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Category: Sports; Ankle Introduction/Purpose: Osteochondral Lesions of the Talus (OLT) may progress into a cascade of cartilage degeneration. While edge-loading on the surrounding tibiotalar articular surfaces has been proposed as principal determinant of cartilage degeneration, the pathophysiological pathways have not yet been clarified. The present study aims to evaluate the patient-specific influence of OLTs on the mechanical behaviour of the surrounding cartilage of the talus and tibia. More specifically, this study aims to investigate whether the location of the OLTs influences their loading characteristics during the range of motion of the ankle joint. Methods: Patient-specific 3D models from 36 patients with an OLT, derived from weightbearing CT, were used to analyse the contact stress on the tibiotalar articulation using Discrete Element Analysis (DEA). A matched, virtual healthy control group was developed for each talus. Mean- , peak contact-stress and contact area were calculated during simulated ankle flexion. Results: The mean talar contact-stress was elevated in the OLT cases, with a notable correlation between ankle flexion and OLT location. Edge loading occurred predominantly in anteromedial lesions during dorsiflexion (2.9 MPa (IQR: 1.3) for OLT versus 2.4 MPa (IQR: 0.9) for the controls), while posteromedial lesions were mostly loaded during plantarflexion (3.5 MPa (IQR: 1.7) for the OLT versus 2.9 MPa (IQR: 1.1) for the controls). Conclusion: OLTs influence the whole-joint articular contact mechanics of the ankle, leading to increased stress on both the talus and the opposing tibia. More specifically, a clear pattern of edge-loading on the surrounding OLT cartilage was found. Anterior lesions had the highest stresses in neutral and dorsiflexion, while Posterior lesions experienced higher stress during plantarflexion. OLT versus Healthy Twin Contact Stress Contact stress plot, depicting the difference between OLT (upper) and the matched, healthy twin (lower) for increasing plantarflexion

Category: Ankle; Sports Introduction/Purpose: Syndesmotic injuries may be associated with subsequent instability, even following operative fixation of etiologic fractures. The development of advanced imaging techniques like weightbearing computed tomography (WBCT) has enabled clinicians to identify subtle syndesmotic instability under physiologic conditions that would otherwise go undetected using conventional CT scans. Moreover, the normal reference ranges for the syndesmotic interval distance, area at 1 cm above the plafond, and volume 5 cm above the plafond have been established. These measurements, however, may be cumbersome and time-consuming to perform. This validation study aims to develop and evaluate the reliability of an automated algorithm that automatically segments WBCTs of the ankle and performs dimensional measurements. Methods: Five bilateral WBCT scans of individuals with operatively confirmed syndesmotic instability were included (10 ankles). An independent observer manually performed the anterior tibiofibular distance (ATFD) at 1 cm above the plafond, posterior talofibular distance (PTFD) at 1 cm above the plafond, the syndesmotic area (SA) at 1 cm above the plafond using 2D ROI, and the syndesmotic volume (SV) at 5 cm above the plafond using 3D ROI. Visage software was used to perform the measurements manually. The same WBCT scans were fed into the automated algorithm to perform the same measurements. The time required to perform the manual and automated measurements was recorded for comparison. The intraclass correlation coefficient (ICC) was measured for repeated automated measurements to evaluate the automation's consistency Results: The manual measurements required 19 (+/-4) minutes on average to perform for each case compared to 9 (+/-1) minutes for the automated measurements (P< 0.05). The ICC between the repeated automated measurements for each case was 0.99. Conclusion: Our automated syndesmosis dimension measurement tool can efficiently perform the ATFD, PTFD, SA, and SV measurements as reliably as an expert clinician would with significantly less time. Incorporating such a tool into existing healthcare software infrastructure, particularly in foot and ankle clinics, may expand the accessibility of this tool and provide immediate data for clinicians to support their decision-making in real time.

Category: Sports; Trauma Introduction/Purpose: Chronic Achilles tendon ruptures (CATR) adefined as those with a diagnosis or treatment exceeding four weeks present with retracted tendon ends and adhesions, complicating treatment and prognosis. Several surgical techniques including flexor hallucis longus (FHL) transfer, turndown flaps, V-Y advancement, and hamstring tendon transfer, have been described as treatment options, each with advantages, drawbacks, and potential complications. Despite the extensive use of patient-reported outcome measurements (PROMs) such as AOFAS, ATRS, and VISA-A, there is a lack of literature concerning comparative analyses of surgical options for CATRs. This study aims to describe the clinical and functional outcomes with each technique, and to providevaluable insights for evidence-based decision-making in the management of this pathology. Methods: This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered on the International prospective register of systematic reviews (PROSPERO, registration No. CRD42023444150). The inclusion criteria encompassed studies reporting clinical outcomes of CATR patients treated with isolated FHL transfer, hamstring tendon transfer, or turndown flaps. Clinical studies reporting at least one of the following outcomes were included: American Orthopedic Foot and Ankle Society (AOFAS) score or complications (wound complications, nerve injury, postoperative deep vein thrombosis, re-rupture, etc.). To be included, the studies had to provide sufficient data for extraction and pooling, including mean value, standard deviation (SD), and the number of subjects. Exclusion criteria comprised studies not published in English, less than 12 months of follow-up, and those with fewer than ten patients. Results: Eleven studies (295 patients) were included for isolated FHL transfer, 9 studies (168 patients) for hamstring transfer, and 6 studies (246 patients) for turndown flaps. All groups demonstrated a comparable improvement in AOFAS scores. The overall weighted complication rates were 4.1% in the Hamstring group, 6.1% in the isolated FHL group, and 12.6% in the turndown flap group. The complication rate in the Hamstring transfer group was significantly lower as compared to the turndown flaps group. The turndown flap group exhibited a significantly higher incidence of wound complications (12.5%, 95% C.I.: 8.4–16.5) compared to the isolated FHL (5.7%, 95% C.I.: 3.2–8.3) and hamstring groups (3.5%, 95% C.I.: 0.9–6.2). Conclusion: While all three techniques yielded comparable improvements in AOFAS scores for CATR management, turndown flaps were associated with a higher incidence of wound complications compared to the other two techniques. Enhanced study designs, incorporating direct comparisons of these different techniques within the same study setting, are essential. This approach will contribute to a clearer path towards identifying the optimal intervention and refining the standard of care for CATR patients.

Category: Sports; Trauma Introduction/Purpose: Achilles Tendon (AT) rupture is one of the most prevalent adult tendon injuries, with the incidence rate estimated to range between 7 to 40 in 100000 person-years. Although some surgical approaches involve incising or removing the Paratenon when repairing injured or degenerative tendons, an alternative perspective suggests preserving the paratenon during AT repair could potentially benefit healing through two proposed mechanisms: retaining the hematoma, which may contain factors with stem cell-like properties and reducing mechanical stress on the skin incision site. The aim of this study was to investigate the potential influence of Paratenon preservation on the outcomes of AT repair in a 5-year follow up study. Methods: After receiving IRB approval, we conducted a single-center study in Tehran, Iran, involving a consecutive series of 52 patients who sustained acute AT ruptures (less than 2 weeks from injury) and underwent a modified surgical technique performed by surgeons affiliated with the local institution. The technique involved careful skin incision while preserving the Paratenon intact and performing the tendon repair over the retained Paratenon (Figure 1). Patients were prospectively evaluated with a mean follow-up duration of 5 years (between 48 to 72 months). Functional outcomes were assessed using the Achilles Tendon Rupture Score (ATRS) and the American Orthopedic Foot and Ankle Society (AOFAS) rating scales in all patients at 6, 9, 18, and 36 months postoperatively. Two complementary follow-up visits at 12 and 24 months after the last visit were scheduled. Results: The mean AOFAS and ATRS scores were 83±4 and 85.7±3.1, respectively, by the 36-month follow-up visit. Approximately 90.1% of patients regained preinjury activity levels during the complementary follow-up visits, including 71.3% of professional athletes returning to prior recreation. Isokinetic testing revealed plantar flexion and dorsiflexion strength deficits of 83.7±5.1% and 87.8±3.6% compared to the uninjured sides at 3 months after the surgery. Calf muscle atrophy was minimal. While 19 patients reported initial activity-related pain, these symptoms resolved within 12 months. No wound complications, nerve injuries, or footwear issues occurred during the study period. Conclusion: Preserving the Paratenon during AT repair showed satisfactory functional and clinical outcomes without any case of the wound complications that are common after open repairs. These findings support the hypothesis that an intact Paratenon aids tendon healing and reduces complication rates. Retaining the Paratenon may also help mitigate the "bowstring" effect on the repaired Achilles tendon. This surgical technique warrants further investigation as a potential strategy for enhancing outcomes following AT ruptures.

Category: Trauma; Ankle Introduction/Purpose: Syndesmosis fixation, a common procedure, is vital for restoring ankle biomechanics, but malreduction occurs in up to 52% of cases, necessitating precise anatomic reduction. While AO guidelines recommend a 20-30 degree trajectory in the coronal plane, the proposed ideal syndesmotic alignment is the line connecting fibula and tibia centroids. Intraoperatively determining the ideal fixation angle is challenging due to non-patient-specific and surgeon-dependent angular direction decisions. This study explores the angle bisector method's potential in establishing a patient- and level-specific syndesmotic fixation angle in cadavers, aiming for reproducibility independent of the surgeon. Additionally, the research assesses the safety of this method concerning major neurovascular structures for potential surgical application. By addressing these aspects, the study contributes to enhancing the precision and reliability of syndesmotic fixation procedures. Methods: Fixations on cadaveric leg specimens were conducted utilizing the angle bisector method at two levels (2 cm and 3.5 cm proximal) parallel to the tibial plafond. Two surgeons employed an open lateral approach for the procedure. The angle bisector method involved using a drill (2.8 mm) and screw (3.5 mm) directed along the bisector of the angle formed between two percutaneously placed K-wires (1.8 mm) at the fixation level, tangent to the anterior and posterior aspects of the fibula and tibia (Figure 1a). Subsequently, CT images of the cadavers were obtained (Figure 1b). The angle between the true centroidal axis (determined by software) and the axis of the screw placed with the angle bisector method was measured. Furthermore, distances between entry points of the centroidal axis and the screw were measured. Distances in millimeters between the positioned K-wires and major neurovascular structures were measured on cadaver dissections. (Sponsored by AOFAS-grant) Results: The mean angle between the centroidal axis and the trajectory of the screw was 2.7 degrees (±2.2, range 0-9.2 degrees) at the 2 cm level and 1.8 degrees (±2.1, 0-7.8 degrees) at the 3.5 cm level. At the 2 cm level, the average distance between the fibular entry points of the centroidal axis and the screw was 1.7 mm (±1.2, range 0-3.2 mm), while at the 3.5 cm level, it was 1.2 mm (±1.3, range 0-2.5 mm). The results exhibited low inter-surgeon variability (ICC > 0.80). The distance between the placed K-wires and major neurovascular structures consistently exceeded 5 mm, ensuring the safety of the technique, as none of these structures incurred damage. Conclusion: Our findings demonstrate that the angle bisector method offers a precise trajectory for syndesmotic fixation, proving its safety and efficacy in surgical applications. It can provide a more precise and patient-specific anatomical trajectory for syndesmotic implant compared to the conventional freehand technique, without increasing fluoroscopy exposure.

