the hallux after the index procedure. Results: From 2000-2015, 292 interpositional arthroplasties were performed at our institution. The overall failure rate was 1.7 % (5/292), which included patients requiring revision surgery (2 patients) or subsequent fusion (3 patients). Autograft interpositional arthroplasty had a failure rate of 2.1% (2/94) and allograft interposition was 1.5% (3/198). Failure and reoperation occurred at an average of 11 months from the index procedure (range, 6-17 months). 88.7% of patients rated their overall satisfaction as excellent or good. Average preoperative VAS score was 8.2 ± 1.5 (range, 6 to 10) and 2.1 ± 1.6 (range, 0 to 7) at latest follow-up, and (79.1%) patients reported tolerance to fashionable shoes. There were no major wound complications. The most common complications were metatarsalgia (8.6%) and cock-up deformity (5.7%). Conclusion: Interpositional arthroplasty demonstrated excellent long-term survivorship and high patient satisfaction at long-term follow-up.

Category: Other Introduction/Purpose: Adult acquired flatfoot deformity (AAFD) is a biomechanical derangement involving the three- dimensional (3D) midfoot and hindfoot osseous complex, which can be challenging to optimally characterize using conventional two-dimensional (2D) plain radiographs. Weightbearing (WB) Cone-Beam CT (CBCT) can better demonstrate the deformity of the 3D structures during WB. Therefore, we compared validated AAFD measurements between non-weightbearing (NWB) and WB CBCT images. Methods: In this prospective, IRB approved study, 20 patients were included, 12 males and 8 females, mean age of 54.21 (20-88) years, with clinical diagnosis of flexible AAFD. Subjects were scanned with standing (WB) and seated (NWB) CBCTs. WB and NWB CBCT images were assessed with traditional flatfoot measurements obtained at sagittal, coronal, and axial planes using predefined anatomical landmarks, by two independent observers. Interobserver reliability was calculated using Pearson correlation. Results: The measurements in patients with AAFD differed significantly between WB and NWB CBCT images. Specifically, WB images showed, when compared to NWB, decreased forefoot arch angle (mean difference: 9.91°, p < 0.0001), increased talus-first metatarsal angle (10.59°, p < 0.0001), increased navicular-medial cuneiform angle (13.89°, p < 0.0001), decreased navicular-floor (coronal 14.05mm/sagittal 14.91mm, p < 0.0001) and navicular-skin distances (coronal 5.87mm/sagittal 8.25mm, p < 0.0001), decreased medial cuneiform-floor (coronal 10.79mm/sagittal 11.07mm, p < 0.0001) and medial cuneiform-skin distances (coronal 4.45mm/sagittal 5.78mm, p < 0.0001), and decreased cuboid-floor (5.78mm, p < 0.0001) and cuboid-skin distances in the sagittal plane (4.60mm, p < 0.0001). Interobserver reliability was good to excellent (0.610-0.991). Conclusion: Traditional adult acquired flatfoot deformity radiographic measurements are obtainable using high resolution 3D WB CBCT imaging, and can help characterize the biomechanical derangements during weightbearing in subjects with flexible AAFD.

Category: Basic Sciences/Biologics Introduction/Purpose: Numerous studies, as evident in literature, have attempted to develop an induced Achilles tendinopathy animal model. The most common models include collagenase injections and mechanical overload of the tendon, but both are controversial. The mechanical overload model creates a chronically induced tendinopathy and is time intensive. In addition, once the stimulus is removed the tissue changes often heal. The collagenase injection model is quicker, rarely evolve to healing but frequently results in an early acute tendon reaction. The primary objective of this study is to compare biomechanical and histological findings between two collagenase induced Achilles tendinopathy protocols. The hypothesis is that consecutive low-dose collagenase injections will result in progressive and long-lasting tendinopathy findings as compared to the traditional single high-dose injection. Methods: In this IRB approved study, the population was composed of forty-eight (n=48) New Zealand breed rabbits. Forty-two (n=42) rabbits were randomly divided into two groups (n=21). The first group, which served as the control, had both Achilles tendons injected by a single dose (0.3 mg) of A1 collagenase (Sigma-Aldrich©), as described in literature. The second experimental group had three low-dose injections (0.10 mg) with 2 weeks between each injection. Another six animals (n=6) were also randomized into two groups (n=3) receiving one-dose versus 3 injections of saline solution with 2 weeks between each injection. The animals were euthanized after 10, 12 and 16 weeks. Histological and biomechanic analysis of the Achilles tendons were carried out using a dynamic mechanical testing machine (Electropuls®, model E10000, Instron®). Mechanical strength and histological scores of tendinopathy (Bonar scoring system) were compared among the groups at each time-point. Results: After 16 weeks, all biomechanical and histological parameters analysed showed consistent differences between the groups (p < 0.05), with more pronounced and long-lasting tendinopathy findings in the Achilles tendon of the experimental group (serial collagenase injections), when compared to the control groups (single collagenase dose and single/multiple saline injections). The mean Bonar sum-score of tendons after 16 weeks in the experimental group was greater than the mean histologic score of control tendons (8.53 ± 1.52 versus 1.1 ± 0.83 in saline group and 5.2 ± 1.12 in single dose group). No statistically significant differences were found between the different collagenase injection groups at weeks 10 and 12. Conclusion: The protocol of three consecutive low-dose collagenase injections has shown biomechanical and histological findings compatible with progressive and long-lasting tendinopathy as compared to single high-dose injection. This protocol represents a feasible and effective animal model of induced Achilles tendinopathy.

