Microcystin-LR Induces Estrogenic Effects at Environmentally Relevant Concentration in Black-Spotted Pond Frogs (Pelophylax nigromaculatus): In Situ, In Vivo, In Vitro, and In Silico Investigations.

Harmful cyanobacterial blooms are frequent and intense worldwide, creating hazards for aquatic biodiversity. The potential estrogen-like effect of Microcystin-LR (MC-LR) is a growing concern. In this study, we assessed the estrogenic potency of MC-LR in black-spotted frogs through combined field and laboratory approaches. In 13 bloom areas of Zhejiang province, China, the MC-LR concentrations in water ranged from 0.87 to 8.77 µg/L and were correlated with sex hormone profiles in frogs, suggesting possible estrogenic activity of MC-LR. Tadpoles exposed to 1 µg/L, an environmentally relevant concentration, displayed a female-biased sex ratio relative to controls. Transcriptomic results revealed that MC-LR induces numerous and complex effects on gene expression across multiple endocrine axes. In addition, exposure of male adults significantly increased the estradiol (E2)/testosterone (T) ratio by 3.5-fold relative to controls. Downregulation of genes related to male reproductive endocrine function was also identified. We also showed how MC-LR enhances the expression of specific estrogen receptor (ER) proteins, which induce estrogenic effects by activating the ER pathway and hypothalamic-pituitary-gonadal (HPG) axis. In aggregate, our results reveal multiple lines of evidence demonstrating that, for amphibians, MC-LR is an estrogenic endocrine disruptor at environmentally relevant concentrations. The data presented here support the need for a shift in the MC-LR risk assessment. While hepatoxicity has historically been the focus of MC-LR risk assessments, our data clearly demonstrate that estrogenicity is a major mode of toxicity at environmental levels and that estrogenic effects should be considered for risk assessments on MC-LR going forward.

Does salinity mediate the toxicity of perfluorooctanesulfonic acid (PFOS) in an estuarine fish?

Perfluorooctanesulfonic acid (PFOS) is detected in estuarine environments, where salinity levels fluctuate regularly. We investigated the effects of salinity on the toxicity of PFOS in embryos and larvae of Cyprinodon variegatus. We crossed six PFOS treatments (0, 1-10,000 µg/L) with two salinities (10, 30 ppt). Larvae exposed to the highest concentration of PFOS under high salinity accumulated over twice the amount of PFOS compared to larvae maintained under low salinity. Embryonic survival was unaffected by PFOS, salinity, or their interaction. PFOS delayed time to hatch and increased salinity reduced time to hatch regardless of PFOS treatment; however, no salinity by PFOS interactions were observed. Conversely, PFOS and salinity interacted in the larval stage, with decreased survival at 30 ppt salinity. This is one of the first studies evaluating interactive effects of PFOS and high salinity and highlights the importance of assessing PFAS toxicity across life stages.

Toxicities of Legacy and Current-Use PFAS in an Anuran: Do Larval Exposures Influence Responses to a Terrestrial Pathogen Challenge?

Legacy polyfluoroalkyl substances (PFAS) [perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA)] are being replaced by various other fluorinated compounds, such as hexafluoropropylene oxide dimer acid (GenX). These alternatives are thought to be less bioaccumulative and, therefore, less toxic than legacy PFAS. Contaminant exposures occur concurrently with exposure to natural stressors, including the fungal pathogen Batrachocytrium dendrobatidis (Bd). Despite evidence that other pollutants can increase the adverse effects of Bd on anurans, no studies have examined the interactive effects of Bd and PFAS. This study tested the growth and developmental effects of PFOS, PFOA, and GenX on gray treefrog (Hyla versicolor) tadpoles, followed by a Bd challenge after metamorphosis. Despite PFAS exposure only occurring during the larval stage, carry-over effects on growth were observed post metamorphosis. Further, PFAS interacted with Bd exposure to influence growth; Bd-exposed animals had significantly shorter SVL [snout-vent length (mm)] with significantly increased body condition, among other time-dependent effects. Our data suggest that larval exposure to PFAS can continue to impact growth in the juvenile stage after exposure has ended. Contrary to predictions, GenX affected terrestrial performance more consistently than its legacy congener, PFOA. Given the role of Bd in amphibian declines, further investigation of interactions of PFAS with Bd and other environmentally relevant pathogens is warranted.

