Water is an essential resource for humans, animals, and plants. Water is also necessary for the manufacture of many products such as milk, textiles, paper, and pharmaceutical composites. During manufacturing, some in-dustries generate a large amount of wastewater containing numerous contaminants. In the dairy industry, for each litre of drinking milk produced, about 10 L of wastewater is generated. Despite this environmental foot-print, the production of milk, butter, ice cream, baby formula, etc., are essential in many households. Common contaminants in dairy wastewater include high biological oxygen demand (BOD), chemical oxygen demand (COD), salts as well as nitrogen and phosphorus derivatives. Nitrogen and phosphorus discharges are one of the leading causes in the eutrophication of rivers and oceans. Porous materials have long held significant potential as a disruptive technology for wastewater treatment. However, thus far they have been understudied for use in dairy wastewater treatment. Ordered porous materials, such as zeolites and metal organic frameworks (MOFs), represent classes of porous materials with significant potential for the removal of nitrogen and phosphorus. This review explores the different zeolites and MOFs applied in the removal of nitrogen and phosphorus from wastewater and the prospect of their potential for use in wastewater management in the dairy industry.

Universal Serial Bus (USB) ports are a ubiquitous feature in computer systems and offer a cheap and efficient way to provide power and data connectivity between a host and peripheral devices. Even with the rise of cloud and off-site computing, USB has played a major role in enabling data transfer between devices. Its usage is especially prevalent in high-security environments where systems are ‘air-gapped’ and not connected to the Internet. However, recent research has demonstrated that USB is not nearly as secure as once thought, with different attacks showing that modified firmware on USB mass storage devices can compromise a host system. While many defenses have been proposed, they require user interaction, advanced hardware support (incompatible with legacy devices), or utilize device identifiers that can be subverted by an attacker. In this paper, we present Time-Print, a novel timing-based fingerprinting method, for identifying USB mass storage devices. We create a fingerprint by timing a series of read operations from different locations on a drive, as the timing variations are unique enough to identify individual USB devices. Time-Print is low overhead, completely software-based, and does not require any extra or specialized hardware. To validate the efficacy of Time-Print, we examine more than 40 USB flash drives and conduct experiments in multiple authentication scenarios. The experimental results show that Time-Print can (1) identify known/unknown brand/model USB devices with greater than 99.5% accuracy, (2) identify seen/unseen devices of the same brand/model with 95% accuracy, and (3) classify USB devices from the same brand/model with an average accuracy of 98.7%.

BACKGROUND: Distinct sets of microbes contribute to colorectal cancer (CRC) initiation and progression. Some occur due to the evolving intestinal environment but may not contribute to disease. In contrast, others may play an important role at particular times during the tumorigenic process. Here, we describe changes in the microbiota and host over the course of azoxymethane (AOM)-induced tumorigenesis. METHODS: Mice were administered AOM or PBS and were euthanised 8, 12, 24 and 48 weeks later. Samples were analysed using 16S rRNA gene sequencing, UPLC-MS and qRT-PCR. RESULTS: The microbiota and bile acid profile showed distinct changes at each timepoint. The inflammatory response became apparent at weeks 12 and 24. Moreover, significant correlations between individual taxa, cytokines and bile acids were detected. One co-abundance group (CAG) differed significantly between PBS- and AOM-treated mice at week 24. Correlation analysis also revealed significant associations between CAGs, bile acids and the bile acid transporter, ASBT. Aberrant crypt foci and adenomas were first detectable at weeks 24 and 48, respectively. CONCLUSION: The observed changes precede host hyperplastic transformation and may represent early therapeutic targets for the prevention or management of CRC at specific timepoints in the tumorigenic process.

Robotic-assisted adult deformity surgery has played a rapidly expanding role since its introduction. As robotic spine technologies improve, the potential to limit complications and morbidity is vast. The improvements in instrumentation accuracy combined with the ability to maintain that accuracy in multiple positions allow creative surgical approaches and techniques that can limit operative time, blood loss, and improve outcomes. In the years to come, robotic-assisted spine surgery and navigation will likely play an expanding role that continues to be defined. LEVEL OF EVIDENCE: 5, expert opinion.