Category: Basic Sciences/Biologics Introduction/Purpose: Managing Charcot Neuroarthropathy (CNA) remains a challenge facing the foot and ankle surgeons. Lack of understanding the pathogenesis of the disease prevents the development of novel therapies. Our previous studies revealed the involvement of fibroblast-like synoviocytes in the pathology of CNA. Residing in the synovium are also mesenchymal stem cells (MSCs), which maintain tissue homeostasis. In this study, MSCs isolated from the synovium of CNA and non-CNA patients were comparatively analyzed for their potential role in the pathology of CNA. Methods: Synovial samples were collected from CNA patients (n=7) and patients with osteoarthritis or intraarticular fracture (non-CNA; n=7), during foot and ankle procedures (approved by IRB). The synovial samples were minced and digested with 0.1% collagenase to isolate MSCs. The cells were plated and cultured in low density for counting colony-forming units-fibroblast (CFU- F), which is indicative of the number of MSCs. The colonies formed by CNA-MSCs and non-CNA MSCs were further characterized by size and imaging density. CNA-MSCs and non-CNA MSCs were cultured in adipogenic, osteogenic and chondrogenic differentiation media. The differentiation potentials of CNA-MSCs and non-CNA MSCs were assessed with histochemical staining and quantitative gene expression. Results: CFU-F: The number of colonies formed by CNA-MSCs was 6 ± 3.5 per (1/2) plate, while it was 43 ± 21.6 by the non- CNA MSCs (p < 0.05; Fig 1). The average size (pixels) of colonies was smaller in the CNA-MSCs than the non-CNA MSCs (4780 vs. 7960). When the colonies were stratified into high, medium and low density subgroups, colonies formed by the CNA-MSCs had a reduced density compared with the non-CNA MSCs (30±6 vs. 35±10) in the high density subgroup. Differentiation: Expression of adipogenic marker gene PPAR-γ by CNA-MSCs was less than half of that by non-CNA MSCs. The expression of osteogenic marker gene RUNX2 by CNA-MSCs was a third of that by the non-CNA MSCs. Similarly, the expression of chondrogenic marker genes, including SOX9 and type II collagen, by the CNA-MSCs declined as compared with the non- CNA MSCs. Conclusion: The synovium in CNA joints had fewer MSCs and that may impact joint’s response to inflammation and tissue repair. Furthermore, CNA-MSCs were declined in differentiation potentials. Analyses of the size and density of the colonies formed by CNA-MSCs showed that a subpopulation of MSCs was particularly affected. Further study will focus on the pathological role of the high-density subpopulation of MSCs in the development of CNA.