MakoTM robotic-arm-assisted total hip and total knee arthroplasty outcomes in an orthopedic oncology setting: A case series.

Background: The MAKO Robotic-Arm system is a cutting-edge technology which combines both computed tomography (CT) scanning and three-dimensional planning to determine the ideal size and orientation of implants prior to bone resection. It is typically utilized within a general orthopedic setting for joint replacement procedures, such as total joint arthroplasties. However, its use within orthopedic oncology, which contains a much more compromised patient population and more complex surgical treatment, is not well documented within the literature. Question/purposes: To determine the patient outcomes of those who underwent a total hip arthroplasty (THA) or total knee arthroplasty (TKA) at Morristown Medical Center using the MAKO Robotic-Arm System. Particularly, we aspired to delve into the use of the MAKO in an orthopedic oncology setting for patients with a degenerative hip or knee and a history of cancer or other orthopedic tumor, impending pathological fracture, PVNS, chondromatosis, radiation therapy, or other oncological related conditions. Patients and methods: Our institution monitored twenty-five individuals with unique orthopedic oncology conditions that underwent MAKO robotic-assisted total hip and knee arthroplasty. This was performed between 2020 and 2022 at Morristown Medical Center in New Jersey. During this time period, 52% (13/25) of the operations were performed on knees and 48% (12/25) were performed on hips. Data regarding patient demographics, body mass index (BMI), medications, hemoglobin, hematocrit, comorbidities, American Society of Anesthesiologists (ASA) Class, operative data, the length of stay (LOS), readmission rates due to infection or periprosthetic fractures, and complications were collected retrospectively. All confidence intervals were calculated at the 95% confidence level. Results: Postoperatively, the average LOS was 3.2 days, and there were no complications after any of the MAKO-assisted joint arthroplasty procedures. Additionally, there were no readmissions at any of our recorded intervals - 1-30, 1-60, 1-90, and 1 year - however one patient presented to the emergency department after falling 4 days post-operatively. X-ray imaging ultimately revealed no periprosthetic fracture or malalignment of the prosthesis. Conclusions: The utilization of the MAKO Robotic-Arm System for joint arthroplasty procedures (THAs and TKAs) on orthopedic oncology patients yielded exceptional outcomes, with no complications or readmissions directly attributed to the use of this innovative robotic technology. Thus, this newly emerging surgical system holds great promise, potentially revolutionizing the approach for selected orthopedic oncology patients undergoing total joint arthroplasty compared to the traditional manual techniques. It further demonstrates that its use in an orthopedic oncology setting - where the cohort of patients are often compromised, leading to more intricate surgeries with heightened risks - elicits safety and provides optimal outcomes for patients. Nevertheless, its role within the field is evolving, and in the coming years, as it gains further popularity and sees broader application by orthopedic oncology surgeons, its potential will become clearer. To solidify its position, future clinical investigations and prospective research should be conducted to support the preference of the MAKO system over traditional manual techniques. This will help provide the necessary evidence to advocate for its widespread adoption and continued advancements in orthopedic oncology procedures.

Chronic Exposure to a PFAS Mixture Resembling AFFF-Impacted Surface Water Decreases Body Size in Northern Leopard Frogs (Rana pipiens).

