A Randomized Clinical Trial on the Use of Antiseptic Solutions for the Pin-Site Care of External Fixators: Chlorhexidine-Alcohol Versus Povidone-Iodine.

Pin-site infections remain a common clinical complication in patients with external fixators. Pin-site care is commonly performed with either chlorhexidine-alcohol solution or povidone-iodine solution. This study aimed to investigate the superiority of chlorhexidine-alcohol solution versus povidone-iodine solution for external fixator pin-site care in pin-site infection. This prospective randomized clinical trial using an open, parallel-group design was conducted in a single Spanish hospital. Eligible consenting patients from November 2018 to May 2019 who underwent placement of an external fixator were included. Patients were randomly assigned to receive pin-site care using either a 2% chlorhexidine-alcohol solution or a 10% povidone-iodine solution. The primary endpoint was the development of a pin-site infection. In total, 568 pins were analyzed (128 patients, with a mean of 4.3 pins per patient). No significant differences were found between groups. However, statistically significant differences were found regarding time and infection variables. The longer the person had the fixator, the higher the risk of infection, t(x) = 5.49, p = .002. Both chlorhexidine-alcohol and povidone-iodine solutions are equally effective antiseptic agents for the prevention of infections in external fixators.

A qualitative method for testing the antimicrobial ability of osteosynthetic fixation material by simulating in vitro contamination by Staphylococcus aureus.

External fixators of serious fractures could be an attractive substrate on which microorganisms can accumulate. Therefore, this study aimed to develop a suitable method for enabling the simulation of a real situation when osteosynthetic fixation material is open for the potential threat of bacterial attack. Agar-based media represented human tissue, and the metallic pin characterized the screw in the fixation. Various types of agar, supplements, and contamination strategy by Staphylococcus aureus were tested. The influence of the initial bacterial concentration was also examined. Surfaces were observed by scanning electron microscopy (SEM), and all results were compared. Brain Heart Infusion Agar with the Egg Yolk Tellurite Emulsion was established in a transparent test tube as a suitable system for enabling the good interpretability of bacterial contamination in the pin's surroundings. Pin contamination has been found to be an appropriate approach for testing microbial growth, rather than agar surface contamination, which distorted obtained results. A lower initial colony forming units (CFU) provided better clarity of the test. SEM observation of the pin surface was comparable with the visual evaluations in the test tubes. Results were assembled for positive and negative control samples as well. Screening method for the most common bacteria S. aureus has been standardized and developed. This experimental setup could also be a useful tool for surface modification with antibacterial properties testing.

Is the proximity of external fixator pins to eventual definitive fixation implants related to the risk of deep infection in the staged management of tibial pilon fractures?

INTRODUCTION: In the staged management of tibial pilon fractures, overlap between definitive internal fixation and external fixation pin sites has been investigated as a risk factor for infection with equivocal conclusions. Our aim was to determine if overlap or proximity of definitive internal fixation to external fixation pin sites influences the risk of deep infection. PATIENTS AND METHODS: We reviewed 280 AO/OTA 43B or 43C type distal tibia fractures in 277 patients at two level-one trauma centers. Patients underwent staged management using early temporizing external fixation followed by definitive open reduction and plate fixation. Primary outcome was the association between pin site overlap and the development of deep infection. Secondary outcome was the relationship between development of deep infection and the distance from pin site to definitive fixation. RESULTS: The average duration between external fixation and definitive internal fixation was 14 days. 24% of fractures developed deep infection requiring surgical intervention. There was no association between pin site overlap and the development of deep infection (p = 0.18). There was no relationship between infection and the distance between proximal plate extent and pin site (p = 0.13). DISCUSSION: We identified no association between pin site overlap and the development of deep infection. We suggest that temporizing external fixation pins should be placed so as to obtain optimal stability of the construct with lesser emphasis on aiming to be absolutely outside the zone of future fixation. LEVEL OF EVIDENCE: Level III Therapeutic Retrospective Comparative study.

Pin tract infection prophylaxis and treatment.