Category: Ankle; Trauma Introduction/Purpose: There has been limited investigation into physician reimbursement trends in foot and ankle procedures. The objective of the present study is to query a large, national insurance claims database to assess how utilization and reimbursement has evolved for ankle arthrodesis (AA) and total ankle arthroplasty (TAR) procedures from 2010 to 2021. Methods: A large national insurance claims database was queried for ankle arthrodesis and total ankle arthroplasty from 2010 to 2021 using Current Procedural Terminology (CPT) codes. Utilization rates, hospital reimbursement rates by payor (commercial, Medicare, Medicaid, Government, cash, other) and demographic data including gender, age, region, payor type, and service location were extracted. Subsequently, physician Medicare reimbursement rates were obtained from 2010 to 2021 using the Physician Fee Look-up Tool from the Centers for Medicare and Medicaid Services. Dollar values were then adjusted using the Consumer Price Index and are reported in 2023 US dollars. Trend analysis of utilization and reimbursement rates was then performed, with a p value of < 0.05 as significant. Results: A total of 16833 TAR patients and 33109 AA patients were identified by the query. Both procedures demonstrated a significantly positive linear trend in volume over the included time period, with increase from 2010 to 2021 of 30.28% (2453 to 3196 patients; p< 0.001) for AA cases and 140.64% for TAR (994 to 2392 patients; p< 0.001). Without consideration of inflation, Medicare physician reimbursement values were stable, demonstrating a non-significant increase for both AA (+2.67%) and TAR (+3.40%) over the included time period. On the other hand, after accounting for inflation, values declined across both AA and TA, with decrease from 2010 to 2021 of 16.78% ($1194.24 to $993.81; p< 0.001) for TAR procedures and 17.37% ($1368.26 to $1130.62) for AA procedures (Figure 1). Conclusion: Despite the growing number of Medicare beneficiaries and utilization of TAR and AA, the present data has demonstrated a decrease in Medicare reimbursement. Knowledge of such trends is important for the orthopedic field in order to advocate for sustainable reimbursement that supports the consistent delivery of high-quality patient care.

Category: Diabetes; Other Introduction/Purpose: Treating chronic diabetic peripheral neuropathic pain poses significant clinical challenges due to variable outcomes and failed trials, along with the difficulty in objectively evaluating improvement and accounting for confounding factors. This study aims to investigate the treatment outcomes of three drugs (pregabalin, gabapentin, duloxetine) for chronic diabetic peripheral neuropathy. Methods: From June 2019 to June 2021, 180 patients with type 2 diabetes diagnosed with diabetic peripheral neuropathic pain received treatment with pregabalin, gabapentin, or duloxetine. The study protocol was approved by the institution’s IRB. Patients were consented and enrolled in a single Korean - center, prospective, randomized cohort study with 60 participants per drug group. Treatment lasted for 3 months, and participants were randomly assigned to groups at a 1:1:1 ratio using 3-multiple block randomization. Group 1 received Gabapentin (300mg bid), Group 2 received Pregabalin (75mg bidX mg ), and Group 3 received Duloxetine (30mg bid PO daily). Efficacy and safety were assessed every 2 weeks over a 6-week period. Baseline assessments included lipidemia profile, blood viscosity tests, BUN/Cr, OT/PT, and HbA1c. Clinical evaluations were performed using the Korean version of pain DETECT, categorizing degrees of improvement. Results: All treatments significantly improved painDETECT scores at 6 weeks of medication compared to their baseline (p=0.001). The mean HbA1c of the three groups showing symptomatic improvement by more than 50% was 9.424 (95% CI, 8.17-10.68) for Group 1, 10.430 (95% CI, 8.65-12.21) for Group 2, and 7.718 (95% CI, 6.74-8.70) for Group 3. There was no significant difference in HbA1c between Groups 1 and 2 regarding symptom improvement by more than 50%. However, the HbA1c of Group 3 was significantly lower than that of Groups 1 and 2 (p=0.001). Improvement of the symptom over 50% varied with HbA1c levels among three groups (p=0.001) . Adverse effects such as dizziness and nausea were significantly higher in the duloxetine group compared to pregabalin and gabapentin groups (p=0.001). Conclusion: All three medications effectively alleviated chronic diabetic peripheral neuropathic pain compared to their baseline level with no difference between the groups. However, HbA1c levels could be considered when selecting drugs because the HbA1c level when symptoms improve is different between the gabapentin, pregabalin, and duloxetine groups. There was no significant difference in the improvement of painDETECT scores in the three treatment groups up to the second week. However, by the sixth week, the pregabalin and duloxetine groups exhibited significantly more improvement in painDETECT scores than the gabapentin group (p=0.001).

Category: Hindfoot; Ankle Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis is a complex procedure for severe ankle and hindfoot pathologies like end-stage osteoarthritis or avascular necrosis of the talus. Proper calcaneal fixation with the talus and tibia is crucial for postoperative stability and neurovascular protection in intramedullary nailing. A cadaveric study by Hyer et al. showed that a wire placed anterograde through the tibial shaft may miss the calcaneus medially. Methodologic limitations included a limited number of cadavers, non-loaded specimens, and a lack of critical examination of hindfoot alignment. This study aims to determine the feasibility of using weightbearing computed tomography (WBCT) and 3D segmentation software to ascertain an optimal entry point for a straight intramedullary nail in TTC arthrodesis in weightbearing patients. Methods: A total of 100 normal ankles (48 left, 52 right) from 52 patients (Age: 39.9 ± 16.7 years; Gender: 68% F; BMI: 28.1 ± 5.8 kg/m^2) with WBCT scans were obtained and subsequently segmented for inclusion in the study. A novel mathematical algorithm was developed to determine the 3D intersection of the distal tibial central axis extension at the inferior calcaneus. The algorithm approximates the central axis by mapping the center point of the tibial medulla at each CT slice, from the shaft to the tibiotalar joint using 3D surface contours in the axial plane. Then, the central axis is extended through the talus and calcaneus to approximate its exit point on the inferior surface of the calcaneus for each individual ankle (Figure 1a). A 2D linear transformation (affine transformation) was applied to obtain a heat map of all intersection points on the inferior surface of the calcaneus. Results: The mean (SD) polar angle of the central axis with respect to the ground was 84.9 ± 2.3 degrees. The root mean (SD) square error of the affine transformation was 1.62 ± 1.02 mm, demonstrating the validity of mapping. The exit points of the central axis across all patients fall predominantly along the sustentaculum tali (Figure 1b). Conclusion: A straight nail passing through the sustentaculum tali places surrounding neurovascular structures at risk and can also compromise the biomechanical stability of the implant. Our novel 3D algorithm shows that intraoperative adjustment of the starting point lateral to the central tibial axis is required to obtain optimal alignment of the hindfoot nail. Additionally, the novel algorithm can also be used preoperatively to estimate the required calcaneal medialization and ensure precise implant positioning. Proper nail alignment may potentially improve the success of TTC arthrodesis and decrease the risk of postoperative complications, including implant failure.

Category: Diabetes; Midfoot/Forefoot Introduction/Purpose: Wound healing in diabetic foot ulcers (DFU) poses challenges, requiring extensive debridement and amputations. Negative pressure wound therapy (NPWT) can be utilized for DFUs with large soft tissue defects to promote granulation tissue growth. The optimal timeframe for successful NPWT lacks extensive studies. Advanced wound scanning with a three-dimensional (3D) camera can enhance DFU area and volume calculations. This study aimed to investigate the efficacy of 3D wound assessment in predicting granulation tissue filling velocity following NPWT in DFUs. Methods: After receiving IRB approval from the single Korean center, a retrospective case series study was performed for 101 DFUs (Wagner classification 3 and 4) undergoing NPWT from September 2018 to June 2019. Demographic data, vascular patency, and wound characteristics were recorded. Wound was irrigated before NPWT. An infra-red 3D camera (inSight ® , eKare, Fairfax, VA, USA) was used to capture digital photographs. Wound area and volume were measured. Measurements were taken weekly from before treatment to one month after using inSight ® cloud software. The risk factors of diabetic foot ulcers related to wound healing were evaluated. Results: NPWT resulted in significant area improvements for open diabetic foot ulcers (p = 0.001). Postoperative 1-week area change velocity was 1.35 cm2/day, peaking at 2 weeks (1.84 cm2/day). Volume also showed significant improvement over time (p = 0.001), with a 1-week peak velocity of 1.20 cm3/day. All peak area and volume changes occurred within two weeks after NPWT application. Midfoot and hindfoot exhibited higher velocity of volume than forefoot (p = 0.001). Postoperative volume change was the fastest with a patent peroneal artery. Conclusion: 3D wound assessment for velocity of granulation tissue filled in an open DFU after NPWT could be effective to predict outcomes. Most wound healing following NPWT in DFUs was completed within two weeks. Application of NPWT for an additional two weeks did not significantly impact the completion of wound healing even though midfoot and hindfoot exhibited higher velocity of volume than forefoot.

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: The diagnosis of fractures can be challenging in specific medical settings due to limited expertise or time. While deep learning has shown promising results, its use is confined to the quality of images and the hassle of importing images to the models. This study aims to develop a model to detect fifth metatarsal fractures based on cell phone photos of radiographs directly taken from a regular screen. Methods: retrospective case-control study was conducted including patients aged > 18 years with fifth metatarsal fractures (n=1240) (Fx), and healthy controls (n=1224) (NoF). Three view radiographs (anterior, posterior, and lateral) were obtained from the Electronic Health Record (EHR) in PNG format. To generate a mixed-quality dataset, Android and iOS smartphones (SP) were used to create two separate datasets for each Fx and NoF group. Two separate deep learning models on each EHR, SP, and combined datasets were developed using Inception V3 architecture (Figure 1.). The models were also tested on a separate SP dataset (SP-test) that was not included in the development process. Area Under the Receiver Operating Characteristics Curve (AUC) along with other performance metrics were calculated and reported. Continuous data were presented as median (interquartile range), and a p-value of < 0.05 was considered to be significant. Results: Baseline analysis revealed differences between the groups with a median age of 56 years (36-68) for the Fx group, and 62 years (51-72) for the NoF group (p < 0.001). Similarly, the racial composition of the groups was also different (Fx: 84.8% white; NoF: 92.2% white; p < 0.001). Initially, the SP model showed the best performance (Youden Index (YI): 0.92, AUC: 0.99) followed by the EHR (YI: 0.74, AUC: 0.96), and combined (YI: 0.52, AUC: 0.97) models. When tested on the SP-test dataset the EHR model’s performance dropped markedly showing a YI of 0.33, an AUC of 0.78, and a sensitivity of 0.49 (Table 1.). However, the SP and combined models continued to perform optimally (YI: 0.94, AUC: 0.99; YI: 0.78, AUC: 0.98, respectively). Conclusion: This study highlights the crucial role of image quality in developing deep learning models for detecting fifth metatarsal fractures. Our findings demonstrate a markedly reduced performance of the EHR model in identifying fractures within lower-quality images. This emphasizes the need for training algorithms on images of varying quality to create more generalizable models capable of operating effectively across diverse settings.

Category: Other Introduction/Purpose: Orthopedic surgery is witnessing a substantial increase in fellowship training, with a notable shift from almost 50% practicing as "generalists" to less than 15% over the least 35 years. The Orthopaedic Fellowship Match has expanded to include various subspecialties, contributing to a favorable job market for fellowship-trained surgeons. However, the surplus of fellowship positions compared to graduating residents raises considerations regarding individualized selection processes and addressing disparities in the orthopedic field. Methods: A scoping review of the literature on orthopedic surgery fellowship choices utilized a literature search following PRISMA-ScR guidelines, which were subsequently analyzed using Covidence systematic review software; inclusion criteria encompassed primary, survey-based studies from 2010-2023, involving orthopedic surgery residents, fellows, attending physicians, and plastic surgery residents pursuing hand surgery fellowships, who completed their residency training in the United States. Data extraction involved compiling an evidence table encompassing respondent training levels, target demographics, survey types, factors considered, survey distribution details, response rates, results, and study limitations. Results: Intellectual curiosity dominated all other reasons for choosing fellowship among orthopedic residents across various studies, even when considering gender discrepancies and differing response measurement forms. The choice of surgical procedures also significantly influences the fellowship preferences of medical residents; factors such as the complexity and case variety, exposure to bread-and-butter cases, and surgical experience consistently emerge as crucial considerations in determining fellowship preferences, reflecting a common trend among applicants. Mentorship plays a pivotal role in residents' choice of subspecialty, particularly for female residents facing challenges finding mentors of the same gender. Other less prevalent contributing factors influencing a resident's decision in pursuing a specific fellowship include family commitments, financial debt, lifestyle preferences, previous research, and timing of their decision. Conclusion: The surge in orthopedic surgery fellowship training is marked by a substantial increase in graduates opting for subspecialization, driven by factors like intellectual interest, the nature of procedures in a specific fellowship, and mentor influence or experience. Our study emphasizes these factors as pivotal in residents' choices. However, the need for extensive prospective studies arises to conclusively ascertain if these influences remain consistent across all residents and if additional unexplored factors might play a more significant role in determining specific fellowship paths.

