Invasive electrical stimulation in the treatment of avascular osteonecrosis of the femoral head - mid-term results

The study aimed to evaluate the outcomes of osteonecrosis of the femoral head (ONFH) in adults after surgical treatment including invasive electromagnetic osteostimulation (E-Stim). Further, the influence of disease stage and several comorbidities on the joint preservation rate should be examined. Sixty patients (66 hip joints) with ONFH were included in this retrospective cross-sectional analysis (mean follow-up: 58 months, 19-110 months). Potential ONFH risk factors and comorbidities (ONFH stage, age, sex, alcohol, smoking, cortisone medication, chemotherapy) were recorded. The influence of specific parameters on the joint preservation rates was evaluated by a multivariate logistic regression analysis. Finally, patients with preserved hip joints underwent an assessment of their last available X-rays. The joint preservation rate depended on the initial ONFH Steinberg stage (I+II: 82.8%, III: 70.8%, ≥ IVa: 38.5%). Initially collapsed ONFH (p ≤ 0.001) and cortisone therapy (p = 0.004) significantly decreased the joint preservation rates. In case of progressed ONFH, the presence of ≥ 2 risk factors resulted in higher THA conversion rates (stage III: OR 18.8; stage ≥IVa: OR 12). In 94% of the available X-rays, the ONFH stage improved or did not progress. No complications could be attributed to the E-Stim device or procedure. The present surgical protocol including minimally invasive E-Stim revealed high joint preservation rates for non-collapsed ONFH after mid-term postoperative follow-up. Especially in progressed ONFH, the-risk profile seems to be crucial and hence, for joint preserving surgery, careful patient selection is recommended.

Duration of antibiotic treatment and risk of recurrence after surgical management of orthopaedic device infections: a multicenter case-control study

Background

Device-related infections in orthopaedic and trauma surgery are a devastating complication with substantial impact on morbidity and mortality. Systemic suppressive antibiotic treatment is regarded an integral part of any surgical protocol intended to eradicate the infection. The optimal duration of antimicrobial treatment, however, remains unclear. In a multicenter case-control study, we aimed at analyzing the influence of the duration of antibiotic exposure on reinfection rates 1 year after curative surgery.

Methods

This investigation was part of a federally funded multidisciplinary network project aiming at reducing the spread of multi-resistant bacteria in the German Baltic region of Pomerania. We herein used hospital chart data from patients treated for infections of total joint arthroplasties or internal fracture fixation devices at three academic referral institutions. Subjects with recurrence of an implant-related infection within 1 year after the last surgical procedure were defined as case group, and patients without recurrence of an implant-related infection as control group. We placed a distinct focus on infection of open reduction and internal fixation (ORIF) constructs. Uni- and multivariate logistic regression analyses were employed for data modelling.

Results

Of 1279 potentially eligible patients, 269 were included in the overall analysis group, and 84 contributed to an extramedullary fracture-fixation-device sample. By multivariate analysis, male sex (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.08 to 3.94, p = 0.029) and facture fixation device infections (OR 2.05, 95% CI 1.05 to 4.02, p = 0.036) remained independent predictors of reinfection. In the subgroup of infected ORIF constructs, univariate point estimates suggested a nearly 60% reduced odds of reinfection with systemic fluoroquinolones (OR 0.42, 95% CI 0.04 to 2.46) or rifampicin treatment (OR 0.41, 95% CI 0.08 to 2.12) for up to 31 days, although the width of confidence intervals prohibited robust statistical and clinical inferences.

Conclusion

The optimal duration of systemic antibiotic treatment with surgical concepts of curing wound and device-related orthopaedic infections is still unclear. The risk of reinfection in case of infected extramedullary fracture-fxation devices may be reduced with up to 31 days of systemic fluoroquinolones and rifampicin, although scientific proof needs a randomized trial with about 1400 subjects per group. Concerted efforts are needed to determine which antibiotics must be applied for how long after radical surgical sanitation to guarantee sustainable treatment success.

Damages with High Consequences: Analysis of Perforations in Surgical Latex Operation Gloves from Orthopedic Surgeries

Introduction

To prevent surgical site infections (SSIs) during operation, the use of sterile surgical latex gloves is common. The aim of this study was to examine the damage of the gloves in surgeries with different mechanical stress and the influence on the kind of damages. Gloves were collected during primary arthroplasty, revision arthroplasty (hip and knee), and arthroscopy (shoulder, hip, and knee).

Materials and methods

Surgical latex operation gloves were collected from surgeons after the operation and were tested with watertightness test (ISO EN 455-1:2000).