Pin tract infection in external fixation (ExFix) is a frequent finding which can eventually lead to loosening, osteomyelitis and loss of fixation. Its diagnosis is based on high empiricism and low validity, although it is possible to distinguish between minor and major infection. The first is limited to soft tissues, whereas the latter includes bone involvement. The rate of infection after conversion of external fixation to intramedullary nailing (IMN) is not well known. Unfortunately, papers referring to infection after the conversion of ExFix to intramedullary nailing (IMN) are of evidence level IV or V. It is suggested that conversion of ExFix to IMN should be carried out in a 2 step regimen. The time interval of 2 step regimen is uncertain although some authors have recommended to occur within 9 days. There is no consensus as to which prophylaxis protocol should be applied prior to conversion. In order to throw more light into this important issue, registries capturing important related parameters to the development of infection should be established.

No role for antiseptics in routine pin site care in Ilizarov fixators: A randomised prospective single blinded control study.

INTRODUCTION: Pin site infection is the commonest complication of Ilizarov external fixation. The aim of the study was to examine if use of antiseptics was superior over control and further if daily dressing was superior to weekly dressing in regular pin site care in reducing the burden of pin site infection in Ilizarov fixators. PATIENTS AND METHODS: A total of 114 patients (2363 pin sites) were randomised to receive regular pin site care alone (30 patients, 638 pin sites) or with additional application of povidone iodine (27 patients, 561 pin sites), silver sulfadiazine (27 patients, 570 pin sites) and chlorhexidine (30 patients, 594 pin sites). The pin tracts were sub-randomised to receive daily (1212 pin sites) or weekly (1151 pin sites) dressings. The primary outcome was pin site infection days rate across all four groups. The secondary outcomes were - mean duration to first episode of infection, differences between daily and weekly dressing groups, mean duration of antibiotic therapy and incidence of re-interventions and sequelae. We also recorded frequency of bacterial pathogens in all microbiological samples submitted. Block randomization using computer-generated random numbers was used. The assessor of outcome was blinded. RESULTS: All patients completed the study. Pin site infection rate days per 1000 pin site days observed was marginally less in chlorhexidine group, but was not statistically significant compared to other antiseptics and control group (Absolute value in control, povidone iodine, silver sulphadiazine and chlorhexidine groups were respectively 2.04 ± 4.27, 2.04 ± 3.65, 1.85 ± 3.37, 1.37 ± 2.35, p value 0.92). Daily dressing category showed slightly less pin site infection days rate within each group and overall, but this was also not statistically significant (1.56 ± 3.99 versus 2.10 ± 5.1, p value 0.35). There was no statistically significant difference among the groups with regard to other secondary outcomes. Methicillin Sensitive Staphylococcus aureus was the most common bacterial pathogen isolated. CONCLUSION: Use of antiseptics does not offer any advantage in regular pin site care in Ilizarov external fixation and daily pin site care is not superior to weekly pin site care. Empirical therapy in early and low grade pin site infections must be targeted against Staphylococcus.

Cure of recurring Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae septic shock episodes due to complicated soft tissue infection using a ceftazidime and avibactam-based regimen: a case report.

BACKGROUND: Infections caused by multidrug-resistant Enterobacteriaceae are hard to treat and life-threatening due to reduced therapeutic options. Systemic infections caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae strains have increased in many European regions, becoming frequent in many clinical settings, and are associated with high mortality. The co-formulation of ceftazidime, a third-generation cephalosporin, with avibactam, a new suicide inhibitor beta-lactamase inhibitor able to block most Klebsiella pneumoniae carbapenemases, has been recently licensed, with promising results in patients with limited or absent therapeutic options. Little is known, however, as to the efficacy of such a combination in patients with soft tissue infections caused by multidrug-resistant Klebsiella pneumoniae carbapenemase-producing strains of Klebsiella pneumoniae. CASE PRESENTATION: A Caucasian 53-year-old man with paraplegia suffered multiple vertebral fractures due to a car crash. He was treated with external fixators that became infected early after insertion and were repeatedly and inefficiently treated with multiple antibiotics. He suffered repeated septic episodes caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae strains with a multidrug-resistant profile. Meropenem, tigecycline, and colistin combinations allowed only temporary improvements, but septic shock episodes recurred, in spite of removal of infected external fixators. After approval of pre-marketing prescription by our local Ethics Committee, full clinical resolution was obtained with a compassionate treatment using meropenem and ceftazidime/avibactam in combination for 16 days. CONCLUSIONS: Our experience provides additional evidence that ceftazidime/avibactam, possibly in combination with meropenem rescued by avibactam, may be an efficacious treatment option also for complicated skin and soft tissue infections caused by multidrug-resistant strains of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae.

