Antibiotic prophylaxis in total hip arthroplastyEffects of antibiotic prophylaxis systemically and in bone cement on the revision rate of 22,170 primary hip replacements followed 0-14 years in the Norwegian Arthroplasty Register

We studied the effects of antibiotic prophylaxis, systemically and in bone cement, on the revision rate of cemented total hip arthroplasties (THAs) in data from the Norwegian Arthroplasty Register during the period 1987-2001. To have comparable groups, only THAs performed because of primary osteoarthritis, using cemented implants with documented good results, and high-viscosity cement were included. If systemic antibiotic prophylaxis had been given, only operations with cephalosporin or penicillin were selected. Cox-estimated survival relative revision risks (RR) are presented with adjustment for differences among groups in gender, age, cement brand, type of systemic antibiotic prophylaxis, type of prosthesis, type of operating room, and duration of the operation. Of 22,170 THAs studied, 696 THAs (3.1%) were revised, 440 (2.0%) for aseptic loosening and 102 (0.5%) for deep infection. We found the lowest risk of revision when the antibiotic prophylaxis was given both systemically and in the cement (15,676 THAs). Compared to this combined regime, patients who received antibiotic prophylaxis only systemically (5,960 THAs) had a 1.4 times higher revision rate with all reasons for revision as endpoint (p= 0.001), 1.3 times higher with aseptic loosening (p= 0.02) and 1.8 times higher with infection as the endpoint (p= 0.01). With the combined antibiotic regime, the results were better if antibiotics were given 4 times on the day of surgery (2,194 THAs), as compared to once (1,424 THAs) (p<0.001), twice (2,680 THAs) (p<0.001), or 3 times (5,522 THAs) (p= 0.02). Those who received systemic prophylaxis a single day 1, 2 or 3 times, as compared to 4 times, had a revision rate 1.8-3.5 times higher with all reasons for revision as endpoint, 1.5-3.1 times higher with aseptic loosening, and 2.7-6.8 times higher with infection. When we compared systemic prophylaxis 4 times in 1 day, no further improvement resulted in those given systemic prophylaxis for 2 days (1,928 THAs) or 3 days (717 THAs). In a subset of data including only the Charnley prosthesis, we obtained similar results. This observational study shows that the best results were recorded when antibiotic prophylaxis was given both systemically and in the bone cement, and if the systemic antibiotic was given 4 times on the day of surgery.     

Stress Mediates the Relationship Between Past Drug Addiction and Current Risky Sexual Behaviour Among Low‐income Women

This study examined the role of stress as a mediator of the relationship between prior drug addiction and current high‐risk sexual behaviour. Eight hundred twenty women aged 18 to 30 years, who received care at community‐based family planning clinics, were interviewed using the Composite International Diagnostic Interview and the Sexual Risk Behavior Assessment Schedule. They also completed the brief version of the Self‐Control Scale as a measure of problem‐solving strategies and measures of recent stressful events, daily hassles and ongoing chronic stress. Regardless of addiction history, stress exposure during the previous 12 months was associated with risky sexual behaviour during the previous 12 months. Structural equation modelling revealed that 12‐month stress levels mediated the relationship between past drug addiction and 12‐month high‐risk sexual behaviours, as well as the negative relationship between problem‐solving strategies and high‐risk sexual behaviours. Problem‐solving strategies did not moderate the relationship between drug addiction and high‐risk sexual behaviours. These findings suggest that stress management training may help reduce risky behaviour among young, low‐income women Copyright © 2014 John Wiley & Sons, Ltd.     

Potential of neonatal organ donation and outcome after transplantation

Organ transplantation is limited by access to suitable organs. Infant recipient waitlist mortality is increased due to the scarcity of size-matched organs. Neonatal organ donors have been proposed as an underutilized source of donor organs. However, the literature on the actual prevalence and outcome of neonatal organ donation and transplantation is fragmented and not well analyzed. This literature review aims to summarize the available literature on the potential of neonatal organ donation and to analyze published cases of neonatal organ transplantation. A systematic search of the Medline and Cochrane databases yielded 2964 articles, which were screened for eligibility. In total, 86 articles were considered eligible, of which 34 were included in the literature review: 8 articles describing the potential of neonatal organ donation programs, and 26 articles describing clinical transplantation. Current evidence suggests there is a large pool of potential neonatal organ donors. In contrast, the literature on neonatal organ donor utilization is sparse. However, case series of successful kidney, heart, liver, hepatocyte, and multivisceral transplantation using organs from neonatal donors are summarized. Although good posttransplant organ function was achieved, the use of neonatal organs is associated with increased risk of thrombosis in both kidney and liver transplantation. Neonatal organ donation is a promising alternative for expanding the current donor pool. Experience is limited, but reported patient and graft survival are acceptable and more research on the subject is warranted.     

Spigelian hernia: CT and ultrasonography diagnosis

The diagnostic potential of CT and sonography in detecting clinically unrecognized cases of spigelian hernia is illustrated and discussed. These imaging modalities can promptly and reliably diagnose spigelian hernia based on the following findings: (1) peritoneal and muscular defect along the spigelian line in the lower abdomen; (2) intraparietal location of the hernial sac; and (3) hernial sac containing omentum and/or mesentery and loops of bowel. Two recently diagnosed cases are presented together with a short review of the literature.     

Predicting Pediatric Age-Matched Weight and Body Mass Index

The empirical scaling from adult to pediatric using allometric size adjustments based on body weight continued to be the mainstream method for pediatric dose selection. Due to the flexibility of a polynomial function to conform to the data trend, an empirical function for simulating age-matched weight and body mass index by gender in the pediatric population is developed by using a polynomial function and a constant coefficient to describe the interindividual variability in weight. A polynomial of up to fifth order sufficiently described the pediatric data from the Center for Disease Control (CDC) and the World Health Organization (WHO). The coefficients of variation to describe the variability were within 17%. The percentages of the CDC simulated weights for pediatrics between 0 and 5 years that fell outside the WHO 90% and 95% confidence boundaries were well within the expected percentage values, indicating that the CDC dataset can be used to substitute for the WHO dataset for the purpose of pediatric drug development. To illustrate the utility of this empirical function, the CDC-based age-matched weights were simulated and were used in the prediction of the concentration–time profiles of tenofovir in children based on a population pharmacokinetic model whose parameters were allometrically scaled. We have shown that the resulting 95% prediction interval of tenofovir in newborn to 5 years of age was almost identical whether the weights were simulated based on WHO or CDC dataset. The approach is simple and is broadly applicable in adjusting for pediatric dosages using allometry.

Electronic supplementary material

The online version of this article (doi:10.1208/s12248-014-9657-9) contains supplementary material, which is available to authorized users.KEY WORDS: Age, Allometry, BMI, Pediatric, Weight