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: Interdigital Neuroma (IN) is a benign enlargement of tissue surrounding the common plantar digital nerve. Traditionally, neurectomy has been performed as the standard surgical treatment for IN. However, recent attention has been given to less invasive surgical decompression by intermetatarsal ligament (IML) release with neurolysis. This study aims to compare the outcomes of IML release with neurolysis to traditional interdigital neurectomy. Methods: A retrospective chart review was conducted on 350 consecutive patients who underwent surgical treatment for IN. Patients who satisfied our inclusion and exclusion criteria were categorized into two groups based on the surgical treatment received: IML release with neurolysis or interdigital neurectomy. Inclusion criteria were patients older than 18 years with symptomatic IN, having an indication for surgical treatment following at least three months of unsuccessful conservative treatment, and at least 12 months of postoperative follow-up. Patients with concurrent procedures at the time of surgery, multiple affected web spaces, trauma to the affected forefoot, or asymptomatic IN without clear indications for surgical treatment were excluded from the study. Evaluated outcomes included recurrence of symptoms, rate of revision surgery, and postoperative wound infection. Results: Out of the 350 patients screened, 127 fulfilled the inclusion and exclusion criteria. Forty (32%) patients experienced recurrence of symptoms within a 12-month follow-up period with an overall mean time-to-recurrence of 3.96 +/- 3.15 months. Patients who underwent IML release with neurolysis had a significantly higher recurrence rate (48%) and mean time-to-recurrence of 4.61 +/- 3.22 months compared to those who underwent interdigital neurectomy (24%) with a mean time-to-recurrence of 3.47 +/- 3.08 months (P< 0.01). The rate of postoperative wound infection was similar between the two groups. The rate of revision surgery among those with symptom recurrence in the IML release group (16%) and neurectomy group (4%) was not statistically significant between both groups (P=0.49). Conclusion: IML release with neurolysis appears to have a higher risk of symptom recurrence compared to interdigital neurectomy. However, patients who did experience symptom recurrence in either operative group had similar rates of revision surgery, which may be due to mild recurrent symptoms in the IML release group that did not warrant revision surgery in these patients. No patient-specific factors were identified as being associated with symptom recurrence. Future studies should consider objective symptom recurrence severity and patient satisfaction.

Category: Midfoot/Forefoot Introduction/Purpose: The popularity of minimally invasive (MIS) techniques in foot and ankle surgery continues to grow exponentially. However, it comes with certain limitations that present notable challenges. One significant hurdle is the absence of direct visualization of neurovascular structures and tendons. This study aims to present fluoroscopic heatmaps that illustrate the trajectories of major structures encountered during MIS midfoot procedures. Methods: Sequential dissection was performed on nine below-knee specimens identifying the following anatomy structures: anterior tibialis tendon (ATT), extensor hallucis tendon (EHL), extensor digitorum longus tendon (EDL), superficial peroneal nerve (SPN) and dorsal neurovascular bundle (DNVB). Subsequently, flexible wires were positioned and securely placed adjacent to the medial and/or lateral borders of these structures to visualize their trajectories on X-ray imaging. Anteroposterior (AP) and oblique fluoroscopy images of the foot, featuring a calibration marker of a known diameter, were taken, alongside macroscopic photos. All fluoroscopy images were adjusted to a uniform scale and standardized to a single foot fluoroscopy. The coordinates of the structures were marked on these standardized foot AP and oblique fluoroscopy views. These coordinates were then inputted into a custom-made Python script to generate heatmaps. Results: Successfully generated heatmaps encompassed the DNVB, ATT, EDL, EHL, and SPN, on AP and oblique fluoroscopy images of the foot. The color gradient used visually represents varying magnitudes, with red indicating the most frequent locations of the structures and blue signifying lower occurrences. These heatmaps also illustrate the highest-risk areas for iatrogenic injury to the structures during MIS procedures. Conclusion: This study can empower surgical navigation and improve safety in MIS midfoot procedures by providing surgeons with a fluoroscopic heatmap detailing the trajectories of major anatomical structures.

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: Osteochondral lesions of the Talus (OLTs) are among the most common injuries that occur in the ankle joint and can be detrimental to the overall function. The size of the lesion is critical in determining the surgical treatment; for smaller lesion sizes, microfracture can be considered but for larger lesions joint level restoring surgical intervention might be required. In this study, talus OLTs with different areas and locations are modeled to biomechanically evaluate the ankle joint stability. Our study aims to evaluate the stress distribution and joint stiffness effect of OLTs on all the 9-cell partition zones of the talar dome in three different ankle positions during gait. Methods: A simplified ankle geometry of an adult female was computationally modeled with 1 mm of cartilage at both sides of the tibiotalar contact. Lesion geometries were created on the talar dome with 4.5, 6.4-, and 9-mm lesion diameters, at each grid partition location on the talus sectioned 1 (anterior) to 9 (posterior). To enhance lesion area fidelity, tilted talar planes were utilized to consider the curvature of the talar dome. The modified models were then transferred to finite element analysis software. The maximum and average von Mises stresses, and stiffness were the biomechanical parameters investigated. Results: Utilizing the design parameters designated for this study, 81 different OLTs are modeled and computationally simulated. It is revealed that the stress parameters are highly misleading and do not predict ankle stability. However, stiffness is found to be a more reliable parameter that has an inverse correlation with the lesion diameter. Zones 8 (posteromedial) and 7 (Figure) on the posterior, and zone 3 on the anterolateral, were observed to be the most critical zones with lesser stiffness which meant decreased ankle joint stability in neutral, dorsiflexion, and plantarflexion, respectively. Zone 9 (posteromedial) was found to be the least critical zone in regard to stiffness. Conclusion: In our Finite Element study, we have found that during the walking gait, lesions in zones 8, 7, and 3 significantly impact joint stability compared to other zones of the same lesion size. This suggests that certain areas have a more pronounced effect on joint stability than others. Our findings challenge the commonly accepted threshold of 150mm² for transitioning from microfracture to other cartilage-restoring surgeries, as it may not be universally valid for all zones.

Category: Sports; Trauma Introduction/Purpose: Achilles Tendon (AT) rupture is one of the most prevalent adult tendon injuries, with the incidence rate estimated to range between 7 to 40 in 100,000 person-years. This study aimed to assess the clinical and functional outcomes of a modified “Gift box” open technique for AT rupture repair. Methods: After receiving IRB approval, in a single center study in Tehran, Iran, we conducted a consecutive case-series study including 36 patients with acute AT rupture who underwent modified gift box AT repair using two mini-incisions and gift box sutures by expert surgeons affiliated with the local hospitals (Figure 1). The postoperative protocol involved all patients discontinuing the use of crutches after 4 weeks and removing their boot after 8 weeks. The AT rupture score (ATRS) and the American Orthopedic Foot and Ankle Society (AOFAS) measure scores were obtained from all patients at 6, 9, 18, and 36 months postoperatively with a complementary follow-up in an average of 24 months (range of 18 to 48 months) after the last follow-up. The study also included other variables such as visual analog scale (VAS) for pain, calf atrophy, and the range of sagittal ankle motion, wound complications, sural nerve injury, and re-rupture rate. Results: The patients treated with modified gift box technique yielded AOFAS scores of 85±3 and ATRS of 84.7±5.4 at 36 months postoperatively, further improving to 86±7 and 85.2±5.1 respectively during extended follow-up (up to 2 years). Approximately 82% of patients regained normal activities of daily living within 4 months, while 91.5% recovered preinjury vigorous activity levels by 6 months postoperatively. Mean VAS pain scores decreased from 7.9±0.9 at 2 months to < 4 after 3 months. Isokinetic testing demonstrated plantar flexion and dorsiflexion strength deficits of 84.9±5.3% and 89.8±4.7% respectively compared to the contralateral uninjured side at 3 months, resolving to equivalent strength by 42 months. Dorsiflexion range of motion reached 94% of normal at 5 years follow-up, though calf circumference remained < 95% of normal size. Conclusion: The modified gift box technique for AT rupture repair using two mini-incisions and gift box sutures, which we assume to be less invasive compared to the previously reported method, demonstrated favorable clinical outcomes with high patient satisfaction levels. Patients experienced significant improvements in functional scores, pain levels, strength, and range of motion over time, with most regaining their ability to perform activities of daily living and returning to preinjury levels of physical activity. While some residual deficits were observed, the procedure was well-tolerated with no significant complications, suggesting it is a safe and effective treatment option.

Category: Midfoot/Forefoot; Hindfoot Introduction/Purpose: Arch-support insoles are frequently used as part of the treatment protocol for a variety of common foot ailments including metatarsalgia, and plantar fasciitis. While custom-molded insoles are considered to be the most efficacious ones, prefabricated insoles are still preferred due to their lower price and availability. However, there's ongoing skepticism about their capacity to meet the diverse and changing biomechanical requirements of every individual over time. In this study, we investigated the effect of a patient-specific, three-level-graded arch support system for the treatment of common foot ailments using patient-reported outcome measures of pain. Methods: A single-armed clinical trial was conducted including patients aged >18 years with a diagnosis of plantar fasciitis or metatarsalgia. Based on initial measurements, each participant was given three specific arch support orthotics (Good Feet™, Dr.’s Own, LLC) with varying arch heights, to be worn at tolerance, along with a pair of sneakers for standardization of the footwear condition. Symptomatic relief was measured at the baseline-, fourth-, eighth-, and twelfth-week appointments using the Patient Reported Outcomes Measurement System (PROMIS) for pain Intensity, pain Interference, and the American Orthopaedic Foot and Ankle Society (AOFAS) questionnaire. Moreover, the structural changes of the foot were also measured using Weight-bearing Computed Tomography (WBCT) scans, and X-rays of the foot with and without the insoles at the initial visit. Data were analyzed employing the T-test, Wilcoxon Signed Rank, and Friedman tests where applicable. A p-value below 0.05 was considered to be statistically significant. Results: A total of 43 patients with a mean (SD) age of 41.69 (12.21) years, a female-to-male ratio of 1.3:1, and a body mass index (SD) of 25 (4.04) were included in the study. PROMIS pain interference and intensity scores improved significantly starting from the fourth week (p=0.017, and 0.003, respectively). Additionally, the AOFAS questionnaire demonstrated enhanced scores notably on the lesser metatarsophalangeal-interphalangeal, and midfoot subscales with p-values of 0.001, and < 0.001, respectively (Figure 1.). Moreover, the navicular height on WBCT and the talo-navicular angle on lateral view X-rays increased when the insoles were utilized (p=0.046, and < 0.001, respectively; Figure 2.). Conclusion: This study revealed the significance of prefabricated graded arch supports for the symptomatic relief of patients with plantar fasciitis and metatarsalgia. These clinical improvements were also supported by discernable anatomical changes as evidenced by foot radiography and WBCT assessments. Given these findings, we believe future research should be focused on evaluating the efficacy of these insoles in managing additional foot pathologies. Moreover, it is imperative to explore the biomechanical ramifications of such supports on the dynamic alignment of the foot, to further understand their role in altering foot structure and function.

