The influence of surgical technique guidance and surgeon's experience on the femoral head assembly in total hip arthroplasty

INTRODUCTION

The importance of the assembly procedure on the taper connection strength is evident. However, existent surgical technique guides frequently lack comprehensive and precise instructions in this regard. The aim of our experimental study was to evaluate the influence of the surgical technique guide on the femoral head assembly procedure in surgeons with differing levels of experience in total hip arthroplasty.

MATERIALS AND METHODS

Twenty-eight participants, divided into four groups based on their lifetime experience in total hip arthroplasty, conducted a femoral head assembly procedure in a simulated intraoperative environment before and after reviewing the surgical technique guide. Demographic information and the number of hammer blows were documented. Hammer velocity and impaction angle were recorded using an optical motion capturing system, while the impaction force was measured using a dynamic force sensor within the impactor.

RESULTS

We observed a high variation in the number of hammer blows, maximum force, and impaction angle. Overall, the number of hammer blows decreased significantly from 3 to 2.2 after reviewing the surgical technique guide. The only significant intragroup difference in the number of hammer blows was observed in the group with no prior experience in total hip arthroplasty. No correlation was found between individual factors (age, weight, height) or experience and the measured parameters (velocity, maximum force and angle).

CONCLUSIONS

The present study demonstrated a high variation in the parameters of the femoral head assembly procedure. Consideration of the surgical technique guide was found to be a limited factor among participants with varying levels of experience in total hip arthroplasty. These findings underline the importance of sufficient preoperative training, to standardize the assembly procedure, including impaction force, angle, and use of instruments.

Systematic enhancement of microbial decontamination efficiency in bone graft processing by means of high hydrostatic pressure using Escherichia coli as a model organism

To obtain bone allografts that are safe for transplantation, several processing steps for decellularization and decontamination have to be applied. Currently available processing methods, although well-established, may interfere with the biomechanical properties of the bone. High hydrostatic pressure (HHP) is known to devitalize tissues effectively while leaving the extracellular matrix intact. However, little is known about the inactivation of the contaminating microorganisms by HHP. This study aims to investigate the ability of high-pressure decontamination and to establish a treatment protocol that is able to successfully inactivate microorganisms with the final goal to sterilize bone specimens. Using Escherichia coli (E. coli) as a model organism, HHP treatment parameters like temperature and duration, pressurization medium, and the number of treatment cycles were systematically adjusted to maximize the efficiency of inactivating logarithmic and stationary phase bacteria. Towards that we quantified colony-forming units (cfu) after treatment and investigated morphological changes via Field Emission Scanning Electron Microscopy (FESEM). Additionally, we tested the decontamination efficiency of HHP in bovine cancellous bone blocks that were contaminated with bacteria. Finally, two further model organisms were evaluated, namely Pseudomonas fluorescens as a Gram-negative microorganism and Micrococcus luteus as a Gram-positive representative. A HHP protocol, using 350 MPa, was able to sterilize a suspension of stationary phase E. coli, leading to a logarithmic reduction factor (log RF) of at least -7.99 (±0.43). The decontamination of bone blocks was less successful, indicating a protective effect of the surrounding tissue. Sterilization of 100% of the samples was achieved when a protocol optimized in terms of treatment temperature, duration, pressurization medium, and number and/or interval of cycles, respectively, was applied to bone blocks artificially contaminated with a suspension containing 104  cfu/mL. Hence, we here successfully established protocols for inactivating Gram-negative model microorganisms by HHP of up to 350 MPa, while pressure levels of 600 MPa were needed to inactivate the Gram-positive model organism. Thus, this study provides a basis for further investigations on different pathogenic bacteria that could enable the use of HHP in the decontamination of bone grafts intended for transplantation.

Identification of Potentially High-risk Patients on the Basis of PROMs in a Certified Centre for Joint Replacement (EndoProthetikZentrum) Using the Example of Primary Knee Arthroplasty

BACKGROUND

The subjective evaluation of the patient's state of health with the help of Patient-reported Outcome Measurements (PROMs) provides valuable information for assessing the treatment outcome and for treatment planning. However, the use of PROMs in the field of arthroplasty is not mandatory, so that there is a lack of standardised recording and interpretation. The present study aims to identify patients, who have not achieved the intended treatment goals with regard to pain, function and quality of life after total knee arthroplasty, more easily in the future on the basis of postoperative PROMs.

MATERIAL AND METHODS

Data collection (for 3-month postoperative follow-up) included a standardised clinical follow-up (NU) and a questionnaire of different PROMs (Oxford Knee Score [OKS], OKS Pain Score [OKSS] and EndoCert Risk Score [ERS]). During the specialist follow-up examination, it was decided whether further medical therapy had to be initiated. Accordingly, patients were grouped into four post-treatment categories (NU not required/further diagnostics/new prescription/revision required).

RESULTS

For individual scores and questions, there were significant differences between the respective groups of consequences resulting from the follow-up examination. The OKS, OKS Pain Score and the ERS are suitable for detecting thresholds to determine the need for a follow-up examination. The postoperative thresholds of the scores are 24 for the OKS total score, 52 for the OKS pain score and 4 for the ERS pain intensity score.

CONCLUSION

In the initial three months after knee arthroplasty, certain PROMs are suitable for identifying patients for whom further diagnostics and therapy are indicated. In particular, the OKS and the pain intensity score of the ERS are suitable for detecting a potentially unfavourable development in rehabilitation after total knee arthroplasty.

IL-6-induced response of human osteoblasts from patients with rheumatoid arthritis after inhibition of the signaling pathway

Interleukin (IL-) 6 is a critical factor in inflammatory processes of rheumatoid arthritis (RA). This is of high interest as the progression of RA may lead to the implantation of joint endoprostheses, which is associated with a pro-inflammatory increase in IL-6 in the periprosthetic tissue. Biological agents such as sarilumab have been developed to inhibit IL-6-mediated signaling. However, IL-6 signaling blockade should consider the inhibition of inflammatory processes and the regenerative functions of IL-6. This in vitro study investigated whether inhibiting IL-6 receptors can affect the differentiation of osteoblasts isolated from patients with RA. Since wear particles can be generated at the articular surfaces of endoprostheses leading to osteolysis and implant loosening, the potential of sarilumab to inhibit wear particle-induced pro-inflammatory processes should be investigated. Both in monocultures and indirect co-cultures with osteoclast-like cells (OLCs), human osteoblasts were stimulated with 50 ng/mL each of IL-6 + sIL-6R and in combination with sarilumab (250 nM) to characterize cell viability and osteogenic differentiation capacity. Furthermore, the influence of IL-6 + sIL-6R or sarilumab on viability, differentiation, and inflammation was evaluated in osteoblasts exposed to particles. Stimulation with IL-6 + sIL-6R and sarilumab did not affect cell viability. Except for the significant induction of RUNX2 mRNA by IL-6 + sIL-6R and a significant reduction with sarilumab, no effects on cell differentiation and mineralization could be detected. Furthermore, the different stimulations did not affect the osteogenic and osteoclastic differentiation of co-cultured cells. Compared to the osteoblastic monocultures, a decreased release of IL-8 was triggered in the co-culture. Among these, treatment with sarilumab alone resulted in the greatest reduction of IL-8. The co-culture also showed clearly increased OPN concentrations than the respective monocultures, with OPN secretion apparently triggered by the OLCs. Particle exposure demonstrated decreased osteogenic differentiation using different treatment strategies. However, sarilumab administration caused a trend toward a decrease in IL-8 production after stimulation with IL-6 + sIL-6R. The blockade of IL-6 and its pathway have no significant effect on the osteogenic and osteoclastic differentiation of bone cells derived from patients with RA. Nonetheless, observed effects on the reduced IL-8 secretion need further investigation.

Wrist Injuries in Climbers

BACKGROUND

Acute and chronic injuries to the wrist are among the most common sport-related complaints of climbing athletes but have not been extensively evaluated in this population. Therefore, it is important to categorize climbing injuries to the wrist, analyze risk factors, and assess treatment outcomes.

PURPOSE

To evaluate the distribution, outcomes, and influencing factors of wrist injuries in climbers.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Climbing athletes with wrist injuries who presented to our specialized sports medical center over the course of 4 years (2017-2020) were selected. All had prospectively completed questionnaires including their climbing-specific background (years of training, climbing level, training methods, etc). Injuries were analyzed (International Climbing and Mountaineering Federation [UIAA] grade and diagnosis), and treatment methods and outcomes were retrospectively assessed with a minimum follow-up of 2 years. Parameters included the climbing score, visual analog scale for pain score, Patient-Rated Wrist Evaluation (PRWE) score, and shortened version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) score including the sport component (DASH-Sport) score before and after treatment as well as time to return to climbing.

