Aim. Debridement, Antibiotics, Irrigation, and implant Retention (DAIR) is a surgical treatment protocol suitable for some patients with fracture related infection (FRI). Clinically relevant pre-clinical models of DAIR are scarce and none have been developed in large animals. Therefore, this project aimed to develop a large animal model for FRI including a DAIR approach and compare outcomes after 2 or 5 weeks of infection. Method. Swiss Alpine sheep (n=8), (2–6 years, 50–80 kg) were included in this study. This study was approved by cantonal Ethical authorities in Chur, Switzerland. A 2 mm osteotomy was created in the tibia and fixed with a 10-hole 5.5 mm steel plate. Subsequently, 2.5 mL of saline solution containing 10. 6. CFU/mL of Staphylococcus aureus MSSA (ATCC 25923) was added over the plate. Sheep were observed for 2 (n=3) or 5 weeks (n=5) until revision surgery, during which visibly infected or necrotic tissues were removed, and the wound flushed with saline. All samples were collected for bacterial quantification. After revision surgery, the sheep were treated systemically for 2 weeks with flucloxacillin and for 4 weeks with rifampicin and cotrimoxazole. After 2 further weeks off antibiotics, the animals were euthanized. Bacteriological culture was performed at the end of the study. Bone cores were isolated from the osteotomy site and processed for Giemsa & Eosin and Brown and Brenn staining. A radiographical examination was performed every second week. Results. Bacteriological evaluation of the retrieved samples during revision surgery showed no significant difference between the 2 vs 5 weeks infection periods in term of total CFU counts. At the end of the study, radiographical examination showed callus formation over the osteotomy site in both groups, although the osteotomy was not completely healed in either group. At euthanasia, the 2 weeks infection group showed a higher soft tissue burden compared to the 5 weeks group, whereby the infection in the 5 weeks group was primarily located in the bone and bone marrow. Conclusions. The large animal model of FRI and DAIR was successfully established. Bacteriological outcomes highlight that the increasing duration of the infection does not change the outcome but the location of the infection from a predominantly soft tissue infection to a deeper bone and intramedullary (IM) channel infection. The debridement of the IM channel could potentially reduce the infection burden by eliminating those bacteria not easily reached by systemic antibiotics, though is not practical using conventional techniques

Abstract. Background. Infections are rare and poorly studied complications of unicompartmental knee athroplasty (UKA) surgery. They are significantly less common compared to infections after total knee arthroplasties (TKAs). Optimal management of periprosthetic joint infections (PJIs) after a UKA is not clearly defined in the literature. We present the results of a multicentre retrospective series of UKA PJIs treated with Debridement, Antibiotics and Implant Retention (DAIR). Methodology. Patients presenting between January 2016 and December 2019 with early UKA infection were identified at three specialist centres using the Musculoskeletal Infection Society (MSIS) criteria. All patients underwent a standardized treatment protocol consisting of the DAIR procedure and antibiotic therapy comprising two weeks of intravenous (IV) antibiotics followed by six weeks of oral therapy. The main outcome measure was overall survivorship free from reoperation for infection. Results. A total of 3225 UKAs (2793 (86.2%) medial and 432 (13.8%) lateral UKAs) were performed between January 2016 and December 2019. Nineteen patients had early infections necessitating DAIR. The mean follow-up period was 32.5 months. DAIR showed an overall survivorship free from septic reoperation of 84.2%, with an overall survivorship free from all-cause reoperation of 78.95%. The most common bacteria were Coagulase-negative Staphylococci, Staphylococcus aureus and Group B Streptococci. Three patients required a second DAIR procedure but remained free from re-infection at follow-up obviating the need for more demanding, staged revision surgery. Conclusions. In infected UKAs, the DAIR procedure produces a high rate of success, with a high survivorship of the implant

Introduction. Debridement, Antibiotics and Implant Retention (DAIR) remains the norm for the treatment of acute periprosthetic joint infection (PJI) despite less than optimal success rates. Intraosseous (IO) administration of vancomycin has been shown to have significantly increased local bone and tissue concentrations compared to systemic antibiotics, with lower systemic antibiotic levels compared to intravenous. The purpose of this study was to evaluate if the addition of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes. Methods. A retrospective review of 35 PJI TKA patients who underwent DAIR combined with IO vancomycin (500mg) was performed with minimum 12-month follow-up. 26 patients were treated for acute perioperative or acute hematogenous infections following primary TKA. Nine were treated for chronic infections with components that were considered unresectable (ie) constructs with ingrown cones, sleeves, or long cemented stems in elderly comorbid patients. Primary outcome was defined by no reoperations for infection nor clinical signs or symptoms of PJI. Results. The average follow up for acute infection was 16.5 months (range 12.1–24.2) and 15.8 months (range 12–24.8) for chronic infections with unresectable components. Overall eradication rates for acute infection was 93.1% while only 44.4% for chronic infections with unresectable components. MSIS host grade was a significant indicator of failure (p<0.001). Conclusion. The use of IO vancomycin at the time of DAIR yielded improved results compared to standard irrigation and debridement in acute periprosthetic infections. Its use in chronic infections should remain cautious. While these results are encouraging, this technique requires longer follow-up before widespread adoption

