Anterior cruciate ligament reconstruction with quadrupled semitendinosus tendon - minimum 6 year clinical and radiological follow-up

This clinical study evaluates the minimum 6 year follow-up clinical, functional, radiological and isometric results after arthroscopic reconstruction of the anterior cruciate ligament (ACL) with quadrupled semitendinosus tendon autograft (femoral endobutton and tibial suture disc fixation). Seventy out of 85 operated patients (lost to follow-up 17%) with an average age of 34.3 years could be clinically examined at a mean follow-up time of 6 years and 4 months after surgery. Results revealed a high subjective satisfaction rate of 93%. The preoperative activity level could be maintained in 71% of the patients. The Lysholm score showed very good and good results in 85% with a mean of 83.6%. Normal or nearly normal results on the IKDC score were reported in 85% of the patients. The KT-1000 arthrometer stability testing showed a difference of less than 3 mm compared to the contralateral knee in 75% of the patients. Five patients (7%) had a graft failure during follow-up time. There were no or only mild degenerative changes at the radiographic evaluation in 85% of the patients. In 15% of the patients a femoral and in 40% a tibial tunnel widening of more than 50% was observed, however without a relevance for the clinical and functional status. Midterm results obtained in this study after arthroscopic ACL reconstruction with the quadrupled semitendinosus tendon confirm the outcomes in the literature after shorter follow-up periods that provide very good and good subjective, functional and stability results in about 80-85% of the patients. This surgical technique can be recommended for the active patient with ACL deficiency. However, patients must be informed that activity level cannot always be maintained and a failure rate of 5-10% must be taken into account in the longer term when decision for surgery is made.     

Is the occurrence of back pain in Germany decreasing? Two regional postal surveys a decade apart

BACKGROUND: Back pain is often perceived as an epidemic disorder with an ever-increasing prevalence. The objective of this paper is to estimate and compare point and period prevalence rates of back pain from two highly comparable postal surveys, a decade apart within a single regional population in the north of Germany. METHODS: In 1991/1992 and 2003 two systematic random samples of German residents of Lübeck aged 25-74 years were independently drawn from the municipal population registry. They received a short postal questionnaire with maximally two reminders. All data were directly standardised on the age, sex, and educational distribution of the merged samples. A sharp decrease in response rates from 81% in the early 1990s to 60% in 2003 required complex considerations of non-response bias. RESULTS: Both the overall and gender-specific point and 1 year prevalence rates of back pain remained fairly stable as well as the rate of severe disabling back pain. The overall prevalence (adjusted for age, sex, and education) of 'back pain today' was 39.2% (1991/92) and 38.2% (2003), the 1 year prevalence was 75.3% (1991/92) and 73.8% (2003), and the prevalence of severe pain was 9.9% (1991/92) and 10.2% (2003). CONCLUSIONS: The data do not support the widespread public notion of a growing epidemic of back pain in Germany.     

Cigarette smoking and cancer risk: modeling total exposure and intensity

A recent analysis showed that the excess odds ratio (EOR) for lung cancer due to smoking can be modeled by a function which is linear in total pack-years and exponential in the logarithm of smoking intensity and its square. Below 15-20 cigarettes per day, the EOR/pack-year increased with intensity (direct exposure rate or enhanced potency effect), suggesting greater risk for a total exposure delivered at higher intensity (for a shorter duration) than for an equivalent exposure delivered at lower intensity. Above 20 cigarettes per day, the EOR/pack-year decreased with increasing intensity (inverse exposure rate or reduced potency effect), suggesting greater risk for a total exposure delivered at lower intensity (for a longer duration) than for an equivalent exposure delivered at higher intensity. The authors applied this model to data from 10 case-control studies of cancer, including cancers of the lung, bladder, oral cavity, pancreas, and esophagus. At lower intensities, there was enhanced potency for several cancer sites, but narrow ranges for pack-years increased uncertainty, precluding definitive conclusions. At higher intensities, there was a consistent reduced potency effect across studies. The intensity effects were statistically homogeneous, indicating that after accounting for risk from total pack-years, intensity patterns were comparable across the diverse cancer sites.     

Resistance to disinfectants in epidemiologically defined clinical isolates of Acinetobacter baumannii

Decreased susceptibility to biocides may contribute to epidemic spread of Acinetobacter baumannii in the hospital. This study was conducted to evaluate the susceptibility of different clinical A. baumannii strains to disinfectants. Twenty A. baumannii strains were examined, ten of which were outbreak-related and ten that were sporadic. Clinical isolates were selected on the basis of demonstrating a unique pulsed-field gel electrophoresis pattern. The in-vitro activities of propanol, combination of 1-propanol, 2-propanol and mecetronium ethylsulphate, polyvinylpyrrolidone (PVP)-iodine, triclosan and chlorhexidine were determined using a broth macrodilution method. Exposure times to the disinfectant ranged from 15 s to 2 min and concentrations ranged from undiluted to a 1:4000 dilution in order to investigate the impact of inadvertent dilution that might occur in clinical practice. Five American Type Culture Collection (ATCC) type strains (A. baumannii, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus) were used as controls. All disinfectants inhibited growth of all isolates at concentrations and contact times recommended by the respective manufacturer. With most of the disinfectants tested, a relevant number of viable bacteria remained if contact times < 30s or diluted agents were used. No significant differences in susceptibility between outbreak-related and sporadic strains were detected, but larger studies would be required to confirm this. Resistance to currently used disinfectants is probably not a major factor in the epidemic spread of A. baumannii. However, even minor deviations from the recommended procedures leading to decreased concentrations or exposure times may play a role in nosocomial cross-transmission.     