Category: Hindfoot Introduction/Purpose: Hindfoot arthrodesis has demonstrated reliable long-term outcomes for treatment of symptomatic hindfoot arthritis, but the incidence of nonunion of the talonavicular joint has been reported as high as 29%. Retrograde percutaneous insertion of a dorsolateral screw in addition to the standard medial distal to proximal screw has been shown to add significant construct stiffness across the talonavicular joint in biomechanical testing. However, placement of this dorsolateral screw may result in increased neurovascular injury. The purpose of this cadaveric study was to investigate the proximity of important anatomic structures to dorsal, percutaneous, screw fixation across the talonavicular joint for hindfoot arthrodesis. Methods: 17 fresh frozen cadaveric limbs without deformity were transected across the supracondylar femur. A single fellowship-trained orthopedic surgeon performed all procedures. Percutaneous dorsolateral fixation across the talonavicular joint was performed with a cannulated screw. A 1.5-cm incision was created over the lateral third of the navicular after localization under fluoroscopy, and a 4.5 mm cannulated screw was inserted using standard AO technique. The guide wire was left within the screw. The incision was extended 2 cm proximal and distal and a separate orthopaedic surgeon used a caliper to measure the distance from the guide wire to the superficial peroneal nerve, extensor hallucis longus, extensor digitorum longus, deep peroneal nerve, and deep peroneal artery. Injuries to neurovascular structures were noted. Finally, solder wire was laid atop the deep neurovascular bundle to allow radiographic imaging of the screw and the bundle. Results: Injury to the deep neurovascular bundle occurred in 6 of 17 specimens (35.3%). There were 5 injuries (29.4%) to the deep peroneal nerve, 3 to the deep peroneal artery, and 2 to branches of the superficial peroneal nerve. The average distances from the guide wire to anatomic structures were superficial peroneal nerve: 1.8 mm (0.5-4.10 mm), extensor hallucis longus: 6.10 mm (0.6-15.0), extensor digitorum longus: 6.8 mm (0.5-14.0 mm), deep peroneal artery: 2.27 mm (0.0-5.1), and deep peroneal nerve: 2.4 mm (0.0-7.10 mm). Conclusion: A high rate of neurovascular injury was observed after percutaneous dorsolateral fixation across the talonavicular joint. These data suggest that this approach should be avoided in favor of an open approach, which allows identification and protection of the superficial peroneal nerve, extensor tendons, and the neurovascular bundle.

Category: Ankle Arthritis Introduction/Purpose: Surgical restoration of the anatomical relationship between talus and tibia is considered crucial for longevity of total ankle arthroplasty (TAA). Weight-bearing (WB) radiographs are the current standard for evaluating the sagittal balance alignment, which are, however, prone to rotational misalignment and potentially altered measurements. Metal artifact reduction sequence (MARS) MRI is a cross-sectional technique that minimizes implant-induced artifacts and affords the visualization of bone-implant interfaces and periprosthetic bone without distortions. Although not weight-bearing, MARS MRI offers the ability to align the image plane to the true sagittal axis of the talar implant and anatomically correct measurements. Therefore, the purpose of this study was to compare sagittal balance alignment measurements on MARS MR images and standard WB radiographs in patients with TAA. Methods: In this IRB-approved, prospective study, 23 subjects [10 men/13 women, age 60(41-73) years; 13(3-24) months post- op] underwent MARS MRI and standard lateral WB radiographs. Standardized MARS MR images were obtained in alignment to the sagittal talar component axis and use of a boot-shaped MRI coil. Maximum-intensity-projection MR images that resemble lateral radiographs were created to bring anatomic landmarks, such as lateral talar process, talonavicular joint line, talar implant, tibial shaft, and posterior talus into one single image. Three board-certified foot ankle surgeons performed sagittal balance alignment measurements twice in an independent, random and blinded fashion. The second set of measurements was obtained 1 months after the first assessment. In accordance with published measurements, lateral talar station (LTS), tibial axis-to-talus (T-T) ratio, and normalized tibial axis-to-lateral-process (T-L) distance were measured. Pearson correlation coefficient (r), Concordance-Correlation-Coefficient (CCC) and Intraclass-Correlation-Coefficient (ICC) were used for statistical analysis. Bonferroni-corrected p-values ≤ 0.01 were considered significant. Results: The intra-observer agreement was excellent for radiographic (CCC = 0.93 - 0.97) and MRI (CCC = 0.90 - 0.97) measurements. Inter-observer agreements were good-to-excellent with overall higher agreements for MRI (ICC = 0.76 - 0.93) than for radiography (ICC = 0.58 - 0.95) measurements. There was statistically significant inter-method correlation between radiographic and MRI measurements including LTS (r=0.83, p < 0.001), T-T ratio (r=0.86, p < 0.001) and normalized T-L distance (r=0.72, p < 0.001). The T-T ratios of radiographs and MRI were statistically not different (p=0.36), whereas LTS and normalized T-L distance were significantly lower on MR images when compared with radiographs (p < 0.001). Conclusion: Sagittal balance measurements performed on standardized weight-bearing radiographs and standardized MARS MR images demonstrate substantial correlation and similarity. Given its high inter- and intra-observer agreement, MARS MRI may be helpful for the evaluation of sagittal balance following TAA.