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Advanced RISC Machines (ARM) processors have recently gained market share in both cloud computing and desktop applications. Meanwhile, ARM devices have shifted to a more peripheral based design, wherein designers attach a number of coprocessors and accelerators to the System-on-a-Chip (SoC). By adopting a System-Level Cache, which acts as a shared cache between the CPU-cores and peripherals, ARM attempts to alleviate the memory bottleneck issues that exist between data sources and accelerators. This paper investigates emerging security threats introduced by this new System-Level Cache. Specifically, we demonstrate that the System-Level Cache can still be exploited to create a cache occupancy channel to accurately fingerprint websites. We redesign and optimize the attack for various browsers based on the ARM cache design, which can significantly reduce the attack duration while increasing accuracy. Moreover, we introduce a novel GPU contention channel in mobile devices, which can achieve similar accuracy to the cache occupancy channel. We conduct a thorough evaluation by examining these attacks across multiple devices, including iOS, Android, and MacOS with the new M1 MacBook Air. The experimental results demonstrate that (1) the System-Level Cache based website fingerprinting technique can achieve promising accuracy in both open (up to 90%) and closed (up to 95%) world scenarios, and (2) our GPU contention channel is more effective than the CPU cache channel on Android devices.

PURPOSE:Evidenced-based decision-making is rooted in comparative clinical studies; however, a small number of outcome event reversals have the potential to change study significance. The purpose of this study was to determine the utility of applying fragility analysis to comparative studies in the published orthopaedic shoulder literature.METHODS:Comparative clinical shoulder research studies reporting 1:1 dichotomous categorical data were analyzed in 6 leading orthopaedic journals between 2006 and 2016. Statistical significance was defined as a P value of less than .05. The fragility index (FI) for each study outcome was determined by the number of event reversals required to change the P value to either greater or less than 0.05, thus changing the study conclusions. The associated fragility quotient (FQ) was determined by dividing the FI by the total population comprising a particular outcome.RESULTS:Of the 23,897 studies screened, 3,591 met search criteria, with 198 comparative studies ultimately included for analysis, 67 of which were randomized controlled trials. There were 357 total outcome events with 74 reported as significant and 283 as not significant. The FI was 4 (IQR 2-6) with an associated FQ of 0.066 (interquartile range [IQR] 0.038-0.102). There was no difference in statistical fragility between randomized and nonrandomized trials with both revealing a FI of 4 and FQ of 0.068 (IQR 0.044-0.107) and 0.065 (IQR 0.031-0.101), respectively.CONCLUSIONS:This current analysis reveals that comparative shoulder studies published in six leading orthopaedic journals are at risk of statistical fragility. As such, contemporary clinical shoulder literature may not be as robust as traditionally perceived with the reversal of only a few outcome events required to change study significance. Therefore, we advocate the reporting of both FI and FQ in addition to the P value as statistical complements to all comparative investigations to provide a more comprehensive understanding of trial stability and significance in the published shoulder literature.CLINICAL RELEVANCE:Comparative study designs are commonly employed in shoulder research. Several studies in both the general medical and orthopaedic literature have identified a lack of statistical robustness through comprehensive fragility analysis. Our findings demonstrate the P value may be an inadequate independent statistical metric requiring the complement of a FI and FQ to aid in the interpretation and understanding of study significance for clinical decision-making.