Results

A total of 1460 surgical gloves were retrieved from 305 elective operations. On average, 15.9% of the gloves showed postoperative lesions, with the highest incidence occurring in revision arthroplasty with 25%. In primary and revision arthroplasty, the index finger of the dominant hand was most frequently affected (62.7% and 58.6%); in contrast, gloves from arthroscopies had most lesions on thumb and middle finger (42.9% each). Tear and perforation size differed from ≤1 mm to >5 mm, and primary and revision arthroplasty showed bigger damages.

Conclusions

Surgical gloves have a high malfunction, which increases with growing mechanical stress. A high rate of perforation occurred mostly in revision arthroplasty. Breaching the integrity of the gloves, especially by high mechanical loads, could lead to an increased rate of infection.

Antibiotics release from cement spacers used for two-stage treatment of implant-associated infections after total joint arthroplasty

Two‐stage revision arthroplasty is the treatment of choice for periprosthetic infection, a serious complication after knee or hip arthroplasty. Our prospective clinical trial aimed to investigate the concentrations of gentamicin and vancomycin in wound exudate and tissue in two‐stage revision arthroplasty. Wound exudate and periprosthetic membrane samples were collected from 18 patients (10 hip and eight knee patients), who were due for two‐stage treatment after a periprosthetic joint infection. Samples were taken during insertion of antibiotic‐impregnated spacers and after their removal. The concentrations of gentamicin and vancomycin in wound exudates and adjacent tissue were analyzed using high‐performance liquid chromatography mass spectrometry. Average time period of spacer implantation was 13.6 weeks (9.3–22.6 weeks). The concentration of vancomycin in wound exudate decreased from a median of 43.28 μg/mL (0.28–261.22) after implantation to 0.46 μg/mL (0.13–37.47) after the removal of the spacer. In the adjacent tissue, vancomycin concentration was mainly undetectable prior to spacer implantation (0.003 μg/g [0.003–0.261]) and increased to 0.318 μg/g [0.024–484.16] at the time of spacer removal. This was also observed for gentamicin in the tissue of patients who previously had cement‐free implants (0.008 μg/g [0.008–0.087] vs. 0.164 μg/g [0.048–71.75]) while in the tissue of patients with previously cemented prosthesis, baseline concentration was already high (8.451 μg/g [0.152–42.926]). Despite the rapid decrease in antibiotics release from spacer cement observed in vitro, in vivo antibiotics are much longer detectable, especially in the adjacent soft tissue. © 2018 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials Published By Wiley Periodicals, Inc. J Biomed Mater Res B Part B, 2019. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1587–1597, 2019.

Copper as an alternative antimicrobial coating for implants - An in vitro study

AIM

To investigate osteoconductive and antimicrobial properties of a titanium-copper-nitride (TiCuN) film and an additional BONIT^® coating on titanium substrates.

METHODS

For micro-structuring, the surface of titanium test samples was modified by titanium plasma spray (TPS). On the TPS-coated samples, the TiCuN layer was deposited by physical vapor deposition. The BONIT^® layer was coated electrochemically. The concentration of copper ions released from TiCuN films was measured by atomic absorption spectrometry. MG-63 osteoblasts on TiCuN and BONIT^® were analyzed for cell adhesion, viability and spreading. In parallel, Staphylococcus epidermidis (S. epidermidis) were cultivated on the samples and planktonic and biofilm-bound bacteria were quantified by counting of the colony-forming units.

RESULTS

Field emission scanning electron microscopy (FESEM) revealed rough surfaces for TPS and TiCuN and a special crystalline surface structure on TiCuN + BONIT^®. TiCuN released high amounts of copper quickly within 24 h. These release dynamics were accompanied by complete growth inhibition of bacteria and after 2 d, no planktonic or adherent S. epidermidis were found on these samples. On the other hand viability of MG-63 cells was impaired during direct cultivation on the samples within 24 h. However, high cell colonization could be found after a 24 h pre-incubation step in cell culture medium simulating the in vivo dynamics closer. On pre-incubated TiCuN, the osteoblasts span the ridges and demonstrate a flattened, well-spread phenotype. The additional BONIT^®coating reduced the copper release of the TiCuN layer significantly and showed a positive effect on the initial cell adhesion.

CONCLUSION

The TiCuNcoating inhibits the formation of bacterial biofilms on orthopedic implants by influencing the “race for the surface” to the advantage of osteoblasts.