Per- and polyfluoroalkyl substances (PFAS) occur in the environment as mixtures, yet mixture toxicity remains poorly understood. Aqueous film-forming foams (AFFFs) are a common source of PFAS. Our objective was to examine chronic effects of a complex PFAS mixture on amphibian growth and development. We tested toxicity of a five-chemical PFAS mixture summing to 10 µg/L and that accounts for >90% of the PFAS in AFFF-affected surface waters: perfluorooctane sulfonate (PFOS, 40%), perfluorohexane sulfonic acid (PFHxS, 30%), perflurooctanoic acid (PFOA, 12.5%), perfluorohexanoic acid (PFHxA, 12.5%), and perfluoropentanoic acid (PFPeA, 5%). We also included treatments to determine whether PFOS drove mixture toxicity and whether PFOS and mixture components act additively. We exposed Northern leopard frog (Rana pipiens) larvae through metamorphosis (∼130 d) in outdoor mesocosms. After 21 days of exposure, the larval body condition fell ∼5% relative to controls in the 4 µg/L PFOS treatment and mixtures lacking PFOS. At metamorphosis, the full 5-component 10 µg/L PFAS mixture reduced mass by 16% relative to controls. We did not observe effects on development. Our results indicate that toxicity of PFOS and other PFAS mixtures typical of AFFF sites act additively and that PFOS is not more inherently toxic than other mixture components.

A Critical Review of Amphibian Per- and Polyfluoroalkyl Substance Ecotoxicity Research Studies: Identification of Screening Levels in Water and Other Useful Resources for Site-Specific Ecological Risk Assessments.

With the goal of aiding risk assessors conducting site-specific risk assessments at per- and polyfluoroalkyl substance (PFAS)-contaminated sites, this critical review synthesizes information on the ecotoxicity of PFAS to amphibians in 10 amphibian species and 16 peer-reviewed publications. The studies in this review consisted of spiked-PFAS chronic toxicity experiments with perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and 6:2 fluorotelomer sulfonate (6:2 FTS) that evaluated apical endpoints typical of ecological risk-based decision making (survival, growth, and development). Body mass was the most sensitive endpoint, showing clear and biologically meaningful population level adverse effect sizes (≥20% adverse effects). From these results, we recommend chronic no observed effect concentration (NOEC) screening levels of 590 µg/L for PFOS and 130 µg/L for PFOA. At or above recommended chronic lowest observed effect concentration screening levels of 1100 µg/L PFOS and 1400 µg/L PFOA, there is an increased chance of adverse biologically relevant chronic effects. Biologically relevant adverse effects were not observed for PFHxS and 6:2 FTS, so unbounded NOECs of 1300 µg/L PFHxS and 1800 µg/L 6:2 FTS are recommended. Screening levels are also provided for the concentration of PFAS in an amphibian diet, amphibian tissue, and moss substrate. In addition, we recommend bioconcentration factors that can be useful to predict concentrations of PFAS in amphibians using concentrations in water; these values are useful for food web modeling to understand risks to vertebrate wildlife that prey on amphibians. Overall, the present study provides a guide to the wealth of ecotoxicological research on PFAS conducted by our research group and highlights the need for additional work that would improve the understanding of chemical risks to amphibians. Environ Toxicol Chem 2023;42:2078-2090. © 2023 SETAC.

Occurrence and implications of per and polyfluoroalkyl substances in animal feeds used in laboratory toxicity testing.

The exceptional thermal and chemical stability and the amphiphilicity of per- and polyfluoroalkyl substances (PFAS) have resulted in widespread use and subsequent contamination in environmental media and biota. Concerns surrounding toxicity have led to numerous animal-based toxicity studies. Due to the ubiquity of PFAS and the low parts per trillion (ppt) health advisory levels for drinking water, several contamination elimination protocols have been implemented. In addition, it is urgently necessary to perform low-dose experiments, but due to unknown pathways for entry of unwanted PFAS, low-dose studies are extremely challenging to conduct. However, animal feed sources are a likely route that could introduce unwanted PFAS into experiments, yet investigations of PFAS in common animal feeds are lacking. Here, we report the examination of PFAS levels in eighteen different animal feeds, representing a range of diets fed to diverse taxa. We evaluated whether PFAS levels in feeds were correlated with ingredient composition (plant versus animal-based) or dietary habits of lab animals (amphibian, fish, invertebrate, mammal). PFOS, PFHxS, PFOA, and short-chain perfluoroalkyl carboxylic acids had the highest detection levels and frequencies across all samples. Different food ingredients led to different PFAS profiles. No meaningful levels of PFAS precursors were detected. We demonstrate that PFAS contamination in animal feed is pervasive. Reducing food-sourced PFAS is a critical, albeit challenging task to improve interpretability of in vivo exposures.