Category: Other Introduction/Purpose: To evaluate interobserver reliability among readers of different clinical experience by applying measurements for adult acquired flatfoot deformity (AAFD) using high-resolution three-dimensional (3D) weightbearing (WB) cone-beam CT (CBCT) examination. Methods: In this IRB approved study, 20 patients with flexible AAFD [12 male, 8 female; mean age 54.2 (20-88) years] were scanned with standing (weightbearing) CTs. Two blinded observers, a medical student and a foot/ankle surgeon, applied validated AAFD measurements in sagittal, coronal, and axial planes using predefined anatomical landmarks. Interobserver reliability was calculated using Pearson correlation. Results: There was significant interobserver agreement with high correlation for the following measurements(p < 0.0001): distances between medial cuneiform to-floor (r=0.981) and to-skin (r=0.986), navicular to-floor (0.992) and to-skin (r=0.900); cuboid to-floor (r=0.975) and to-skin (r=0.978), and calcaneus-to-fibula (r=0.808); calcaneal inclination angle (r=0.795); forefoot arch angle (r=0.983); and subtalar horizontal angles at 25%, 50%, and 75% of the anteroposterior joint length (r=0.784, 0.891, 0.809). Significant agreement with moderate correlation was additionally demonstrated for talar-first metatarsal angle (r=0.553, p < 0.014), medial cuneiform-first metatarsal angle (r=0.668, p < 0.001), and navicular-cuneiform angle (r=0.746, p < 0.0002). Level of training did not influence the reliability of any measurements except medial cuneiform-first metatarsal angle (specialist: 8.83°; student: 1.61°; p < 0.01). Statistically insignificant difference between readers (p>0.05) was noted in mean talar-first metatarsal and subtalar horizontal angles. Conclusion: While literature describes large variability for AAFD measurements from plain radiographs among readers of varying medical experience, 3D WB CBCT can yield similar measurements using predefined planes with high reliability, independent of reader experience.

Category: Basic Sciences/Biologics Introduction/Purpose: The pathology of Charcot neuroarthropathy (CNA) presents inflammation, and bone and cartilage destruction. It is still unclear how the neuropathic signals lead to joint inflammation and destruction. Neuropeptides are secreted by neurons and involve in the regulation of inflammation. Synovium is richly innervated and known to play a critical role in the pathology of inflammatory arthritis. This study is designed to investigate the distribution of several neuropeptides, such as vasoactive intestinal peptide (VIP), substance P (SP) and calcitonin gene-related peptide (CGRP), in CNA synovium, in comparison with non-CNA synovium, with immunohistochemistry. Methods: Synovial samples were collected from CNA patients (n=3) and patients with osteoarthritis and intraarticular fracture (non-CNA; n=3), during foot and ankle surgery (approved by IRB). The tissue samples were fixed with 4% paraformaldehyde, embedded in O.T.C media and sectioned with a cryostat. From each patient, 6-9 sections were randomly selected for immunohistochemistry. After blocking the tissue sections with normal serum, primary antibody of SP, VIP and CGRP was separately applied and incubated at 4ºC overnight. The biotinylated secondary antibody and ABC kit (Victor Laboratories) were applied subsequently. DAB (3,3’-diaminobenzidine) was used for colorimetric detection (brown) of immunohistochemical reactions. The cell nuclei were stained with hematoxylin. The staining was viewed under a microscope and images were taken with a digital camera. Results: In the non-CNA synovium, SP was stained around neuro-vascular bundles and intensely stained on the surface of the synovium, i.e. the intimal layer. In the CNA synovium, SP staining was increased and more diffuse into the subintimal layer of the synovium (Fig 1). In non-CNA synovium, VIP was detected along the surface area of the synovium but not limited in the intimal layer. In CNA synovium, VIP was a similar staining pattern with a reduced staining intensity. The CGRP staining was primarily limited in the intimal layer in the non-CNA synovium. In CNA synovium, CGRP was stained in the intimal layer with an increased intensity. Conclusion: SP, VIP and CGRP are well-studied neuropeptides and have broad biological and pathological functions. All of them were detected in the intimal layer, where fibroblast-like synoviocytes are located. Fibroblast-like synoviocytes are fundamental elements of joint inflammation and are capable of degradation of bone and cartilage directly and indirectly. The changed patterns of SP, VIP and CGRP distributions in CNA synovium revealed by immunohistochemistry indicate a possible pathological pathway in CNA development: the unbalanced neuropathic signals direct fibroblast-like synoviocytes to an inflammatory state, which trigger the cascade of bone and cartilage destruction in CNA.

