Implant-related infection is one of the leading reasons for failure in orthopaedics and trauma, and results in high social and economic costs. Various antibacterial coating technologies have proven ...to be safe and effective both in preclinical and clinical studies, with post-surgical implant-related infections reduced by 90% in some cases, depending on the type of coating and experimental setup used. Economic assessment may enable the cost-to-benefit profile of any given antibacterial coating to be defined, based on the expected infection rate with and without the coating, the cost of the infection management, and the cost of the coating. After reviewing the latest evidence on the available antibacterial coatings, we quantified the impact caused by delaying their large-scale application. Considering only joint arthroplasties, our calculations indicated that for an antibacterial coating, with a final user's cost price of €600 and able to reduce post-surgical infection by 80%, each year of delay to its large-scale application would cause an estimated 35 200 new cases of post-surgical infection in Europe, equating to additional hospital costs of approximately €440 million per year. An adequate reimbursement policy for antibacterial coatings may benefit patients, healthcare systems, and related research, as could faster and more affordable regulatory pathways for the technologies still in the pipeline. This could significantly reduce the social and economic burden of implant-related infections in orthopaedics and trauma.
: C. L. Romanò, H. Tsuchiya, I. Morelli, A. G. Battaglia, L. Drago. Antibacterial coating of implants: are we missing something?
2019;8:199-206. DOI: 10.1302/2046-3758.85.BJR-2018-0316.
The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. ...Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed. In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups. After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate. Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes.
The objective of this study was to determine the association between ambient temperature and humidity, vaginal temperature, and automated activity monitoring in synchronized cows. Lactating Holstein ...cows (n = 641; 41.5 ± 9.4 kg of milk/d) were fitted with leg-mounted pedometers, resulting in 843 evaluated activity episodes of estrus. Vaginal temperature was monitored using thermometers attached to an intravaginal device as part of a timed artificial insemination (TAI) protocol; vaginal temperature was recorded every 10 min for 3 d. Ambient temperature and relative humidity were monitored using an external thermometer placed in the center of each pen. Milk production and body condition score (BCS) data were collected at the time of thermometer insertion. All statistical analysis was performed in R (https://www.r-project.org/) using Pearson correlation, analysis of variance, and logistic regression. Heat stress was calculated based on the percentage of time the cow spent with a vaginal temperature ≥39.1°C (PCT39) 9 to 11 d before TAI, and was classified as high (≥22.9%) or low (<22.9%). The mean vaginal temperature was 38.9 ± 0.2°C, and the mean maximum and minimum vaginal temperatures were 39.7 ± 0.5°C and 38.0 ± 0.8°C, respectively, with an average amplitude of 1.71 ± 0.9°C. Mean relative increase (RI) of estrus walking activity was 237.0 ± 160%. Animals with low BCS had a lower RI compared with cows with medium BCS (260.31 ± 17.45% vs. 296.42 ± 6.62%). Cows in early lactation showed lower RI compared with mid- and late-lactation animals (265.40 ± 9.90% vs. 288.36 ± 11.58% vs. 295.75 ± 11.29% for early, mid, and late lactation, respectively). Temperature-humidity index (THI) conditions categorized as low (THI ≤65) were associated with greater RI compared with medium (>65 to <70) and high THI (≥70). We detected no significant effect of PCT39 or milk production on RI, whereas parity exhibited a tendency. Cows that displayed greater RI at estrus had greater pregnancies per artificial insemination (P/AI) than cows with low RI (27 vs. 20%) or no RI (27 vs. 12%). Primiparous cows had greater P/AI than multiparous cows (27 vs. 20%), and cows in early and mid lactation had improved P/AI than those in late lactation (26 vs. 22 vs. 16% for early, mid, and late lactation, respectively). An interaction was observed between PCT39 and THI on P/AI, where a subpopulation of cows with high PCT39 had decreased P/AI under high THI conditions, but no differences in P/AI were observed for high PCT39 cows under medium or low THI conditions (13 vs. 24 vs. 26%). Future research should aim to refine variables related to hyperthermia and to understand the effects of body temperature on estrus expression and pregnancy rates.