Assessing vaccine efficacy for the prevention of acute otitis media by pneumococcal vaccination in children: a methodological overview of statistical practice in randomized controlled clinical trials

Acute otitis media (AOM) is the most common bacterial infectious disease among children. Vaccination is proposed to prevent otitis and several clinical trials were performed to assess the efficacy of pneumococcal vaccines. The way vaccine efficacy is analysed varies among trials. However, the clinical meaning of an estimate of vaccine effect and its statistical test depends on the applied statistical method. We aim to bring the meaning and validity of statistical trial results to the attention of researchers. We consider all methodological approaches for analysing vaccine efficacy applied in pneumococcal vaccination trials included in a recent Cochrane Review. We demonstrate how different methods address different scientific questions on the effect of vaccination, how they can complement each other and why some methods can produce misleading results.     

Efficient priming against classical swine fever with a safe glycoprotein E2 expressing Orf virus recombinant (ORFV VrV-E2)

An increasing demand in livestock animal husbandry for intervention or emergency vaccination strategies requires a rapid onset of protection linked to prevention of infectious agent spread. Using the new recombinant parapoxvirus (PPV) Orf virus (ORFV) as a vaccine expressing the CSFV E2 glycoprotein we demonstrate that a single intra-muscular application confers solid protection. In the prime only concept, multi-site application of the vector vaccine turned out to be superior to single-site application as no pyrexia occurred after virulent CSFV challenge and CSFV neutralizing serum antibodies regularly were detectable before challenge. Vector virus vaccinated swine were able to cope with the lymphocyte and in particular B-cell depression in peripheral blood after challenge showing no clinical signs and no viremia. Early after challenge CSFV-specific IFN gamma production (IFN-gamma) and high neutralizing serum antibody titers clearly differentiated na?ve from vaccinated and protected animals. After CSFV challenge neutralizing serum antibodies titers in vector vaccinated swine were significantly higher than those in sera from live attenuated vaccine primed animals. Horizontal challenge virus transmission was prevented under strict sentinel isolation before mingling but not in next-door stables separated by a wooden barrier at the day of challenge. The presence of CSFV-specific pre-challenge serum antibodies although in low titers is a good prognostic parameter for solid protection after ORFV vector vaccination even when a significant CSFV-specific IFN-gamma production was not detectable before challenge. A heterologous prime-boost regimen as a combination of prime with baculovirus-expressed glycoprotein E2 followed by boost with the parapoxvirus vector turned out to be a better immune stimulant than a homologous prime/boost with the modified live CSFV vaccine. A similar beneficial effect became evident when the challenge infection mimicked the booster vaccination after a single PPV vector prime.     

Stratification for the propensity score compared with linear regression techniques to assess the effect of treatment or exposure

Stratifying and matching by the propensity score are increasingly popular approaches to deal with confounding in medical studies investigating effects of a treatment or exposure. A more traditional alternative technique is the direct adjustment for confounding in regression models.This paper discusses fundamental differences between the two approaches, with a focus on linear regression and propensity score stratification, and identifies points to be considered for an adequate comparison. The treatment estimators are examined for unbiasedness and efficiency. This is illustrated in an application to real data and supplemented by an investigation on properties of the estimators for a range of underlying linear models. We demonstrate that in specific circumstances the propensity score estimator is identical to the effect estimated from a full linear model, even if it is built on coarser covariate strata than the linear model. As a consequence the coarsening property of the propensity score-adjustment for a one-dimensional confounder instead of a high-dimensional covariate-may be viewed as a way to implement a pre-specified, richly parametrized linear model. We conclude that the propensity score estimator inherits the potential for overfitting and that care should be taken to restrict covariates to those relevant for outcome.     

Shared random effects analysis of multi-state Markov models: application to a longitudinal study of transitions to dementia

Multi-state models are appealing tools for analysing data about the progression of a disease over time. In this paper, we consider a multi-state Markov chain with two competing absorbing states: dementia and death and three transient non-demented states: cognitively normal, amnestic mild cognitive impairment (amnestic MCI), and non-amnestic mild cognitive impairment (non-amnestic MCI). The likelihood function for the data is derived and estimates for the effects of the covariates on transitions are determined when the process can be viewed as a polytomous logistic regression model with shared random effects. The presence of a shared random effect not only complicates the formulation of the likelihood but also its evaluation and maximization. Three approaches for maximizing the likelihood are compared using a simulation study; the first method is based on the Gauss-quadrature technique, the second method is based on importance sampling ideas, and the third method is based on an expansion by Taylor series. The best approach is illustrated using a longitudinal study on a cohort of cognitively normal subjects, followed annually for conversion to mild cognitive impairment (MCI) and/or dementia, conducted at the Sanders Brown Center on Aging at the University of Kentucky.     

Women's use of information regarding hormone replacement therapy

For perimenopausal women, an important decision is whether or not to use hormone replacement therapy (HRT). The decision is complex because HRT involves judgment in weighing gains and losses related to physiological risk. Gains involve relief of hot flashes and prevention of osteoporosis; losses include cancer mortality and side effects of medication. A policy-capturing study of 283 perimenopausal women showed that the factor of most frequent concern was relief of hot flashes. Cluster analyses identified four major groups. Group 4 had an n of 9 and the lowest R2, making interpretation of data questionable. The largest group responded to hot flashes alone; the second to hot flashes and osteoporosis; and the third to hot flashes, somewhat to osteoporosis, but also to side effects of estrogen/progestin therapy. Results indicate nursing interventions should anticipate differences in women's concerns and tailor counseling appropriately.