Management of Modular Mega-Implant Infection of the Lower Extremity.

INTRODUCTION: Revision arthroplasty involving mega-implants is associated with a high complication rate. In particular, infection is a serious complication of revision arthroplasty of hip and knee joints and has been reported to have an average rate of 18%, and for mega-implants, the range is from 3 to 36%. This study was designed to analyze the strategy of treatment of infection of mega-endoprostheses of the lower extremities in our patient cohort, particularly the management of chronic infection. MATERIAL AND METHODS: This was a retrospective study that focused on the results of the treatment of periprosthetic infections of mega-implants of the lower extremities. We identified 26 cases with periprosthetic infections out of 212 patients with 220 modular mega-endoprostheses of the lower extremities who were treated in our department between September 2013 and September 2019. As a reinfection or recurrence, we defined clinical and microbiological recurrences of local periprosthetic joint infections after an antibiotic-free period. RESULTS: In this study, 200 cases out of 220 were investigated. The average follow-up period was approximately 18 months (6 months to 6 years). Endoprosthesis infections after implantation of mega-implants occurred in 26 cases (13%). This group comprised 2 early infections (within the first 4 weeks) and 24 chronic infections (between 10 weeks and 6 years after implantation). Nineteen cases out of the identified 26 cases with infection (73.1%) belong to the group of patients who were operated on due to major bone loss following explantation of endoprosthetic components due to previous periprosthetic joint infection. The remaining seven cases with infection comprised four cases following management of periprosthetic fracture, two cases following treatment of aseptic loosening, and one case following tumor resection. All infections were treated surgically. In all cases, the duration of continuous antibiotic treatment did not exceed 6 weeks. Both cases with early infection were treated by exchanging polyethylene inlays and performing debridement with lavage (two cases). In two (7.7%) cases with chronic infection, one-stage surgery was performed. In all remaining cases with chronic infection (22 cases; 84.6%), explantation of all components and temporary implantation of cement spacers were carried out prior to reimplantation. CONCLUSION: There is still no gold standard therapeutic regimen for the management of periprosthetic infection of mega-implants, though radical surgical debridement and lavage accompanied by systemic antibiotic therapy are the most important therapeutic tools in all cases of periprosthetic infections, regardless of the time of onset. Further studies are needed to standardize management strategies of such infections. Nevertheless, it is not uncommon for compromises to be made based on the particular condition of the individual.

Dual spindles assemble in bovine zygotes despite the presence of paternal centrosomes.

The first mitosis of the mammalian embryo must partition the parental genomes contained in two pronuclei. In rodent zygotes, sperm centrosomes are degraded, and instead, acentriolar microtubule organizing centers and microtubule self-organization guide the assembly of two separate spindles around the genomes. In nonrodent mammals, including human or bovine, centrosomes are inherited from the sperm and have been widely assumed to be active. Whether nonrodent zygotes assemble a single centrosomal spindle around both genomes or follow the dual spindle self-assembly pathway is unclear. To address this, we investigated spindle assembly in bovine zygotes by systematic immunofluorescence and real-time light-sheet microscopy. We show that two independent spindles form despite the presence of centrosomes, which had little effect on spindle structure and were only loosely connected to the two spindles. We conclude that the dual spindle assembly pathway is conserved in nonrodent mammals. This could explain whole parental genome loss frequently observed in blastomeres of human IVF embryos.

Corrigendum to "Comparability of Self-Ratings and Observer Ratings in Occupational Psychosocial Risk Assessments: Is There Agreement?"

[This corrects the article DOI: 10.1155/2019/8382160.].

Mortality, complications and long-term functional outcome in elderly patients with fragility fractures of the acetabulum.