BACKGROUND CONTEXT Sagittal alignment is integral to a patient's quality of life. Posterior spinal fusion (PSF) is currently the standard for correcting adolescent idiopathic scoliosis (AIS). Vertebral body tethering (VBT) is a fusionless growth modulating surgical technique used to treat AIS. It relies on the Hueter-Volkmann Law. Indications for this procedure include patients who have coronal curves up to 50 °, growth remaining, and no excessive thoracic kyphosis. VBT has been shown to have good coronal plane deformity correction. There have been less examinations of the sagittal effects of VBT. Sagittal alignment is significantly associated with a patient's quality of life. This underscores the importance of sagittal alignment when correcting the coronal deformity in these patients. PURPOSE We show that VBT for correction of AIS is non-inferior with regards to sagittal alignment compared to PSF. STUDY DESIGN/SETTING Retrospective review of AIS patient treated by VBT and PSF at a single medical center. PATIENT SAMPLE Data was collected from our AIS database of VBT and PSF fusion patients. OUTCOME MEASURES Our outcome measures are sagittal vertical axis (SVA), cervical SVA (cSVA), pelvic tilt (PT), thoracic kyphosis (TK), cervical lordosis (CL), L4-S1 lordosis, L5 slope, T1 pelvic angle (TPA) and pelvic incidence lumbar lordosis mismatch (PI-LL). METHODS We propensity matched by age, Risser score and Lenke classification. We compared preoperative and postoperative sagittal parameters measured by Surgimap with statistical significance set at p<0.050. RESULTS Comparing PSF to VBT there was no statistically significant difference in change between preoperative and postoperative cSVA (-.45, SD=6.85 vs .97, SD=5.59, P=.48); PT (4.12, SD=6.49 vs 3.41, SD=4.50, P=.68); TK (1.65, SD=12.12 vs -1.59, SD=10.49, P=.35); CL (3.62, SD=8.87 vs 9.04, SD=13.82, P=.16); L4-S1 lordosis (3.25, SD=7.78 vs 6.09, SD=10.19 , P=.34); SVA (-14.95, SD=30.92 vs -26.82, SD=35.76, P=.34); L5 slope (-1.36, SD=5.91vs -2.95, SD=5.43, P=.44); TPA (4.42, SD=7.69 vs 5.21, SD=6.40, P=.74); and PI-LL (5.48, SD=10.96 vs 6.49, SD=10.80 P=.76). CONCLUSIONS VBT and PSF for AIS result in statistically similar changes in sagittal alignment parameters. The fact that we showed similar results comparing sagittal alignment in fusion and VBT groups indicates that VBT is non-inferior from a sagittal perspective. It is important to maintain sagittal alignment when correcting AIS. Future work can examine the long-term effect of VBT on sagittal alignment. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Sagittal alignment is integral to a patient's quality of life. Posterior spinal fusion (PSF) is currently the standard for correcting adolescent idiopathic scoliosis (AIS). Vertebral body tethering (VBT) is a fusionless growth modulating surgical technique used to treat AIS. It relies on the Hueter-Volkmann Law. Indications for this procedure include patients who have coronal curves up to 50 °, growth remaining, and no excessive thoracic kyphosis. VBT has been shown to have good coronal plane deformity correction. There have been less examinations of the sagittal effects of VBT. Sagittal alignment is significantly associated with a patient's quality of life. This underscores the importance of sagittal alignment when correcting the coronal deformity in these patients. We show that VBT for correction of AIS is non-inferior with regards to sagittal alignment compared to PSF. Retrospective review of AIS patient treated by VBT and PSF at a single medical center. Data was collected from our AIS database of VBT and PSF fusion patients. Our outcome measures are sagittal vertical axis (SVA), cervical SVA (cSVA), pelvic tilt (PT), thoracic kyphosis (TK), cervical lordosis (CL), L4-S1 lordosis, L5 slope, T1 pelvic angle (TPA) and pelvic incidence lumbar lordosis mismatch (PI-LL). We propensity matched by age, Risser score and Lenke classification. We compared preoperative and postoperative sagittal parameters measured by Surgimap with statistical significance set at p<0.050. Comparing PSF to VBT there was no statistically significant difference in change between preoperative and postoperative cSVA (-.45, SD=6.85 vs .97, SD=5.59, P=.48); PT (4.12, SD=6.49 vs 3.41, SD=4.50, P=.68); TK (1.65, SD=12.12 vs -1.59, SD=10.49, P=.35); CL (3.62, SD=8.87 vs 9.04, SD=13.82, P=.16); L4-S1 lordosis (3.25, SD=7.78 vs 6.09, SD=10.19 , P=.34); SVA (-14.95, SD=30.92 vs -26.82, SD=35.76, P=.34); L5 slope (-1.36, SD=5.91vs -2.95, SD=5.43, P=.44); TPA (4.42, SD=7.69 vs 5.21, SD=6.40, P=.74); and PI-LL (5.48, SD=10.96 vs 6.49, SD=10.80 P=.76). VBT and PSF for AIS result in statistically similar changes in sagittal alignment parameters. The fact that we showed similar results comparing sagittal alignment in fusion and VBT groups indicates that VBT is non-inferior from a sagittal perspective. It is important to maintain sagittal alignment when correcting AIS. Future work can examine the long-term effect of VBT on sagittal alignment.

Touchscreen-based mobile devices such as smartphones and tablets are used daily by billions of people for productivity and entertainment. This paper uncovers a new security threat posed by a side-channel leakage through the power line, called Charger-Surfing, which targets these touchscreen devices. We reveal that while a smartphone is charging, its power trace, which can be measured via the USB charging cable, leaks information about the dynamic content on its screen. This information can be utilized to determine the location on the touchscreen where an animation is played by the mobile OS to indicate, for instance, that a button press has been registered. We develop a portable, low cost power trace collection system for the side-channel construction. This leakage channel is thoroughly evaluated on various smartphones running Android or iOS, equipped with the two most commonly used screen technologies (LCD and OLED). We validate the effectiveness of Charger-Surfing by conducting a case study on a passcode unlock screen. Our experiments show that an adversary can exploit Charger-Surfing across a wide range of smartphone models to achieve an average accuracy of 98.7% for single button inference, and an average of 95.1% or 92.8% accuracy on the first attempt when cracking a victim’s 4-digit or 6-digit passcode, respectively. The inference accuracy increases to 99.3% (4-digit) or 96.9% (6-digit) within five trials. We further demonstrate the robustness of Charger-Surfing in realistic settings and discuss countermeasures against it.