RESULTS

A total of 69 patients (25 female, 44 male) with 78 wrist injuries were identified and analyzed. Of these, 7 injuries were bilateral, occurring at the same time, and 2 injuries were independent reinjuries to either the same or the contralateral side. In addition, 24 injuries (30.8%) were acute, while 54 (69.2%) were chronic. Overall, 2 injuries had a UIAA grade of 3; all others had a UIAA grade of 2. The most frequent injuries were synovitis of the ulnocarpal recess, ulnar impaction, bone marrow edema of the lunate, wrist sprains (joint capsular pain with stress, with no pathological finding on magnetic resonance imaging), and wrist ganglion cysts. Nonoperative treatment was performed for 61 of the injuries, while 17 were treated surgically. In 51 cases (65.4%), injuries healed without consequences; in 27 cases (34.6%), discomfort remained. The visual analog scale pain score decreased from 4.8 ± 1.9 before treatment to 0.7 ± 1.0 after treatment (P < .001), the PRWE score decreased from 53.6 ± 24.9 to 10.3 ± 13.1 (P < .001), the QuickDASH score improved from 53.0 ± 16.6 to 20.0 ± 20.2 (P < .001), and the DASH-Sport score improved from 82.0 ± 16.1 to 38.1 ± 23.5 (P < .001). The climbing score improved from 2.5 ± 1.1 to 4.3 ± 1.0 points (P < .001). The patient-reported number of days with pain was negatively correlated with changes in the PRWE score (r = -0.351; P < .001), QuickDASH score (r = -0.316; P = .007), and climbing score (r = -0.264; P = .025) as well as the number of days without climbing (r = -0.266; P = .025). The number of days without climbing was positively correlated with changes in the PRWE score (r = 0.369; P < .001).

CONCLUSION

Wrist injuries in climbers constituted a diverse set of diagnoses. Ulnar-sided injuries were most common, and many patients had >1 diagnosis. Outcomes for all treatment methods (surgery and nonoperative care) were favorable, but approximately one-third of climbers had persistent wrist discomfort after treatment, underscoring the need for accurate diagnoses and acute and expert care.

Net Promoter Score: a prospective, single-centre observational study assessing if a single question determined treatment success after primary or revision hip arthroplasty

BACKGROUND

Our study aimed to identify the relationship between treatment outcome assessed by patient-reported outcomes (PROMs) and satisfaction measured by calculation of the Net Promoter Score (NPS), which identifies promoters, following total hip arthroplasty (THA). The aim was to evaluate this association separately in primary and revision THA and to determine thresholds based on PROMs that identify detractors of the surgical procedure or the centre.

METHODS

A total of 1,243 patients who underwent primary or revision THA at our hospital were asked to complete questionnaires of the Oxford Hip Score (OHS), Euroquol-5D (EQ-5D) and information on pain intensity preoperatively, three and 12 months after surgery. Postoperatively, the patients were additionally asked about their satisfaction with the procedure and the hospital by using three different NPS questions. The association between PROMs and NPS was evaluated based on group comparisons of primary or revision THA and receiver operating characteristics analysis (ROC) to determine threshold values.

RESULTS

At 12 months the NPS of all three questions were invariably linked to treatment outcome in patients after primary THA and patients with a single revision. In these two treatment groups, promoters always showed significantly better PROM scores than detractors. The NPS score was always higher in the primary group in comparison to the single revision group, e.g. 66.4% would undergo the procedure again in the first group, while only 33.0% would opt for this in the latter group. The high thresholds for the PROMs at 12 months, that were calculated by ROC analysis to identify promoter/detractors, indicate that patients` satisfaction required very good joint function and pain relief. However, the NPS was not a suitable tool to identify patients who need further care in an early phase after surgery.

CONCLUSIONS

With NPS already a single question or a single parameter provides the desired information regarding patient satisfaction and also treatment success.

TRIAL REGISTRATION

The study was approved by the Ethics Committee at the Medical Faculty of the University Rostock: "Ethikkommission an der Medizinischen Fakultät der Universität Rostock", Address: St.-Georg Str. 108 18055 Rostock, Germany, reference number: A2015-0055.

Surgical Treatment of Adolescent Idiopathic Scoliosis with the ApiFix Minimal Invasive Dynamic Correction System-A Preliminary Report of a 24-Month Follow-Up

Adolescent idiopathic scoliosis (AIS) is a three-dimensional growth disorder. Corrective surgical procedures are the recommended treatment option for a thoracic angle exceeding 50° and a lumbar major curve of 40°. Over the past few years, dynamic growth modulation implants have been developed as alternatives to permanent fusion. The ApiFix system was designed as a 2D "posterior dynamic device" for curve correction. After implantation in a minimally invasive procedure, it uses polyaxial joints and a self-adjusting rod to preserve the degree of motion and to accommodate the patient's growth. It provides an effective method of controlling deformity and fills the gap between the conservative treatment of major curves that are >35° and the fusion procedure. The objective of the two-center cohort study was the analysis of the correction results of patients, who underwent surgical intervention with the ApiFix system. The inclusion criteria were AIS, Lenke type 1 or type 5, a major curve on bending films of ≤30°, and an angle of the major curve of between 35° and 60°. Postoperative radiograph data were obtained longitudinally for up to 24 months of follow-up and compared to preoperative (preop) values. For comparisons of the different time points, non-parametric tests (Wilcoxon) or paired t-tests for normally distributed values were used to analyze repeated measures. Overall, 36 patients (25 female and 11 male) were treated with the ApiFix system from April 2018 to October 2020. Lenke type 1 was identified in 21 (58%) cases and Lenke type 5 was identified in 15 (42%) cases. The average angle of the thoracic major curve for Lenke 1 was 43°. The preoperative lumbar major curve (Lenke 5) was determined to be 43°. Over a follow-up of 24 months, a correction of the major curve to an average of 20° was observed for Lenke 1 and that to an average of 15° was observed for Lenke 5. Lenke type 1 and type 5 showed significant changes in the major curve over the individual test intervals in the paired comparisons compared to the starting angle (Lenke 1: preop-24 months, 0.002; Lenke 5: preop-24 months, 0.043). Overall, 11 events were recorded in the follow-up period, that required revision surgery. We distinguished between repeated interventions required after reaching the maximum distraction length of the implant due to the continued growth of the patient (n = 4) and complications, such as infections or problems associated with the anchorage of the implant (n = 7). The results from the present cohort revealed a statistically significant improvement in the postoperatively measured angles of the major and minor curves in the follow-up after 24 months. Consequently, the results were comparable to those of the already established vertebral body tethering method. Alignment in AIS via dynamic correction systems in combination with a possible growth modulation has been a treatment alternative to surgical fusing procedures for more than a decade. However, the long-term corrective effect has to be validated in further studies.

Intraoperative control by Schanz-screws is inaccurate to achieve the exact amount of correction in de-rotational osteotomies

PURPOSE

The accuracy of intraoperative control of correction commonly is achieved by K-wires or Schanz-screws in combination with goniometer in de-rotational osteotomies. The purpose of this study is to investigate the accuracy of intraoperative torsional control in de-rotational femoral and tibial osteotomies. It is hypothesized, that intraoperative control by Schanz-screws and goniometer in de-rotational osteotomies around the knee is a safe and well predictable method to control the surgical torsional correction intraoperatively.

METHODS

55 consecutive osteotomies around the knee joint were registered, 28 femoral and 27 tibial. The indication for osteotomy was femoral or tibial torsional deformity with the clinical occurrence of patellofemoral maltracking or PFI. Pre- and postoperative torsions were measured according to the method of Waidelich on computed tomography (CT) scan. The scheduled value of torsional correction was defined by the surgeon preoperatively. Intraoperative control of torsional correction was achieved by 5 mm-Schanz-screws and goniometer. The measured values of torsional CT scan were compared to the preoperative defined and intended values and deviation was calculated separately for femoral and tibial osteotomies.