Synthetic cartilage implant hemiarthroplasty versus cheilectomy for the treatment of hallux rigidus.

Degenerative arthritis of the first metatarsophalangeal joint, hallux rigidus, is the most common type of arthritis of the foot, affecting nearly 2.5% of the population over the age of 50. Hallux rigidus can be treated surgically with either Cheilectomy or Synthetic cartilage implant (SCI) hemiarthroplasty. The purpose of this study is to compare outcomes from a single institution on the treatment of hallux rigidus using cheilectomy and SCI hemiarthroplasty. Between 2012 and 2020, 49 patients underwent either a SCI (Polyvinyl alcohol hydrogels) hemiarthroplasty or Cheilectomy for the treatment of hallux rigidus. Functional scores were assessed pre and postoperatively using the American Orthopedic Foot and Ankle scoring System (AOFAS) and the Foot and Ankle Outcome Score survey (FAOS). Plantar and Dorsal range of motion was also assessed pre and postoperatively. Outcomes, complications, and any reoperations were recorded for all patients. Mean pre-op AOFAS for Cheilectomy and SCI were 49.6 and 54.8, respectively, compared to 85.3 and 89.7, respectively, after surgery (p value < 0.05). Mean pre-op Dorsal range of motion (ROM) for Cheilectomy and SCI were 24.0 and 26.0 degrees, respectively, compared to 38.0 and 42.6 degrees, respectively, after surgery (p value < 0.05). SCI hemiarthroplasty patients had higher AOFAS and dorsal ROM at the latest follow up (p value < 0.05). Synthetic cartilage implant (SCI) hemiarthroplasty and cheilectomy both offer promising results and remain viable treatment options to decrease pain, improve function, and maintain motion for hallux rigidus. SCI hemiarthroplasty may offer superior range of motion and functional outcomes than cheilectomy for hallux rigidus. LEVEL OF CLINICAL EVIDENCE: 3.

Mini-Open Achilles Tendon Repair: Improving Outcomes While Decreasing Complications.

An acute rupture of the Achilles tendon is a traumatic injury that can cause considerable morbidity and reduced function. Nonoperative intervention may put patients at higher risk of rerupture, whereas surgical intervention carries risk of infection, wound complications, and iatrogenic nerve injury. The mini-open Achilles tendon repair technique has been popularized in helping decrease complications. The goal of this study was to examine and compare the functional outcomes and rate of complications in patients treated with a mini-open repair technique versus a traditional open repair for acute Achilles tendon ruptures. A retrospective review was performed of all patients with a complete Achilles tendon rupture that were treated by a single foot and ankle fellowship-trained surgeon. Functional outcome scores were assessed using the American Orthopaedic Foot and Ankle scoring system (AOFAS) and the Achilles Tendon Rupture Score (ATRS). Eighty-one patients with a complete Achilles tendon rupture underwent mini-open repair and 22 patients underwent traditional open repair surgery between 2013 and 2020. The mean follow-up was 38.40 months (range, 12-71). Mean preoperative AOFAS and ATRS improved in the mini-open group from 45.60 and 47.18 respectively, to 90.29 and 87.97 after surgery (p < .05). Mean preoperative AOFAS and ATRS scores for the traditional open repair (n = 22) cohort were 44.02 and 42.27, respectively. Postoperatively, the AOFAS and ATRS scores improved to 85.27 and 86.64 (P value < .05), respectively. There was no statistically significant difference in postoperative ATRS scores. However, the mini-open repair group showed a statistically higher postoperative AOFAS score (90.30) than the traditional open-repair group (85.27) (P value < .05). The overall complication rate for our study was 2.9% (2 mini-open repair and 1 traditional open repair). The complication rate in the mini-open repair group and traditional open repair cohort were 2.4% and 4.5%, respectively (P value > .05). One patient in the mini-open repair cohort (1.2%) reruptured his Achilles tendon 4 months postoperatively. A second patient in the mini-open repair group (1.2%) developed a superficial skin infection and suture irritation. One patient (4.5%) in the traditional open repair group developed a superficial skin infection. There were no sural nerve injuries in our series. The mini-open approach to repair a ruptured Achilles tendon is a viable treatment option to decrease the incidence rate of postoperative complications and rerupture rates while also producing a superior cosmetic result.Level of Evidence: 3 (retrospective cohort study N ≥ 30).