Fast corroding, thin magnesium coating displays antibacterial effects and low cytotoxicity

Bacterial colonisation and biofilm formation are characteristics of implant-associated infections. In search of candidates for improved prosthetic materials, fast corroding Mg-based coatings on titanium surfaces were examined for their cytotoxic and antimicrobial properties. Human osteoblasts and Staphylococcus epidermidis were each cultured on cylindrical Ti samples coated with a thin layer of Mg/Mg₄₅Zn₅Ca, applied via magnetron sputtering. Uncoated titanium samples served as controls. S. epidermidis was quantified by counting colony forming units. The biofilm-bound fraction was isolated via ultrasonic treatment, and the planktonic fraction via centrifugation. Biofilm-bound S. epidermidis was significantly decreased by approximately four to five orders of magnitude in both Mg- and Mg₄₅Zn₅Ca-coated samples after seven days compared to the control. The osteoblast viability was within the tolerance threshold of 70% stated in DIN EN ISO 10993-5:2009-10 for Mg (~80%) but not for Mg₄₅Zn₅Ca (~25%). Accordingly, Mg-coated titanium was identified as a promising candidate for an implant material with antibacterial properties and low cytotoxicity levels. The approach of exploiting fast corrosion contrasts with existing methods, which have generally focused on reducing corrosion.

Thin magnesium layer confirmed as an antibacterial and biocompatible implant coating in a co‑culture model

Implant-associated infections commonly result from biofilm-forming bacteria and present severe complications in total joint arthroplasty. Therefore, there is a requirement for the development of biocompatible implant surfaces that prevent bacterial biofilm formation. The present study coated titanium samples with a thin, rapidly corroding layer of magnesium, which were subsequently investigated with respect to their antibacterial and cytotoxic surface properties using a Staphylococcus epidermidis (S. epidermidis) and human osteoblast (hOB) co-culture model. Primary hOBs and S. epidermidis were co-cultured on cylindrical titanium samples (Ti6Al4V) coated with pure magnesium via magnetron sputtering (5 µm thickness) for 7 days. Uncoated titanium test samples served as controls. Vital hOBs were identified by trypan blue staining at days 2 and 7. Planktonic S. epidermidis were quantified by counting the number of colony forming units (CFU). The quantification of biofilm-bound S. epidermidis on the surfaces of test samples was performed by ultrasonic treatment and CFU counting at days 2 and 7. The number of planktonic and biofilm-bound S. epidermidis on the magnesium-coated samples decreased by four orders of magnitude when compared with the titanium control following 7 days of co-culture. The number of vital hOBs on the magnesium-coated samples was observed to increase (40,000 cells/ml) when compared with the controls (20,000 cells/ml). The results of the present study indicate that rapidly corroding magnesium-coated titanium may be a viable coating material that possesses antibacterial and biocompatible properties. A co-culture test is more rigorous than a monoculture study, as it accounts for confounding effects and assesses additional interactions that are more representative of in vivo situations. These results provide a foundation for the future testing of this type of surface in animals.

Prospective data collection and analysis of perforations and tears of latex surgical gloves during primary endoprosthetic surgeries

Introduction: Surgical gloves are used to prevent contamination of the patient and the hospital staff with pathogens. The aim of this study was to examine the actual effectiveness of gloves by examining the damage (perforations, tears) to latex gloves during surgery in the case of primary hip and knee prosthesis implantation.

Materials and methods: Latex surgical gloves used by surgeons for primary hip and knee replacement surgeries were collected directly after the surgery and tested using the watertightness test according to ISO EN 455-1:2000.

Results: 540 gloves were collected from 104 surgeries. In 32.7% of surgeries at least one glove was damaged. Of all the gloves collected, 10.9% were damaged, mainly on the index finger. The size of the perforations ranged from ≤1 mm to over 5 mm. The surgeon’s glove size was the only factor that significantly influenced the occurrence of glove damage. Surgeon training level, procedure duration, and the use of bone cement had no significant influence.

Conclusions: Our results highlight the high failure rate of surgical gloves. This has acute implications for glove production, surgical practice, and hygiene guidelines. Further studies are needed to detect the surgical steps, surface structures, and instruments that pose an increased risk for glove damage.

Augmented recovery of microorganisms from swabs by homogenization: a novel standardizable high-throughput approach

A new approach introducing a quantitative and standardizable step into sample processing was evaluated by homogenizing in vitro inoculated swab tips with Precellys 24 high-throughput homogenizer. Recovery of microorganisms from homogenized swab tips was significantly higher as compared to conventional processing methods. Thus, swab homogenization is a promising approach introducing a new quality in microbial analysis.

Potential infection control risks associated with roaming healthcare industry representatives

BACKGROUND

Healthcare industry representatives (HCIR) visit multiple hospitals every day. Most enter hygiene sensitive areas and work in close proximity to caregivers and patients.

OBJECTIVE

The objective of the present study was to evaluate the HCIRs' current status in hygiene training and vaccination.