Abstract. Objectives:. Evaluate the correlation between aortic stenosis and perioperative mortality in patients following surgical fixation of proximal femur fractures. Design:. Retrospectively reviewed case series. Setting:. Two Academic, Level 1 Trauma Centers. Patients/Participants:. One hundred fifty-eight patients, definitively diagnosed with aortic stenosis by means of echocardiogram, who underwent surgical fixation for an isolated proximal femur fracture (OTA/AO 31-A, 31-B, 32-A, 32-B, and 32-C fractures) between January 2000 and June 2015. The severity of the aortic stenosis was based upon accepted echocardiographic hemodynamic parameters designated by the 2014 American Heart Association guidelines. Main Outcome Measures:. Post Injury mortality, 30-day mortality, and 1-year mortality. Secondary Outcome Measures:. Postoperative mortality stratified by severity of aortic stenosis based on aortic valve area (AVA) and ejection fracture (EF) as determined by preoperative echocardiography. Results:. One hundred fifty-eight patients were available for final analysis. Kaplan–Meier survival analysis revealed a significantly longer time to mortality among Non-severe aortic stenosis patients compared to Severe aortic stenosis patients, P value .006. Twenty-three percent of patients with Severe aortic stenosis and 10% of patients with Non-severe aortic stenosis died within 30 days of surgery. No significant difference was observed in mean survival among AS patients who underwent surgery within 48 hours of injury (34.5 months) and those delayed more than 48 hours after injury (25.0 months), P value .116. Among the commonly measured hemodynamic parameters of aortic stenosis, only AVA and EF were significantly associated with mortality, P value .015, and P value < .001, respectively. There were no significant effects for Aortic Vmax, Peak ΔP, and Mean ΔP. An AVA of 0.8 cm2 or less is associated with a significantly shorter (22 months) postinjury mortality than patients with an AVA > 0.8 cm2. (37 months), P value .009. Conclusions:. Severe aortic stenosis is associated with a shorter postoperative time to mortality after surgical fixation of hip fractures compared to patients with Non-severe stenosis. Aortic valve area and Ejection Fraction are the only hemodynamic parameters significantly associated with postoperative mortality. Level of Evidence: Prognostic Level III

The use of suture button (SB) devices in the treatment of syndesmotic ankle injuries is increasing. These constructs have demonstrated better syndesmotic reduction, improved clinical outcomes, and lower rates of hardware removal compared with screw fixation. However, placing a SB device without a fibular plate can be technically challenging. In this technique tip, we use an illustrative case to demonstrate a technique tip that minimizes the risk of anterior or posterior cortical breach of the fibula and helps facilitate more accurate placement of a SB device.Levels of Evidence: Level V: Expert opinion.

Background. Syndesmotic disruption occurs in 20% of ankle fractures and requires anatomical reduction and stabilization to maximize outcomes. Although screw breakage is often asymptomatic, the breakage location can be unpredictable and result in painful bony erosion. The purpose of this investigation is to report early clinical and radiographic outcomes of patients who underwent syndesmotic fixation using a novel metal screw designed with a controlled break point. Methods. We performed a retrospective review of all patients who underwent syndesmotic fixation utilizing the R3lease Tissue Stabilization System (Paragon 28, Denver, CO) over a 12-month period. Demographic and screw-specific data were obtained. Postoperative radiographs were reviewed, and radiographic parameters were measured. Screw loosening or breakage was documented. Results. 18 patients (24 screws) met inclusion criteria. The mean follow-up was 11.7 months (range = 6.0-14.7 months). 5/24 screws (21%) fractured at the break point. No screw fractured at another location, nor did any fracture prior to resumption of weight bearing; 19 screws did not fracture, with 8/19 intact screws (42.1%) demonstrating loosening. There was no evidence of syndesmotic diastasis or mortise malalignment on final follow-up. No screws required removal during the study period. Conclusion. This study provides the first clinical data on a novel screw introduced specifically for syndesmotic fixation. At short-term follow up, there were no complications and the R3lease screw provided adequate fixation to allow healing and prevent diastasis. Although initial results are favorable, longer-term follow-up with data on cost comparisons and rates of hardware removal are needed to determine cost-effectiveness relative to similar implants. Level of Evidence: Level IV: Retrospective case series