An Environmentally Relevant Mixture of Perfluorooctanesulfonic Acid and Perfluorohexanesulfonic Acid Does Not Conform to Additivity in Northern Leopard Frogs Exposed Through Metamorphosis.

Per- and polyfluoroalkyl substances (PFAS) are chemicals associated with adverse health effects. At aqueous film-forming foam sites, they occur as mixtures, with perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) commonly co-occurring in the highest concentrations. Although PFOS and PFHxS toxicities have been studied, few studies have tested their potential interaction. Using Rana pipiens, the present study compared toxicities of a 1:1 PFOS:PFHxS mixture to PFOS and PFHxS individually with the prediction that responses would be additive. Gosner stage 25 (GS 25) tadpoles were exposed through metamorphosis (GS 46) to 0.5 and 1 ppb PFOS or PFHxS alone or to a mixture of 0.5 ppb PFOS and 0.5 ppb PFHxS. Tadpoles were weighed and measured (snout-vent length [SVL]) at day 31, metamorphic climax (GS 42), and GS 46. These values were used to calculate the scaled mass index (SMI), a measure of body condition. Body burdens were quantified on day 31 and at GS 46. The PFOS and PFHxS body burdens were elevated relative to controls at GS 46. No effects were observed on survival, SVL, or mass. Single PFAS effects included a 17% reduction in SMI at day 31 (0.5 ppb PFHxS) and a 1.1-day longer metamorphic period (1 ppb PFHxS) relative to controls. Mixture results deviated from additivity-SMIs were higher than expected on day 31 and lower than expected at GS 42. In addition, time to GS 42 in the PFAS mixture exceeded expected additivity by 12 days. Results from a chronic exposure to a 1:1 PFOS:PFHxS mixture resulted in changes in body condition and length of metamorphosis that deviated from additivity. More PFAS mixture toxicity studies conducted at relevant ratios and concentrations are needed. Environ Toxicol Chem 2022;41:3007-3016. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Dietary exposure and accumulation of per- and polyfluoroalkyl substances alters growth and reduces body condition of post-metamorphic salamanders.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern due to their persistence, potential to bioaccumulate, and toxicity. While dietary exposure is the primary route of exposure for terrestrial species, data on dietary PFAS uptake and adverse effects are largely restricted to mammals. As such, substantial data gaps exist that hinder ecological risk assessment, including environmentally relevant exposure levels and taxa. Using a 30-d laboratory experiment, we examined the effects of dietary PFAS-exposure on post-metamorphic tiger salamanders (Ambystoma tigrinum). We fed salamanders crickets exposed to perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), or 6:2 fluorotelomer sulfonate (6:2 FTS) at low (<1.0), medium (2-5), or high (16-62) ng PFAS/g/d (wet weight) dose rates. We found that only PFOS resulted in substantial biomagnification. Despite limited evidence for biomagnification, PFAS altered growth and generally reduced body condition. Salamanders with the highest burdens of PFOS grew less and had lower body conditions, while burdens of PFHxS and PFOA were only associated with reduced growth. There was no evidence that environmentally relevant doses of PFAS increase liver size in salamanders. Our results demonstrate that dietary exposure and accumulation of PFAS can impact fitness-related traits in amphibians and contribute to trophic transfer in terrestrial food webs.

Updated Analysis of the Oncology Section of the OITE from 2007 to 2019.