METHODS

An anonymous walking intercept study was used based on questionnaires to evaluate industry representatives in comparison to physicians and nurses (n = 311 participants, participation rate 30.2%) after their visit to the MEDICA Congress. The valid participants consisted of HCIR (n = 208), hospital nurses (n = 49) and physicians (n = 41). A total of 82.2% (n = 171) HCIR worked in varying hospitals.

RESULTS

They frequently request access to hygiene and data-privacy sensitive areas: Among them 51.9% (n = 108) accessed the outpatient clinic, 41.8% (n = 87) the operating room (OR), 33.7% (n = 70) the central supply and sterilisation department (CSSD), and 32.7% (n = 68) the intensive care unit. HCIR requesting access to hygiene sensitive areas showed the lowest scores in hygiene training and a significantly lower Hepatitis B vaccination status, i.e. 37.5% compared to 70.7% for physicians and 53.1% for nurses.

DISCUSSION

Status of HCIR hygiene training was inadequate - as was vaccination and contamination control. Therefore, HCIR are exposed to increased infection risk and may unknowingly act as infection vector between different hospitals.

Examination of cross contamination risks between hospitals by external medical staff via cross-sectional intercept survey of hand hygiene

Introduction: Work in hospitals is supported by contributions of life sciences industry representatives (IR) in various ways of fields. Close contact between them, caretakers and patients is unavoidable, even in situations where hygiene is critical.

The present study investigates whether IR display comparable levels of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) contamination after being exposed to a shared environment for a minimum of 4 hours.

Material and methods: An anonymous survey to sample a group of healthcare professionals for traces of fingertip contamination was performed. We used dip slides (S. aureus and MRSA) to evaluate 311 healthcare professionals at the medical exhibition MEDICA. After applying exclusion criteria 298 participants remained valid, they consisted of 208 industry representatives, 49 nurses and 41 physicians.

Results: IR where engaged in hospitals, operating rooms and outpatient clinics (82%, 41.8%, 51.9% respectively). 65.9% of IR (vs. 48.8% physicians and 40.8% nurses) carried a microbiological burden ≥10⁴ CFU (colony forming units). Neither S. aureus (≥10⁴ CFU) in IR (40.9%) did show statistical differences in contamination patterns in comparison to physicians (43.9%, p=0.346) and nurses (36.7%, p=0.878) nor did MRSA (physicians p=0.579, nurses p=0.908). We were unable to differentiate transient from pre-existing permanent colonization.

Conclusion: Exposure to the same environment may result in similar hand contamination patterns of IR when compared caregivers. This supports the concern that industry representatives can cause cross infection between hospitals and hygiene sensitive areas like operation room, intensive care unit and central sterilization units particularly. Further study is required to clarify whether pre-existing bacterial colonization is an influencing factor and how industry is taking care of this to create a safe working environment for their employees, the customers and ultimately the patients.

Autoimmune pancreatitis in MRL/Mp mice is a T cell-mediated disease responsive to cyclosporine A and rapamycin treatment

BACKGROUND

Autoimmune pancreatitis (AIP) in humans invariably responds to steroid treatment, but little is known about the underlying pathogenesis and the benefits of alternative treatments.

OBJECTIVE

To study the pathogenesis, and the efficacy of alternative immunosuppressant agents in the MRL/Mp mouse model of AIP.

DESIGN

MRL/Mp mice were pretreated for 4 weeks with polyinosinic:polycytidylic acid to induce AIP. Pancreatic sections of mice genetically deleted for CTLA-4 were analysed. Blockage of CTLA-4 was achieved by intraperitoneal antibody treatment with 2 μg/g anti-mouse-CD152. Subsequent therapeutic studies were performed for a period of 4 weeks using cyclosporine A (40 μg/g), rapamycin (1 μg/g) or azathioprine (15 μg/g).

RESULTS

Blockage of CTLA-4 in MRL/Mp mice suppressed regulatory T cell (Treg) function and raised the effector T cell (Teff) response with subsequent histomorphological organ destruction, indicating that AIP is a T cell-driven disease. Using an established histopathological score, we found that dexamethasone, cyclosporine A and rapamycin, but less so azathioprine, reduced pancreatic damage. However, the beneficial effects of cyclosporine A and rapamycin were achieved via different mechanisms: cyclosporine A inhibited Teff activation and proliferation whereas rapamycin led to selective expansion of Tregs which subsequently suppressed the Teff response.

CONCLUSIONS

The calcineurin inhibitor cyclosporine A and the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, improve the course of AIP in MRL/Mp mice via different mechanisms. These findings further support the concept of autoreactive T cells as key players in the pathogenesis of AIP and suggest that cyclosporine A and rapamycin should be considered for treatment of AIP in humans.