RESULTS

The surgeon's intraoperative measured mean value of correction in all osteotomies was 15.2° (SD 4.6; range 10-27), whereas the postoperatively measured mean value on CT scan was 15.6 (6.8; 5.0-28.5). Intraoperatively the femoral mean value measured 17.9° (4.9; 10-27) and 12.4° (1.9; 10-15) for the tibia. Postoperatively the mean value for femoral correction was 19.8 (5.5; 9.0-28.5) and 11.3 (5.0; 5.0-26.0) for tibial correction. When considering a deviation of plus or minus 3° to be acceptable femorally 15 osteotomies (53.6%) and tibially 14 osteotomies (51.9%) fell within these limits. Nine femoral cases (32.1.%) were overcorrected, four cases undercorrected (14.3%). Four tibial cases of overcorrection (14.8%) and 9 tibial cases of undercorrection (33.3%) were observed. However, the observed difference between femur and tibia regarding the distribution of cases between the three groups did not reach significance. Moreover, there was no correlation between the extent of correction and the deviation from the intended result.

CONCLUSION

The use of Schanz-screws and goniometer in de-rotational osteotomies as an intraoperative control of correction is an inaccurate method. Every surgeon performing derotational osteotomies must consider this and include postoperative torsional measurement in his postoperative algorithm until new tools or devices are available to guarantee a better intraoperative accuracy of torsional correction.

STUDY DESIGN

Observational study.

LEVEL OF EVIDENCE

III.

Knot tying in arthroplasty and arthroscopy causes lesions to surgical gloves: a potential risk of infection

PURPOSE

Recent studies have shown that the incidence of glove lesions during arthroscopy is much lower than that during primary and revision arthroplasty. However, the rate of glove damage after knot tying has not yet been systematically recorded. Therefore, the aim of the study was to determine the impact of surgical knot tying on glove integrity. It was hypothesized that knot tying increases the rate of glove damage, especially in arthroscopic surgery, which could be of special relevance in the treatment of rotator cuff tears.

METHODS

Gloves that were changed immediately before suturing and only worn during knot tying were investigated for their integrity by means of water tightening test according to EN455. A total of 234 gloves from 40 total hip arthroplasties (THAs), 42 total knee arthroplasties (TKAs) and 36 rotator cuff repairs (RCRs) were collected. A bacterial pass-through test (BPTT) on glove lesions was performed under simulated sterile surgical conditions for 3 surgeons after a wear duration of 45 min.

RESULTS

Glove damage by knot tying occurred in 25% of THA, 36.6% of TKA and 25% of RCR surgeries. In THA, the pulling hand (PH) was affected in 46.2%, and the main area of damage (15.4%) was detected on the tip of the middle finger; in TKAs the PH was damaged in 75%, and in RCRs the PH was affected in 66.7%, with most of the lesions (20% each) occurring on the tip of the index finger and the ring finger. The BPTT showed Staphylococcus hominis and Bacillus cereus.

CONCLUSION

Intraoperative knot tying causes damage to gloves, which is of special relevance for arthroscopic surgery. Whereas knot tying is only partly responsible for glove damage in arthroplasty, the general rate of glove damage in arthroscopic surgery is low without knot tying. The surgical knot tying process must be understood as a possible damaging impact on the glove. Therefore, single gloving is not recommended, which is especially important in arthroscopic surgery, where double gloving is not yet standard.

LEVEL OF EVIDENCE

IV.

Identification of Potential High-Risk Patients on the Basis of PROMs in a Certified Centre for Joint Replacement (EndoProthetikZentrum) Using the Example of Hip Arthroplasty

BACKGROUND

In addition to clinical parameters, the subjective assessment by the patient to evaluate the operative outcome of an arthroplasty is becoming increasingly important. Questionnaires are used to identify patients who have not achieved the treatment goal at an early stage so that further interventions can be indicated.

MATERIAL AND METHODS

A questionnaire consisting of different PROMs was completed pre- and 3 months postoperatively by patients who had been treated with a hip arthroplasty. A standardised follow-up examination of these patients was carried out 12 to 16 weeks postoperatively, after which it was determined whether further therapy was necessary to achieve the treatment goal. Different consequences were defined for this.

RESULTS

Significant differences were found between the groups of consequences of follow-up examinations over both time points, but also when postoperative scores were considered exclusively. Furthermore, the correlations for the postoperative scores and some consequences of the clinical follow-up for the Oxford Hip Score (OHS), the OHS functional score and the Euroquol-5D show moderate effects. Thus, the collection of these postoperative scores is sufficient to identify potential high risk patients. Based on a receiver operating characteristic (ROC) analysis, threshold values could be determined for these scores, for which a follow-up examination is recommended.

CONCLUSION

Patients who could not achieve functional improvement, pain reduction and improvement in quality of life after implantation of a total hip replacement must be identified at an early stage. The results of our study show that with the help of the Oxford Hip Score and Euroquol-5D, which are answered by the patients three months postoperatively, such high risk patients can be identified. This finding is an added value for the further development of the EndoCert certification system and holistic quality assurance in arthroplasties, while the personnel and time effort remain manageable.

Intraoperative damage to surgical gloves during various operations on the musculoskeletal system: a multicenter study

INTRODUCTION

Various orthopedic surgical procedures cause mechanical stress for gloves. In some cases, sharp-edged objects impact on the glove surfaces. The systematic description of lesions is still missing.

METHODS

2289 gloves from 409 surgeries [primary hip and knee arthroplasties (PA), revisions arthroplasties (RA) and arthroscopic shoulder, hip and knee surgery (AY)] from 3 clinics were examined for lesions using water tightening test according to the European norm EN 455-1.

RESULTS

Arthroscopies showed the lowest rate of operations with damaged gloves (6.9%). Depending on clinic, 32.7% and 59.2% of PA surgeries generated damaged gloves, while in RA, these numbers rose to 76.0% and 72.8%, respectively. In PA and RA, the most affected finger was the index finger, whereas in arthroscopies, more damage occurred on the middle finger and the thumb. The size of the lesions was rather small with the vast majority being 1 mm or 2 mm in size.

CONCLUSION

All investigated interventions led to glove lesions. With increasing mechanical stress, the number of glove defects increased. EN 455 does not account for the intraoperative tear risk. Stricter requirements for gloves should be introduced. Glove change intervals should be defined and implemented, and new materials should be developed.

Severe polymicrobial and fungal periprosthetic osteomyelitis persisting after hip disarticulations treated with caspofungin in risk patients: a case series

BACKGROUND

Periprosthetic fungal infections are considered rare and opportunistic infections. Treatment is difficult, and established standards do not yet exist. The choice of the appropriate antifungal drug might affect the patient outcome.

CASES

All the three cases presented showed polybacterial recurrent infection of the revision hip arthroplasty. All patients were of younger age, had multiple revisions of the endoprosthesis, each had a large partial femoral replacement greater than 40% of the femoral length, gentamycin-loaded cement, and a long anchoring distance of the used intramedullary stem. Due to the severe life-threatening infection with deep osteomyelitis, an amputation had to be performed. However, despite surgical intervention, the fungal dominated infection persisted. Finally, only the use of caspofungin allowed permanent infection control.

CONCLUSION

The polybacterial infection is driven by the symbiosis between fungi and bacteria. Therefore, eradication of the fungus is required to achieve elimination of the bacteria. Antimycotics of the echinocandin-class, such as caspofungin, may be considered as initial treatment.

Evaluation of the standard procedure for treatment of periprosthetic joint infections of total knee and hip arthroplasty: a comparison of the 2015 and 2020 census in total joint replacement centres in Germany

BACKGROUND

There are different procedures for both, the diagnosis and the therapy of a periprosthetic joint infection (PJI), however, national or international guidelines for a standardised treatment regime are still lacking. The present paper evaluates the use of the predominant treatment protocols for PJI in certified total joint replacement centres (EPZ) in Germany based on an EndoCert questionnaire.

MATERIALS AND METHODS

The questionnaire was developed in cooperation with the EndoCert Certification Commission to survey the treatment protocols for septic revision arthroplasties in EPZ. Questions targeted the various treatment options including prosthesis preserving procedures (DAIR - Debridement, antibiotics, irrigation, and retention of the prosthesis), one-stage revision, two-stage revision, removal of the endoprosthesis and diagnostic sampling prior to re-implantation. All certified EPZ participated (n = 504) and the results from the current survey in 2020 were compared to data from a previous analysis in 2015.