Category: Ankle; Sports Introduction/Purpose: Osteochondral lesions of the talus (OLT) commonly arise after chronic ankle sprains and fractures. Conservative treatment is the first step, yet surgical intervention is often warranted in patients with persistent symptoms. The effect of social determinants of health (SDOH) on treatment outcomes of this patient population has rarely been investigated to date. Methods: Patients with OLT who were 18 years of age and older and underwent operative treatment, with at least one patient-reported outcome and SDOH data available, were included. Patient-Reported Outcome Measures (PROMs) and Visual Analog Scale (VAS) pain scores were collected, and their trends were analyzed based on the patients’ SDOH, including Area DeprivationIndex(ADI)andSocialVulnerabilityIndex(SVI). Pre-operativePROMsorVAS pain scores had to have been collected within 90 days of surgery, immediate post-operative PROMs or VAS scores were recorded within 90 days of surgery were and post-operative PROMs or VAS scores within 180 days (± 30 days). Exclusion criteria were presence of concomitant pathologies such as fractures, bone lesions, cysts, foot and ankle deformities, presence of hardware, and lack of follow-up visits and lack of any patient reported outcomes in their profile. A P-value < 0.5 was considered statistically significant. Results: 109 of 551 confirmed patients with OLT met the inclusion criteria. Significant correlations were found between SDOH and PROMs, elucidating disparities in pain scores, physical function, and depression. A multitude of SVI components, but most profoundly overall SVI, and ADI rank, were found to be significantly correlated to VAS pain scores (Table 1.). Furthermore, insurance status showed a significant impact on pain intensity and depression measures. Nuanced influences of race, insurance status, and social vulnerability were observed. Conclusion: This study shows that SDOH have a significant effect on postoperative PROMs and VAS scores. Based on our results, these most prominently include overall SVI, insurance status, ethnicity, and race. Systemic interventions guided by neighborhood-level measures of disadvantage are key in advancing health equity.

Category: Diabetes; Midfoot/Forefoot Introduction/Purpose: The therapeutic efficacy of negative pressure wound therapy (NPWT) in treating skin defects in diabetic foot ulcers has been demonstrated, although the management of bacterial biofilms remains controversial. Limited clinical data exist on outcomes when utilizing polyhexamethylene biguanide (PHMB) alongside NPWT. This study aims to assess the efficacy of PHMB in diabetic foot ulcers compared to conventional methods during NPWT. Methods: After receiving IRB approval from a single center Korean institution, sixty patients with Wagner 3 or 4 diabetic foot ulcers undergoing open amputation of forefoot and midfoot were included from March 2020 to August 2021. NPWT was administered at two-day intervals post-amputation by an expert surgeon affiliated with the institution. Patients were assigned to 3 different adjuvant therapies; 1) Saline; 2) povidone iodine; and 3) hydrochloric PHMB irrigation solutions. Bacterial cultures were performed, assessing time to negative bacterial culture. Wound analysis utilized a three-dimensional infrared camera (inSight ® , eKare, Fairfax, VA, United States) to measure volume and area continuously and its correlation of risk factors. Results: Patients with hydrochloric PHMB therapy exhibited faster wound recovery rates in terms of volume and area compared to those treated with saline and povidone iodine solutions (p=0.001) (Figure 4 and 5). Hydrochloric PHMB and povidone iodine groups showed significantly shorter times to bacterial negativity compared to the saline group (p=0.001) (Figure 6). HbA1c, body mass index, dialysis status, age, smoking history, and diabetes duration did not significantly impact wound recovery rates. Conclusion: Hydrochloric PHMB with NPWT can be useful to treat open diabetic foot ulcers, with a high wound recovery rate and moderate antimicrobial efficacy, as the combination decreases wound toxicity and intermediate bactericidal effects in comparison to normal saline and povidone-iodine solutions.

Category: Ankle; Ankle Arthritis Introduction/Purpose: Supramalleolar osteotomy (SMO) is a surgical procedure commonly used for load shifting in ankle arthritis, particularly in cases of early varus ankle arthritis. Correction of the tibial plafond into valgus alignment has been proposed to address varus ankle arthritis, with the belief that a larger medial distal tibial angle (MDTA) aids in load shifting. However, evidence supporting the amount of the correction as superior for joint preservation is lacking. We hypothesized that the load distribution of the ankle joint was unevenly changed following the supramalleolar osteotomy (SMO) in primary ankle osteoarthritis. The aim of the study is to investigate the specific load distribution change of the ankle joint and three-dimensional radiographic changes after the SMO in primary ankle osteoarthritis. Methods: A single-center retrospective study conducted in Seoul, Korea, analyzed 36 cases of SMO performed from 2018 to 2022 for primary varus ankle osteoarthritis at Takakura stage 3a. The study included 17 female and 19 male patients with an average follow-up of 54 months. Preoperative and final follow-up assessments involved clinical evaluations using visual analog scale (VAS) for pain and foot function index (FFI), along with radiological assessments using weight-bearing plain radiograph and CT measurements such as medial distal tibial angle (MDTA), anterior distal tibial angle (ADTA), talar tilt, medial clear space (MCS), and talus center migration (TCM) were taken preoperatively and at the last follow-up. Hindfoot alignment parameters were also measured and compared. The contact stress changes between the distal tibia and talar dome were evaluated preoperatively. At the last follow-up, the contact stress changes were assessed according to four sections of the talus. Results: The study demonstrated significant improvements in various parameters following SMO. Preoperatively, the mean medial distal tibial angle (MDTA) was 87.75±3.57, significantly improving to 93.54±2.97 postoperatively (p=0.001). Talar tilt decreased from 3.19±2.86 to 2.24±2.40 (p=0.002), and talar center of migration (TCM) shifted laterally (p=0.001). Hindfoot alignment angle (HAA) and hindfoot alignment ratio (HAR) significantly improved (p=0.001). Visual analog scale (VAS) and foot function index (FFI) scores decreased significantly (p=0.001). The size of the medial open wedge correlated positively with changes in MDTA and negatively with changes in HAR and hindfoot moment arm (HMA). Median medial clear space (MCS) increased postoperatively (p=0.001), correlating moderately with the change in open wedge size (p=0.03). Contact stress on the talus decreased significantly, particularly in the anteromedial aspect (p=0.001). Conclusion: Supramalleolar osteotomy in primary varus ankle osteoarthritis demonstrates clinical and radiological improvement. However, the degree of medial open wedge in SMO affects variables such as MDTA, TCM, HAR, and HMA, while it does not influence talar tilt or HAA. Additionally, a negative correlation exists between the degree of medial open wedge and FFI, indicating that increased wedge size correlates with decreased FFI. SMO in primary ankle osteoarthritis may lead to anteromedial load changes as a result of open wedge osteotomy of the tibia; it may not influence talus rotation.

Category: Hindfoot; Sports Introduction/Purpose: While MIS Zadek osteotomy offers numerous advantages, it does come with a significant drawback as it impedes the direct measurement of the planned resection, depending solely on the surgeon's perception. This reliance can result in either insufficient or excessive resection of the calcaneus. The aim of this study is to elucidate the impact of each burr pass on the extent of correction, gap size, and calcaneal morphology following MIS Zadek osteotomy. Methods: en cadaveric specimens devoid of apparent foot pathology underwent a minimally invasive Zadek osteotomy utilizing a 3.1 mm Shannon burr. The osteotomy initiation point was anterior to the attachment of the calcaneal plantar fascia, preserving the plantar cortex and extending dorsally to the anterior aspect of the posterosuperior tubercle of the calcaneus. Following each burr pass, the created defect was closed and maintained in a reduced state during subsequent burr passes. This sequence was reiterated five times, and neutral lateral x-rays were captured before and after each burr pass to quantify the impact of individual passes. Measurements were calibrated using markers placed during radiological examination. These measurements encompassed the defect size formed with each burr passage, determined by the change (shortening) in the overall length of the dorsal calcaneal cortex. Additionally, alterations in various foot alignment parameters were assessed, including Böhler angle, Calcaneal X/Y ratio, and Fowler Philip angle. Results: The dorsal calcaneal cortical length exhibited an average reduction with each burr pass as follows: 2.1 mm during the 1st pass, 1.9 mm during the 2nd pass, 1.6 mm during the 3rd pass, 1.2 mm during the 4th pass, and 0.9 mm during the 5th pass. The Böhler Angle (°), X/Y Ratio (%), and Fowler Philip Angle consistently decreased with each successive burr passage. Conclusion: Our research showcased that employing a percutaneous 3.1 mm burr in Zadek osteotomy sequentially can result in a 10 mm dorsal wedge size after 5 burr passes. The calcaneal geometry, assessed through the X/Y ratio, Fowler-Philip angle, and Böhler angle, exhibited gradual alterations with each burr pass. The insights gained from this study offer valuable information for foot surgeons, deepening their comprehension of the influence of each burr pass on gap size and foot alignment parameters in minimally invasive Zadek osteotomy.

Category: Ankle; Trauma Introduction/Purpose: Osteochondral lesions of the talus (OLT) impact both sedentary individuals and athletes, affecting both daily function as well as athletic performance. Purported causations include trauma, genetics, and hypovascularity. Although it is known that the talar dome’s vascularity is mainly supplied the posterior tibialis artery (PTA) and to a lesser degree the sinus tarsi artery (STA), the pathophysiological impact of talar dome hypovascularity on OLT remains poorly studied. Our first hypothesis was that the patients with OLT have a lower diameter of PTA (dPTA) and STA (dSTA), and the second hypothesis was that among the group of the patients with OLT, the patients that require surgery have a lower d PTA and dSTA. Methods: This was a retrospective study that included 77 patients with OLT, and for the control group 77 patients with peroneal tendinitis. To mitigate the effect of comorbidities the patients between 30 to 40 years of age were included and the ones with a history of smoking, diabetes, rheumatologic, and peripheral artery diseases were excluded. The dPTA measurements were done in three different levels for all groups: at the level of 1 cm above plafond, at the level of plafond and at the level of medial malleolar tip (MMT). dSTA was measured at the level of talar neck. Area, volume, depth, and localization of OLT were recorded, as well. Results: The study group had significantly lower dPTA at three levels (1.05±0.22mm, 0.99±0.18mm, 0.98±0.31mm, proximal to distal) compared to the control group (1.25±0.23mm, 1.20±0.22mm, 1.14±0.18mm, proximal to distal) (P< 0.001). The dSTA was also lower in study group as compared to control group (0.5±0.11mm vs. 0.57±0.08mm, respectively P=0.001). ROC Curve analysis revealed the cutoff values for OLT occurrence after ankle injury as; 1.115 mm for the level of 1 cm above plafond, 1.075 mm for the level of plafond,1.055 mm for the level of MMT, 1.085 mm for mean dTPA and 0.5665mm for dSTA (Table-1). A significant negative correlation was observed between OLT size area (mean: 42.24±24.76 mm 2 ) and arterial diameters (P< 0.01, P< 0.01, and P=0.014 for three different levels of dPTA and P< 0.001 for dSTA). Conclusion: Smaller dPTA and dSTA appear to be associated with the occurrence of OLT, with the defect size inversely correlated to arterial diameters. The determined cutoff values for dPTA may help clinicians identify high risk patients to develop OLT after an acute ankle injury. Further elucidation of these vascular abnormalities, particularly dPTA, could hold significant prognostic potential and be used to predict disease progression as well as the likelihood of surgical success in OLT treatment.

Category: Hindfoot; Trauma Introduction/Purpose: Fractures of the calcaneus are the most frequent form of fractures among the tarsal bones. The treatment plan depends on various fracture characteristics, particularly the extension of the fracture line into the subtalar joint surfaces. While X-rays are the primary diagnostic tool, Computed Tomography (CT) scans are often necessary as they provide a more detailed description of these fractures, especially if the articular surfaces are involved. Although informative, CT scans expose patients to higher doses of ionizing radiation, and they might not be readily available in certain settings. This study aims to develop a deep learning model that will first detect calcaneal fractures and then classify the type of fracture based on its extension into the subtalar joint surfaces. Methods: A retrospective case-control study was conducted. Patients aged >18 years who sustained a calcaneal fracture were included in the case group, along with the same number of healthy adults for the control group. Various X-ray views of the foot including anterior, posterior, lateral, along with the axial and lateral calcaneal views were obtained. Two experienced orthopaedic researchers screened the dataset and confirmed the type of fracture. Two models were developed using an Inception V3 architecture and a split ratio of 60:20:20 for training, validation, and testing purposes. The first model was designed for fracture detection, and the second one was designed for detecting intra-articular fracture extension, if present. Conventional model metrics including sensitivity, specificity, Youden index, area under the receiver operating characteristic curve (AUC), and F1 score were reported for each model. A p-value below 0.05 was statistically significant. Baseline values are presented in median and interquartile ranges (IQR). Results: A total of 1102 individuals (n=551 for each group) with a female-to-male ratio of 1.6:1 were included. Baseline comparisons showed a significant difference in the age of the groups [cases: 55 (IQR 42, 67) years; controls: 62 (IQR 51, 72 years), p-value < 0.001]. The first model for fracture detection demonstrated a high performance with an AUC of 0.99 and a Youden index of 0.96. The intra-articular fracture detection model showed a slightly lower performance with an AUC of 0.97 and a Youden index of 0.88 (Table 1, Figure 1). Conclusion: Our study showed promising results with the utility of deep learning methods for detecting calcaneal fractures and classifying intra- vs extra-articular fractures. This algorithm may help facilitate the diagnosis and treatment of patients with suspected calcaneal fractures, serving as a decision-support tool in settings where CT scanning is not available.