Several reports in the literature have identified an association between cortisol levels and the presence of chronic pain in conditions such as rheumatoid arthritis, low back pain or whiplash. In ...contrast, few have examined the association of cortisol and pain in people with osteoarthritis (OA). The purpose of this systematic review was to verify the association between cortisol and pain in the OA population.
The databases MEDLINE, CINAHL, EMBASE were searched systematically for human studies written in English up to December 2018. Two researchers screened titles and abstracts against predefined inclusion criteria; a third resolved discrepancies. Articles were included if they measured the cortisol levels in adults with pain in the OA population. Methodological quality was assessed using Methodological Index for non-randomized Studies (MINORS) score.
Seven studies reporting on 415 patients were included in this review. The MINORS scale yielded mean scores of 8.6 of 16 and 17.5 of 24, for the cohort and case–control studies respectively. In general, the studies were of poor quality. A discrepancy of noteworthy associations between cortisol level comparison and pain was found.
This study shows that there is a discrepancy in the relationship between cortisol and pain dependent on how and when cortisol is measured. Evidence from three low-quality studies suggest increased cortisol levels in patients with pain but the conclusions have a high risk of bias. It was not possible to make a quantitative analysis comparing the relationship between cortisol and pain in the OA population.
Living in biofilms is probably the most common condition for bacteria and fungi and biofilm-related infections account for the majority of bacterial infectious diseases worldwide. Among others ...biofilm-related infections, those associated with implanted biomaterials have an enormous and still largely underestimated impact in orthopaedics and trauma, cardio-surgery and several other surgical disciplines. Given the limited efficacy of existing antibiotics in the prevention and treatment of bacterial biofilms, new strategies are needed to protect implants and host tissues, overcoming the striking ability of the microorganisms to adhere on different surfaces and to immediately protect themselves by forming the biofilm matrix. Adhesion is a necessary first step in microbial colonization and pathogenesis and provides a potential target for new preventive and treatment approach. Among various polymers, tested as antibacterial coatings, hyaluronic acid and some of its composites do offer a well-established long-term safety profile and a proven ability to reduce bacterial adhesion and biofilm formation. Aim of the present review is to summarize the available evidence concerning the antiadhesion/antibiofilm activity of hyaluronic acid and some of its derivatives to reduce/prevent bacterial adhesion and biofilm formation in various experimental and clinical settings.
•Estimation of human-structure interaction when no statistical model is available.•Reduced numerical complexity for the computation of human-induced effects.•Capability to describe transients of ...structures affected by human interaction.
This article addresses the estimation of the effects of human-structure interaction on the dynamic behaviour of slender structures. The paper proposes a method able to provide predictions of human-structure interaction effects in cases in which no models of human dynamic behaviour can be used/are available and only experimental data have to be used. The proposed approach describes the coupled system composed by the structure and the people on it, splitting the action of people into two components: passive and active forces. The sum of the two provides the global action of each person on the dynamics of the structure. Furthermore, an analytical treatment based on modal coordinates and convolution operations is proposed in order to use experimental data, related to the dynamic behaviour of humans, for predicting the vibration level of the occupied structure. An experimental campaign on a slender staircase provided data employed to validate the approach discussed in the article.
Purpose
The best method for treating chronic periprosthetic knee infection remains controversial. Randomized, comparative studies on treatment modalities are lacking. This systematic review of the ...literature compares the infection eradication rate after two-stage versus one-stage revision and static versus articulating spacers in two-stage procedures.
Methods
We reviewed full-text papers and those with an abstract in English published from 1966 through 2011 that reported the success rate of infection eradication after one-stage or two-stage revision with two different types of spacers.
Results
In all, 6 original articles reporting the results after one-stage knee exchange arthoplasty (n = 204) and 38 papers reporting on two-stage revision (n = 1,421) were reviewed. The average success rate in the eradication of infection was 89.8% after a two-stage revision and 81.9% after a one-stage procedure at a mean follow-up of 44.7 and 40.7 months, respectively. The average infection eradication rate after a two-stage procedure was slightly, although significantly, higher when an articulating spacer rather than a static spacer was used (91.2 versus 87%).