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

INTRODUCTION. Surgical site infections (SSI) in orthopaedics are a major source of postoperative morbidity. Although perioperative antibiotic prophylaxis is a common practice, orthopaedic infections are still high in numbers, due to the increasing use of osteosynthesis material and implants. Implants are avascular and can be easily colonized with biofilm-producing germs. For both, effective prophylaxis and treatment of orthopaedic infections, the right choice of the antibiotics used, the mode of application (only systemic or systemic & local), the timing, dosage and the duration of antibiotics are of extremely high importance. Their inappropriate use does not only lead to failures in prevention or treatment of infections, but may also promote microbial resistance development and may cause serious side effects for the patients. SELECTION & USE OF ANTIBIOTICS. Prophylaxis. Broad-spectrum prophylactic antibiotics should help to eliminate the germs before they start to colonize the implant. For prophylactic purposes the recently published AAOS guidelines [1] recommend the use of cephalosporins, such as cefazolin or cefuroxim, administered within one hour prior to surgery. In cases of suspected beta-lactam allergy, clindamycin or vancomycin can be used. The latter one is also recommended in cases of MRSA colonisation. Due to extended infusion times, vancomycin should be started within two hours prior to incision. In cases of blood loss or long op duration, antibiotic administration must be repeated (e.g. cefazolin, every 2–5 hrs; vancomycin, every 6–12 hrs). There is no evidence of a benefit of continued antibiotic administration past 24 hrs of end of surgery [2]. Treatment. In cases of established infections, use of antibiotics is only considered as an adjuvant to surgical debridement. Typically, the choice of the appropriate antibiotic depends on the bacteria, its antibiotic sensitivity profile and the health state of the patient. A combination of rifampicin & a quinolone (or rifampicin & vancomycin in cases of MRSA) for at least 2 wks up to several months has shown good results [3]. In chronic infections with biofilm involvement, all foreign material must be removed and locally delivered antibiotics via e.g. PMMA as carrier (spacers, PMMA-chains) are of additional clinical benefit. ROLE OF LOCAL ANTIBIOTICS. There is general consensus that PMMA chains or PMMA spacers loaded with specific antibiotics support the eradication of bone and joint infections, because of the high local concentrations achieved. The exact treatment time is, however, variable, ranging from few weeks up to several months. Only small amounts of these local antibiotics are systemically detectable and do not represent a major risk for side effects. Still a matter of debate is the benefit of antibiotic impregnated PMMA for infection prophylaxis. Although common practice in Europe, its routine use in e.g. primary arthroplasty is still discussed in other world regions. Meanwhile, evidence accumulates that joint infection rates are, indeed, lower, if antibiotic loaded bone cement with high initial release rates is routinely used in arthroplasty. 4.

OBJECTIVE. Debridement, Antibiotics and Implant Retention (DAIR) procedure is well established for Prosthetic Joint Infection (PJI) in acute setting after total hip and knee replacements. We present our perspective of DAIR in a relatively a small cohort following hip and knee replacements in a District General Hospital (DGH) in United Kingdom, where we delivered comparable results to leading tertiary centers in short to mid-term followup. METHODS. We undertook a retrospective study involving 14 patients, who underwent DAIR in our DGH between August 2012 and December 2015. Patient cohort included primary, complex primary and revision hip and knee replacements. Multiple samples were taken intraoperatively for cultures and histology. mMicrobiological support was provided by a microbiologist with interest in musculoskeletal infections. RESULTS. 14 patients [9 males, 5 females; age 62–78 years (Mean 70.7); BMI 22–44.2 (Mean 33.8)] with multiple comorbidities underwent DAIR procedure within 3 weeks of onset of symptoms, (although the time from index surgery ranged from 15 days to 58 months). Patient selection was made by two Hip surgeons. 12 out of 14 grew positive cultures with two growing Vancomycin resistant Enterococcus. IV antibiotics were stated after samples intraoperatively and continued in six patients after discharge using (OPAT), while 8 were discharged with oral antibiotics. One patient died in immediate post operative period due to generalised sepsis. Another patient died of myocardial infarction 2 years after DAIR. 12 (85.7%) patients are doing well with regular followup (Mean 20 months) in clinics. CONCLUSIONS. With good patient selection, DAIR is a far simpler solution and a safe and reproducible surgical option in PJI in hip and knee replacements compared to one or two stage revisions with the implications. But published Data in contemporary literature is predominantly from specialized centers. Our small series provides a perspective of early to mid term results of DAIR from a DGH

Debridement Antibiotics Implant Retention (DAIR) is a recognised procedure in the management of acute prosthetic joint infection (PJI). We present an experience of DAIR following hip and knee replacements in a District General Hospital. A retrospective review of 14 patients who underwent DAIR procedures between August 2012 and December 1015 were collated. The cohort included primary, complex primary and revision hip and knee replacements. All patients received multidisciplinary care with surgery performed by one of two arthroplasty surgeons. 9 males and 5 females with age 62 − 78 years (Mean 70.7) and BMI 22–44.2 (Mean 33.8) with various co-morbidities underwent DAIR. Surgical criteria required DAIR to be performed within 3 weeks of the onset of symptoms of infection. The time from index surgery however ranged from 15 days to 58 months. 12 of 14 grew positive cultures including two growing Vancomycin Resistant Enterococcus. Intravenous antibiotics were commenced after intraoperative samples and tailored OPAT. Antibiotic schedule varied from six weeks to eight months. 12 (85.7%) patients remain under follow up. Mean follow is 20 months (RANGE 6months-3years10months) with no recurrence of infection or reoperation. With appropriate patient selection, DAIR is safe and reproducible surgical option in PJI in hip and knee replacements, avoiding the implications of a one or two stage revision. Published Data in contemporary literature is predominantly from specialised centres. Our small series provides a perspective of early to mid term results of DAIR to DGH. Interestingly each procedure is categorised as a failed implant on the National Joint Register