Category: Bunion; Other Introduction/Purpose: Hallux valgus (HV) is a prevalent forefoot deformity that leads to pain, stiffness, and difficulties with footwear. Conventional diagnosis of HV relies on clinical and radiographic examination, which can be cumbersome and expose patients to ionizing radiation. The emergence of 3D scanning technologies, such as structured light, integrated into smartphones, presents a novel approach to early detection and diagnosis of HV, potentially allowing for earlier intervention and subsequent reduction in the progression of the deformity. Methods: This prospective non-randomized clinical trial recruited patients from the foot and ankle clinic, identifying cases and controls based on the presence or lack of clinically diagnosed HV. Patients older than 18 years of age and able to consent were included. The 3D scanning of the foot utilized structured light technology integrated into smartphones, with an algorithm developing a surrogate angle for HV detection. This angle was correlated with conventional radiographic measurements, including hallux valgus angle (HVA) and intermetatarsal angle (IMA) from weightbearing radiographs. A cluster analysis assessed the algorithm’s capacity to identify deformity severity according to radiographic severity grading. The algorithm's accuracy and performance were assessed using the area under the receiver operating characteristic curve, precision-recall Curves, and the leave-one-out cross-validation method. Results: 120 patients were enrolled in this trial. Out of 240 feet examined, HV was present in 29.1% of cases. The algorithm's surrogate angle showed a robust correlation with the clinical hallux valgus angle (HVA), with a correlation coefficient of 0.91 and a specificity of 0.882. Notably, the surrogate angle's correlation with the intermetatarsal angle (IMA) was also significant, albeit lower (r = 0.65). The area under the ROC curve (AUC) was 0.947, and the precision-recall AUC scores for positive and negative classes were 0.89 and 0.92, respectively. These metrics confirmed the algorithm's potential as a reliable diagnostic tool for detecting HV and determining its severity through non-invasive, commonly available smartphone technology. Conclusion: This study validates the accuracy of a smartphone-based 3D scanning algorithm in detecting and grading HV deformity, providing a low-cost, accessible decision-support tool for physicians and patients. This approach could improve early detection, reduce the need for clinical visits, and potentially expand to remote monitoring of HV and other pathologies, aligning with the growing trend of telemedicine and personalized healthcare.

Category: Trauma; Ankle Introduction/Purpose: Syndesmosis injuries, often involving the posterior malleolus (PM), are common in rotational ankle fractures. Concomitant intra-articular involvement, along with deltoid ligament rupture and open reduction and internal fixation (ORIF) affects outcomes predisposing to postoperative complications. Our study aims to investigate the outcomes of posterior malleolar fractures with concomitant syndesmosis injuries and identify prognostic factors associated with these injuries. Methods: This retrospective study investigated posterior malleolar ankle fractures with syndesmotic injury in 71 patients between January 2004 and March 2021. Among these, there were 54 cases of trimalleolar fractures and 17 cases of trimalleolar equivalent fractures. After receiving IRB approval from a single Korean center institution, demographic data, revision surgeries, syndesmotic implant removal, deltoid ligament rupture, deltoid ligament repair, types of implants, and insurance status were evaluated by an expert surgeon affiliated with the institution. Weight-bearing plain radiographs were analyzed for various parameters including superior and medial clear space (MCS), tibiofibular overlap, tibiofibular clear space, implant height, fibular shortening, and synostosis. Radiographic parameters were recorded preoperatively, postoperatively, at 3-month follow-up, and final follow-up. CT scans were utilized to assess posterior malleolar fracture involvement and evaluated using the Haraguchi classification. The severity of ankle joint obliteration was determined. Fibular shortening and synostosis presence were assessed from follow-up radiographs. Results: All radiographic parameters showed significant improvement over time (p-=0.001). No significant differences were found between groups with and without deltoid ligament rupture, except for postoperative 3-month TFO, which showed a significantly higher value in group of the deltoid ligament rupture (p=0.001). Fixation of the posterior malleolar fracture was significantly associated with a preoperative MCS with optimal cut off value of 3.72 mm as absolute value and 84% as the percent divided by the superior clear space as in area under curve (p=0.001, AUC=0.717). Male sex was significantly associated with unexpected syndesmotic implant removal. Deltoid rupture was significantly associated with postoperative ankle osteoarthritis. Preoperative TFC and ORIF of the posterior malleolar fracture were negatively associated with postoperative ankle osteoarthritis. Conclusion: A preoperative medial clear space measurement of 3.72 mm or more in posterior malleolar fractures with syndesmotic injury may be beneficial in deciding the fixation approach for posterior malleolar fractures. Male gender is identified as a risk factor for unplanned removal of syndesmotic implants. Deltoid ligament rupture, preoperative tibiofibular clear space (TFC), and the need for posterior malleolar fixation may be regarded as risk factors for postoperative ankle osteoarthritis.

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: Lisfranc injuries have a reported incidence of 1 in 55,000 people. However, given the subtle displacement present in some of these injuries, up to one third are missed on initial diagnosis. Weightbearing imaging is the gold standard for evaluation and diagnosis of the Lisfranc complex, and diastasis between the medial cuneiform and second metatarsal (C1-M2) is the most commonly discussed parameter. However, no explicit consensus on precisely where within the Lisfranc complex to measure the diastasis has been established. Therefore, the aim of this study was to determine what specific diastasis measurement is most sensitive in diagnosing Lisfranc instability using weightbearing radiographs and computed tomography (WBCT). Methods: A total of 159 adult patients with bilateral foot WBCTs were included: 44 with confirmed Lisfranc instability and 115 controls. A subset had unilateral weightbearing X-rays (38 and 83 patients, respectively). Lisfranc instability was confirmed intraoperatively or by physical exam. Exclusion criteria were: prior midfoot surgery, Charcot arthropathy, severe midfoot arthropathy, cuneiform fractures, and significantly displaced 1st-3rd metatarsal base fractures. In the axial plane, C1-M2 diastasis was measured on weightbearing radiograph and WBCT. In the coronal plane, diastasis was measured at different levels between C1-M2 (dorsal, interosseus, plantar, planter apex) and C1-M3 (plantar apex) on WBCT. For WBCT measurements, percent difference between feet was calculated. Case and control measurements were compared with Mann-Whitney U tests (p < 0.05). Diagnostic cutoffs were determined using receiver operator curves (ROC) and minimum distance to the corner. Sensitivity, specificity, negative and positive predictive values, and area under the curve were calculated for each cutoff value. Results: A significant portion of the subjects were female (Lisfranc instability: 60% and controls: 61%). Average age was 39±17 years and 44±17 years for the Lisfranc instability and control groups, respectively. Mann-Whitney U testing revealed a significant difference between groups for all measurements except plantar C1-M2 (p=0.13), C1-M2 plantar apex (p=0.69) and C1-M3 plantar apex (p=0.07). Figure 1 summarizes the diagnostic cutoff values and the associated efficacy measures. Axial WBCT diastasis was the most effective diagnostic measure, followed by dorsal coronal WBCT diastasis. Using a percent difference cutoff of 34%, axial WBCT diastasis (AUC=0.90) demonstrated outstanding diagnostic capability. Dorsal coronal WBCT diastasis with a percent difference cutoff of 46% (AUC=0.80) demonstrated excellent capability. The remaining measurements provided less reliable diagnostic capability, including diastasis on radiograph (AUC=0.77). Conclusion: Axial WBCT diastasis and dorsal coronal WBCT diastasis both effectively diagnose Lisfranc instability on WBCT, with axial WBCT diastasis demonstrating outstanding diagnostic capability. The traditional method of C1-M2 diastasis on weightbearing radiograph is not as effective as either of these WBCT measurements and only provides adequate diagnostic capability. Our results emphasize the value of diastasis measurements using bilateral WBCT imaging to diagnose Lisfranc instability. These results also suggest that diastasis measurements should be performed in the axial plane and on the dorsal aspect of the Lisfranc complex.

Category: Midfoot/Forefoot Introduction/Purpose: Pes Planus (flatfoot) and Pes Cavus (high arch) are common foot deformities requiring clinical assessment and radiographic imaging for diagnosis and subsequent management. While effective, traditional diagnostic methods pose limitations such as cost, radiation exposure, and accessibility, particularly in underserved areas. With the advent of artificial intelligence and its integration into mobile cameras, we aim to develop a tool that detects and classifies such deformities using photos taken with smartphone cameras. Methods: An algorithm that integrated a deep learning, convolutional neural network (CNN) into a smartphone camera was utilized to detect Pes planus and Pes cavus deformities. The study was conducted at a tertiary hospital with participants recruited from two orthopaedic foot and ankle clinics. The CNN model was trained and tested using photographs of the medial aspect of participants’ feet. Participants included subjects with standard foot alignment, pes planus, or pes cavus determined by an expert clinician using the Foot Posture Index (FPI). The model’s performance was compared to clinical assessment and radiographic measurements, including the lateral tarsal-first metatarsal angle (LTMA) and calcaneal inclination angle (CIA). Results: The CNN model demonstrated high accuracy in diagnosing Pes planus and Pes cavus, with an optimized area under the curve of 0.897 for Pes Planus and 0.898 for Pes cavus. It showed a specificity and sensitivity of 84% and 87% for Pes Planus detection, respectively; for Pes cavus, 97% and 70%, respectively. The model’s prediction correlated moderately and significantly with radiographic LTMA measurements (r=-0.65, P< 0.001), indicating the model’s excellent reliability in assessing food arch deformity. Conclusion: Our smartphone-based CNN model is highly accurate as a decision-support tool, and it is reliable and accessible for predicting Pes planus and Pes cavus deformities. This tool may be very useful in underserved healthcare settings and for patients with limited access to expert clinical assessment. Future efforts should enhance this technology for pediatric use and improve severity differentiation, paving the way for more personalized and inclusive healthcare solutions.

