Predilection for developing a hematogenous orthopaedic implant-associated infection in older versus younger mice

BACKGROUND: The pathogenesis of hematogenous orthopaedic implant-associated infections (HOIAI) remains largely unknown, with little understanding of the influence of the physis on bacterial seeding. Since the growth velocity in the physis of long bones decreases during aging, we sought to evaluate the role of the physis on influencing the development of Staphylococcus aureus HOIAI in a mouse model comparing younger versus older mice. METHODS: In a mouse model of HOIAI, a sterile Kirschner wire was inserted retrograde into the distal femur of younger (5-8-week-old) and older (14-21-week-old) mice. After a 3-week convalescent period, a bioluminescent Staphylococcus aureus strain was inoculated intravenously. Bacterial dissemination to operative and non-operative legs was monitored longitudinally in vivo for 4 weeks, followed by ex vivo bacterial enumeration and X-ray analysis. RESULTS: In vivo bioluminescence imaging and ex vivo CFU enumeration of the bone/joint tissue demonstrated that older mice had a strong predilection for developing a hematogenous infection in the operative legs but not the non-operative legs. In contrast, this predilection was less apparent in younger mice as the infection occurred at a similar rate in both the operative and non-operative legs. X-ray imaging revealed that the operative legs of younger mice had decreased femoral length, likely due to the surgical and/or infectious insult to the more active physis, which was not observed in older mice. Both age groups demonstrated substantial reactive bone changes in the operative leg due to infection. CONCLUSIONS: The presence of an implant was an important determinant for developing a hematogenous orthopaedic infection in older but not younger mice, whereas younger mice had a similar predilection for developing periarticular infection whether or not an implant was present. On a clinical scale, diagnosing HOIAI may be difficult particularly in at-risk patients with limited examination or other data points. Understanding the influence of age on developing HOIAI may guide clinical surveillance and decision-making in at-risk patients

Blood Transfusions in Revision Surgery for Prosthetic Hip and Knee Infection

Background: Surgery for prosthetic joint infection (PJI) can often have significant blood loss necessitating allogeneic blood transfusion (ABT). ABT is associated with higher rates of morbidity and death in revision TJA, particularly in the treatment of PJI. It is important to understand how the rates of ABT differ among the various surgical treatments of PJI. We compared ABT rates by procedure type among patients treated for PJI a multimodal blood conservation protocol. Methods: We retrospectively reviewed 143 operative cases of revision arthroplasty for hip and knee PJI involving 102 patients at a single institution between 2016 and 2018. Procedures were categorized as 1. irrigation and debridement (I&D) with modular component exchange (“modular component exchange”), 2. explantation with I&D and placement of antibiotic spacer (“explantation”), 3. I&D with antibiotic spacer exchange (“spacer exchange”), or 4. antibiotic spacer removal and prosthetic reimplantation (“reimplantation”). ABT rates and number of units transfused were assessed for the four procedures. Factors associated with ABT were assessed with a multilevel mixed-effects regression model. Results: Seventy-seven cases (54%) received ABT. The highest rates of ABT occurred during explantations (74%) and spacer exchanges (72%), followed by reimplantations (36%) and modular component exchanges (33%). After adjusting for perioperative variables, lower preoperative hemoglobin level was associated with higher odds of ABT (odds ratio [OR], 1.9 [per 1-g/dL decrease]; 95% confidence interval [CI]: 1.5–2.5). Explantation (OR, 14; 95% CI: 4.0–50), reimplantation (OR, 4.3; 95% CI: 1.1–16), and spacer exchanges (OR, 5.6; 95% CI: 1.1–28) were associated with greater odds of ABT. Antibiotic spacer exchanges (OR, 26; 95% CI: 2.1-315) and explantations (OR, 11; 95% CI: 2.1-61) were associated with greater odds of multiple unit transfusions. Discussion: Despite a restrictive transfusion protocol, ABT rates remain high in the surgical treatment of PJI. Antibiotic spacer exchange and explantation procedures had high rates of multiple unit transfusions, and additional units of blood should be made available. Preoperative anemia should be treated when possible, and further refinement of blood management protocols in prosthetic joint infection is necessary