INTRODUCTION. Deep infection is a potentially catastrophic complication of joint replacement surgery. Early intervention in suspected prosthetic joint infection in the form of aggressive Debridement and targeted Antibiotics can lead to successful Implant Retention (DAIR). In our centre, we adopt an aggressive approach to suspected prosthetic joint infection, working in a multi-disciplinary team with microbiologists and an infection surveillance team to identify and treat suspected infected cases at the earliest opportunity. OBJECTIVES. To evaluate the efficacy of the treatment of prosthetic joint infection with DAIR. METHODS. All cases of primary prosthetic joint infection between March 2009 and September 2011 were identified. Data was retrospectively collected from root cause analysis data, patient records and hospital electronic results systems. RESULTS. 48 cases of confirmed deep infection were identified from a total of 5037 primary joint replacements. Mean age was 67.3. The mean time between index procedure and return to theatre for debridement was 18 days. 10 patients underwent a second debridement and 3 returned to theatre for a third debridement. Mean total duration of antibiotic treatment was 10.5 weeks with mean duration of intravenous antibiotics 2.7 weeks. There were two early and three late failures on antibiotics. These went on to have successful two stage revision. The mean interval to debridement in failed cases was 15 days. The primary implant was successfully retained in 90% of cases (n=43) at a mean follow up of 30 months. CONCLUSION. DAIR is an effective means of treating early prosthetic joint infection in a multi-disciplinary setting

Introduction: The effect of different temperatures to antibiotics is unknown. What is the dose-response curve of bone chips impregnated with different kinds of antibiotics?

Material and Methods: Five different antibiotic pills and solutions (cefazolin, clindamycin, linezolid, oxacillin, vancomycin) were stored at −80°C, −20°C, 4°C, 20°C and 37°C. Also, bone chips were impregnated with cefazolin and vancomycin solution and were stored at −80°C and −20°C. After 1 month, 6 months and 1 year, reaction of the antibiotics to Staphylococcus epidermidis was measured using an inoculated iso-agar. Activity of the antibiotics was measured as the diameter of the Staphylococcus epidermidis-free zone.

Also, five cefazolin and vancomycin solutions were used to impregnate bone chips and to make dose-response curves. Furthermore, 1 gram bone chips was impregnated with 5ml cefazolin or 5ml vancomycin solution.

Results: A decrease of the diameter free zone Staphylococcus epidermidis was seen when oxacillin and cefazolin solutions were stored at 37°C for 1 month and when vancomycin was stored for 6 months (37°C). Also, when cefazolin and oxacillin solutions were stored at 20°C, a decrease was noticed. The storage of other antibiotic solutions, pills and bone/antibiotics composite showed no differences in reaction. Dose-response curves show that with increasing antibiotic quantity, diameter free zone increases according to a logarithmic function.

Conclusion and discussion: With the dose-response curve the optimal concentration(s) for local application can be determined. It gives the opportunity to determine the amount of antibiotics present in the patient locally. Freezing of antibiotics does not affect the activity of the investigated antibiotics.

Introduction: Intraoperative tissue culture remains the “gold standard” in diagnosing periprosthetic infection (PPI). However, an organism is not always cultured and this has been attributed to the fact that preoperative antibiotics were administered. This study intends to examine if preoperative antibiotics prevent isolation of intraoperative organisms. Methods: 91 total joint arthroplasty patients diagnosed with PPI during (1999–2005) and who had positive aspiration culture were included in the study. All intravenous antibiotics that were given to the patient within seven days of surgery were documented. The total number of positive intraoperative fluid and tissue samples of patients who did and did not receive antibiotics was calculated. Susceptibility of the organism(s) to antibiotics was determined by antibiogram of the preoperative and intraoperative culture. Results: 60 out of 91 patients received preoperative antibiotics within seven days of surgery. Antibiotics prevented isolation of an intraoperative organism in 6 out of the 60 (10%) cases. All of the 31 patients who did not receive any preoperative antibiotics had positive intraoperative cultures. Chi-square analysis revealed no significant difference between giving preoperative antibiotics within 7 days and isolating an intraoperative organism (p=0.068). Giving antibiotics that specifically targets the culprit organism did not significantly affect the fluid (p=0.585) or tissue culture yield (p=0.152) either. Discussion: Although, giving preoperative antibiotics can prevent isolation of intraoperative organisms in 10% of cases, this is not statistically or clinically significant in patients with positive aspiration cultures because the organism is known beforehand. However, it is clinically and medicolegally relevant to withhold antibiotics in patients with negative aspiration cultures since the postoperative treatment antibiotic is tailored according to the organism cultured

Aim

The duration of systemic antibiotic therapy following first-stage surgery is contentious. Our Institution's philosophy is to perform an aggressive debridement, use high concentration targeted antibiotics through cement beads and systemic prophylactic antibiotics alone. In the presence of significant soft tissue infection or microbiological diagnostic uncertainty; systemic antibiotics may be prescribed for 5 days whilst awaiting tissue culture results. The aim of this study was to assess the success of our philosophy in the management of PJI of the hip using our two-stage protocol.

Aim. Debridement Antibiotics and Implant Retention(DAIR) is a procedure to treat a periprosthetic joint infection(PJI) after Total Hip Arthroplasty(THA) or Total Knee Arthroplasty(TKA). The timing between the primary procedure and the DAIR is likely a determinant for its successful outcome. There are few retrospective studies correlating timing of a DAIR with success (1,2). However, the optimal timing of a DAIR and the chance of success still remains unclear. We aimed to assess the risk of re-revision within one year after a DAIR procedure and to evaluate the timing of the DAIR in primary THA and TKA. An estimation of the chance of a successful DAIR will help clinicians and patients in their decision-making process in case of an acute postoperative PJI. Method. We used data from the Dutch Arthroplasty Register(LROI) and selected all primary THA and TKA in the period 2007–2016 who underwent a DAIR within 12 weeks after primary procedure. A DAIR was defined as a revision for infection in which only modular parts were exchanged. A DAIR was successful if not followed by a re-revision within 1 year after DAIR. The analyses were separated for THA and TKA procedures. Results. 207 DAIRs were performed <4 weeks after THA of which 41(20%) received a re-revision within 1 year; 87 DAIRs were performed between 4–8 weeks of which 15(17%) were re-revised and 11 DAIRs were performed >8 weeks and 2(18%) received a re-revision. 126 DAIRs were performed <4 weeks after TKA of which 27(21%) received a re-revision within 1 year; 68 DAIRs were performed between 4–8 weeks of which 14(21%) were re-revised and 15 DAIRs were performed >8 weeks and 3(20%) received a re-revision. Conclusions. There was no difference in 1-year re-revision rate after a DAIR procedure by timing of DAIR procedure for total hip and knee arthroplasty based on Dutch registry data