RESULTS

The number of centres that performed DAIR up to a maximum of 4 weeks and more than 10 weeks after index surgery decreased since 2015, while the number of centres that provided a one-stage revision as a treatment option increased (hip: + 6.3%; knee: + 6.6%). The majority of the centres (73.2%) indicated a 4-8 week period as the preferred interval between prosthesis removal and re-implantation in two-stage revision in hip as well as knee revisions. Centres with a higher number of revision surgeries (> 200 revisions/year), opted even more often for the 4-8 week period (92.3%). In two-stage revision the use of metal-based spacers with/without reinforcement with antibiotic-containing cement as an interim placeholder was significantly reduced in 2020 compared to 2015. There was also a clear preference for cemented anchoring in two-stage revision arthroplasty in the knee in 2020, whereas the majority of hip replacements was cementless. Additionally, in 2020 the number of samples for microbiological testing during the removal of the infected endoprosthesis increased and 72% of the centres took five or more samples. Overall, the number of EPZ with a standardised protocol for the procedure expanded from 2015 to 2020.

CONCLUSION

While there was a trend towards standardised therapeutic algorithms for PJI with more uniform choices among the centres in 2020 compared to 2015, the treatment often remains an individual decision. However, since a consistent treatment regime is of vital importance with an expected rise of total numbers of revision arthroplasties, uniform definitions with regard to comparability and standardisation are necessary for the further development of the EndoCert system.

Is Single Gloving Still Acceptable? Investigation and Evaluation of Damages on Sterile Latex Gloves in General Surgery

(1) Background: The sterile latex surgical glove is an important part of protecting both the patient and the surgical team from infections. However, mechanical stress can damage the integrity of the glove material and thus may lead to infections. (2) Method: A total of 896 gloves from 448 surgeries were tested and evaluated by the water tightening test according to EN455 and ASTM D5151-19. (3) Results: From 448 surgeries, 18.8% of the interventions showed glove damage. In vascular surgery, gloves were damaged in 20.8%, in thoracic surgery 9.1%, in laparoscopic interventions 21.7%, in the subgroup hernia surgeries (TAPP) 17.6% and in open interventions 17.6%. A total of 101 damages were found on 896 gloves; one glove could have several damages. During vascular surgery, 60% of the damages were on the subordinated hand of the surgeon, and 73.3% of the damages had a size of 1 mm. In laparoscopic procedures, the subordinated hand was also more frequently affected (61.3%) than the dominant hand; 64.5% of the damages were 1 mm in size. In the hernia surgery subgroup (TAPP), no damage was larger than 1 mm; 66.7% were in the subordinated hand area. The duration of surgery had no influence on the lesion rate. (4) Conclusion: The damage rate in low impact procedures is high and represents an underestimated problem in soft tissue surgery. The use of single gloving can therefore lead to the risk of infection. EN455 and ASTM D5151-19 does not take into consideration the risk of intraoperative lesions. Double gloving and glove change algorithms should be established.

Periprosthetic Fungal Infections in Severe Endoprosthetic Infections of the Hip and Knee Joint-A Retrospective Analysis of a Certified Arthroplasty Centre of Excellence

The treatment of periprosthetic joint infections (PJI), and especially of re-infections, poses a highly complex problem in orthopaedic surgery. While fungal infections are rare, they present a special challenge. The therapy is often protracted and based on limited evidence. A total of 510 hip and knee revision surgeries were analysed for the occurrence of bacterial and fungal PJI. In patients with PJI, the duration of the hospital stay and the incidence of disarticulation of the infected joint were recorded. Out of the analysed revision arthroplasties, 43.5% were due to PJI. Monomicrobial infection occurred in 55.2%, dual microbial infection in 21.4%, and polymicrobial (≥3 different bacterial or fungal species) infection in 17.2% of the cases. Overall, Candida species were detected in 12.4% cases. Candida albicans was the main fungal pathogen. In 6.9% of cases, disarticulation of the joint was the only option to control PJI. The detection of polymicrobial infection more than doubled in follow-up revisions and there was a strong association between detection of Candida infection and disarticulation (OR 9.39). The majority of fungal infections were mixed infections of bacteria and Candida albicans. The choice of a biofilm penetrating antimycotic, e.g., caspofungin, together with a sufficient standard procedure for detection and surgical treatment can help to control the infection situation. Fungal infection often proves to be more difficult to treat than anticipated and is more frequent than expected.

Increased Diagnostic Certainty of Periprosthetic Joint Infections by Combining Microbiological Results with Histopathological Samples Gained via a Minimally Invasive Punching Technique

Background: The diagnosis of low-grade infections of endoprostheses is challenging. There are still no unified guidelines for standardised diagnostic approaches, recommendations are categorised into major and minor criteria. Additional histopathological samples might sustain the diagnosis. However, ambulatory preoperative biopsy collection is not widespread. Method: 102 patients with hip or knee endoprosthesis and suspected periprosthetic joint infection (PJI) were examined by arthrocentesis with microbiological sample and histopathological punch biopsy. The data were retrospectively analysed for diagnosis concordance. Results: Preoperative microbiology compared to intraoperative results was positive in 51.9% (sensitivity 51.9%, specificity 97.3%). In comparison of preoperative biopsy to intraoperative diagnostic results 51.9% cases were positive (sensitivity 51.9%, specificity 100.0%). The combination of preoperative biopsy and microbiology in comparison to intraoperative results was positive in 70.4% of the cases (sensitivity 70.4%, specificity 97.3%). Conclusion: The diagnosis of PJI is complex. One single method to reliably detect an infection is currently not available. With the present method histopathological samples might be obtained quickly, easily and safely for the preoperative detection of PJI. A combination of microbiological and histopathological sampling increases the sensitivity up to 18.5% to detect periprosthetic infection.

Influence of Metallic Deposition on Ceramic Femoral Heads on the Wear Behavior of Artificial Hip Joints: A Simulator Study

Several retrieval studies have reported on metallic depositions on ceramic femoral heads, but the effect on the wear behavior of artificial hip joints has not been investigated in wear simulator studies. In the present study, retrieved ceramic heads with metallic depositions as third particles were tested against cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners in a hip wear simulator. The amount of liner wear and expansion of metallic depositions on the heads were determined before and after wear testing with digital microscopy. The surface roughness of the heads was investigated in areas with and without metallic depositions by laser scanning microscopy. After five million load cycles, a non-significant reduction in the metallic formation on the retrieved heads was found. The metallic areas showed a higher surface roughness compared to unconcerned areas. The liners showed a higher wear rate of 1.57 ± 1.36 mg/million cycles for 28 mm heads and 2.42 ± 0.82 mg/million cycles for 36 mm heads with metallic depositions, in comparison with new ceramic heads with a 28 mm size ((-0.06 ± 0.89) mg/million cycles) and 36 mm size ((2.04 ± 0.46) mg/million cycles). Metallic transfer on ceramic heads can lead to an increased surface roughness and higher wear rates at the UHMWPE liners. Therefore, metallic contact of the ceramic femoral head should be avoided.

Retrospective Comparative Study of the Influence on Quality of Primary Total Hip Arthroplasty by the EndoCert-Certification System in a Communal Hospital

The EndoCert^®-Initiative system sets specific requirements for the structural, process and result quality in certified Arthroplasty Centers in Germany. However, it remains unclear to what extent the certification process can increase the quality in total hip and knee arthroplasty. Aim of the comparative retrospective study is to analyse the change in quality of total hip arthroplasty in a communal hospital before and after the certification process. All primary total hip arthroplasties (n = 366) between 2013 and 2016 were included in the study retrospectively and grouped by treatment period. Treatment was performed in group 1 without clinical pathways, in group 2 pathway-controlled without a valid certificate and in group 3 pathway-controlled after final completion of the certification process. Outcome quality was analysed using quality indicators defined by the EndoCert-Initiative and further predefined indicators. Results show quality improvement under certified pathway-controlled treatment, e.g. time of surgery, cup and stem positioning, blood transfusion rate, periprosthetic fractures. However, improvements were not significantly in all cases and limitations must be recognized. Positive effects of the certification process legitimate capital investment and efforts. Further quality indicators may be implemented in the certification process to improve quality of treatment in arthroplasty.

Influence of Revision Surgeries and Revision Rate on Quality Indicators in Certified Centres for Joint Replacement (EndoProthetikZentren)

Background The annual report of EndoCert publishes the results of the quality indicators (QI) and key figures of all certified centres for joint replacement (EndoProthetikZentren – EPZ). For some results it seems that centres with fewer revisions might have higher complication rates. However, to avoid misinterpretation the results have to be evaluated in more detail. The influence of the quantity of the revisions or the revision quotient on the quality of outcome was investigated.