Infected tibial nonunion in children: Is radical debridement mandatory?

Nonunion is a devastating complication of tibial fractures with a debilitating effect. Several studies reporting tibial nonunions in adults are available; however, the reports on infected nonunions in children are scarce. The purpose of this study was to evaluate the results of treating paediatric infected tibial nonunion using Ilizarov fixator without radical resection. MATERIALS AND METHODS: The study included 36 cases with infected nonunion of the tibia with 31 males and 5 females, and an average age of 11.4 years. The mean number of previous operations was 3.5. The duration before presentation averaged 10.4 months. At presentation, 24 cases were draining nonunions, while 12 patients had quiescent sinuses. Preoperative shortening was evident in 31 patients ranging from 1 to12 cm. Six cases had equinus foot deformity. Stiffness of the ankle and/or knee was present in 11 cases. Angular deformity of more than 10° was evident in 13 nonunions. The monofocal compression-distraction was used for 10 cases managed by bloodless technique, and four draining cases managed by limited debridement and compression distraction. Limited debridement and bone transport was used in the remaining cases including proximal chondrodiastasis (two cases), proximal tibial corticotomy (17 cases), and partial osteotomy (three cases). RESULTS: The mean follow-up duration was 51.9 months. The external fixation period averaged 5.3 months. Delayed union occurred in three cases treated by repeating compression-distraction. Eventually, union was achieved in all cases. Two cases suffered refracture. Four cases had residual angular deformity of about 5-7°. Infection recurred in one case. ASAMI bone results were excellent in 29 patients, good in three patients, fair in two patients, and poor in two patients. The ASAMI functional results were excellent in 27 cases, good in 5 cases, fair in two cases, and poor in two cases. CONCLUSION: The Ilizarov method provides a viable treatment method for treating paediatric infected nonunions in a single stage of management. Limited debridement was enough to control infection and achieved good results without radical resection.

The effects of blood conditioning films on the antimicrobial and retention properties of zirconium-nitride silver surfaces.

External bone fixation devices provide support and rehabilitation for severely damaged/broken bones, however, this invasive procedure is prone to infection. Zirconium nitride/silver (Ti-ZrN/Ag) coatings were characterised for surface topography, chemical composition, physicochemistry and antimicrobial efficacy (against Staphylococcus aureus and Staphylococcus epidermidis), in the presence of a blood conditioning film. The conditioning film altered the width of the microtopography of the surfaces however, the depth of the features remained relatively constant. The conditioning film also altered the coatings from hydrophobic to hydrophilic/partially hydrophilic surfaces. Following the MATH assay, the presence of a conditioning film reduced affinity towards the hydrocarbons for both microorganisms. The addition of a blood conditioning film reduced the antimicrobial efficacy of the Ti-ZrN/Ag coatings but also reduced the number of retained bacteria. This study suggests that the presence of a pre-defined blood conditioning film may result in surfaces with anti-adhesive properties, potentially leading to a reduction in bacterial retention. This, combined with the antimicrobial efficacy of the coatings, could reduce the risk of infection on biomaterial surfaces.

Does temporary external fixation and staged protocol for closed fractures lead to bacterial contamination of the surgical site and associated complications? - A prospective trial.

INTRODUCTION: Temporary external fixation is a viable option for numerous conditions and fixations in orthopaedic and trauma surgery. If the external fixator is left in place it is necessary to disinfect it prior to surgery, yet the subsequent risk for bacterial contamination of the surgical site originating from the external fixator remains unknown. MATERIAL AND METHODS: In a prospective study, samples were taken at the time of definitive osteosynthesis to assess bacterial contamination of the surgical site and the external fixator in twenty consecutive patients treated with temporary external fixation for closed fractures from October 2016 until March 2017. RESULTS: Twenty external fixators of twenty patients with complete sampling and a mean follow-up of seven months (range: 3-14) were available for analysis. Ten out of 120 cultures of the surgical site (8.3%) were positive for bacterial growth in a total of seven patients (35%). Pathogen's detected were Propionibacterium acnes (60%) and Staphylococcus epidermidis (30%). No contamination of the external fixator was detected. CONCLUSION: We conclude that the presented perioperative management to decontaminate external fixators allows for a safe definitive osteosynthesis in a staged protocol without increasing bacterial contamination of the surgical site. It is safe to leave the external fixator in place for definitive osteosynthesis.