Category: Sports Introduction/Purpose: Non-insertional Achilles tendinitis is a common cause of posterior ankle and heel pain in active and sedentary patients. Though the majority of patients respond to first-line non-operative management including activity modification, immobilization, orthotics, and physical therapy with tendon stretching, there is no consensus for patients that fail these treatments. We evaluate the role of iliac crest bone marrow aspirate concentrate (BMAC) as a safe and effective treatment option for recalcitrant cases. Methods: A retrospective chart review was conducted of patients with greater than 12 months of non-insertional Achilles tendinitis symptoms despite appropriate conservative treatment. Each patient had BMA harvested from the iliac crest, concentrated by centrifugation, and then injected into the Achilles tendon. Symptoms were assessed using the Visual Analogue Scale (VAS) pain score, collected at the preoperative office visit and at 6 weeks, 12 weeks, and 24 weeks after the procedure. Co- morbidities, concurrent procedures, and complications were also recorded. Results: A total of 21 patients (22 feet) were treated with iliac crest BMA concentrate injections. Preoperatively, the average VAS pain score was 6.8 (SD 2.0). Postoperatively, the average VAS was 4.0 (SD 2.5) at 6 weeks, 2.7 (SD 2.1) at 12 weeks, and 2.2 (SD 2.1) at 24 weeks. At 24 weeks postoperatively, there was a statistically significant decrease VAS score from baseline (p < 0.001), with a mean decrease by 4.6 (SD 3.1). There were no adverse effects reported at the surgical site or donor site morbidity at the iliac crest such as wound infection, hematoma, or persistent pain. Conclusion: Iliac crest BMAC appears to be a safe, effective, and potentially lasting treatment option for patients with intractable, non-insertional Achilles tendinitis. Patients demonstrated a statistically significant decrease in VAS pain score postoperatively with no complications at the donor or injection site.

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) is an often successful treatment for end-stage ankle arthritis; however, a subset of patient presents with ankle pain following TAA and concern for early failure. Although radiographs are often diagnostic, patients with normal radiographs and continued pain pose a diagnostic challenge. In those patients, magnetic resonance imaging (MRI) may be helpful to evaluate periprosthetic bone and soft tissues. Traditional high-bandwidth (high-BW) metal artifact reduction sequence (MARS) MRI lessens metal artifacts, but image distortions remain with Cobalt-Chromium implants. Slice- Encoding-Metal-Artifact-Correction (SEMAC) is a recently FDA-approved, advanced MARS technique that promises more powerful metal suppression. Therefore, we prospectively tested the hypothesis that SEMAC MARS MRI facilitates better metal reduction and visibility of periprosthetic structures than does traditional MARS MRI in patients with TAA. Methods: In this IRB-approved study, 20 volunteers [10 females/10 males; age, 59 (41-73) years, 15 (3-24) months post- operatively] with TAA were prospectively enrolled. The research protocol consisted of high-BW and SEMAC MARS MRI using a clinical 1.5 Tesla MRI scanner and a dedicated boot-shaped MRI coil. For each technique, intermediate-weighted and fat- suppressed MR images were obtained in axial, sagittal and coronal orientation. Three observes (2 foot/ankle surgeons and 1 musculoskeletal radiologist) evaluated the high-BW and SEMAC MR images in an independent, random and blinded fashion. Equidistance 5-point Likert scales (1=non-diagnostic, 5=very good) were used to grade image quality as well as the quality of metal suppression and visibility of bone-metal interfaces, tendons, ligaments, bone and joints. Differences between the two MARS techniques were assessed with a Kruskall-Wallis test, and interobserver agreement was graded with Intraclass-Correlation- Coefficient (ICC). Bonferroni-corrected p-values ≤ 0.01 were considered significant. Results: All 20 subjects completed the research protocol. There was good agreement between observers (ICC = 0.79; 95% CI, 0.78-0.80). Image quality of high-BW and SEMAC MR images was similar for tissue contrast, fat suppression, and fluid brightness, whereas image sharpness was one interval higher on high-BW images than on SEMAC images (p < 0.01). Metal reduction of TAA components was significantly better (p < 0.01) on SEMAC images (very good) than on high-BW images (poor-to-adequate). At level of the implants, long flexor and peroneal tendons, deep deltoid, syndesmotic and lateral collateral ligaments, and medial and lateral gutters were significantly better seen (p < 0.01) on SEMAC images (good-to-very good) than on high-BW images (poor-to- adequate). Similar visibility (good-to-very good) was found for the remainder of the tendons, ligaments, bones and joints. Conclusion: Based on the results of our study, we accept the hypothesis that SEMAC MARS MRI outperforms traditional high- BW MARS MRI in the degree of metal artifact reduction as well as visibility of bone implant interfaces and periprosthetic tendons and ligaments at level of the joint line. We believe advanced MARS MRI can be a valuable clinical tool to assess osseous integration and soft tissue lesions in patients following TAA.