The relationship between shelf life and in vivo wear for polyethylene acetabular liners

Abstract: Although laboratory studies have correlated shelf life for gamma-irradiated-in-air polyethylene with material degradation, it is unknown whether this clinically affects wear. Therefore, we examined the relationship between shelf life and clinical wear for 152 gamma-irradiated-in-air acetabular liners. True wear rates were calculated from computer-assisted head penetration analyses of serial radiographs. Follow-up averaged 6.6 years. Shelf life averaged 11.8 months with 96% of liners having shelf lives of less than 3 years. Data analysis revealed no correlation between shelf life and true wear rates (r2 = 0.002; P = .60). This study provides useful information for surgeons concerned about shelf life as a potential cause of high wear in previously implanted components. For conventional liners in inventory less than 3 years, we found no evidence of increased wear in vivo.     

Severe traumatic brain injury in a large Canadian health region

BACKGROUND: Although severe traumatic brain injury (sTBI) is a devastating condition with tremendous public health implications, the epidemiology of this disease has not previously been described in Canada. We sought to define the incidence, risk factors and outcome of patients suffering sTBI in a large Canadian region. METHODS: A population-based surveillance cohort design was utilized to identify all Calgary Heath Region residents who were victims of trauma with an injury severity score > or = 12. Subsequent application of a specific sTBI case definition defined the final cohort. RESULTS: The annual incidence of sTBI was 11.4 per 100,000 population. The incidence of sTBI was significantly higher for males as compared to females [17.1 vs. 5.9 per 100,000; relative risk (RR) = 2.91, 95% confidence interval; 2.17, 3.94; p<0.0001]. There was a striking increase in the annual age specific population incidence of sTBI observed among those older than 74 years of age. The relative risk among the highest risk group of elderly (>85 years) males as compared to the lowest risk female group (50-64 years) was 19.78 (95% CI; 6.27, 62.3; p<0.0001). One hundred and eight patients died prior to hospital discharge for a mortality rate of 5.1 per 100,000 per year. CONCLUSIONS: Severe traumatic brain injury is common among residents of the Calgary Health Region and is associated with a high mortality rate. Males and the elderly are at the highest risk for acquiring sTBI and may represent target groups for preventive efforts.     

Randomized clinical trial of the efficacy of bupropion combined with nicotine patch in the treatment of adolescent smokers

Adolescent smokers (N = 211) were randomized to 1 of 2 groups: (a) nicotine patch plus bupropion SR (sustained release; 150 mg per day) or (b) nicotine patch plus placebo. Group skills training sessions were conducted each week by research staff. Abstinence rates at Weeks 10 and 26 were as follows: (a) patch plus bupropion, 23% and 8%, (b) patch plus placebo, 28% and 7%. Despite the lack of a treatment effect, a large majority of adolescents in both treatment groups reduced their consumption to a few cigarettes per day or less and maintained this reduction over time. Similarly, an examination of survival curves revealed that by the end of treatment many had managed to avoid a return to daily smoking. These findings are encouraging and suggest new avenues for research. For example, treatments of the kind examined in this report, augmented by extended maintenance therapies, may yield higher long-term success rates.     

Computed tomography to assess pelvic lysis after total hip replacement

To assess the accuracy of a computer-assisted computed tomography image analysis program in determining the location and volume of periacetabular osteolysis, we designed an osteolysis model by implanting bilateral total hip replacements in human pelvic cadavers and creating osteolytic lesions of varying sizes. The volumes of 48 defects were measured physically, and axial computed tomography scans were obtained. The computed tomography images were processed with streak artifact reduction and segmentation algorithms. The location and volume of lesions were determined from these images. Eighty-one percent (39 lesions) were identified correctly from the computed tomography scans. Detection was location-dependent. More lesions were detected in the ilium (100%) and at the rim (89%) than in the ischium (78%) or the pubis (50%). Computed tomography overestimated lesion volume by a mean of 0.5 +/- 2.3 cm. The volumetric error was unrelated to lesion location but was dependent on lesion size. As lesion size increased above 10 cm, the mean percentage error decreased to 1.8%. Computed tomography image analysis can be used more accurately than plain radiographs to investigate the effectiveness of treatment and the natural history of pelvic osteolysis.     

SARS-CoV antibody prevalence in all Hong Kong patient contacts

A total of 1,068 asymptomatic close contacts of patients with severe acute respiratory (SARS) from the 2003 epidemic in Hong Kong were serologically tested, and 2 (0.19%) were positive for SARS coronavirus immunoglobulin G antibody. SARS rarely manifests as a subclinical infection, and at present, wild animal species are the only important natural reservoirs of the virus.     

A contest to create media messages aimed at recruiting adolescents for stop smoking programs

This project engaged adolescents in a contest to create advertising messages aimed at recruiting teens for stop smoking programs. Middle school students were invited to design a media message for television, radio, Web, or print (newspaper or billboard). Of 4,289 students in eight middle schools of Rochester, Minn., 265 (6.2%) developed 172 stop smoking messages. The quality of their work confirmed that teens can design media messages to encourage their smoking adolescent peers to enroll in a program to stop smoking.     

Focus groups of Y-K Delta Alaska Natives: attitudes toward tobacco use and tobacco dependence interventions

BACKGROUND: Tobacco dependence interventions developed for Alaska Natives are virtually nonexistent. Alaska Natives residing on the Yukon-Kuskokwim (Y--K) Delta in southwestern Alaska use a unique form of smokeless tobacco (ST) known as Iqmik. This study employed focus group methodology to explore attitudes toward tobacco use and tobacco dependence interventions among Alaska Natives residing on the Y-K Delta. METHODS: Twelve focus groups of former and current tobacco users were conducted in four villages in the Y-K Delta. Participants were 35 adults (83% female) and 22 adolescents (27% female). Participants completed a brief demographic and tobacco use history form. Statements from the focus groups were transcribed for content coding and analysis of the major themes. RESULTS: Use of Iqmik in the villages is thought to be ubiquitous. Y-K Delta Alaska Natives are introduced to Iqmik at a very young age. Iqmik is mostly used and prepared by young Alaska Natives and adult women. There are few perceived adverse health effects of Iqmik or other tobacco use. Although there is interest in stopping, there is a perceived lack of availability of tobacco dependence interventions. The major barriers to preventing the initiation of and stopping tobacco use are the social acceptance and widespread use and availability of tobacco. CONCLUSION: The attitudes toward tobacco and identified barriers to stopping will be useful in developing tobacco dependence interventions for Alaska Natives.     

Effectiveness of smoking cessation self-help materials in a lung cancer screening population

Randomized controlled trials of smoking interventions have not been well-documented for lung cancer screening populations. In this study, we randomly assigned 171 current smokers who were undergoing low-dose fast spiral chest CT (SCTS) for lung cancer screening to receive either standard written self-help materials or a written list of Internet resources for smoking cessation. At the 1-year follow-up, more of the subjects receiving Internet-based resources reported making a stop attempt (68% versus 48%, P=0.011). However, there were no statistically significant differences in 7-day point prevalence quit rates (5% versus 10%) or advancement in motivational readiness to stop smoking (27% versus 30%), respectively, between the groups. Clearly, more investigation is warranted into how to tailor smoking interventions for cancer screening participants.