Water is a key solvent, fundamental to supporting life on earth. It is equally important in many industrial processes, particularly within agricultural and pharmaceutical industries, which are major drivers of the global economy. The results of water contamination by common activity in these industries is well known and EU Water Quality Directives and Associated Regulations mandate that NH4+ concentrations in effluent streams should not exceed 0.3 mg L-1, this has put immense pressure on organisations and individuals operating in these industries. As the environmental and financial costs associated with water purification begin to mount, there is a great need for novel processes and materials (particularly renewable) to transform the industry. Current solutions have evolved from combating toxic sludge to the use of membrane technology, but it is well known that the production of these membrane technologies creates a large environmental footprint. Zeolites could provide an answer: their pore size and chemistry enable efficient removal of aqueous based cations via simple ion exchange processes. Herein, we demonstrate efficient removal of NH4+ via both static and dynamic methodology for industrial application. Molecular modelling was used to determine the cation-framework interactions which will enable customisation and design of superior sorbents for NH4(+) capture in wastewater. (C) 2019 The Korean Society of industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Large, open, public events, such as marathons and festivals, have always presented a unique safety challenge. These sprawling events, which can take up entire city blocks or stretch for many miles, can draw tens to hundreds of thousands of spectators and in some cases have open admission. As it is impracticable to guarantee the subjection of every event-goer to a security screening, we propose a crowd-based explosive detection system that uses a multitude of low-cost ChemFET sensors which are distributed to attendees. As the sensors offer limited accuracy, we further propose a server-based decision-making framework that utilizes a two-level feedback loop between the sensors and the server and explores spatial and temporal locality of the collected data to overcome the inherent low-accuracy of individual sensors. We thoroughly explore two distinct detection schemes, stressing their performance under a myriad of conditions, thus showing that such a crowd-based detection system comprised of low-cost and low-accuracy sensors can deliver high detection accuracy with minimal false positives.

Orthopedic implant removal is a commonly performed procedure. While implant removal can be associated with improved symptoms, risks of the surgery are notable. Stripped screws, broken and retained hardware, and morbidity associated with soft tissue compromise during difficult removal are all common. Familiarity with the instruments is critical to procedure success. The purpose of this study is to assist removal of unfamiliar screws in upper extremity surgery by offering a reference for screw and driver compatibility across manufacturers. Inclusion of device manufacturers was determined by market share. Screw size, drive configuration, and screw removal system compatibility data was collected and recorded. Screw, guide-wire, and screwdriver compatibility was assessed and compared to two commonly utilized universal implant-removal sets. Eight upper extremity implant vendors were included. The data was compiled in table format according to manufacturer and sub-categorized to facilitate screw identification according to radiographically identifiable characteristics. The diversity of orthopaedic implants in upper extremity surgery requires careful preoperative planning to identify the appropriate equipment for implant removal. The goal of this work is to provide a centralized reference of commonly implanted screws, guide-wires, and drivers for the upper extremity to facilitate removal.

REVIEW Volume 21 October 2020 59 Spinopelvic Mobility as it Relates to Total Hip Arthroplasty Cup Positioning: A Case Report and Review of the Literature Alexander M. Crawford, MD1 Patrick K. Cronin, MD1 Jeffrey K. Lange, MD2 James D. Kang, MD3

Roller compaction (RC) is a dry granulation technique applied to improve the flow and compressibility of drug formulations. RC implementation for high drug load formulations can be challenging due to flow issues and a high consumption of active pharmaceutical ingredient (API) for robust process development. This work addresses these challenges using process modelling for design and scale-up of an RC process on the same equipment and transfer to different equipment. A modified application of existing models incorporating a new description of mass transport in the feed screw is evaluated for guaifenesin formulations with a 90% drug loading. The model is calibrated using low-throughput data on a Vector Freund TF Mini RC and used to predict ribbon density and throughput for various process settings at high-throughput. It is found that the modelling framework can reasonably predict high-throughput behaviour on the same RC but the predictive performance decreases for transfer between equipment.