The aim of this study was to compare the clinical and radiographic results of a interlocking nail with a releasing antibiotic core of PMMA with a standard interlocking nail for the treatment of open fractures of the tibia. Prospective, controlled trial, randomized by surgeon preference, including 30 patients with open fractures of the tibia. Patients were divided into two groups according to the treatment method: Group I (STD), consisting of 14 patients treated by delayed interlocking standard nailing, after an antibiotic treatment and bed rest. Group II (SAFE) comprising 16 patients treated with a interlocking intramedullary nail with a core of PMMA cement with antibiotics, 5 of which had a temporary stabilization with an external fixator. Antibiotics chosen to impregnate the SAFE nail in cases without prior bacteriology were vancomycin (2gr) and flucloxacillin (2gr). There were no statistically significant differences between groups with respect to demographic data (age, gender), type of fracture and degree of exposure (p>0,05). The mean follow-up was 2.4 years (5 months to 4 years) for the STD group and 2.1 years (4 months to 3 years) for the SAFE group. 15 of the 30 patients had positive bacteriology, including 13 cases with aggressive agents predominating Enterobacter, Enterococcus, Pseudomonas and MSSA groups. The infection rate after nailing was 43% (6/14 patients) for the STD group and 6% (1/16 cases) to the SAFE group, a statistically significant difference (p=0.02). The mean time to union was 7.5 months (3 months to 1.5 years) for the STD group and 4.5 months (2 months to 8.5 months) for the SAFE group, a statistically significant difference (p=0.02). The complication rate was 64% (9/14) in the STD group and 25% (4/16) for the SAFE, including a infection rate of 43% in the STD group and 6% in the SAFE group, a statistically significant difference (p=0.03). We observed that the open fractures of the tibia treated with SAFE nails presented a statistically significant lower rate of infection, faster consolidation and fewer complications compared with treatment with deferred standard nails. Compared to similar devices available on the market, it has the advantage of allowing selection of the type and dose of antibiotics, it allows fixation with screws of intermediate bone segments, it shorten the period of hospitalization and treatment time, reducing the costs associated with the treatment of this pathology

Introduction

The management of open long bone fractures is well described and has been standardised through a number of well-established guidelines. However, there is no consensus regarding the application of local antibiotics into the open fracture site as a means of reducing infection rates.

Background

Fracture-related infection (FRI) is treated by adequate debridement, lavage, fracture stabilization (if indicated), adequate soft tissue coverage and systemic antimicrobial therapy. Additional administration of local antibiotics (LA), placed directly in the surgical field, is thought to be beneficial for successful eradication of infection.

The duration of systemic antibiotics following first-stage surgery is contentious. Our Institution's philosophy is to perform an aggressive debridement, high concentration of targeted antibiotics through cement beads and systemic prophylactic antibiotics alone. In the presence of significant soft tissue infection or microbiological diagnostic uncertainty; systemic antibiotics may be prescribed for 5 days whilst awaiting tissue culture results. The aim of this study was to assess the success of our philosophy for two-stage hip revision.

A retrospective review of our Institution's prospective database was performed to identify all intended two-stage hip revision procedures for PJI. All patients had a confirmed PJI as per MSIS 2013 criteria, minimum 5-years follow up and outcomes according to the MSIS working group outcome-reporting tool; then grouped into “successful” or “unsuccessful” (suppressive antibiotics, further revision for infection, death within 1 year).

383 intended two-stage hip revisions were identified; of which 299 met our inclusion criteria, in 289 patients (6 repeat ipsilateral two-stage, 4 bilateral two-stage). Median follow up was 10.7 years (IQR 6.3 – 15.0). 258 (86%) patients proceeded to 2^nd stage surgery. 91% success rate was observed for those patients who underwent reimplantation, although dropping to 86% when including the patients who did not proceed to second stage. The median duration of post-operative systemic antibiotics was 5 days (IQR 5–9). No significant difference was observed in patients who received either; < / = 48 hours (86%; n=70) compared to > 48 hours antibiotics (86%; n=229; p=0.96) or </= 5 days of antibiotics (88%; n=202) compared to > 5 days antibiotics (82%; p=0.38). A significant majority had gram-positive (88%) infection with 30% being polymicrobial. Greater success rates were observed with two-stage exchange or gram-positive PJI (86%); than for gram-negative PJI (81%) and polymicrobial infection (74%) (p=0.36). Fungal PJI was observed to have a significantly reduced rate of success (n=3; 33%; p=0.03).

Aggressive surgical debridement with high concentration, targeted local antibiotic delivery at time of first stage to manage PJI of the hip provides a high rate of success, responsible antibiotic stewardship and reduced hospital costs.