Material and Methods This study included all certified EPZ and centres of excellence for joint replacement (EPXmax) (n = 492) and evaluated the data from 2016. Centres beyond the action limit were identified with the help of funnel plots and a confidence limit of 99.7% as action limit. Additionally data of the quality indicators were analysed with ANCOVA. The level of significance was p < 0.05.

Results The comparison by ANCOVA with number of revisions as co-variate showed no differences in the complication rates when related to the quantity of revisions. When considering a so called revision quotient (ratio of revision to all joint replacements) significant differences in the rate of fractures and fissures as well as in mortality for hip replacements and also in mortality for knee replacements were observed.

Conclusion EPZ with fewer revisions do not have higher complication rates than centers with high numbers of revisions. Thus, the quantity of revisions has no influence on the quality of the outcome, considering that on the basis of the data of the EndoCert system no risk adjustment of patient-specific data was performed. Therefore the revisioin quotient of an EPZ shows that quantity is not equal with quality.

Overexpression of the MYB29 transcription factor affects aliphatic glucosinolate synthesis in Brassica oleracea

KEY MESSAGE

Overexpression of BoMYB29 gene up-regulates the aliphatic glucosinolate pathway in Brassica oleracea plants increasing the production of the anti-cancer metabolite glucoraphanin, and the toxic and pungent sinigrin. Isothiocyanates, the bio-active hydrolysis products of glucosinolates, naturally produced by several Brassicaceae species, play an important role in human health and agriculture. This study aims at correlating the content of aliphatic glucosinolates to the expression of genes involved in their synthesis in Brassica oleracea, and perform functional analysis of BoMYB29 gene. To this purpose, three genotypes were used: a sprouting broccoli, a cabbage, and a wild genotype (Winspit), a high glucosinolate containing accession. Winspit showed the highest transcript level of BoMYB28, BoMYB29 and BoAOP2 genes, and BoAOP2 expression was positively correlated with that of the two MYB genes. Further analyses of the aliphatic glucosinolates also showed a positive correlation between the expression of BoAOP2 and the production of sinigrin and gluconapin in Winspit. The Winspit BoMYB29 CDS was cloned and overexpressed in Winspit and in the DH AG1012 line. Overexpressing Winspit plants produced higher quantities of alkenyl glucosinolates, such as sinigrin. Conversely, the DH AG1012 transformants showed a higher production of methylsulphinylalkyl glucosinolates, including glucoraphanin, and, despite an up-regulation of the aliphatic glucosinolate genes, no increase in alkenyl glucosinolates. The latter may be explained by the absence of a functional AOP2 gene in DH AG1012. Nevertheless, an extract of DH AG1012 lines overexpressing BoMYB29 provided a chemoprotective effect on human colon cells. This work exemplifies how the genetic diversity of B. oleracea may be used by breeders to select for higher expression of transcription factors for glucosinolate biosynthesis to improve its natural, health-promoting properties.

Analysis of Cellular Activity Short-Term Exposure to Cobalt and Chromium Ions in Mature Human Osteoblasts

In aseptic loosening of endoprosthetic implants, metal particles, as well as their corrosion products, have been shown to elicit a biological response. Due to different metal alloy components, the response may vary depending on the nature of the released corrosion product. Our study aimed to compare the biological effects of different ions released from metal alloys. In order to mimic the corrosion products, different metal salts (CoCl₂, NiCl₂ and CrCl₃ × 6H₂O) were dissolved and allowed to equilibrate. Human osteoblasts were incubated with concentrations of 10 µM to 500 µM metal salt solutions under cell culture conditions, whereas untreated cells served as negative controls. Cells exposed to CoCr28Mo6 particles served as positive controls. The cell activity and expression of osteogenic differentiation and pro-osteolytic mediators were determined. Osteoblastic activity revealed concentration- and material-dependent influences. Collagen 1 synthesis was reduced after treatment with Co(2+) and Ni(2+). Additionally, exposure to these ions (500 µM) resulted in significantly reduced OPG protein synthesis, whereas RANKL as well as IL-6 and IL-8 secretion were increased. TLR4 mRNA was significantly induced by Co(2+) and CoCr28Mo6 particles. The results demonstrate the pro-osteolytic capacity of metal ions in osteoblasts. Compared to CoCr28Mo6 particles, the results indicated that metal ions intervene much earlier in inflammatory processes.

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.

Comparison of different cell culture plates for the enrichment of non-adherent human mononuclear cells

While tissue-resident monocytes and macrophages are considered to be vital players in the in vivo interaction between biomaterials and surrounding tissue, their isolation is limited. In order to establish in vitro models elucidating implant and tissue interactions, peripheral blood mononuclear cells (PBMCs) represent a viable source for bone marrow-derived monocytes and an alternative to tissue-resident cells. The aim of present study was to analyse different adhesion-preventing tissue culture plates for their potential to facilitate the culture of monocytes without differentiation into macrophages. Freshly isolated PBMCs were seeded into four commercially available tissue culture plates with different adhesive properties and were tested for surface CD14 and CD68 expression using flow cytometry following 7 days in culture. When PBMCs were cultivated in RPMI on Cellstar^® Cell culture plates with Cell-Repellent Surface, a significant increase in CD14-positive cells was observed compared with cultivation in standard tissue culture-treated plates. This was accompanied by elevated cytokine production of interleukin-6 (IL6) and interleukin-8 (IL8); however, overall cell growth was not affected. When PBMCs were pre-cultured in cell-repellent plates, there was a higher yield of adherent cells after subsequent transfer into standard tissue culture-treated plates. Cultivation of PBMCs on cell-repellent culture plates favoured a monocytic phenotype and thus, represents an alternative to increase the fraction of monocytes yielded from PBMCs.

In Vitro Analysis of the Differentiation Capacity of Postmortally Isolated Human Chondrocytes Influenced by Different Growth Factors and Oxygen Levels

OBJECTIVE

In the present in vitro study, we analyzed the chondrogenic differentiation capacity of human chondrocytes postmortally isolated from unaffected knee cartilage by the addition of transforming growth factor-β1 (TGF-β1) and/or insulin-like growth factor-1 (IGF-1) and different oxygen levels.

DESIGN

After 14 and 35 days, DNA concentrations and protein contents of Col1, Col2, aggrecan as well as glycosaminoglycans (GAGs) of chondrocytes cultivated as pellet cultures were analyzed. Additionally, expression rates of mesenchymal stem cell (MSC)-associated differentiation markers were assessed in monolayer cultures.

RESULTS

All cultivated chondrocytes were found to be CD29⁺/CD44⁺/CD105⁺/CD166⁺. Chondrocytic pellets stimulated with TGF-β1 showed enhanced synthesis rates of hyaline cartilage markers and reduced expression of the non-hyaline cartilage marker Col1 under hypoxic culture conditions.

CONCLUSIONS

Our results underline the substantial chondrogenic potential of human chondrocytes postmortally isolated from unaffected articular knee cartilage especially in case of TGF-β1 administration.

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.

Effects of Build Orientation on Surface Morphology and Bone Cell Activity of Additively Manufactured Ti6Al4V Specimens

Additive manufacturing of lightweight or functional structures by selective laser beam (SLM) or electron beam melting (EBM) is widespread, especially in the field of medical applications. SLM and EBM processes were applied to prepare Ti6Al4V test specimens with different surface orientations (0°, 45° and 90°). Roughness measurements of the surfaces were conducted and cell behavior on these surfaces was analyzed. Hence, human osteoblasts were seeded on test specimens to determine cell viability (metabolic activity, live-dead staining) and gene expression of collagen type 1 (Col1A1), matrix metalloprotease (MMP) 1 and its natural inhibitor, TIMP1, after 3 and 7 days. The surface orientation of specimens during the manufacturing process significantly influenced the roughness. Surface roughness showed significant impact on cellular viability, whereas differences between the time points day 3 and 7 were not found. Collagen type 1 mRNA synthesis rates in human osteoblasts were enhanced with increasing roughness. Both manufacturing techniques further influenced the induction of bone formation process in the cell culture. Moreover, the relationship between osteoblastic collagen type 1 mRNA synthesis rates and specimen orientation during the building process could be characterized by functional formulas. These findings are useful in the designing of biomedical applications and medical devices.