Preoperative International Normalized Ratio Thresholds in Hip Fracture: An Analysis of the National Surgical Quality Improvement Program

Background: Hip fractures are one of the most common orthopaedic injuries among the elderly, and as life expectancy continues to rise, the incidence of hip fractures has increased. The international normalized ratio (INR) is routinely obtained preoperatively to assess a patient’s readiness for surgery to evaluate bleeding risk. We aimed to 1) assess the relationship between preoperative INR in hip fracture patients and postoperative complication rates and 2) establish an INR threshold under which patients would be safe to proceed to surgery without INR correction. Methods: We retrospectively reviewed cases of hip fracture surgical stabilization in the American College of Surgeons National Surgical Quality Improvement Program from January 1, 2012 to December 31, 2018. Cases were stratified into four groups based on preoperative INR levels: 1) \u3c 1.4, 2) ≥1.4 and Results: Thirty-five thousand nine hundred-ten cases were identified, with 33,484 (93.2%) performed on patients with preoperative INR \u3c 1.4, 867 (2.4%) on INR ≥1.4 and Conclusions: In this study we found a threshold of INR\u3c 1.6 to be safe for patients prior to undergoing hip fracture surgery. Below this value patients avoid an increased risk of both transfusions and 30-day mortality seen at higher INR values. These findings may allow for adjustments to preoperative protocols and improve outcomes of hip fracture surgery in this population

Histological Examination in Obtaining a Diagnosis in Patients with Lymphadenopathy in Lima, Peru.

The differential diagnosis for lymphadenopathy is wide and clinical presentations overlap, making obtaining an accurate diagnosis challenging. We sought to characterize the clinical and radiological characteristics, histological findings, and diagnoses for a cohort of patients with lymphadenopathy of unknown etiology. 121 Peruvian adults with lymphadenopathy underwent lymph node biopsy for microbiological and histopathological evaluation. Mean patient age was 41 years (Interquartile Range 26-52), 56% were males, and 39% were HIV positive. Patients reported fever (31%), weight loss (23%), and headache (22%); HIV infection was associated with fever (P < 0.05) and gastrointestinal symptoms (P < 0.05). Abnormalities were reported in 40% of chest X-rays (N = 101). Physicians suspected TB in 92 patients (76%), lymphoma in 19 patients (16%), and other malignancy in seven patients (5.8%). Histological diagnoses (N = 117) included tuberculosis (34%), hyperplasia (27%), lymphoma (13%), and nonlymphoma malignancy (14%). Hyperplasia was more common (P < 0.001) and lymphoma less common (P = 0.005) among HIV-positive than HIV-negative patients. There was a trend toward reduced frequency of caseous necrosis in samples from HIV-positive than HIV-negative TB patients (67 versus 93%, P = 0.055). The spectrum of diagnoses was broad, and clinical and radiological features correlated poorly with diagnosis. On the basis of clinical features, physicians over-diagnosed TB, and under-diagnosed malignancy. Although this may not be inappropriate in resource-limited settings where TB is the most frequent easily treatable cause of lymphadenopathy, diagnostic delays can be detrimental to patients with malignancy. It is important that patients with lymphadenopathy undergo a full diagnostic work-up including sampling for histological evaluation to obtain an accurate diagnosis

Life-Expectancy Disparities Among Adults With HIV in the United States and Canada: The Impact of a Reduction in Drug- and Alcohol-Related Deaths Using the Lives Saved Simulation Model.