Physisorbent metal-organic materials (MOMs) have shown benchmark performance for highly selective CO2 capture from bulk and trace gas mixtures. However, gas stream moisture can be detrimental to both adsorbent performance and hydrolytic stability. One of the most effective methods to solve this issue is to transform the adsorbent surface from hydrophilic to hydrophobic. Herein, we present a facile approach for coating MOMs with organic polymers to afford improved hydrophobicity and hydrolytic stability under humid conditions. The impact of gas stream moisture on CO2 capture for the composite materials was found to be negligible under both bulk and trace CO2 capture conditions with significant improvements in regeneration times and energy requirements.

Study Design. Retrospective cohort study. Objective. To develop a comprehensive understanding of the prognostic value of laboratory markers on morbidity and mortality following epidural abscess. Summary of Background Data. Spinal epidural abscess is a serious medical condition with high rates of morbidity. The value of laboratory data in forecasting morbidity and mortality after epidural abscess remains underexplored. Methods. We obtained clinical data on patients treated for epidural abscess at two academic centers from 2005 to 2017. Our primary outcome was the development of one or more complications within 90-days of presentation, with mortality a secondary measure. Primary predictors included serum albumin, serum creatinine, platelet-lymphocyte ratio, and ambulatory status at presentation. We used multivariable logistic regression techniques to adjust for confounders. The most parsimonious set of variables influencing both complications and mortality were considered to be clinically significant. These were then examined individually and in combination to assess for synergy along with model-discrimination and calibration. We performed internal validation with a bootstrap procedure using sampling with replacement. Results. We included 449 patients in this analysis. Complications were encountered in 164 cases (37%). Mortality within 1-year occurred in 39 patients (9%). Regression testing determined that serum albumin, serum creatinine, and ambulatory status at presentation were clinically important predictors of outcome, with albumin more than 3.5 g/dL, creatinine less than or equal to 1.2 mg/dL, and independent ambulatory function at presentation considered favorable characteristics. Patients with no favorable findings had increased likelihood of 90-day complications (odds ratio [OR] 5.43; 95% confidence intervals [CI] 1.98, 14.93) and 1-year mortality (OR 8.94; 95% CI 2.03, 39.37). Those with one favorable characteristic had greater odds of complications (OR 4.00; 95% CI 2.05, 7.81) and mortality (OR 5.71; 95% CI 1.60, 20.43). Conclusion. We developed a nomogram incorporating clinical and laboratory values to prognosticate outcomes after treatment for epidural abscess. The results can be used in shared-decision making and counseling.

INTRODUCTION:Determining deltoid ligament incompetence in supination external rotation (SER) injuries commonly relies on stress radiography, given several studies demonstrating low predictive value of physical examination. Stress radiography can be difficult to obtain and may result in suboptimal radiographs with equivocal determination of stability. This study revisits the concept of medial ankle tenderness and its association with mortise instability.METHODS:Patients who presented with an isolated lateral malleolus fracture underwent prospective data collection. VAS scores were recorded with palpation at the lateral malleolar fracture site, anterior deltoid ligament, and posterior deltoid ligament. Three non-weightbearing radiographs of the ankle and a gravity stress view were obtained. Statistical analysis was performed to determine a correlation between tenderness and instability defined as MCS widening > 4 mm on gravity stress x-ray.RESULTS:51 patients met inclusion criteria. Group I (stable) and Group II (unstable) demonstrated no difference in tenderness over the lateral malleolus (p = 0.94) or anterior deltoid (p = 0.12), but patients in Group II reported significantly more tenderness over the posterior deltoid (p = 0.03). Taking the higher pain score from either anterior or posterior deltoid palpation, patients with unstable ankle fractures reported significantly more tenderness with medial palpation (p = 0.02). The relative risk of having an unstable ankle fracture with any tenderness to palpation over either the anterior or posterior deltoid ligament was 1.77 (95% CI 1.03 - 3.06, P = 0.039). When comparing no pain versus the presence of any pain with palpation medially, the sensitivity for any medial tenderness to detect an unstable ankle fracture was 0.76 (specificity 0.59, PPV 0.79, NPV 0.56).CONCLUSION:Patients with any medial tenderness were at significantly higher risk of having an unstable SER ankle fracture in this study, but strict reliance on the presence or absence of medial tenderness without stress radiographs would lead to an unacceptable number of both false positive and false negative determinations of instability. However, our findings suggest that medial tenderness is associated with instability. The 0.79 PPV of any medial tenderness for instability may be useful to cast doubt on equivocal stress radiography and prompt surgeons to repeat stress radiography or shorten the interval for radiographic follow up.LEVEL OF EVIDENCE:Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]).