Conclusions
The methodological limitations of this study and the heterogeneous material in the studies reviewed notwithstanding, this systematic review shows that, on average, a two-stage procedure is associated with a higher rate of eradication of infection than one-stage revision for septic knee prosthesis and that articulating spacers are associated with a lower recurrence of infection than static spacers at a comparable mean duration of follow-up.
Level of evidence
IV.
This paper presents a general approach for modelling human–structure interaction in the case of vertical vibrations that is based on a model of the system and on a solution procedure that is able to ...account for the most complex dynamic conditions, such as people ascending/descending light staircases. The approach combines the effects of changes in pedestrians’ positions along the structure and changes in pedestrians’ postures during movement. Furthermore, the model used describes the coupled system composed by the structure and the people on the structure, splitting the actions of pedestrians into two components: passive and active forces. This approach and two further enhancements of the model were used to evaluate the dynamic interactions between pedestrians and a staircase, and the results were validated via an extensive experimental campaign carried out using a staircase in the Bovisa Campus of Politecnico di Milano as a test case structure.
•Analysis of OP-AMP outputs in negative capacitance circuit for piezoelectric shunt.•Methods for decreasing OP-AMP output without deteriorating attenuation.•Comparison between different negative ...capacitance layouts.•Guidelines for designing and building negative capacitances for piezoelectric shunt.
One way to enhance the performance of vibration control with piezoelectric shunt is to use a negative capacitance in the shunt circuit. This component is very effective and provides good results in terms of attenuation improvement without significantly increasing the complexity of the shunt network. However, negative capacitances are built using operational amplifiers and, in some applications, the risk of saturation of the outputs of the operational amplifier exists. This constitutes a non-negligible aspect since it leads to a non-proper functioning of the control system which significantly deteriorates the control performance or even triggers instability phenomena. In light of this limitation, this paper proposes strategies to decrease the outputs of the operational amplifier in order to reduce the risk of saturation acting just on the values of the circuit components, without worsening the attenuation performance. However, when the achievable reduction is not sufficient, it is also possible to act on other components accepting a deterioration of the attenuation performance. Guidelines are provided for properly choosing the best shunt circuit configuration accounting for both the extent of the operational amplifier outputs and the control performance. The paper also evidences that the mechanical part of the system cannot be neglected in the analysis when assessing the operational amplifier outputs. Furthermore, two different circuit types used to build the negative capacitance are compared in terms of output requirements. This analysis shows that there is no circuit always less demanding than the other and that the choice of the circuit is not always straightforward. Therefore, a multi-degree of freedom model is presented, which is essential to understand which configuration of the negative capacitance has to be used in a given engineering application. All the presented outcomes are validated through an experimental campaign.
Analysis of joint fluid is of paramount importance for the diagnosis of prosthetic joint infections. Different markers of inflammation and/or infection in joint fluid have been proposed for diagnosis ...of these infections. In this study we evaluated the performance of leucocyte esterase, C-reactive protein (CRP) and glucose assays in synovial fluids from 129 patients with septic (n = 27) or aseptic (n = 102) prosthetic joint failure. Samples were collected in serum tubes and centrifuged to limit the presence of corpuscle interfering with the assays. Determinations of leucocyte esterase and glucose were carried out by means of enzymatic colorimetric reactions performed on strips for urine analysis. Tests were considered positive when graded + or ++ whereas traces or absence of colour were considered negative. CRP was measured using an automated turbidimetric method and considered suggestive for infections when >10 mg/L. Leucocyte esterase was positive in 25/27 infected patients and negative in 99/102 not infected patients (sensitivity 92.6%, specificity 97.0%). CRP was higher than the threshold in 22/27 infected patients and in 6/102 not infected patients (sensitivity: 81.5%; specificity: 94.1%) whereas glucose showed the lowest sensitivity (77.8%) and specificity (81.4%), being negative in 21/27 and 19/102 infected and not infected patients, respectively. CRP led to a correct diagnosis in 19 of 22 patients with discordant esterase and glucose results. In conclusion, evaluation of leucocyte esterase, glucose and CRP may represent a useful tool for rapid diagnosis of prosthetic joint infections.
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