Category: Midfoot/Forefoot; Trauma; Other Introduction/Purpose: Metatarsal fractures account for over 35% of all foot fractures, and of these 68% specifically involve the fifth metatarsal [1],[2]. Subgroups of fractures affecting the fifth metatarsal base may be at higher risk of nonunion and therefore benefit from early surgical fixation, but traditional predictive models focus on the location of the fracture and little else. In this study, we aimed to determine predictive factors associated with non-union of fifth metatarsal fractures to assist surgeons and patients, alike, in identifying those at higher risk of nonunion. Methods: A retrospective machine learning-based analysis of 1,000 patients, >=18 y/o, diagnosed with a fifth metatarsal fracture at three tertiary medical centers was conducted. The fifth metatarsal base fracture was confirmed radiographically. We gathered imaging and narrative data including demographics (age, height, weight, BMI, gender, race, smoking habits, activity level), medications, chronic conditions, and fracture status (fracture zone, displacement, treatment method, healing status, and healing time). Non-union was described as failing to heal within 180 days of initial injury [3]. A machine learning analysis together with Pearson's correlation test and T-test were utilized where applicable. Five imputation methods were used to fill in missing datapoints. P

Category: Ankle; Other Introduction/Purpose: Portable fluoroscopy devices provide point-of-care imaging in emergency and out-patient clinics. In patients suffering from ankle syndesmosis injuries, imaging under physiologic load can lead to more accurate diagnosis, particularly in subtle cases. In this study, we compared weightbearing images obtained using a novel lightweight portable battery-powered fluoroscopy device with a conventional radiography device regarding syndesmosis examination measurements. Methods: In this prospective study, eleven healthy participants underwent bilateral three-view weightbearing imaging of both ankles using a radiography (X-ray group) device and a portable fluoroscopy system (Smart-C group). Radiographic measurements were done by two observers on anteroposterior, mortise, and lateral views were compared between the two techniques. These measurements included talar tilt, tibiofibular clear space, tibiofibular overlap, plafond malleolar angle, medial distal tibial angle, medial clear space, lateral distal tibial angle, anterior and posterior tibiofibular distance were measured using the appropriate view. Data were compared between the two techniques; the interobserver agreement was calculated within each group. P

Category: Other; Ankle Introduction/Purpose: Over the last decade, simultaneous or overlapping procedures in orthopedic surgery have come under increased media attention and public scrutiny. While little is known about what surgeons consider to be 'critical portions' of the myriad of foot and ankle procedures performed, even less is known about the expectations and opinions of patients themselves. In this study we aimed to elucidate patients' expectations of foot and ankle surgeons regarding their presence at different portions of a given surgery and what portions of a surgery they considered to be 'critical'. Methods: In this survey, data was collected using a questionnaire that was filled out by 49 patients presenting to an orthopedic foot and ankle tertiary referral clinic. The questions were designed around three common foot and ankle procedures: open reduction, internal fixation of fractures (ORIF), Achilles tendon repair, and ankle arthroscopy. For each procedure, the key steps were identified, and the responding patient was asked to characterize each step as 'Always Critical' 'Often Critical' 'Sometimes Critical' 'Rarely Critical' or 'Never Critical.' Additionally, demographics, education level, number of prior surgeries, and profession were also collected from the patients. Data were described using means, ranges, and percentages. Results: Of the 49 patients surveyed, the average age was 52.9 years old; 59% were female and 41% were male; 76% of respondents were college graduates, 8% completed some college, and 12% were high school graduates. Overall, 12% of respondents work in a healthcare related field. The average number of previous surgeries was 2.0, with a minimum of 0 and a maximum of 14. In all three procedures, the steps for which more than 50% of the patients identified as 'Always Critical' were discussion of risks, benefits, and alternatives, marking the surgical site, pre-operative time-out, skin incision for ORIF, soft tissue dissection, reduction of fracture, fracture fixation with hardware, repair of the tendon, and scoping the ankle. Across all three procedures, transferring the patient between operating table and bed, applying a sterile bandage, and applying a splint were categorized as the least critical portions of the procedure (Figure 1). Conclusion: The result of this study offers insight on what the most critical portion of three common foot and ankle procedures from the patient's perspective. Generally speaking, patients perceived initial dissection and even closure to be critical, in addition to procedural elements such as fracture reduction. Ongoing research aims to correlate these findings with the perceptions of foot and ankle surgeons themselves. Nonetheless, it highlights the potential discrepancy in perceptions between clinicians and patients as it pertains to 'critical portions' of a given procedure.

Category: Ankle Arthritis; Trauma Introduction/Purpose: Social and demographic determinants of health including gender, race, ethnicity and language, have been shown to impact treatment pathways across medical specialties. Very little such research, however, has focused explicitly on orthopaedic foot and ankle patients. Given the debilitating health implications of ankle arthritis, this study aimed to investigate the effect of demographic and social factors on the treatment pathways and outcomes of patients presenting to orthopaedic foot and ankle surgeons with end-stage ankle arthritis. Methods: In this retrospective, cross-sectional study, ICD 9/10 codes were used to identify 3,219 adult patients presenting to seven academic and community hospitals with ankle arthritis between 2011-2021. These patients were screened for end-stage ankle arthritis (Grade 3 or 4 on Kellgren-Lawrence Classification) and 509 patients were included in the final sample. For the primary variables of interest, patients were grouped by race (White/ Non-white), ethnicity (Hispanic/ Non-Hispanic), and primary spoken language (English/ non-English). Other demographic data included sex, age, body mass index, tobacco use, and insurance profile. The type of treatment (operative or nonoperative), length of postoperative admission, postoperative complication rates, and reoperation rates were compared between the groups using Chi square tests. Linear regression models were used to determine if the primary explanatory variables were among the factors affecting the time between initial consultation and surgical treatment, and duration of hospital stay. P0.05). Linear regression revealed that, among the explanatory variables, Hispanic ethnicity (Unstandardised coefficient=18.017; p=0.021), and history of former or no tobacco use (Unstandardised coefficient=9.156; p=0.021) significantly predicted the time gap between the diagnosis of end-stage ankle arthritis and surgical treatment. Regression models also showed that primary language being non-English and septic arthitis as a predisposing cause of arthitis significantly predicted hospital stay duration (Unstandardised coefficient= 3.409, 13.228 respectively, p= 0.010,

Category: Ankle; Other Introduction/Purpose: Finding factors that can exacerbate or ameliorate the incidence of Venous thromboembolism (VTE) can affect the process of making decision on whether to start prophylaxis or not, especially when on the verge of whether to-give or not-to-give prophylaxis. Among each patient's profile, medications are of the most important factors influencing surgeon's decision on the prophylactic methods in VTE-vulnerable patients. Among medications, Statins were shown to reduce the incidence of VTE in patients who were receiving them for hyperlipidemia and cardiovascular conditions. However, none of the current VTE prediction methods, particularly in orthopaedic practice, have considered statins protective. Herein we aimed to determine any correlations between statin consumption and the incidence of VTE in ankle fractures and whether to include statins in prediction models of VTE. Methods: In this case-control machine learning-based study, approved by the Institutional Review Board (IRB), the ICD and CPT codes were used to identify the patients who were diagnosed with ankle fracture in the Mass General Brigham database from 2004 to end of May 2021. After screening approximately 16,421 patients with ankle fractures, a total of 1,176 patients who were suspect VTE according to their signs and symptoms were recruited, 239 had confirmed VTE (case group) and 937 did not have VTE (controls). Forty-nine cases and 396 controls were statin users. Using a semi-automated machine learning-based algorithm, patients' demographics, past medical and surgical history, fracture characteristics and weber classification, and statin consumption status were obtained, and values were organized in a numerical analyzable manner in the dataset. We used chi-squared and Pearson correlation tests where applicable, and outcomes were displayed and interpreted using p-value (p

Category: Basic Sciences/Biologics; Other Introduction/Purpose: Patients undergoing nerve decompression surgery often report persistent symptoms. Some have suggested that wrapping the affected nerve with amniotic membrane may improve outcomes if the nerve is wrapped with amniotic membrane at the time of surgery, possibly related to anti-inflammatory, antifibrotic, or pro-regenerative effects. There is little in the foot and ankle literature to support such approaches. The aim of this preliminary study was to assess the initial safety of amniotic membrane use outcomes in foot and ankle surgery during nerve decompression procedures as an initial study in anticipation of a randomized, prospective trial. Methods: We retrospectively reviewed outcomes among 22 patients, >=18 years old, who had undergone amniotic membrane neurorrhaphy for lower extremity nerves including sural, saphenous, superficial peroneal, common peroneal, deep peroneal, digital (Morton's neuroma), Baxter's and posterior tibial nerve. Patients may have had multiple nerves wrapped and have had other procedures done. All patients had failed conservative treatments including cortisone injections, orthotics, nonsteroidal anti- inflammatory drugs, and physical therapy. Patients' demographics, postoperative complications, patient reported outcome measures (PROMs), and preoperative/postoperative Visual Analog Scores (VAS) for pain was collected. Data were reported in a descriptive manner. Results: Twenty-two patients, 16 females and 6 males averaging 51 years of age were assessed. Only one patient of the twenty- two reported a higher postoperative VAS compared to the preoperative VAS. There were no post-operative infections or reactions to the amniotic membrane. No patient required repeat surgery. The average pre- and post-operative VAS were 6.36 and 2.77, respectively. The average PROMs Pain Interference and Pain Intensity (Short Form 4a and 3a, respectively) were 42.02 and 35.94, respectively, that were within the normal range. Conclusion: The use of amniotic membrane wrap in lower extremity nerve decompression procedures was shown to be safe regarding post-operative short-term complications in this series of patients. However, in order to prove the usefulness of this technique for pain and function improvement, further studies with larger populations, particularly randomized clinical trials with long term follow up are necessary.

Category: Ankle Introduction/Purpose: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have determined that 100 Newtons (N) is the required force applied when performing the LFST to detect syndesmotic instability. We hypothesize that surgeons do not uniformly nor consistently apply 100N of force when performing the LFST and that substantial variation exists. Fundamentally, this could lead to under-detection of syndesmotic instability as surgeons may not be applying the requisite force in a consistent manner. Methods: A biomechanical SawBones lower leg model including simulated soft tissue envelope (SawBones inc., Vashon Island, Washington) was mounted to a board and a 1cm diameter hole was drilled across the tibia and fibula in the area of the syndesmosis. An industrial force gauge (Nidec-Shimpo, Kyoto, Japan) was then mounted. A metal extension piece was passed from the force gauge through the hole and positioned so that the tip was exposed on the lateral side of the model. A commonly utilized reduction clamp was affixed to the force gauge. Orthopaedic attending surgeons and trainees were asked to perform a series of LFSTs and to simulate the force they typically apply intra-operatively and this force was recorded in Newtons (N). Basic demographic data was collected on each participant. Results: 33 surgeons participated in the study, including 18 trainees. The median (IQR) force applied during the LFST was 96.42(71.42-126.33), 87.49 (69.19-117.40), 99.99(79.91-137.49), for the pooled group, attendings, and trainees respectively. Over half (54.5%) of all trials were less than 100N (57.8% of surgeons, 51.8% trainees). The distribution of pulls is shown in Figure 1. Intraobserver correlation was excellent within the overall cohort (0.92, p

Category: Ankle; Other Introduction/Purpose: The risk of venous thromboembolism (VTE) after foot and ankle surgery is significantly lower than rates after hip/knee arthroplasty, but it isn't zero. Specific subgroups of patients may be at higher risk, forcing patients and clinicians to navigate the risks and benefits of chemoprophylaxis with insufficient data. Efforts have been made to add clarity to such decision making using conventional data-analysis and risk-scoring methods, but none of these methods were patient-specific or built on robust models of a given patient's individual characteristics. In this study we used machine-learning to determine the potential risk factors for VTE after ankle fracture. We aimed to develop a patient-specific predictive model to assist clinicians and patients in deciding upon the use of postoperative chemoprophylaxis after foot and ankle surgery. Methods: In this preliminary machine-learning-based case-control study, 16,421 patients with ankle fractures were recruited retrospectively. We used an automated-string search method to find patients who were clinically suspected to have developed VTE. Among 1176 such patients, 239 had confirmed VTE within 180 days of sustaining an ankle fracture (cases) and 937 did not (controls). Groups were further sub-divided in patients who had been receiving chemoprophylaxis and those who hadn't. Over 110 factors and variables including patient demographics, past-medical and surgical history, fracture characteristics, treatment, medications, and laboratory values were included in our machine-learning dataset. Three analytical algorithms were used in our machine-learning methods including backward-logistic-regression, decision-tree-classifier (depth=5), and neural networks (two dense layers (n=16 and 4), two drop-out layers, and a sigmoid classifier). Conventional statistics were also used to compare the case and control groups (chi-squared, t-test, p

Category: Basic Sciences/Biologics Introduction/Purpose: Plantar fasciitis is a common condition affecting approximately one in ten people in their lifetime. Treatment is typically conservative and symptoms are self-limiting. Operative treatment is indicated in recalcitrant cases. Minimally-invasive partial plantar fasciotomy can be performed using ultrasound-guided percutaneous techniques and is an attractive alternative to traditional surgery. Methods: A retrospective review was performed on consecutive patients who underwent either an ultrasound-guided fasciotomy or a combined percutaneous fasciotomy with a flowable amniotic matrix allograft. All ultrasound-guided percutaneous fasciotomy procedures were performed using the Tenex TX2 cutting device. Human amniotic allograft consisted of an injection of 0.5 mL of a flowable placental tissue matrix. Outcomes were assessed at short-term (2, 8, and 16 weeks) and long-term follow-up (26 and 52 weeks). Results: Both groups demonstrated a significant reduction in pain from baseline after the respective interventions and demonstrated a high level of patient satisfaction. The only significant difference in the 2 groups was at short-term follow-up in which the percutaneous fasciotomy with the amniotic membrane allograft (n=12) showed a statistically-significant reduction (p