Inflammatory Response of Human Peripheral Blood Mononuclear Cells and Osteoblasts Incubated With Metallic and Ceramic Submicron Particles

Inflammatory reactions associated with osteolysis and aseptic loosening are the result of wear particles generated at the articulating surfaces of implant components. The aim of the present study was to analyze the biological response of human osteoblasts and peripheral blood mononuclear cells (PBMCs) after exposure to metallic and alumina ceramic particles regarding cellular differentiation, cytokine release, and monocyte migration. Cells were exposed to particles (0.01 and 0.05 mg/ml) from an alumina matrix composite (AMC) ceramic and a CoCr28Mo6 alloy with an average size of 0.5 µm over 48 and 96 h. The expression rates of osteogenic (Col1A1, ALP) and pro-osteoclastic (RANK, Trap5b) differentiation markers as well as pro-osteolytic mediators (MMP-1, TIMP-1, IL-6, IL-8, MCP-1) were determined and soluble protein concentrations of active MMP-1, IL-6, IL-8, and pro-collagen type 1 in cell culture supernatants were evaluated. Additionally, the capacity of particle-treated osteoblasts to attract potentially pro-inflammatory cells to the site of particle exposure was investigated by migration assays using osteoblast-conditioned media. The cellular morphology and metabolism of human osteoblasts and adherent PBMCs were influenced by particle type and concentration. In human osteoblasts, Col1A1 expression rates and protein production were significantly reduced after exposing cells to the lower concentration of cobalt-chromium (CoCr) and AMC particles. Exposure to AMC particles (0.01 mg/ml) resulted in increased mRNA levels of RANK and Trap5b in adherent PBMCs. For MMP-1 gene expression, elevated levels were more prominent after incubation with CoCr compared to AMC particles in osteoblasts, which was not reflected by the protein data. Interleukin (IL)-6 and IL-8 mRNA and protein were induced in both cell types after treatment with AMC particles, whereas exposure to CoCr particles resulted in significantly upregulated IL-6 and IL-8 protein contents in PBMCs only. Exposure of osteoblasts to CoCr particles reduced the chemoattractant potential of osteoblast-conditioned medium. Our results demonstrate distinct effects of AMC and CoCr particles in human osteoblasts and PBMCs. Complex cell and animal models are required to further evaluate the impact of cellular interactions between different cell types during particle exposure.

The Impact of Metal Ion Exposure on the Cellular Behavior of Human Osteoblasts and PBMCs: In Vitro Analyses of Osteolytic Processes

Osteolysis in the periprosthetic tissue can be caused by metallic wear particles and ions that can originate from implant surface corrosion. These products influence cellular behavior and stimulate the expression of proinflammatory cytokines. The purpose of this study was to evaluate the impact of CoCr29Mo6 ions on cell survival, differentiation, and cytokine expression in human osteoblasts and peripheral blood mononuclear cells (PBMCs). Thus, we exposed cells with a mixture of 200 µg/L ion solution and determined cell viability and apoptosis/necrosis. Gene expression analyses of osteoblastic and osteoclastic differentiation markers as well as pro-osteolytic mediators (IL-6, IL-8, TNF-α, MCP-1, MMP1, TIMP1) were performed. These markers were also investigated in mixed cultures of adherent and non-adherent PBMCs as well as in co-cultures of human osteoblasts and PBMCs. The ion solution induced necrosis in osteoblasts and PBMCs in single cultures. All examined mediators were highly expressed in the co-culture of osteoblasts and PBMCs whereas in the single cell cultures only IL-6, IL-8, and MMP1 were found to be stimulated. While the applied concentration of the CoCr29Mo6 ion solutions had only marginal effects on human osteoblasts and PBMCs alone, the co-culture may provide a comprehensive model to study osteolytic processes in response to Co and Cr ions.

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.

Impact of increasing fruit and vegetables and flavonoid intake on the human gut microbiota

Epidemiological studies have shown protective effects of fruits and vegetables (F&V) in lowering the risk of developing cardiovascular diseases (CVD) and cancers. Plant-derived dietary fibre (non-digestible polysaccharides) and/or flavonoids may mediate the observed protective effects particularly through their interaction with the gut microbiota. The aim of this study was to assess the impact of fruit and vegetable (F&V) intake on gut microbiota, with an emphasis on the role of flavonoids, and further to explore relationships between microbiota and factors associated with CVD risk. In the study, a parallel design with 3 study groups, participants in the two intervention groups representing high-flavonoid (HF) and low flavonoid (LF) intakes were asked to increase their daily F&V intake by 2, 4 and 6 portions for a duration of 6 weeks each, while a third (control) group continued with their habitual diet. Faecal samples were collected at baseline and after each dose from 122 subjects. Faecal bacteria enumeration was performed by fluorescence in situ hybridisation (FISH). Correlations of dietary components, flavonoid intake and markers of CVD with bacterial numbers were also performed. A significant dose X treatment interaction was only found for Clostidium leptum-Ruminococcus bromii/flavefaciens with a significant increase after intake of 6 additional portions in the LF group. Correlation analysis of the data from all 122 subjects independent from dietary intervention indicated an inhibitory role of F&V intake, flavonoid content and sugars against the growth of potentially pathogenic clostridia. Additionally, we observed associations between certain bacterial populations and CVD risk factors including plasma TNF-α, plasma lipids and BMI/waist circumference.

Rifaximin modulates the colonic microbiota of patients with Crohn's disease: an in vitro approach using a continuous culture colonic model system

OBJECTIVES

Rifaximin, a rifamycin derivative, has been reported to induce clinical remission of active Crohn's disease (CD), a chronic inflammatory bowel disorder. In order to understand how rifaximin affects the colonic microbiota and its metabolism, an in vitro human colonic model system was used in this study.

METHODS

We investigated the impact of the administration of 1800 mg/day of rifaximin on the faecal microbiota of four patients affected by colonic active CD [Crohn's disease activity index (CDAI > 200)] using a continuous culture colonic model system. We studied the effect of rifaximin on the human gut microbiota using fluorescence in situ hybridization, quantitative PCR and PCR-denaturing gradient gel electrophoresis. Furthermore, we investigated the effect of the antibiotic on microbial metabolic profiles, using (1)H-NMR and solid phase microextraction coupled with gas chromatography/mass spectrometry, and its potential genotoxicity and cytotoxicity, using Comet and growth curve assays.

RESULTS

Rifaximin did not affect the overall composition of the gut microbiota, whereas it caused an increase in concentration of Bifidobacterium, Atopobium and Faecalibacterium prausnitzii. A shift in microbial metabolism was observed, as shown by increases in short-chain fatty acids, propanol, decanol, nonanone and aromatic organic compounds, and decreases in ethanol, methanol and glutamate. No genotoxicity or cytotoxicity was attributed to rifaximin, and conversely rifaximin was shown to have a chemopreventive role by protecting against hydrogen peroxide-induced DNA damage.

CONCLUSIONS

We demonstrated that rifaximin, while not altering the overall structure of the human colonic microbiota, increased bifidobacteria and led to variation of metabolic profiles associated with potential beneficial effects on the host.

In vitro evaluation of the fermentation properties and potential prebiotic activity of Agave fructans

AIMS

This study was carried out to evaluate in vitro the fermentation properties and the potential prebiotic activity of Agave-fructans extracted from Agave tequilana (Predilife).

METHODS AND RESULTS

Five different commercial prebiotics were compared using 24-h pH-controlled anaerobic batch cultures inoculated with human faecal slurries. Measurement of prebiotic efficacy was obtained by comparing bacterial changes, and the production of short-chain fatty acids (SCFA) was also determined. Effects upon major groups of the microbiota were monitored over 24 h incubations by fluorescence in situ hybridization. SCFA were measured by HPLC. Fermentation of the Agave fructans (Predilife) resulted in a large increase in numbers of bifidobacteria and lactobacilli.

CONCLUSIONS

Under the in vitro conditions used, this study has shown the differential impact of Predilife on the microbial ecology of the human gut.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study reporting of a potential prebiotic mode of activity for Agave fructans investigated which significantly increased populations of bifidobacteria and lactobacilli compared to cellulose used as a control.