BACKGROUND: Early operative treatment of acetabulum fractures in geriatric patients has been suggested to reduce pain and allow for earlier mobilization. The aim of this study was to determine mortality, complications and functional outcome after operative and non-operative treatment. METHODS: Patients aged ≥60 years with operative treatment of low-energy fragility fracture of the acetabulum from 2009 to 2016 and a follow-up of at least 24 months were identified. The patients were contacted by phone and a modified Merle d'Aubigné score was obtained. If patients or their relatives were not available for follow-up, mortality data was assessed using a national social insurance database. RESULTS: One hundred seventy-six patients (mean age 78, SD 10 years; 73 female) were available for analysis of mortality data. At final follow-up (68 months, SD 26, range, 24 to 129), 99/176 patients (56.3%) had deceased. One-year-mortality was 25.0% and 2-year mortality 35.8%. Type of treatment (non-operative vs. operative) did not affect mortality at 1 and 2 years (p = .65 and p = .10). Hospital-acquired infections were observed in 31/176 cases (17.6%), thromboembolic events and delirium in 6 patients (3.4%). In-hospital mortality was 5.7%. Patients who underwent operative treatment were more likely to have an in-hospital infection (p = .02) but less likely to sustain thromboembolic events (p = .03). The mean hospital stay was 14 days (SD 10 days, range, 1 to 66). Patients with operative treatment were longer hospitalized than patients with non-operative treatment (p < .001). The rate of secondary conversions to THA was 12.4%, this was not affected by initial treatment. The mean modified Merle d'Aubigné Score of those patients available for a final follow-up (n = 47; follow-up 56 months, SD 28, range, 24 to 115) was 14/18 points, SD 3 (range 7 to 18). Functional results at final follow-up between operatively and non-operatively treated patients were without difference. CONCLUSIONS: All-cause mortality and in-hospital complications are high among geriatric patients with low-energy fractures of the acetabulum even when treated operatively. Secondary conversion rates to THA are similar to those seen in younger patients. Mid-term functional outcome in those surviving is fair.

Comparability of Self-Ratings and Observer Ratings in Occupational Psychosocial Risk Assessments: Is There Agreement?

OBJECTIVE: The suitability of self-ratings and observer ratings within organisational management approaches is controversial. The aim of this study was to compare the degree of agreement between self-rated and observer-rated occupational psychosocial demands. The comparison took place within a work-activity and not worker-centred assessment, according to official policies for psychosocial risk assessment. Through simultaneous application of two versions of the same instrument, we aimed to reduce the rating bias to a minimum demonstrating the suitability of self-ratings and observer ratings in companies of all kinds. METHODS: A multimethod online assessment of 22 different work activities was conducted in Germany from October 2016 to October 2017. Workers (self-ratings) and occupational safety and health (OSH) committees (observer ratings) rated the occupational psychosocial risks of each activity with the same instrument (N = 669). The instrument measured psychosocial risk conditions at work. Reliability and agreement indices were computed. RESULTS: The within-group agreement (WGA; r wg,mean = .42) of the workers' self-ratings was good for each psychosocial risk and the interrater reliability (IRR) was excellent on average (ICC 2 = .77) with a medium effect size of ICC 1 = .15. The interrater agreement (IRA) between the two groups varied across the activities depending on rating group and activity composition (from ICC unjust,mean = .39 to ICC unjust,mean = .86) but was good to excellent on average (ICC unjust,mean = .71). CONCLUSION: The reasonable agreement and excellent reliability in workers' self-ratings justify aggregation of item means at the group level. Furthermore, if the work activities are homogenous and the committee consists of members from different OSH specialties, observer ratings and self-ratings provide comparable results. According to this study's results, both methods are reliable assessment strategies in the context of psychosocial risk assessment. The observer rating approach is especially suitable for small-to-medium enterprises that do not have access to a large anonymous survey assessment.

Mysteries in embryonic development: How can errors arise so frequently at the beginning of mammalian life?

Chromosome segregation errors occur frequently during female meiosis but also in the first mitoses of mammalian preimplantation development. Such errors can lead to aneuploidy, spontaneous abortions, and birth defects. Some of the mechanisms underlying these errors in meiosis have been deciphered but which mechanisms could cause chromosome missegregation in the first embryonic cleavage divisions is mostly a "mystery". In this article, we describe the starting conditions and challenges of these preimplantation divisions, which might impair faithful chromosome segregation. We also highlight the pending research to provide detailed insight into the mechanisms and regulation of preimplantation mitoses.