Category: Ankle; Trauma Introduction/Purpose: Despite the fact that stress fluoroscopy is the most common method of quantifying lateral ankle instability, ultrasound evaluation has grown in popularity as a way to assess ankle stability at the point of care due to its simplicity, accuracy, low cost, and lack of exposure. The aim of this study is to introduce a new method for evaluating lateral ankle instability using ultrasound. Methods: A 37-year-old man with history of lateral ankle ligament injury underwent ultrasound and fluoroscopic evaluation. The anterior drawer distance (ADD) was quantified under anterior drawer stress. During ADD measurement, the patient sat with the knee extended and the heel on the examination table or chair, and the examiner performed the anterior drawer test (Image 1a). The amount of talar movement was measured as an ADD using an ultrasound probe placed on the posteromedial side of the ankle (Image 1b). A lateral clear space (LCS) was also measured under varus stress using ultrasound from the tip of the lateral malleolar to the lateral process of the talus. The aforementioned measurements were repeated under stress fluoroscopy and compared with ultrasound findings. Results: On ultrasound evaluation, the ADD was 7.1 mm and the LCS was 17.1 mm. Furthermore, the stress fluoroscopic evaluation yielded a similar result, with an ADD of 8.7 mm and an LCS of 17.5 mm. Conclusion: Our findings suggest that this new method of evaluation of lateral ankle instability under dynamic ultrasound appears to be a highly accurate and useful alternative for assessing lateral ankle stability at the point of care in a radiation-free, non- invasive, and low-cost manner.

Background: Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability. The goal of this study is to test the validity of a new clinical examination maneuver, the lateral drawer test, against the gravity stress view (GSV) in a cohort of patients with Weber B fibula fractures. Secondary goals included assessing pain tolerability of the lateral drawer test, as well as testing interobserver reliability. Methods: Sixty-two patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three nonweightbearing radiographic views of the ankle as well as a GSV were obtained. Radiographs were not visualized before conducting the lateral drawer test. Two foot and ankle fellowship–trained orthopaedic surgeons performed and graded the lateral drawer test. Radiographs were then examined and medial clear space (MCS) was measured. Visual analog scale (VAS) pain scores were obtained before and after testing. The results of the lateral drawer test were compared with radiographic measurements of MCS on GSV. A cadaveric experiment was devised to assess interobserver reliability of the lateral drawer test. Results: Thirty (48%) of 62 consecutively enrolled patients demonstrated radiographic instability with widening of the MCS ≥5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 86%. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (Spearman correlation ρ = 0.82, P < .005). Patients tolerated the maneuver well with an average increase of 0.7 on the VAS pain scale. Testing of 2 observers utilizing the cadaveric model demonstrated a Cohen’s Kappa coefficient of 0.7 indicating moderate interobserver agreement. Conclusion: The lateral drawer test demonstrates high sensitivity, specificity, PPV, and NPV with moderate interobserver reliability compared with the MCS on GSV in patients presenting with Weber B fibula fractures. Although further external validation is required, the lateral drawer test may offer an adjunct tool via physical examination to help determine mortise stability. Level of Evidence: Level II, Prospective Cohort Study.

Background: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have used 100 N as the force applied when performing the LFST to detect syndesmotic instability, though no evidence-based requisite force has been described for the test. We hypothesize that surgeons do not apply force uniformly or consistently when performing the LFST and that substantial variation exists. Fundamentally, this could lead to inconsistent diagnosis of syndesmotic instability as surgeons may not be applying the force in a consistent manner. Methods: A biomechanical ankle model consisting of an industrial force gauge attached through a SawBones model was fashioned. Orthopaedic attending surgeons and trainees were asked to perform a series of LFSTs and to simulate the force they typically apply intraoperatively. Basic demographic data were collected on each participant. Results: Thirty-three surgeons participated in the study, including 18 trainees. The median (IQR) force applied during the LFST was 96.42 (71.42-126.33), 87.49 (69.19-117.40), 99.99 (79.91-137.49), for the pooled group, attendings, and trainees respectively. More than half (54.5%) of all trials were less than 100 N (57.8% of surgeons, 51.8% trainees). Intraobserver correlation was excellent within the overall cohort (0.92, P < .001), trainees (0.90, P < .001), and attendings (0.94, P < .001), respectively. Interobserver reliability was fair among the overall cohort (κ =0.28, P = .49), and poor between the attendings (κ = 0.11, P = .69) and the trainees (κ = 0.05, P = .82), respectively. Conclusion: Our study demonstrates that the amount of force applied by typical surgeons when performing the LFST test is highly variable. Variable force application when performing the LFST may lead to inconsistent detection of syndesmotic instability, which may portend a poorer outcome. Clinical Relevance: In this study, we demonstrate the wide variability in the amount of force used during a lateral fibular stress test. High variability of force application when performing the LFST may lead to inconsistent diagnosis of syndesmotic instability, which may portend a poorer outcome. Our findings suggest the need for further investigation into the technical aspects of syndesmotic testing that will permit more reproducible and valid interrogation of the syndesmosis.

Category: Ankle; Sports; Trauma Introduction/Purpose: Numerous radiographic studies examining Weber B fibular fractures demonstrate no change in tibiotalar contact area until the deltoid ligament is disrupted. In contrast, more recent studies using weight-bearing CT scan (WBCT) and 3D volume analysis suggest that medial clear space (MCS) volume can in fact increase in the setting of a Weber B fibular fracture even if initial radiographs are reassuring, possibly due to a loss of fibular buttress. This study aims to evaluate the ability of WBCT to quantify the impact of isolated Weber B fractures on MCS volume (3D), as well as understand the implication of increasing fibular displacement among patients with symmetric MCS distance (1D) on initial radiographs. Methods: The study group included 18 patients with unilateral Weber B ankle fractures who underwent preoperative bilateral foot and ankle WBCT. The control group consisted of 60 patients without ankle injury who underwent similar imaging. Measurements on WBCT images included: 1) MCS distance, 2) syndesmotic area, 3) anterior, middle, and posterior distal tibiofibular distance, 4) fibular rotation, 5) distance from fibular tip to plafond, and 6) fibular fracture displacement. Additionally, volumetric measurements included: 1) MCS volume 2) syndesmotic joint volume from the tibial plafond extending to 3cm and 5 cm proximally, and 3) lateral clear space volume were calculated. Area under the receiver operating characteristic (ROC) curve analysis and Delong test were used, and optimal cutoff values to distinguish between stable and unstable Weber B fractures without syndesmotic instability and MCS widening were determined using Youden's J statistic. Results: Among patients with unilateral Weber B ankle fractures, all WBCT measurements showed no side-to-side difference in any parameter, except MCS volume (p-values

Category: Midfoot/Forefoot; Trauma Introduction/Purpose: Diagnosis of subtle Lisfranc joint instability, as a commonly missed foot injury, has remained a concern since it can result in future disabilities if inadequately treated. Weightbearing radiographs (WBR) and conventional CT scans are the most frequent methods in healthcare centers all around the world that are used to assess tarsometatarsal injuries, specifically the Lisfranc joint. However, their accuracy in detecting subtle cases varies depending on the experience and expertise of the interpreter as well as the quality of the images. We aimed to evaluate the use of deep learning and deep convolutional neural network (DCNN) in the detection of subtle Lisfranc instability using WBR and CT scans. Our hypothesis was that this method can increase the accuracy and hasten the interpretation using these modalities. Methods: We gathered 200 WBR and 200 CT scans of cases with subtle Lisfranc instability who were diagnosed intraoperatively; 200 WBR and 200 CT scans of patients with otherwise healthy feet were added as the control group. To increase the confidence in the results we implemented saliency maps to visualize the location of the injury as a heat map and exhibit the process of decision-making by the algorithm. The data of the study was expressed as sensitivity, specificity, accuracy, and the area under the curve (AUC). We used Inception DCNN model as the pre-trained DCNN model in this study. Results: The performance of the DCNN using WBR resulted in sensitivity=93.6%, specificity=91.1%, Accuracy= 94.7, AUC=98.2%. DCNN applied on CT scan resulted in sensitivity=95.8%, specificity=96.9%, accuracy= 93.2, and AUC=98.4%. In cases that the injury was detected correctly by the DCNN, the saliency map had shown the location of the injury correctly as well (100%, Figure 1 ). Conclusion: Here we showed that using DCNN on the currently used interpretation method can significantly improve the accuracy of interpretation using WBR and CT scans in the detection of subtle Lisfranc instability. WBR has lower costs and a lower rate of radiation, thus, improving its performance using deep learning methods can lead to a significant improvement in healthcare quality for the patient and reduced costs for the system.

Category: Ankle; Trauma Introduction/Purpose: The ability to compare the ankle joints bilaterally in a 3D manner under physiologic weight provided by weight-bearing CT has led to a more accurate diagnostic method. While weight-bearing computed tomography (WBCT) allows 3D visualization of the distal syndesmosis, image interpretation has largely relied on 1D distance and, more recently, 2D area measurements. This study aimed to: 1) determine the sensitivity and specificity of 2D area and 3D volume WBCT measurements towards detecting subtle syndesmotic instability, 2) evaluate whether the patterns of changes in the 3D shape of the syndesmosis can be attributed to the type of ligament injury. Methods: A total of 24 patients with unilateral subtle syndesmotic instability and 24 individuals with uninjured ankles (controls) with bilateral ankle WBCT were assessed retrospectively. First, 2D areas at 0, 1, 3, 5,10 cm, and 3D volumes at 1, 3, 5, and 10cm above the tibial plafond were measured bilaterally. Secondly, given the volume measurement at the level of 5 cm proximal to the platform as the most sensitive and specific method introduced in this study, the 3D model of the distal tibiofibular space was created based on WBCT in a subset of 8 patients out of 24 in whom the type of ligament injury was recognized via MRI. The 3D model of the injured side was superimposed on the uninjured contralateral side to visualize the pattern of changes in different planes. P=39% at 5 cm height while without IOL injury the volume increased up to 26% (figure 1). The percentage of changes in 2D areas and 3D volumes showed significant differences in areas at 0cm (19.2%; p=0.004), 1cm (24.1%; p=0.002), 3cm (27.3%; p=0.003), 5cm (28%; p=0.002), and 10cm (29.3%; p=0.003) as well as volumes at 1cm (31.2%; p=0.003), 3cm (26.5%; p=0.001), 5cm (25.4%; p

Category: Ankle; Trauma Introduction/Purpose: Weightbearing CT (WBCT) scan provides an ability to compare the ankle joints bilaterally in a 3D manner under physiologic load. According to our recent investigations, 3D volume measurement of the syndesmosis, if measured up to 5cm proximal to the tibial plafond, can detect the instability with an accuracy of 90%, sensitivity of 95.8%, and specificity of 83.3%. However, these values can differ based on the knowledge and experience of the human interpreter. Deep learning, as a subset of machine learning, has shown promising potentials in processing and analyzing images and detecting abnormalities within the images using deep convolutional neural networks (DCNN). Herein, we aimed to assess the accuracy, sensitivity, and specificity of 3D volume WBCT evaluation using DCNN algorithms in patients with subtle syndesmotic instability. Methods: In this study 140 bilateral ankle WBCT scans of patients with subtle syndesmotic instability who were diagnosed intraoperatively were allocated to the patient group. The control group comprised 140 bilateral ankle WBCT images of healthy individuals. We utilized inception V3 model for our DCNN. Data augmentation and transfer learning were used; however, the images were not preprocessed in terms of change in size and resolution. The data were divided as 80:10:10 for training, validation, and test subsets, respectively. The outcome of the study was expressed as sensitivity, specificity, F-score, and the area under the curve (AUC). Results: The performance of our DCNN algorithm showed a sensitivity of 99.41%, specificity of 99.34%, F-score of 99.37%, and 99.99% AUC ( Figure 1 ). The change in loss value of the train data was plateaued after 40 iterations. Axial images were the most appropriate images that were used by the algorithm to detect the instability. Conclusion: In this study we observed that using DCNN in the process of WBCT image interpretation for diagnosis of syndesmotic instability, particularly in subtle cases, makes this modality almost perfect with a very small chance of missing a case. Training a DCNN using a greater number of inputs is still recommended to improve the validity and reliability of this method. Providing a heat map will also help clinicians discover the process of decision-making by these algorithms as DCNNs are sometimes called 'black box'.