Potential prebiotic activity of oligosaccharides obtained by enzymatic conversion of durum wheat insoluble dietary fibre into soluble dietary fibre

BACKGROUND AND AIMS

Epidemiological evidence indicates that cereal dietary fibre (DF) may have several cardiovascular health benefits. The underlying mechanisms have not yet been elucidated. Here, the potential nutritional effects of physico-chemical properties modifications of durum wheat dietary fibre (DWF) induced by enzyme treatment have been investigated.

METHODS AND RESULTS

The conversion of the highly polymerised insoluble dietary fibre into soluble feruloyl oligosaccharides of DWF was achieved by a tailored enzymatic treatment. The in vitro fermentation and release of ferulic acid by intestinal microbiota from DWF before and after the enzymatic treatment were assessed using a gut model validated to mimic the human colonic microbial environment. Results demonstrated that, compared to DWF, the enzyme-treated DWF (ET-DWF) stimulated the growth of bifidobacteria and lactobacilli. Concurrently, the release of free ferulic acid by ET-DWF was almost three times higher respect to the control. No effect on the formation of short chain fatty acids was observed.

CONCLUSIONS

The conversion of insoluble dietary fibre from cereals into soluble dietary fibre generated a gut microbial fermentation that supported bifidobacteria and lactobacilli. The concurrent increase in free ferulic acid from the enzyme-treated DWF might result in a higher plasma ferulic acid concentration which could be one of the reasons for the health benefits reported for dietary fibre in cardiovascular diseases.

In vitro fermentation of carbohydrates by porcine faecal inocula and their influence on Salmonella Typhimurium growth in batch culture systems

The aim of this study was to evaluate in vitro the influence of fermentable carbohydrates on the activity of porcine microbiota and survival of Salmonella Typhimurium in a batch culture system simulating the porcine hindgut. The carbohydrates tested were xylooligosaccharides, a mixture of fructooligosaccharides/inulin (FIN), fructooligosaccharides (FOS), gentiooligosaccharides (GEO) and lactulose (LAC). These ingredients stimulated the growth of selected Bifidobacterium and Lactobacillus species in pure cultures. In batch cultures, the carbohydrates influenced some fermentation parameters. For example, GEO and FIN significantly increased lactic acids compared with the control (no added carbohydrate). With the exception of LAC, the test carbohydrates increased the production of short-chain fatty acid (SCFA) and modified SCFA profiles. Quantitative analysis of bacterial populations by FISH revealed increased counts of the Bifidobacterium group compared with control and, with exception of FOS, increased Lactobacillus, Leuconostoc and Weissella spp. counts. Salmonella numbers were the lowest during the fermentation of LAC. This work has looked at carbohydrate metabolism by porcine microbiota in a pH-controlled batch fermentation system. It provides an initial model to analyse interactions with pathogens.

Fecal water as a non-invasive biomarker in nutritional intervention: comparison of preparation methods and refinement of different endpoints

The assessment of cellular effects by the aqueous phase of human feces (fecal water, FW) is a useful biomarker approach to study cancer risks and protective activities of food. In order to refine and develop the biomarker, different protocols of preparing FW were compared. Fecal waters were prepared by 3 methods: (A) direct centrifugation; (B) extraction of feces in PBS before centrifugation; and (C) centrifugation of lyophilized and reconstituted feces. Genotoxicity was determined in colon cells using the Comet assay. Selected samples were investigated for additional parameters related to carcinogenesis. Two of 7 FWs obtained by methods A and B were similarly genotoxic. Method B, however, yielded higher volumes of FW, allowing sterile filtration for long-term culture experiments. Four of 7 samples were non-genotoxic when prepared according to all 3 methods. FW from lyophilized feces and from fresh samples were equally genotoxic. FWs modulated cytotoxicity, paracellular permeability, and invasion, independent of their genotoxicity. All 3 methods of FW preparation can be used to assess genotoxicity. The higher volumes of FW obtained by preparation method B greatly enhance the perspectives of measuring different types of biological parameters and using these to disclose activities related to cancer development.

Whole-grain wheat breakfast cereal has a prebiotic effect on the human gut microbiota: a double-blind, placebo-controlled, crossover study

Epidemiological studies have shown an inverse association between dietary intake of whole grains and the risk of chronic disease. This may be related to the ability to mediate a prebiotic modulation of gut microbiota. However, no studies have been conducted on the microbiota modulatory capability of whole-grain (WG) cereals. In the present study, the impact of WG wheat on the human intestinal microbiota compared to wheat bran (WB) was determined. A double-blind, randomised, crossover study was carried out in thirty-one volunteers who were randomised into two groups and consumed daily 48 g breakfast cereals, either WG or WB, in two 3-week study periods, separated by a 2-week washout period. Numbers of faecal bifidobacteria and lactobacilli (the target genera for prebiotic intake), were significantly higher upon WG ingestion compared with WB. Ingestion of both breakfast cereals resulted in a significant increase in ferulic acid concentrations in blood but no discernible difference in faeces or urine. No significant differences in faecal SCFA, fasting blood glucose, insulin, total cholesterol (TC), TAG or HDL-cholesterol were observed upon ingestion of WG compared with WB. However, a significant reduction in TC was observed in volunteers in the top quartile of TC concentrations upon ingestion of either cereal. No adverse intestinal symptoms were reported and WB ingestion increased stool frequency. Daily consumption of WG wheat exerted a pronounced prebiotic effect on the human gut microbiota composition. This prebiotic activity may contribute towards the beneficial physiological effects of WG wheat.

Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients

BACKGROUND

Animal studies suggest that prebiotics and probiotics exert protective effects against tumor development in the colon, but human data supporting this suggestion are weak.

OBJECTIVE

The objective was to verify whether the prebiotic concept (selective interaction with colonic flora of nondigested carbohydrates) as induced by a synbiotic preparation-oligofructose-enriched inulin (SYN1) + Lactobacillus rhamnosus GG (LGG) and Bifidobacterium lactis Bb12 (BB12)-is able to reduce the risk of colon cancer in humans.

DESIGN

The 12-wk randomized, double-blind, placebo-controlled trial of a synbiotic food composed of the prebiotic SYN1 and probiotics LGG and BB12 was conducted in 37 colon cancer patients and 43 polypectomized patients. Fecal and blood samples were obtained before, during, and after the intervention, and colorectal biopsy samples were obtained before and after the intervention. The effect of synbiotic consumption on a battery of intermediate bio-markers for colon cancer was examined.

RESULTS

Synbiotic intervention resulted in significant changes in fecal flora: Bifidobacterium and Lactobacillus increased and Clostridium perfringens decreased. The intervention significantly reduced colorectal proliferation and the capacity of fecal water to induce necrosis in colonic cells and improve epithelial barrier function in polypectomized patients. Genotoxicity assays of colonic biopsy samples indicated a decreased exposure to genotoxins in polypectomized patients at the end of the intervention period. Synbiotic consumption prevented an increased secretion of interleukin 2 by peripheral blood mononuclear cells in the polypectomized patients and increased the production of interferon gamma in the cancer patients.

CONCLUSIONS

Several colorectal cancer biomarkers can be altered favorably by synbiotic intervention.

Bovine eotaxin (CCL11)--an unusual member of the eotaxin group--attracts eosinophils in vitro but is not responsible for eosinophilia in the ovary

Under physiological conditions normally characterised by low tissue infiltration of eosinophils, a conspicuous number of these cells are attracted into the human and ruminant ovary. Eosinophils suddenly increase in the thecal layer of the preovulatory follicle and corpus luteum at very early development. Currently, we only have a limited understanding of the mechanism for the recruitment of the ovarian eosinophils. Eotaxin (CCL11) may be one of the chemoattractants involved in stimulating eosinophils to migrate selectively into ovary. As a prerequisite for the analysis of eotaxin expression in the bovine ovary, we determined the complete bovine eotaxin mRNA sequence since it was not available from databases. The bovine eotaxin is the first member of the monocyte chemoattractant protein (MCP)/eotaxin subfamily with two mRNA isoforms varying in length in the untranslated 3'-untranslated region. The unusual amino-acid sequence of bovine eotaxin contains structural features that are so far known to be characteristic for MCP, but not eotaxin. In our microchemotaxis assays, recombinant bovine eotaxin showed a functional pattern orthologous to known eotaxins. Thus, the chimeric structure of bovine eotaxin did not affect the favoured chemotactic activity on eosinophils. Semiquantitative RT-PCR was used to investigate the expression of eotaxin in different regions of the bovine ovary. We only detected faint eotaxin mRNA signals that did not indicate physiological significance even in stimulated granulosa cell cultures, follicle-derived macrophages or fibroblasts. Taken together, bovine eotaxin attracts eosinophils in vitro but is not responsible for eosinophilia in the ovary. Its unusual chimeric structure confirms the unity of the MCP/eotaxin subfamily of CC chemokines and distinguishes it from other CC chemokine subfamilies.