The Orthopaedic In-Training Exam (OITE) is administered annually to orthopedic surgery residents to assess their medical knowledge. The authors provide a comprehensive review of the orthopedic oncology portion of the exam in order to aid residents in preparation for future in-training and licensing examinations as well as to help guide oncology residency education curriculum. All of the orthopedic oncology questions on the OITE from 2007 to 2019 were reviewed. Analysis included (1) the number of oncology questions each year, (2) question topic, (3) question taxonomy (knowledge versus interpretation), (4) the type of imaging modalities (radiological, histological), (5) most commonly cited references, and (6) level of evidence. Descriptive statistics were utilized to compare means between variables. From 2007 to 2019, there was a total of 292 tumor-related questions with a mean of 22.5 tumor-related questions (range 19-28) per year. Of the questions, 54.8% pertained to malignant tumors and 45.2% to benign tumors. Assessment of question taxonomy showed that 79.8% of questions required interpretation of imaging and analysis of the information provided versus 20.2% of questions being knowledge recall type. Of the questions, 76.7% required interpretation of radiological images, pathological images, or both. Orthopaedic Knowledge Update, Journal of the American Academy of Orthopaedic Surgeons, and Journal of Bone and Joint Surgery were the three most commonly cited question sources. Only 29 (9.84%) oncology questions over the past 13 years have been supported by level I or II sources of evidence. Better understanding of the OITE make-up, question distribution, and number and style of question, reference sources can improve an orthopedic residents' performance as well as better guide educational curriculum to prepare residents in their orthopedic oncology education.

Distally Unlocked Intramedullary Nailing With Cement Fixation for Impending and Actual Pathologic Humerus Fractures: A Retrospective Case Series.

The humerus is a common site of metastatic tumor involvement and pathologic fracture. Intramedullary nailing is a treatment option that offers the benefit of protecting a long segment of diseased bone, but it is not without complications. This study aims to examine the survival, functional outcomes, and complications of patients treated with cement-augmented unlocked intramedullary nailing for actual and impending pathologic fractures of the humeral shaft. Methods: From 2014 to 2019, 26 patients were treated with this technique. Functional outcomes were assessed using the Musculoskeletal Tumor Society scoring system. Outcome scores, complications, reoperations, and mortality were determined by retrospective chart reviews and direct patient examinations. Results: The mean age at the time of surgery was 66.8 years. The mean follow-up was 20.2 months. Patients reported significant improvement in the mean Musculoskeletal Tumor Society score from 10.5 preoperatively to 26.1 after surgery (P < 0.001). Five patients died of disease during the follow-up period. One patient had intraoperative fracture propagation during implant placement, and one patient experienced a postoperative rotator cuff tear. Discussion: Unlocked intramedullary nailing with cement augmentation is a reliable treatment method for actual and impending pathologic fractures of the humerus that results in favorable outcomes, including consistent pain relief and restoration of function.

Nail Salon a Potential Source of a Rare Mycobacterium Fortuitum Infection In Proximal Tibia Megaprosthesis? A Case Report.

Mycobacterium Fortuitum (M. Fortuitum) is a type of opportunistic pathogen commonly found in water/soil and belongs to the nontuberculosis mycobacteria (NTM) family. Prosthetic joint infection due to M. Fortuitum is extremely rare. We present a case of a 21-year-old female with an infection following a radical resection of the proximal tibia due to a parosteal osteosarcoma.

The cost-effectiveness of antibiotic-loaded bone cement versus plain bone cement following total and partial knee and hip arthroplasty.