Category: Ankle; Sports; Other Introduction/Purpose: To optimize clinical outcomes, accurate diagnosis and treatment of syndesmotic instability is critical, but subtle instability can be challenging to identify. Weightbearing computed tomography (WBCT) has proved to be a reliable tool for diagnosing syndesmotic instability under physiologic load. We aimed to examine the cost-effectiveness of WBCT with radiographs and/or conventional CT for the diagnosis of syndesmotic instability from a patient perspective. Methods: A decision tree model was constructed to examine the cost-effectiveness of WBCT versus conventional CT (NWB CT) versus weightbearing (WB) radiographs versus non-weightbearing (NWB) radiographs (base case) as initial imaging with additional possible imaging for1268 patients with suspected syndesmotic instability. Patient's clinical and radiological notes were evaluated until the diagnosis of syndesmotic instability was established. The decision tree's probabilities, durations, and image counts were based on patient data. The main outcomes were 1) total imaging costs needed before syndesmotic instability was diagnosed, 2) quality-adjusted life-years (QALYs), 3) incremental cost-effectiveness ratios (ICERs), and 4) overall radiation dose prior to diagnosis. Imaging costs and radiation dose were derived from National Medicare reimbursement rates and the American College of Radiology, respectively. An incremental cost-effectiveness ratio threshold of $50,000 per quality-adjusted life years was used to evaluate cost-effectiveness. In addition, one-way and two-way sensitivity analyses were performed to determine the robustness of our findings. Results: WBCT resulted in 0.057 additional QALY gained per week compared with NWB radiographs, indicating WBCT to be more effective than NWB radiographs. Costs for WBCT imaging were $38.71 higher than NWB radiographs for an ICER of $38,563.96/QALY. Applying a commonly used threshold of $50,000 per QALY, the patient's willingness-to-pay for the amount of quality-adjusted life-year gained from using WBCT as an initial imaging modality was $54.41, suggesting WBCT first imaging strategy was a cost-effective intervention. In our study, the cost of WBCT imaging was $157.35. Sensitivity analyses demonstrated that WBCT was more cost effective than NWB radiographs up to a cost of $173.05. Additionally, initial WBCT resulted in lower overall radiation dosage (6.4 uSv) compared to the use of the other three imaging modalities as initial imaging strategy (initial NWB radiographs - 12.41 uSv; initial WB radiographs - 8.30 uSv, NWB CT first - 25 uSv). Conclusion: WBCT leads to higher QALYs compared to other diagnostic imaging modalities, resulting in improved outcomes for patients by eliminating redundant imaging.

Category: Ankle; Trauma Introduction/Purpose: Early and accurate detection of ankle fractures is crucial for reducing future complications. Radiographs are the most abundant imaging techniques for assessing fractures. We believe deep learning (DL) methods, through adequately trained deep convolutional neural networks (DCNNs), can assess radiographic images fast and accurate without human intervention. In this study, we aimed to assess the performance of two different DCNNs in detecting ankle fractures using radiographs compared to the ground truth. Methods: In this retrospective study, our DCNNs were trained using radiographs obtained from 1050 patients with ankle fracture and the same number of individuals with otherwise healthy ankles. Inception V3 and Renet50 pre-trained models were used in our algorithms. Danis-Weber classification method was used. Out of 1050, 72 individuals were labeled as occult fractures as they were not detected in the primary radiographic assessment. Using single-view radiographs was compared with 3-views (anteroposterior, mortise, lateral) for training the DCNNs. Results: Our DCNNs showed a better performance using 3-views images versus single-view based on greater values for accuracy, F-score, and area under the curve (AUC). The sensitivity and specificity in detection of ankle fractures using 3-views were 97.5% and 93.9% using Resnet50 compared to 98.7% and 98.6 using inception V3, respectively. Resnet50 missed 3 occult fractures while Inception V3 missed only one case. In cases that detected the fracture, the saliency map showed the location of the fracture ( Figure 1 ). Conclusion: The performance of our DCNNs showed a promising potential that can be considered in developing the currently used image interpretation programs or as a separate assistant to the clinicians to detect ankle fractures faster and more precisely.

Category: Ankle; Sports; Trauma Introduction/Purpose: Malreduction of the fibula within the incisura is often caused by an eccentric clamp or screw placement and short fibular length. Weightbearing computed tomography (WBCT) has proven to be a reliable method to diagnose syndesmotic instability and can be used as a template to determine the syndesmotic axis and optimal position to place the clamp. We aimed to determine the anatomic axis of the syndesmosis, or the trans-syndesmotic angle (TSA) in healthy individuals on WBCT, and to see if side-to-side and gender based variations exist. We also aimed to determine the clamp's medial tine placement along the trans-syndesmotic axis. Methods: The study group was made up of patient population without ankle injury who underwent bilateral foot and ankle WBCT imaging (n = 100; 200 ankles). Measurements on bilateral WBCT images included: 1) TSA at 1cm, 2cm, and 3cm proximal to tibial plafond, respectively; 2) Medial tine of the clamp positioning at 1cm and 2 cm along the syndesmotic axis. The medial tine clamp position was described in terms of the percentage of anterior to posterior tibial diameter from the anterior cortical boundary. In addition, the aforementioned TSA measurements were compared to historically defined 30 degrees of syndesmotic axis. Paired t-test was used to compare side to side and gender based differences. A p-value < 0.05 was considered statistically significant. Results: In the uninjured healthy population, the mean trans-syndesmotic angles were 17.60, 21.60, and 24.10 at 1cm, 2cm, and 3cm proximal to the tibial plafond respectively. The clamp's medial tine should be positioned 24.7% and 21.3% of the AP tibial cortical distance, posterior to the anterior tibial cortex at 1cm and 2 cm proximal to the tibial plafond. There was no significant side to side or gender based differences for any of the measurements. Additionally, all three weightbearing TSA measurements were significantly larger than the historically defined syndesmotic angle of 30 degrees (p

Category: Ankle; Trauma Introduction/Purpose: Diagnosing and treating syndesmotic instability that occurs in some Weber B ankle fractures is essential to restore normal ankle joint kinematics and optimize clinical outcomes however subtle instability can be difficult to identify. WBCT evaluates the syndesmotic joint under physiologic load. We compared the diagnostic sensitivities of one-dimensional (1D) distance, two-dimensional (2D) area, and three-dimensional (3D) volumetric measurement of the injured syndesmotic joint on WBCT, in patients with unilateral Weber B ankle fractures with surgically-confirmed syndesmotic instability, to the contralateral uninjured side. Methods: Patients with unilateral surgically confirmed syndesmotic instability accompanying a Weber B type lateral malleolar ankle fracture (n = 23) who underwent preoperative bilateral foot and ankle WBCT were included. A separate group of patients with unilateral Weber B ankle fractures without syndesmotic instability and who underwent bilateral WBCT were included as a control group (n = 18). With the uninjured side serving as an internal control, measurements on bilateral WBCT images included: 1) syndesmotic area, 2) tibiofibular distance measured at the anterior, middle, and posterior aspect of the distal tibiofibular articulation, 3) fibular rotation, 4) distance from fibular tip to plafond, 4) fibular fracture displacement and 5) medial clear space distance. In addition, 3D volumetric measurements: 1) syndesmotic joint volume from the tibial plafond extending to 3cm and 5cm proximally, respectively 2) medial clear space volume, and 3) lateral clear space volume were calculated, and their sensitivities were compared to the aforementioned measurements. Results: Among patients with unilateral syndesmotic instability with Weber B ankle fractures, all WBCT measurements except medial clear space distance, syndesmotic area, and anterior and posterior tibiofibular distance were significantly greater on the injured compared to the uninjured side (p-values ranging from

Category: Ankle; Trauma; Other Introduction/Purpose: Recent studies have shown that weight-bearing computed tomography (WBCT) that allows 3D volume measurement of the distal syndesmosis while under physiologic load brings about a higher accuracy in detection of syndesmotic instability, especially if subtle. Since the volume measurement method is complex, time-consuming, and has a noticeable interobserver bias, most clinicians might not still be interested in utilizing it in practice. Automatization of this measurement using computer-assisted methods will not only reduce the interobserver bias but also will be faster and more applicable in practice. This study aimed to develop an automated 3D syndesmosis volume measurement tool using image processing methods and compare the speed and the interobserver bias with human interpreters. Methods: We included 30 patients with subtle syndesmotic instability who had undergone WBCT and were diagnosed intraoperatively. Thirty individuals with otherwise healthy ankles who had WBCT images were allocated to the control group. The volume measurement up to 5cm proximal to the tibial plafond was considered as the most sensitive and specific method to assess syndesmotic stability based on the literature. An algorithm was developed using MATLAB software that could recognize and calculate the syndesmotic volume using WBCT images. The volume measurement method was used by two orthopaedic surgeons for the same population. The time spent by each surgeon and the algorithm was measured. Finally, the values were compared using the t-test; the interobserver correlation coefficient (ICC) was also calculated. P

Category: Ankle Arthritis; Ankle; Basic Sciences/Biologics Introduction/Purpose: Osteoarthritis (OA) is a chronic disease and a significant cause of joint pain, tenderness, and limitation of motion. At present, no specific treatment is available and mesenchymal stem cells (MSCs) have shown promising potentials in this regard. Herein, we aimed to evaluate the repairing potentials of stem cells derived from synovium and fat pad in treatment of OA in ankle joint. Methods: Twenty-eight male rats (220+-20 g, aged 10-12 weeks), were randomly divided into four groups (n=7): C1: non- treated, C2: Hyalgan treated, E1: Adipose-tissue derived stem cell treated, and E2: synovial-membrane based stem cell treated groups. Collagenase type II enzyme was injected into the left ankle; after eight weeks, OA was developed. Then, stem cells were injected and rats were followed for three months. Afterwards, rats were euthanized and specimens and radiological images were provided. P-value

Category: Midfoot/Forefoot; Sports; Trauma Introduction/Purpose: Early detection of Lisfranc instability is critical for optimizing clinical outcomes. Injuries causing a more subtle instability, however, can be difficult to diagnose. The aim of this study was to compare the injured Lisfranc joint to the healthy contralateral side using weightbearing computed tomography (CT) in patients with known Lisfranc instability. We also aimed to define the range of normal measurement variation by comparing the Lisfranc joint measurements between the left and right foot in individuals without foot injury who underwent similar imaging. Our hypothesis was that compared to the healthy contralateral side, weightbearing CT area and volume measurements were increased in patients diagnosed with subtle Lisfranc instability. Methods: Patients with unilateral Lisfranc instability requiring operative fixation (n = 14) underwent preoperative bilateral foot and ankle weightbearing CT. A separate group of patients without foot injury who also underwent similar imaging were included as comparative controls (n = 36). For each weightbearing CT, 2 dimensional axial and coronal plane Lisfranc joint parameters, Lisfranc area, intercuneiform area, C1-M2 distance, C1-C2 distance, M1-M2 distance, first and second tarsometatarsal (TMT 1 and 2) alignment; and first and second tarsometatarsal (TMT 1and 2) dorsal step off were measured to evaluate the Lisfranc anatomy at a level 10 mm below the dorsal surface of medial cuneiform (Figures I and II). In addition, the volume of the Lisfranc joint was also evaluated. Values were recorded by two independent observers to assess interobserver reliability. Results: Among those with unilateral Lisfranc instability, values differed largely between the injured and the healthy contralateral side for all measurements performed (p-value range, 0.008 -