A call for Applied Knowledge and Lived Interdisciplinarity in the medical care of depressed employees: a cross-sectional survey with German occupational physicians and psychotherapists.

OBJECTIVES: To identify approaches for an effective patient-centred care of depressed employees, we investigated occupational physicians' (OPs) and psychotherapists' (PTs) knowledge about job stressors on the development of depression, application of this knowledge, interdisciplinary cooperation and perceived barriers. STUDY DESIGN: A cross-sectional online survey. PARTICIPANTS: OPs (163; 48.5% male) and PTs (69; 43.5% male) providing complete data on the survey out of 257 OPs and 112 PTs who started the survey. There have been 458 (OPs) and 821 (PTs) initial clicks. METHODS: Main outcome measures were the importance ratings of specific job stressors, the frequency of asking patients about those stressors, the need for interdisciplinary cooperation, as well as perceived barriers for cooperation. We performed multivariate analysis of variance, intraclass correlation coefficients (ICCs) and Spearman's rank-order correlations. RESULTS: The achieved response rate for OPs was 56.1% and for PTs 13.6%. Both disciplines agreed on the importance of job stressors regarding depression (ICC=0.90; 95% CI: 0.54 to 0.98), but both ranked these factors differently from the current state of research. As to knowledge application, OPs showed positive associations between the importance of job stressors and the frequency of asking employees about them (eg, job insecurity (rs=0.20, p=0.005)) and PTs for social stressors (eg, interpersonal conflicts (rs=0.38, p=0.001)). OPs (mean=3.41) reported a higher necessity of interdisciplinary cooperation than PTs (mean=3.17; F(1,230)=7.02, p=0.009). Furthermore, cooperation was reported as difficult to implement. PTs perceived barriers (eg, time restriction) as more hindering (mean=3.2) than OPs (mean=2.8; F(1,171)=8.16, p=0.005). CONCLUSIONS: Both disciplines are aware of the relevance of job stressors as risk factors for depression, but should be encouraged to ask employees more frequently about them. The need for interdisciplinary cooperation and possible barriers are discussed. It is crucial to emphasise the meaning of sufficient cooperation, since closing this gap for improving patient-centred care especially for employees suffering from depression is necessary.

Dual-spindle formation in zygotes keeps parental genomes apart in early mammalian embryos.

At the beginning of mammalian life, the genetic material from each parent meets when the fertilized egg divides. It was previously thought that a single microtubule spindle is responsible for spatially combining the two genomes and then segregating them to create the two-cell embryo. We used light-sheet microscopy to show that two bipolar spindles form in the zygote and then independently congress the maternal and paternal genomes. These two spindles aligned their poles before anaphase but kept the parental genomes apart during the first cleavage. This spindle assembly mechanism provides a potential rationale for erroneous divisions into more than two blastomeric nuclei observed in mammalian zygotes and reveals the mechanism behind the observation that parental genomes occupy separate nuclear compartments in the two-cell embryo.

Live imaging of cell division in preimplantation mouse embryos using inverted light-sheet microscopy.

Systematic studies of cell divisions at the beginning of mammalian life are of fundamental importance for our understanding of embryonic development and fertility. However, in the past the challenges of in vitro embryo culture and the embryo's pronounced light sensitivity have precluded a detailed investigation of preimplantation cell divisions. This protocol is based on recent technological breakthroughs in inverted light microscopy tailored for mouse embryology. Due to its reduced light dose, and therefore low phototoxicity, as well as higher acquisition speed, light-sheet microscopy allows extended 3D time-lapse imaging of early embryonic development with very high spatial and temporal resolution. This imaging approach enables imaging of key subcellular structures during the critical cell cycles from the zygote up to the blastocyst stage, with a resolution that allows automatic computational tracking and quantitative analysis of the dynamics of mitotic organelles.

Chromosome Segregation: Is the Spindle All About Microtubules?

The spindle segregates chromosomes in cell division and it has long been discussed whether it is microtubules alone that build this fundamental molecular machine. Recent work in mouse oocytes now shows that actin filaments co-assemble with microtubules to promote faithful chromosome segregation.