BACKGROUND: Postoperative infection is one of the most prevalent complications following total joint arthroplasty (TJA). As such procedures become more prevalent, it is imperative that we develop new prophylactic methods to prevent the need for revision procedures. In recent years, surgeons have opted to use antibiotic-loaded bone cement (ALBC) rather than plain bone cement (PBC) in primary hip and knee replacements due to its theoretical potential of lowering infection rates. However, the cost-effectiveness of this intervention remains in question.Questions/Purposes: To determine the rate of infection and cost-effectiveness of antibiotic-loaded bone cement as compared to plain bone cement in hip and knee arthroplasty. PATIENTS AND METHODS: We reviewed 4116 primary hip and knee arthroplasty cases performed between 2016 and 2018 at Morristown Medical Center in New Jersey. Data regarding demographics, complications, and any readmissions due to deep infection were collected retrospectively. During that time period there were a total of 4016 knee cases (423 ALBC, 3593 PBC) and 123 hip cases (63 ALBC, 60 PBC). The average cost for one bag of antibiotic-loaded bone cement and plain bone cement for hip and knee arthroplasty was $336.42 and $72.14, respectively. A statistical analysis was performed using Fisher's exact test; the National Healthcare Safety Network (NHSN) surgical site infection guidelines were used to distinguish between superficial and deep infections. RESULTS: Ten patients were readmitted due to deep infection, all of whom had undergone total knee arthroplasty. Of those cases, plain bone cement was used for the index procedure in seven instances and antibiotic-loaded cement was used in three. This resulted in an infection rate of 0.19% and 0.62%, respectively, p = 0.103. There was no statistically significant difference in infection rates between the two groups. A total of 778 bags of ALBC were used in 423 knee surgeries, and 98 bags of ALBC were used in 63 hip cases. The total cost for ALBC in TKA and THA procedures was $261,734.76 (778*336.42) and $32,969.16 (98*336.42), respectively. If PBC had been used during all index procedures, it would have resulted in a total savings of $231,509.28. CONCLUSIONS: Antibiotic-loaded cement did not significantly reduce the rate of infection for either knee or hip arthroplasty. Thus, the routine use of antibiotic-loaded cement in primary hip and knee arthroplasty may be an unnecessary financial burden to the healthcare system. A larger sample size and a randomized controlled trial would help confirm our findings and would provide further information on the cost-effectiveness of ALBC cement versus PBC.Significance/Clinical Relevance: In this review of cases performed from 2016 to 2018 there was no statistically significant difference between the rate of infection and the need for revision surgeries for patients treated with ALBC versus PBC. As hospital systems continue to transition towards a bundled payment model, it becomes imperative for providers to reduce any unnecessary costs in order to increase quality and efficiency. We estimate that our hospital system could save nearly $120,000/year by using plain bone cement instead of antibiotic-loaded cement.

"Purse-String" Capsular Closure for Decreasing Dislocation Rates in Proximal Femur Replacements.

Hip joint dislocation is the most common complication after a proximal femur replacement. As the utilization of proximal femur replacements continues to increase, it becomes imperative for surgeons to find the optimal method to decrease postoperative dislocation and its sequelae. These cases often involve extensive soft-tissue deficits that require reconstruction to provide postoperative strength and stability. Patients report good functional outcomes; however, dislocation remains a concern. Although "described" previously in the literature, the authors illustrate the "purse-string" hip joint capsular closure technique to help other surgeons understand it and apply to their practice as deemed necessary. We also present the senior author's results with using a modified version of the "purse-string" hip joint capsular closure technique.

Effects of larval atrazine exposure in mesocosms on Blanchard's cricket frogs (Acris blanchardi) reared through overwintering and to reproductive age.

We exposed Blanchard's cricket frog (Acris blanchardi) tadpoles to atrazine in simulated aquatic communities (outdoor mesocosms) at nominal concentrations of 0, 1, 10, 100, and 200 µg/L and tracked the effects of exposure to spring emergence in the laboratory, as well as to reproductive age in outdoor, terrestrial enclosures. We tested hypotheses that 1) atrazine addition increases the prevalence and intensity of testicular ova (TO) among phenotypic males at metamorphosis and after overwintering, 2) atrazine reduces maturation of ova after overwintering among phenotypic females, and 3) atrazine alters mass, time, and survival to metamorphosis, as well as growth and survival across terrestrial life stages. Atrazine addition increased probability of TO presence at metamorphosis, but only when treatments were pooled and compared to the control, where background atrazine was detected. Atrazine did not influence the intensity of TO among metamorphs. We observed TO among males at spring emergence and at reproductive age regardless of exposure concentration. We found no evidence for effects of exposure on gonadal maturation among females after overwintering. Exposure to 200 µg/L reduced survival to metamorphosis, but atrazine did not affect mass at metamorphosis, time to metamorphosis, or survival or mass after overwintering. We demonstrate that atrazine addition can increase TO prevalence relative to background rates at metamorphosis and that TO are also present among phenotypic males after overwintering. We suggest that this non-model species is sensitive to effects of larval EDC exposures on gonadal development and morphology and that further work with cricket frogs is warranted.

Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 µg/L.

We exposed Blanchard's cricket frogs (Acris blanchardi) to ecologically relevant concentrations (0, 0.1, 1, and 10 µg/L) of a commercial formulation of atrazine throughout the larval period to determine effects on survival, somatic growth and development (time to metamorphosis and mass at metamorphosis), and gonadal development (sex ratio at metamorphosis and the prevalence of testicular ova in phenotypic males). We tested the following hypotheses: 1) atrazine feminizes the sex ratio, 2) atrazine increases the proportion of phenotypic males with testicular ova, and 3) atrazine differentially affects somatic growth (mass at metamorphosis) and development (time to metamorphosis) for males and females. Although the control sex ratio was male-biased, exposure to 0.1 and 10 µg/L atrazine feminized sex ratios, because these treatments produced 51 and 55% fewer males than the control, respectively. We did not observe testicular ova. Atrazine did not impact survival or metamorphosis, and we did not detect sexually dimorphic impacts on time to metamorphosis or mass at metamorphosis. However, males metamorphosed 2.3 d later than females, regardless of treatment. Sex biases in timing of metamorphosis are underexplored in anurans, but if prevalent, could have important implications for theory surrounding the impact of environmental factors on metamorphosis. Our data suggest that cricket frog sex ratios are sensitive to environmentally relevant concentrations of atrazine and that feminization in the field is likely. Environ Toxicol Chem 2018;37:427-435. © 2017 SETAC.

Effectiveness of a Low-Cost, Graduate Student-Led Intervention on Study Habits and Performance in Introductory Biology.

Institutions have developed diverse approaches that vary in effectiveness and cost to improve student performance in introductory science, technology, engineering, and mathematics courses. We developed a low-cost, graduate student-led, metacognition-based study skills course taught in conjunction with the introductory biology series at Miami University. Our approach aimed to improve performance for underachieving students by combining an existing framework for the process of learning (the study cycle) with concrete tools (outlines and concept maps) that have been shown to encourage deep understanding. To assess the effectiveness of our efforts, we asked 1) how effective our voluntary recruitment model was at enrolling the target cohort, 2) how the course impacted performance on lecture exams, 3) how the course impacted study habits and techniques, and 4) whether there are particular study habits or techniques that are associated with large improvements on exam scores. Voluntary recruitment attracted only 11-17% of our target cohort. While focal students improved on lecture exams relative to their peers who did not enroll, gains were relatively modest, and not all students improved. Further, although students across both semesters of our study reported improved study habits (based on pre and post surveys) and on outlines and concept maps (based on retrospectively scored assignments), gains were more dramatic in the Fall semester. Multivariate models revealed that, while changes in study habits and in the quality of outlines and concept maps were weakly associated with change in performance on lecture exams, relationships were only significant in the Fall semester and were sometimes counterintuitive. Although benefits of the course were offset somewhat by the inefficiency of voluntary recruitment, we demonstrate the effectiveness our course, which is inexpensive to implement and has advantage of providing pedagogical experience to future educators.

Short-term atrazine exposure at breeding has no impact on Blanchard's cricket frog (Acris blanchardi) reproductive success.

Studies of endocrine-disrupting contaminants have focused on early-life exposures, but later exposures could impact fitness. We exposed adult frogs (Acris blanchardi) at reproduction to ecologically relevant atrazine concentrations (0, 1, or 10 µg/L) in outdoor arenas. We measured likelihood of breeding and number of resulting tadpoles. Atrazine impacted neither the probability of breeding nor the number of tadpoles produced, suggesting anuran reproductive success may not be impacted by short-term exposure to low concentrations. Environ Toxicol Chem 2017;36:3284-3288. © 2017 SETAC.