Aim: Antibiotics are currently used during fracture healing for prevention or treatment of infection. Quinolones are well known to delay fracture healing, but little is known about other antibiotics. Cefazolin is the most commonly used drug for antibiotic prophylaxis, but many centres use cefuroxime. When allergy to cephalosporins is present, current recommendations include clindamicin or vancomicin. The purpose of this study is to know if other commonly used antibiotics can delay fracture healing. Methods: 100 male 3-months-old Wistar rats were used. After anaesthesia with ketolar, a closed fracture in the middle third of the femur was carried out. Rats were divided in five groups (20 rats each): one receiving cefazolin (a first generation cephalosporin, CZ), other receiving cefuroxime (a second generation cephalosporine, CF), other vancomicin (group V), other clindamicin (group CL) and the other receiving placebo (P) for 4 weeks. Group CZ received a subcutaneous dose of 50mg/kg/daily, Group CF received a dose of 100 mg/Kg/daily, Group V received a dose of 20 mg/Kg/daily, Group CL received a dose of 25 mg/Kg/daily and group P received water. 4 weeks later rats were killed and femora extracted. A mechanical test (low speed torsion) was performed to evaluate healing. All four groups (CZ, CF, V, CL) were compared to placebo through ANOVA. Results: Six bones were discarded because of technical errors, no infections were found. The maximum torque achieved by the calluses before breaking were 240 mNm in group P (n=18), 238 in group CZ (n=20), 178 in group CF (n=19), 167 in group V (n=19), and 205 in group CL (n=18). When compared to placebo, cefazolin and clindamicin showed no statistical differences (N.S, p> 0,10), vancomicin had lower callus strength (p=0,015), and cefuroxime had also lower callus strength near the significance level (p=0,084). Conclusion: The mechanical strength of fracture callus is similar when rats are given cefazolin or clindamicin during fracture healing. The mechanical strength of fracture callus is lower when vancomicin (and probably cefuroxime) is given. If these results are similar to human, cefazolin and clindamicin are safe drugs to use during fracture healing. If possible, vancomicin (and perhaps cefiuroxime) use during fracture healing should be restricted

Aim

There is a lack of data supporting the use of doxycycline as a single agent after removing infected orthopaedic metalwork. We evaluated the efficacy and safety of doxycycline compared with other single antibiotic regimens used at our specialist orthopaedic hospital.

Our study sought to establish the necessity of prolonged pre-operative antibiotic prophylaxis in patients presenting with zone II and zone V acute flexor tendon injuries (FTI). We hypothesized that a single dose of prophylactic antibiotic was adequate in prevention of post-operative wound infection in acute zone II and V FTI.

This was a prospective study of 116 patients who presented with zone II and zone V acute FTI. The study included patients who were 18 years and older. Those with macroscopic contamination, immunocompromised, open fractures, bite injuries, and crush injuries were excluded. Patients were randomised into a group receiving a single dose of prophylactic antibiotic and another group receiving a continuous 8 hourly antibiotic doses until the day of surgery. Each group was subdivided into occupational and non-occupational injuries. Their post-operative wound outcomes were documented 10 – 14 days after surgery. The wound outcome was reported as no infection, superficial infection (treated with wound dressings), and deep infection (requiring surgical debridement).

There was 0.9% rate of deep post-operative wound infections, which was a single zone V acute FTI case in a single dose prophylactic antibiotic group. There was a 7.8% superficial post-operative wound infection rate, which was mainly zone II acute FTI in both antibiotic groups. There was a strong association between zone II acute FTI and post-operative wound infection (p < 0.05). There was no association between (antibiotic dosage or place of injury) with post-operative wound infection (p > 0.05).

There is no benefit in prescribing prolonged pre-operative antibiotic in patients with acute, simple lacerations to zone II and zone V FTI if there is no macroscopic wound contamination.

High doses of intra-articular (IA) antibiotics has been shown to effectively achieve a minimal biofilm eradication concentration which could mitigate the need for removal of infected but well-ingrown cementless components of a total hip arthroplasty (THA). However, there are concerns that percutaneous catheters could lead to multi-resistance or multi-organism peri-prosthetic joint infections (PJI) following single stage THA revisions for PJI.

Eighteen single-stage revision procedures were performed for acute (N=9) or chronic (N=9) PJI following a primary (N=12) or revision (N=6) cementless THA. Modular and loosened components were replaced. All well ingrown components were retained. Two Hickmann catheters were placed in the joint space. Along with intravenous antibiotics, IA antibiotics were injected twice a day for two weeks, followed by 3 months of oral antibiotics.

Per-operative cultures demonstrated 4 multi-bacterial PJIs. None of the patients developed post-operatively an AB related renal or systemic dysfunction. At a mean follow-up of 38 months [range, 8–72] all patients had normal erythrocyte sedimentation rate and white blood cell count. Four had a slightly elevated C-reactive protein but were completely symptom free and did not show any sign of loosening at a mean of 27 months [range, 16–59].

Addition of high doses of IA antibiotics following single-stage revision for PJI in cementless THA, is an effective and safe treatment option that allows for retention of well-ingrown components. We found no evidence for residual implant infection or catheter induced multi-resistance.

Total hip arthroplasty, revision surgery, Periprosthetic Joint Infection, Intra-articular antibiotics

Level 4 (Case series)

Aim

This study investigated the effect of the choice of antibiotic regime on outcome of patients treated for fracture-related infection (FRI) at 3 centres, in the UK and the Netherlands between 2015 and 2019.

Aim

The current antibiotic treatment of periprosthetic joint infection (PJI) is optimized by measuring concentrations in plasma. However, it remains unclear whether effective concentrations of the antibiotics are reached at the site of PJI. Nonetheless, adequate target site concentrations are important to achieve effective eradication of the micro-organism. In order to determine the efficacy of cefuroxime and flucloxacillin in synovial fluid, synovial tissue and bone tissue in relation to the minimal inhibitory concentration (MIC) of the pathogen causing the PJI, we perform a pharmacokinetic/pharmacodynamic (PK/PD) study. Therefore, we aimed to develop validated analytical methods for analysis of cefuroxime and flucloxacillin in synovial fluid, synovial tissue and bone tissue.