Fecal Water Genotoxicity Is Predictive of Tumor-Preventive Activities by Inulin-Like Oligofructoses, Probiotics (Lactobacillus rhamnosus and Bifidobacterium lactis), and Their Synbiotic Combination

The measurement of fecal water genotoxicity in human colon cells could be a useful biomarker to study effects of diet in the colon. Here we assessed aqueous fecal extracts of samples from a chronic study with rats fed prebiotics, probiotics, and their combination. Treatments were maltodextrins (controls), inulin/oligofructoses (prebiotic), Lactobacillus rhamnosus, and Bifidobacterium lactis (probiotics) or both (synbiotic). Azoxymethane (AOM) was administered to initiate tumors. Rat feces were collected at 0 and 10 days and 2, 4, and 8 mo, and cecal contents were collected at 8 mo. Aqueous phases were prepared and tested for genotoxicity in HT29 colon cells using the comet assay. The studied types of intervention reduced fecal and cecal genotoxicity. DNA damage by samples from AOM-treated, tumor-free rats was significantly lower than from tumor-bearing animals, especially after 4 mo of synbiotic and prebiotic interventions. Inulin-based diets reduced exposure to genotoxins in the feces, directly reflecting the reported reduction of tumor incidence in these animals. Evidence is provided for the validity of this measurement as a biomarker of chemoprevention because 1) fecal water genotoxicity reflected genotoxic exposure in the cecum, 2) tumor incidence and fecal genotoxicity were directly related, and 3) these interventions reduced tumor risks by reducing exposure to genotoxins in the gut.

Expression of glutathione S-transferases (GSTs) in human colon cells and inducibility of GSTM2 by butyrate

The glutathione S-transferases (GSTs) are a multigene family of enzymes largely involved in the detoxification of chemicals. In animals, enhanced expression is mediated by products of gut fermentation. Of these, butyrate induces GSTP1 protein expression and GST activity in the human colon tumor cell line HT29. The aim of the following investigations was to further elucidate butyrate-modulated induction of additional colonic GSTs in HT29 and to determine baseline expression in non-transformed cells, isolated from human colorectal tissue. We measured five GST protein subunits (GSTA1/2-composed of GST A1-1, A1-2 and A2-2-GSTM1, GSTM2, GSTP1, GSTT1) by western blot, GST activity using 1-chloro-2,4-dinitrobenzene as substrate and GSTM2 mRNA expression with RT-PCR. GSTP1, followed by GSTT1, were major subunits in all colon cells. Cells isolated from colon tissue were identified to be colonocytes and colon fibroblasts, both of which also expressed substantial levels of GSTM1 and GSTM2. The inter-individual variation of GST subunits in coloncytes of 15 individuals was marked, with total GST protein per 106 cells differing by more than a factor of four. In HT29, butyrate significantly enhanced GSTA1/2 (3.5-fold), GSTM2 (not detectable in controls), GSTP1 (1.5-fold) and GST activity (1.4-fold), but not GSTM1 or GSTT1. GSTM2 mRNA expression was significantly induced after 24 ( approximately 14-fold) and 72 h treatment ( approximately 8-fold). In colon fibroblasts, butyrate (4 mM, 72 h) also induced GSTM2 protein (1.7-fold) and GST activity (1.4-fold). Colonocytes were too short lived to be used for inducibility studies. In conclusion, GSTs are expressed with high inter-individual variability in human colonocytes. This points to large differences in cellular susceptibility to xenobiotics. However, butyrate, an important luminal component produced from fermentation of dietary fibers, is an efficient inducer of GSTs and especially of GSTM2. This indicates that butyrate may act chemoprotectively by increasing detoxification capabilities in the colon mucosa.

Iron-overload induces oxidative DNA damage in the human colon carcinoma cell line HT29 clone 19A

Dietary iron may contribute to colon cancer risk via production of reactive oxygen species (ROS). The aim of the study was to determine whether physiological ferric/ferrous iron induces oxidative DNA damage in human colon cells. Therefore, differentiated human colon tumour cells (HT29 clone 19A) were incubated with ferric-nitrilotriacetate (Fe-NTA) or with haemoglobin and DNA breaks and oxidised bases were determined by microgelelectrophoresis. The effects of Fe-NTA were measured with additional H(2)O(2) (75microM) and quercetin (25-100microM) treatment. Analytic detection of iron in cell cultures, treated with 250microM Fe-NTA for 15 min to 24h, showed that 48.02+/-5.14 to 68.31+/-2.11% were rapidly absorbed and then detectable in the cellular fraction. Fe-NTA (250-1000microM) induced DNA breaks and oxidised bases, which were enhanced by subsequent H(2)O(2) exposure. Simultaneous incubation of HT29 clone 19A cells with Fe-NTA and H(2)O(2) for 15 min, 37 degrees C did not change the effect of H(2)O(2) alone. The impact of Fe-NTA and H(2)O(2)-induced oxidative damage is reduced by the antioxidant quercetin (75-67% of H(2)O(2)-control). Haemoglobin was as effective as Fe-NTA in inducing DNA damage. From these results we can conclude that iron is taken up by human colon cells and participates in the induction of oxidative DNA damage. Thus, iron or its capacity to catalyse ROS-formation, is an important colon cancer risk factor. Inhibition of damage by quercetin reflects the potential of antioxidative compounds to influence this risk factor. Quantitative data on the genotoxic impact of ferrous iron (e.g. from red meat) relative to the concentrations of antioxidants (from plant foods) in the gut are now needed to determine the optimal balance of food intake that will reduce exposure to this type of colon cancer risk factor.

The aspartic proteinase from the rodent parasite Plasmodium berghei as a potential model for plasmepsins from the human malaria parasite, Plasmodium falciparum

The gene encoding an aspartic proteinase precursor (proplasmepsin) from the rodent malaria parasite Plasmodium berghei has been cloned. Recombinant P. berghei plasmepsin hydrolysed a synthetic peptide substrate and this cleavage was prevented by the general aspartic proteinase inhibitor, isovaleryl pepstatin and by Ro40-4388, a lead compound for the inhibition of plasmepsins from the human malaria parasite Plasmodium falciparum. Southern blotting detected only one proplasmepsin gene in P. berghei. Two plasmepsins have previously been reported in P. falciparum. Here, we describe two further proplasmepsin genes from this species. The suitability of P. berghei as a model for the in vivo evaluation of plasmepsin inhibitors is discussed.

Assembly of phosphofructokinase-1 from Saccharomyces cerevisiae in extracts of single-deletion mutants

Phosphofructokinase-1 from Saccharomyces cerevisiae is an octameric enzyme comprising two non-identical subunits, alpha and beta, which are encoded by the unlinked genes PFK1 and PFK2. In this paper, assembly and reactivation of the enzyme have been studied in cell-free extracts of single-deletion mutants. In contrast to the previously described lack of phosphofructokinase-1 activity in cell-free extracts of these mutants, we could measure a temporary enzyme activity immediately after lysis of protoplasts. This result supports the assumption that each of the subunits forms an enzyme structure which is active in vivo but not stable after cell disruption. Upon mixing of separately prepared cell-free extracts of both deletion mutants very low activity could be measured. About 40% of the wild-type activity was regained when both mutants were mixed prior to disruption. The reactivation rate could be slightly increased by addition of ATP and fructose 6-phosphate and was found to be a function of the growth state, particularly of the beta-subunit-carrying cells. The individual subunits did not interact with Cibacron Blue F3G-A, a biomimetic ligand of phosphofructokinase-1. After reassembly of both subunits in vitro a strong affinity of the reconstituted phosphofructokinase-1 to the dye-ligand was observed. The inability of the subunits to reconstitute under certain conditions seems to result from alterations of the intracellular environment following disruption. These changes give rise to induce an unproductive side reaction like self-aggregation of the subunits. Because reconstitution of phosphofructokinase-1 from S. cerevisiae behaves in a similar way to that of hemoglobin and luciferase, we would speculate a general mechanism for assembly of oligomeric proteins in vivo.