Postoperative complications associated with external skeletal fixators in cats.

OBJECTIVES: The objective of this study was to quantify complications associated with external skeletal fixators (ESFs) in cats and to identify potential risk factors. METHODS: A retrospective review of medical records and radiographs following ESF placement was performed. RESULTS: Case records of 140 cats were reviewed; fixator-associated complications (FACs) occurred in 19% of cats. The region of ESF placement was significantly associated with complication development. Complications developed most frequently in the femur (50%), tarsus (35%) and radius/ulna (33%). Superficial pin tract infection (SPTI) and implant failure accounted for 45% and 41% of all FACs, respectively. SPTI occurred more frequently in the femur, humerus and tibia, with implant failure more frequent in the tarsus. No association between breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, degree of fracture load sharing, and the incidence or type of FAC was identified. No association between region of placement, breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, fracture load sharing and the time to complication development was identified. CONCLUSIONS AND RELEVANCE: Complication development is not uncommon in cats following ESF placement. The higher complication rate in the femur, tarsus and radius/ulna should be considered when reviewing options for fracture management. However, cats appear to have a lower rate of pin tract infections than dogs.

Can applied external fixators be sterilized for surgery? A prospective cohort study of orthopaedic trauma patients.

BACKGROUND: Temporary external fixators are often used to stabilize fractures when definitive fracture surgery must be delayed. Sometimes, external fixators are left in place during repeat operations, including definitive internal fixation of tibial pilon and tibial plateau fractures. It is unknown how well current surgical preparation sterilizes these devices, which become part of the surgical field. Our hypothesis was that our institution's standard surgical preparation creates a low rate of culture-positive environments on external fixators at the time of surgical skin incision. METHODS: We prospectively consented and enrolled patients to obtain cultures (48 patients, 55 external fixators, 165 sets of culture data). After standard preparation and immediately before incision, cultures were obtained from three sites on each external fixator: 1) most distal pin 1cm from pin-skin interface, 2) most distal bar at midpoint between pin and clamp connectors, and 3) most distal clamp at bar-clamp interface. Our standard preparation for patients with external fixation in place is to don sterile gloves and wipe down all components of the external fixator with 70% alcohol-soaked sterile 4×4in gauze sponges before skin preparation. The skin and external fixator are then prepped in the usual fashion with ChloraPrep for closed wounds or with povidone iodine scrub and paint for open wounds. Swabs were processed and organisms from cultures identified. Clinicians were blinded to study results until study completion. RESULTS: Two of 165 cultures (1.2%; 95% confidence interval [CI]: 0-2.9%) were positive for common pathogens sometimes observed in surgical site infection. Four cultures (2.4%; 95% CI: 0-4.8%) had pathogens that are rarely associated with surgical site infection, and four (2.4%; 95% CI: 0-4.8%) had nonpathogenic organisms. CONCLUSION: Using 70% alcohol on external fixators plus either ChloraPrep for closed wounds or povidone iodine for open wounds seems to result in a low rate of positive cultures. Most species that were isolated are infrequently identified as sources of surgical site infections. This preparation protocol might be effective at producing a relatively clean environment at the time of surgery for patients with external fixators already in place.

Pin-site care: can we reduce the incidence of infections?

BACKGROUND: This study was conducted to determine the pin-site care protocols currently in use and to analyse their effectiveness and outcomes. METHODS: PubMed, the Cochrane Library and Embase databases were screened for manuscripts that described comparative studies of different methods of pin-site care and referred to complications related to any kind of external fixator application. RESULTS: A total of 369 manuscripts were screened and only 13 of these met the inclusion criteria evaluating different protocols of pin-site care. This review is based on a total of 574 patients. Infection rates were very variable depending on the type of implant used and the protocol of pin-site care applied. CONCLUSIONS: None of the different protocols of pin-site care that were evaluated in this study were associated with a 0% infection rate. There is currently no consensus in the international literature about which protocol should be applied universally. Meticulous surgical technique during pin insertion and implementation of one of the existing protocols of pin-site care are the mainstay of prevention and/or reduction of the incidence of pin-site infections.