Improvements in life expectancy among people living with human immunodeficiency virus (PLWH) receiving antiretroviral treatment in the United States and Canada might differ among key populations. Given the difference in substance use among key populations and the current opioid epidemic, drug- and alcohol-related deaths might be contributing to the disparities in life expectancy. We sought to estimate life expectancy at age 20 years in key populations (and their comparison groups) in 3 time periods (2004-2007, 2008-2011, and 2012-2015) and the potential increase in expected life expectancy with a simulated 20% reduction in drug- and alcohol-related deaths using the novel Lives Saved Simulation model. Among 92,289 PLWH, life expectancy increased in all key populations and comparison groups from 2004-2007 to 2012-2015. Disparities in survival of approximately a decade persisted among black versus white men who have sex with men and people with (vs. without) a history of injection drug use. A 20% reduction in drug- and alcohol-related mortality would have the greatest life-expectancy benefit for black men who have sex with men, white women, and people with a history of injection drug use. Our findings suggest that preventing drug- and alcohol-related deaths among PLWH could narrow disparities in life expectancy among some key populations, but other causes of death must be addressed to further narrow the disparities

A qualitative study of stakeholders' perspectives on the social network service environment

Over two billion people are using the Internet at present, assisted by the mediating activities of software agents which deal with the diversity and complexity of information. There are, however, ethical issues due to the monitoring-and-surveillance, data mining and autonomous nature of software agents. Considering the context, this study aims to comprehend stakeholders' perspectives on the social network service environment in order to identify the main considerations for the design of software agents in social network services in the near future. Twenty-one stakeholders, belonging to three key stakeholder groups, were recruited using a purposive sampling strategy for unstandardised semi-structured e-mail interviews. The interview data were analysed using a qualitative content analysis method. It was possible to identify three main considerations for the design of software agents in social network services, which were classified into the following categories: comprehensive understanding of users' perception of privacy, user type recognition algorithms for software agent development and existing software agents enhancement

Taking Ownership: Our Pledge to Educate All of Detroit's Children

Excellent Schools Detroit represents a broad and diverse cross section of Detroit's education, government, civic and community, parent, organized labor, and philanthropic leaders who are committed to ensuring that all Detroit children receive the great education they deserve. This citywide education plan reflects months of discussions and deliberations by coalition members, as well as a series of six community meetings in November and December, youth focus groups, small group discussions with multiple stakeholders, and other outreach efforts. We appreciate the thoughtful recommendations from the many Detroiters who are as passionate as we are about the need to prepare all students for college, careers, and life in the 21st century

Cohort Profile: Antiretroviral Therapy Cohort Collaboration (ART-CC)

The advent of effective combination antiretroviral therapy (ART) in 1996 resulted in fewer patients experiencing clinical events, so that some prognostic analyses of individual cohort studies of human immunodeficiency virus-infected individuals had low statistical power. Because of this, the Antiretroviral Therapy Cohort Collaboration (ART-CC) of HIV cohort studies in Europe and North America was established in 2000, with the aim of studying the prognosis for clinical events in acquired immune deficiency syndrome (AIDS) and the mortality of adult patients treated for HIV-1 infection. In 2002, the ART-CC collected data on more than 12,000 patients in 13 cohorts who had begun combination ART between 1995 and 2001. Subsequent updates took place in 2004, 2006, 2008, and 2010. The ART-CC data base now includes data on more than 70 000 patients participating in 19 cohorts who began treatment before the end of 2009. Data are collected on patient demographics (e.g. sex, age, assumed transmission group, race/ethnicity, geographical origin), HIV biomarkers (e.g. CD4 cell count, plasma viral load of HIV-1), ART regimen, dates and types of AIDS events, and dates and causes of death. In recent years, additional data on co-infections such as hepatitis C; risk factors such as smoking, alcohol and drug use; non-HIV biomarkers such as haemoglobin and liver enzymes; and adherence to ART have been collected whenever available. The data remain the property of the contributing cohorts, whose representatives manage the ART-CC via the steering committee of the Collaboration. External collaboration is welcomed. Details of contacts are given on the ART-CC website (www.art-cohort-collaboration.org