Aim

Analysis of microbiological spectrum and resistance patterns as well as the clinical outcome of patients who underwent a Debridement, antibiotics and implant retention (DAIR) procedure in the early phase following failed two-stage exchange arthroplasty of the knee and hip.

Introduction and Objective

Management of bone loss associated with bone contamination or infection represents a double biological and clinical challenge frequent in traumatology. The advent of new biomaterials can allow a different approach in the treatment of bone gap. The purpose of this study was to evaluate the prophylactic and therapeutic effectiveness of addition of a new absorbable bone substitute (BS) eluting different antibiotics in reconstruction of bone defects after infections and fractures with soft tissue damage.

Aim

Staphylococcus epidermidis (S. epidermidis) is one of the main pathogens responsible for bone and joint infections especially those involving prosthetic materials (PJI). Although less virulent than S. aureus, S. epidermidis is involved in chronic infections notably due to its ability to form biofilm. Moreover, it is frequently multiresistant to antibiotics. In this context, the development of additional or alternative antibacterial therapies targeting the biofilm is a priority.

This study aimed to identify the success rate of debridement, antibiotics and implant retention (DAIR) for prosthetic joint infection (PJI) in a large prospective cohort of patients undergoing total knee arthroplasty (TKA). The ability for different PJI classification systems to predict DAIR success was assessed.

A prospective, multicenter study of PJIs occurring between July 2014 and December 2017 in 27 hospitals across Australia and New Zealand was performed. First time PJIs following primary TKA that were managed with DAIR were analyzed. DAIR success was defined as the patient being alive with documented absence of clinical or microbiological evidence of infection and no ongoing antibiotics for the index joint at 2-year follow-up. Multivariate analysis was performed for multiple PJI classification systems to assess their ability to predict DAIR success using their respective definitions of “early” PJI (Coventry ≤1 month, International Consensus Meeting ≤90 days or Auckland <1 year), or as hematogenous versus chronic PJI (Tsukayama).

189 PJIs were managed with DAIR, with an overall success rate of 45% (85/189). Early PJIs had a higher rate of DAIR success when analyzed according to the Coventry system (adjusted odds ratio = 3.85, p = 0.008), the ICM system (adjusted odds ratio = 3.08, p = 0.005) and the Auckland system (adjusted odds ratio = 2.60, p = 0.01). DAIR success was lower in both hematogenous (adjusted odds ratio = 0.36, p = 0.034) and chronic PJIs (adjusted odds ratio = 0.14, p = 0.003) occurring more than one year since the primary TKA.

DAIR success is highest when performed in infections occurring within one year of the primary TKA. Late infections had a high DAIR failure rate irrespective of their classification as hematogenous or chronic. Time since primary is a useful predictor of DAIR success.

Aim

To analyse the prevalence of culture negative periprosthetic joint infections (PJI) when adequate culture techniques are applied, and to evaluate the outcome of patients who were treated with antibiotics for a culture negative PJI versus those in whom treatment was withheld.

Antibiotic-laden bone cement is an important strategy of treatment for an established bone infection. It was aimed to find the safe antibiotic dose intervals of the antibiotic cements soaked in Phosphate Buffered Saline solution and to determine whether there was a difference in terms of mechanical strength between the prepared samples.

This study was done in our institute Microbiology and Metallurgy laboratories. All samples were prepared using manual mixing technique using 40 g radiopaque Biomet® Bone cement (Zimmer Biomet, Indiana, USA) under sterile conditions at 19 ± 2 ºC.

In this study, vancomycin (4 groups − 0.5, 2, 4, 6 g), teicoplanin (4 groups − 0.8, 1.2, 2, 2.4 g), daptomycin (4 groups − 1, 2, 2.5, 3 g), piperacillin-tazobactam (4 groups − 0.125, 0.5, 1, 2 g) and meropenem (4 groups − 0.5, 2, 4, 6 g) were measured in a assay balance and added to the cement powder. Antibiotic levels ranged from the lowest 0.625% to the highest 15%.

80×10×4 mm rectangle prism-shaped sample for mechanical measurements in accordance to ISO 5833 standart and 12×6×1 mm disc-shaped samples for microbiological assesments were used. Four sample for each antibiotic dose and control group was made. Prepared samples were evaluated macroscopically and faulty samples were excluded from the study. Prepared samples were kept in Phosphate Buffered Saline solution renewed every 24 hours at 37 ºC. At the end of 6 weeks, all samples were tested with Instron ® 3369 (Norwood Massachusetts, USA) four point bending test.

Staphylococcus aureus (ATCC 29213) strain was used for samples of antibiotics containing vancomycin, teicoplanin and daptomycin after the samples prepared for antibiotic release were maintained under sterile conditions and kept in Phosphate Buffered Saline solution as appropriate. For samples containing meropenem and piperacillin - tazobactam antibiotics, Pseudomonas aeruginosa (ATCC 27853) strain was used.

The addition of more than 5% antibiotics to the cement powder was significantly reduced mechanical strength in all groups(p <0.05) however the power of significance was changed depending on the type of antibiotic. In general, adding antibiotics with 2.5% and less for cement amount was not cause significant changes in mechanical measurements. There was a negative correlation between the increase in the amount of antibiotics mixed with cement and the durability of the cement (p: <0.001, r: −0.883 to 0.914).

In this study, especially the antibacterial effects of piperacillin-tazobactam, containing 0.25 gr and 0.5 gr antibiotic doses, were found to be low. There was no bacterial growth in all other groups for 21 days. Considering the mechanical properties of groups containing meropenem, vancomycin, daptomycin and teicoplanin, it was observed that all antibiotic cements remained above the limit value of 50 MPa in the bending test at concentrations containing 2.5% and less antibiotics. This was not achieved for the piperacillin-tazobactam group. The findings of the study showed that each antibiotic has different MPa values at different doses. Therefore, it could be concluded that not only the antibiotic dose but also the type oould change the mechanical properties. In the light of these findings, mixing more than 2.5% antibiotics in cement for the antibiotic types included in the study was ineffective in terms of antibacterial effect and mechanically reduces the durability of cement below the standard value of 50 MPa.