Bone transport for the treatment of infected forearm nonunion.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of the treatment of infected forearm nonunion by bone transport. MATERIALS AND METHODS: We retrospectively reviewed 16 patients with infected forearm nonunion treated by bone transport. Our study included 10 males and 6 females with a mean of age 38.25 years. The site of bone defects involved 9 radius and 7 ulna. The average length of the bone defects after radical debridement was 3.81cm (range 2.2-7.5cm). RESULTS: The mean follow-up after removal of the frame was 39.63 months (range 26-55 months). No patient was lost to follow-up. All the patients had bone union and no recurrence of infection was observed. The mean external fixation time was 6.19 months (range 3-10 months), and the mean external fixation index was 1.63 months/cm (range 1.14-2.00 months/cm). The mean degrees of wrist flexion were 49.69° (range 45-55°), and the mean degrees of wrist extension were 50.63° (range 40-60°). The mean degrees of elbow flexion were 143.12° (range 135-150°), and the mean degrees of elbow extension were 4.69° (range 0-20°). The mean degrees of forearm pronation were 82.50° (range 70-90°), and the mean degrees of forearm supination were 83.75° (range 75-90°). CONCLUSION: Our study suggested that bone transport in the treatment of infected forearm nonunion acquired satisfied functional results. Radical debridement is the key step to control bone infection.

Antimicrobial activity of nanocomposite zirconium nitride/silver coatings to combat external bone fixation pin infections.

During external fixation, temporary implants are used to penetrate the skin, muscle and bone to support severely fractured bones. This creates a biologically critical interface at the site of entry, which potentially allows a risk of infection. The aim of this study, therefore, was to investigate potential antimicrobial nanocomposites to combat infection. Magnetron sputtering was used to produce zirconium nitride/silver nanocomposite coatings, which were prepared at two different silver concentrations of 15.5 at.% and 29.8 at.%. These coatings were characterized for morphology, chemical composition, and antimicrobial activity in comparison to pure zirconium nitride and stainless steel. Staphylococcus aureus and Staphylococcus epidermidis were used as in vitro test organisms in a range of antimicrobial assays; retention of the bacteria on the surfaces and their survival using LiveDead™ staining; the use of a metabolic redox dye to indicate a contact kill and zone of inhibition assays to indicate leaching of inhibitory silver ions. Antimicrobial tests demonstrated a significant kill when the bacterial cells came in contact with the coatings containing silver at both 15.5 at.% and 29.8 at.%. No inhibitory leaching from the surfaces occurred. These surfaces demonstrate potential for use as antimicrobial fixation pin coatings.

Bacteria on external fixators: which prep is best?

BACKGROUND: There are no established guidelines for the surgical prep of an external fixator in the operative field. This study investigates the effectiveness of different prep solutions and methods of application. METHODS: Forty external fixator constructs, consisting of a rod, pin, and pin to rod coupling device, were immersed in a broth of Staphylococcus aureus (lux) for 12 hours. Constructs were then randomized into four treatment groups: chlorhexidine-gluconate (CHG) (4%) scrub, CHG (4%) spray, povidone-iodine (PI) (10%) scrub, and PI (10%) spray. Each construct was imaged with a specialized photon capturing camera system yielding the quantitative and spatial distribution of bacteria both before and after the prep. Each pin to bar clamp was loosened and moved 2 cm down the construct, simulating an external fixator adjustment, and reimaged. Spatial distribution of bacteria and total bacteria counts were compared. RESULTS: There was a similar reduction in bacteria after surgical prep when comparing all four groups independently (p = 0.19), method of application (spray vs. scrub, p = 0.27), and different solutions (CHG vs. PI, p = 0.41). Although bacteria were evident in newly exposed areas after external fixator adjustment, most notably within the loosened pin to bar clamp, it did not result in an increase in bacteria counts (all four groups, p = 0.11; spray vs. scrub, p = 0.18; CHG vs. PI, p = 0.99). CONCLUSIONS: Although there was no increase in bacteria counts after the simulated external fixator adjustment, it did expose additional bacteria previously unseen. Although there was no difference in surgical prep solution or method of application, consideration must be given to performing an additional surgical prep of the newly exposed surface after loosening of each individual external fixator component as this may further minimize potential bacteria exposure.