Aim

Prompt and sufficient broad spectrum empirical antibiotic treatment is key to prevent infection following open tibial fractures. Succeeding co-administration, we dynamically assessed the time for which vancomycin and meropenem concentrations were above relevant epidemiological cut-off minimal inhibitory concentrations (T>MIC) in tibial compartments for the bacteria most frequently encountered in open fractures. Low and high MIC-targets were applied: 1 and 4 µg/mL for vancomycin and 0.125 and 2 µg/mL for meropenem.

Aims

Prophylactic antibiotic regimens for elective primary total hip and knee arthroplasty vary widely across hospitals and trusts in the UK. This study aimed to identify antibiotic prophylaxis regimens currently in use for elective primary arthroplasty across the UK, establish variations in antibiotic prophylaxis regimens and their impact on the risk of periprosthetic joint infection (PJI) in the first-year post-index procedure, and evaluate adherence to current international consensus guidance.

Aims

Here we used a mature seven-day biofilm model of Staphylococcus aureus, exposed to antibiotics up to an additional seven days, to establish the effectiveness of either mechanical cleaning or antibiotics or non-contact induction heating, and which combinations could eradicate S. aureus in mature biofilms.

Aim

Rifampicin plays an important role in the treatment of staphylococcal prosthetic joint infection, as rifampicin-containing combinations have shown a high efficacy against S. aureus biofilm infections. However, the emergence of rifampin-resistant strains is a feared complication and the use of rifampicin in those cases seems unwarranted. Therefore, we evaluated the activity of bacteriophage Sb1 in combination with different antibiotics against the biofilm of four rifampicin-resistant MRSA strains as alternative therapeutic approach.

Background

DAIR is an attractive treatment for PJI. The purpose of this study is to determine predictive factors of failure.

By modifying only the nanofeatures on material surfaces without changing surface chemistry, it is possible to increase tissue growth of any human tissue by controlling the endogenous adsorption of adhesive proteins onto the material surface. In addition, our group has shown that these same nanofeatures and nano-modifications can reduce bacterial growth without using antibiotics, which may further accelerate the growth of antibiotic resistant microbes. Inflammation can also be decreased through the use of nanomaterials. Finally, nanomedicine has been shown to stimulate the growth and differentiation of stem cells, which may someday be used to treat incurable disorders, such as neural damage. This strategy also accelerates FDA approval and commercialization efforts since new chemistries are not proposed, rather chemistries already approved by the FDA with altered nanoscale features. This invited talk will highlight some of the advancements and emphasize current ceramic nanomaterials approved by the FDA for human implantation. It will also emphasize the future of nanomaterials in medicine, such as their use in personalized medicine as internal sensors to detect and fight alterations in health.

Aim

To describe the management of PJI due to S. aureus in CRIOAcs in 2019 and to particularly focus on the evaluation of the efficacy of DAIR regarding control of infection and risk factors for failure up to 12 months.

Introduction

Perioperative antibiotic prophylaxis use in modern orthopaedic procedures is well established. Studies have shown significant reduction in risk of post-operative infections. However, as effectiveness of these antibiotics is dependent on achieving high serum and tissue concentrations that exceed the minimum inhibitory concentrations of infective organisms for operation duration, the timing of prophylaxis is crucial. Although, optimal timing for administering prophylaxis varies in the literature, 30 to 60 minutes prior to skin incision or inflation of tourniquet is considered best standards.

Aim

Prosthetic Joint Infection (PJI) remains one of the leading cause for revision arthroplasty.^1,2 Early recognition and appropriate initial treatment of early PJI with debridement, antibiotics and implant retention (DAIR) can eradicate infection on first attempt and prevent implant failure. We evaluated the outcome after one year of patients who were treated for an early PJI after primary total knee arthroplasty (TKA) or total hip arthroplasty (THA) with DAIR. Furthermore, we determined preoperative infection markers, microbiology, and treatment factors related to treatment failure after DAIR procedure.

Introduction

We aim to evaluate the outcome of debridement and implant retention (DAIR) procedures performed for primary total hip prosthetic joint infections (PJI) and to identify factors correlating with a successful outcome.

Thermostability is a key property in determining the suitability of local delivery of antibiotics in the treatment of orthopaedic infections. Herein, we aimed to assess the thermal stability and antibacterial activity of ciprofloxacin, ceftriaxone, gentamycine and vancomycine in high temperature conditions. Using a standardized E-test method, minimally inhibited concentration of each antibiotic substance against Staphylococcus aureus cultures were determined. The solutions of antimicrobial drugs ciprofloxacin 2 mg/ml, ceftriaxone 200 mg/ml, gentamycine 40 mg/ml and vancomycine 200 mg/ml were diluted twofold in deionised water. Acquired solutions were divided into three aliquots. The first aliquot was held at 40°C for 30 min in a waterbath, the second and the third aliquots were exposed to 80 and 100°C for 30 min in hot-air sterilizer, respectively. The treated solutions were tested for residual activity against S. aureus using a standardized disk diffusion method. Mediums with untreated antibiotic solutions and S. aureus were used as control. Plates were incubated at 37°C, at which time zones of inhibition (ZoI) were measured to the nearest whole millimeter for 14 days. The investigation indicated that the temperature elevation impacted considerably on antimicrobial activity and antibiotic stability overall. The in vitro temperature-response curves showed that ZoI diameter decreases logarithmically with elevated temperatures. Gentamicin was the only drug that was found to be affected to some extent. Results from the study provides a valuable dataset for orthopaedic surgeons considering local application of antibiotics and methods of antibiotic impregnation.