Decreasing bacterial colonization of external fixation pins through nitric oxide release coatings.

OBJECTIVE: Bacterial infection of the pin tract represents the most common complication associated with external fixation. This study was designed to evaluate the antibacterial activity of nitric oxide (NO)-releasing xerogel films applied to commercially pure titanium pins in a rat model. METHODS: Pins were coated with xerogel solution through a dip-coating procedure. Half of the xerogel-coated implant pins were modified into NO donors and served as the NO-releasing group, whereas the remaining pins were left unmodified to serve as non-NO-releasing xerogel-coated controls. Acid-etched pins served as uncoated controls. Animal selection was randomized and every rat had one pin from each of the three groups randomly allocated to the third, fourth, or fifth tail vertebrae. Quantification of bacterial infection was performed 48 days postoperatively and the tissue-implant interface was inspected for clinical signs of infection on Days 14 and 28 postimplantation. RESULTS: Pin tract bacterial colony counts of the NO-releasing group (170,000 ± 181,000) were significantly lower than both the xerogel-coated group (677,000 ± 675,000) and the control group (1,181,000 ± 2,717,000) 48 days postoperatively (P < 0.05). No significant difference in colony counts was observed between the xerogel-coated group and the control group. The NO-releasing group also had significantly fewer clinical signs of infection than both the coated and the control groups on postoperative Day 28 (P < 0.05). CONCLUSION: The application of NO-releasing xerogel coatings can inhibit bacterial colonization of external fixation pins both during the initial postsurgical period and up to 48 days postimplantation.

The pin-bone interface in external fixator: a standardized analysis in a sheep osteotomy model.

OBJECTIVES: The hypothesis of the study was that the incidence of pin loosening and pin infection would increase, whereas the general stability of the pin-bone interface would decrease with ongoing implantation time. The aim of this study was to analyze the biologic reactions of the bone tissue adjacent to the pin to determine the relationship among the osseous anchorage of pins, the incidence of infections, and the histologic appearance. METHODS: Three groups of sheep received a tibial osteotomy stabilized by external fixators. The pin-bone interface was analyzed biomechanically, radiologically, microbiologically, and histologically after 3, 6, and 9 weeks. RESULTS/CONCLUSIONS: Contrary to common opinion, pin anchorage was not altered biomechanically throughout the 9 weeks of the study. This effect might be attributed to an increasing remodeling found in the callus and cortex around the pins and was likely assisted by a strict pin care routine and a low infection rate.

Antimicrobial efficacy of surface-coated external fixation pins.

In clinical applications, colonization of metal implants by adhesive and biofilm-forming bacteria not only prolong healing but create additional healthcare costs for implant revision and antimicrobial treatment. An in vitro assay was established investigating the antimicrobial surface activity of external fixation pins intended for use in bone fractures and deformities. Test articles made out of stainless steel and coated with a polymer-containing nanoparticulate silver were compared to non-coated reference controls out of stainless steel, copper and titanium. Staphylococcus epidermidis, known as a predominant cause for implant-related infections was used as test organism. Test pins and bacteria were incubated for a period of 20 h found to be sufficient for initiating biofilm formation. After removing non- and low-adherent bacteria by rinsing, two methods were used to isolate high-adherent (sessile) bacteria from the implant surfaces. Besides shaking the implants in a solution containing small glass beads, a cytobrush technique was used to mechanically harvest viable bacteria. Finally, the amount of detached bacteria was determined by plate counts. Several parameters identified to be critical within the different removal procedures such as the inoculum concentration and the shaking time in the presence of glass beads as well as time of the cytobrush treatment were analysed. The final test scheme resulted in the use of an inoculum of 10(5) colony forming units (CFU) per millilitre, ten rinsing steps for the removal of low adherent bacteria and 5 min of shaking in the presence of glass beads, detaching the high-adherent bacteria. Due to subjective variations impacting the outcome of the procedure, the cytobrush technique was not favoured and finally rejected. Using the in vitro assay developed, it could be demonstrated that fixation pins coated with silver show a 3 log step reduction in the number of biofilm-forming bacteria compared to a non-coated stainless steel or titanium implant. Pins made out of copper showed the highest antimicrobial efficacy, as the number of detached bacteria was found to be below the detection limit, they served as a positive control within this test.