Aims

Intra-articular administration of antibiotics during primary total knee arthroplasty (TKA) may represent a safe, cost-effective strategy to reduce the risk of acute periprosthetic joint infection (PJI). Vancomycin with an aminoglycoside provides antimicrobial cover for most organisms isolated from acute PJI after TKA. However, the intra-articular doses required to achieve sustained therapeutic intra-articular levels while remaining below toxic serum levels is unknown. The purpose of this study is to determine the intra-articular and serum levels of vancomycin and tobramycin over the first 24 hours postoperatively after intra-articular administration in primary cementless TKA.

Introduction

Periprosthetic joinTt infection (PJI) remains an uncommon, yet devastating complication of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Debridement with antibiotics and implant retention (DAIR) provides an alternative to staged revision. Chronic infection is considered to be a contraindication to DAIR, however, outcomes stratified by chronicity have not been documented.

Aims

This study investigated vancomycin-microbubbles (Vm-MBs) and meropenem (Mp)-MBs with ultrasound-targeted microbubble destruction (UTMD) to disrupt biofilms and improve bactericidal efficiency, providing a new and promising strategy for the treatment of device-related infections (DRIs).

Aims

Delayed postoperative inoculation of orthopaedic implants with persistent wound drainage or bacterial seeding of a haematoma can result in periprosthetic joint infection (PJI). The aim of this in vivo study was to compare the efficacy of vancomycin powder with vancomycin-eluting calcium sulphate beads in preventing PJI due to delayed inoculation.

Aim

To retrospectively evaluate infection eradication rate of DAIR procedures performed in our tertiary referral center. We analyzed whether the outcome was influenced by time of infection after arthroplasty, previous surgery or causative pathogen.

Introduction

Treatment of prosthetic joint infection (PJI) following total knee arthroplasty (TKA) may guided by PJI classification, taking into account infection duration and potential for biofilm formation. Debridement, antibiotics and implant retention (DAIR) is recommended for ‘post-operative’ and ‘acute’ haematogenous PJI. However, the time cut-off for ‘post-operative’ PJI varies across classification systems. Furthermore, poor DAIR success rates have been reported in acute haematogenous PJIs. This study aimed to determine the success of DAIR in a large cohort of PJIs, and assess the utility of current classification systems for predicting DAIR outcomes.

The reported success rate after treatment with debridement, antibiotics and implant retention (DAIR) of hip prosthesis infections has been found variable. We evaluated all reoperations performed because of infection and reported to Swedish Hip Arthroplasty Register (SHAR) between 1999 and 2016. The analyses were separated into reoperations performed for the first time and those which had been preceded by at least one previous reoperation performed because of the same reason. The outcome was repeated reoperation performed because of infection.

1,882 were first-time procedures (Group I) and 2,275 had been preceded by at least one reoperation due to infection (Group II). Head and/or liner exchange had been performed in 47% of the cases in group I, and in 22% in Group II. The mean age varied between 70 and 71 years and there was a dominance of males in all groups (52–59%). Compared to all primary THR performed during this period (n=319,813) patients with inflammatory disease, idiopathic femoral head necrosis and sequel after childhood disease were overrepresented for this type of procedure.

Between 1999 and 2016 the number of DAIR procedures increased from 29 to 383 per year corresponding to 21 and 72 % of all reoperations performed due to infection. In first time reoperations the survival was 74.5±3.1% if the head/liner had been exchanged and 46.2±3.2% if only irrigation and synovectomy had been performed. In patients reoperated at least one time previously due to infection the survival rates dropped to 68.6±4.6% and 34.5±2.4%.

Compared to first time reoperation with exchange of femoral and/or liner, synovectomy and irrigation without exchange of any implant part(s) resulted in an almost tripled risk of a second reoperation due to same reason (Hazard Ratio: 2.8, 95% confidence interval: 2.4–3.3). In cases previously reoperated because of infection (Group II) exchange of head/liner and debridement had a 28% increased risk of failure compared to the corresponding first time reoperations (1.28 1.02–1.6). If none of the components were replaced in Group II, the risk ratio for a new failure increased almost 4 times (3.8 3.3–4.4). Presence of a cemented stem increased the risk for further reoperations due to infection (1.14 1.02–1.28), but not presence of a cemented cup (1.06 0.92–1.19). All hazard ratios were adjusted for age, gender, diagnosis and type of fixation.

The comparatively good results observed after exchange of head and liner might indicate that this is necessary to perform a sufficiently radical debridement. This observation could also be biased by a surgeon related factor suggesting that component exchange mainly is performed by surgeons with long experience of revision surgery.

Aim

The increase of antimicrobial resistance reduces treatment options for implant-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Bacteriophages present a promising alternative to treat biofilm-related infections due to their rapid bactericidal activity and activity on multi-drug resistant bacteria. In this study, we investigated the synergistic activity of lytic bacteriophage Sb-1 with different antibiotics against MRSA biofilm, using a real-time highly sensitive assay measuring growth-related heat production (microcalorimetry).

Aims

Poly(methyl methacrylate) (PMMA)-based bone cements are the industry standard in orthopaedics. PMMA cement has inherent disadvantages, which has led to the development and evaluation of a novel silorane-based biomaterial (SBB) for use as an orthopaedic cement. In this study we test both elution and mechanical properties of both PMMA and SBB, with and without antibiotic loading.

Aim

Previous studies of primary internal fixation of infected non-unions have reported high failure rates. Local antibiotic carriers and coatings have been advocated to reduce infection around implants and allow bone healing. We evaluated the effect of a calcium sulphate/hydroxyapatite antibiotic-loaded composite on bone healing and the eradication of infection in combination with internal fixation.