Antibiotic resistance profiles of deep surgical site infections in hip hemiarthroplasty; comparing low dose single antibiotic versus high dose dual antibiotic impregnated cement

Risk for re-revision and type of antibiotic-loaded bone cement in hip or knee arthroplasty revisions: report of the Dutch Arthroplasty Register

BACKGROUND AND PURPOSE

High-dose dual antibiotic-loaded bone cement (ALBC) may reduce the risk of revision after total hip and knee replacements. The aim of our study therefore was to determine the risk of re-revision following first time aseptic hip or knee revision using single versus dual ALBC.

PATIENTS AND METHODS

Patients from the Dutch Arthroplasty Register treated from 2007 to 2018 with first time cemented aseptic hip (n = 2,529) or knee revisions (n = 7,124) were incorporated into 2 datasets. The primary endpoint of this observational cohort study was subsequent all-cause re-revision. Multivariable Cox proportional hazard and competing risk was analyzed for both groups.

RESULTS

There was no difference in re-revision rate (any reason) with single versus dual ALBC (hazard ratio 1.06, 95% confidence interval [CI] 0.83-1.35 for hip and 0.93, CI 0.80-1.07 for knee revisions). The 10-year crude cumulative re-revision rate also showed no differences for single versus dual ALBC use. The crude cumulative 7-year THA re-revision and 9-year TKA re-revision rates did not show any difference in implant survival for common cement types used.

CONCLUSION

We could not confirm the potential benefit of using dual ALBC compared with single ALBC for aseptic hip and knee revisions.

A Low Rate of Periprosthetic Infections after Aseptic Knee Prosthesis Revision Using Dual-Antibiotic-Impregnated Bone Cement

AIM

The incidence of periprosthetic joint infections (PJI) following aseptic knee revision arthroplasty lies between 3% and 7.5%. The aim of this study was to verify the hypothesis that the use of dual-antibiotic-impregnated cement in knee revision arthroplasty leads to a lower rate of periprosthetic joint infections.

METHODS

We retrospectively reviewed 403 aseptic revision knee arthroplasties performed between January 2013 and March 2021 (148 revisions of a unicompartmental prosthesis, 188 revisions of a bicondylar total knee arthroplasty (TKA), 41 revisions of an axis-guided prosthesis, and 26 revisions of only one component of a surface replacement prosthesis). The bone cement Copal G+C (Heraeus Medical, Wertheim, Germany) with two antibiotics-gentamycin and clindamycin-was used for the fixation of the new implant. The follow-up period was 53.4 ± 27.9 (4.0-115.0) months.

RESULTS

Five patients suffered from PJI within follow-up (1.2%). The revision rate for any reason was 8.7%. Survival for any reason was significantly different between the types of revision (p = 0.026, Log-Rank-test), with lower survival rates after more complex surgical procedures. The 5-year survival rate with regard to revision for any reason was 91.3% [88.2-94.4%] and with regard to revision for PJI 98.2% [98.7-99.9%], respectively.

CONCLUSION

The use of the dual-antibiotic-impregnated bone cement Copal G+C results in a lower rate of periprosthetic infections after aseptic knee prosthesis replacement than that reported in published prosthesis revisions using only one antibiotic in the bone cement.

High-dose dual-antibiotic loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomised controlled trial

BACKGROUND

Hip fracture is the most common injury requiring treatment in hospital. Controversy exists regarding the use of antibiotic loaded bone cement in hip fractures treated with hemiarthroplasty. We aimed to compare the rate of deep surgical site infection in patients receiving high-dose dual-antibiotic loaded cement versus standard care single-antibiotic loaded cement.

METHODS

We included people aged 60 years and older with a hip fracture attending 26 UK hospitals in this randomised superiority trial. Participants undergoing cemented hemiarthroplasty were randomly allocated in a 1:1 ratio to either a standard care single-antibiotic loaded cement or high-dose dual-antibiotic loaded cement. Participants and outcome assessors were masked to the treatment allocation. The primary outcome was deep surgical site infection at 90 days post-randomisation as defined by the US Centers for Disease Control and Prevention in an as-randomised population of consenting participants with available data at 120 days. Secondary outcomes were quality of life, mortality, antibiotic use, mobility, and residential status at day 120. The trial is registered with ISRCTN15606075.

FINDINGS

Between Aug 17, 2018, and Aug 5, 2021, 4936 participants were randomly assigned to either standard care single-antibiotic loaded cement (2453 participants) or high-dose dual-antibiotic loaded cement (2483 participants). 38 (1·7%) of 2183 participants with follow-up data in the single-antibiotic loaded cement group had a deep surgical site infection by 90 days post-randomisation, as did 27 (1·2%) of 2214 participants in the high-dose dual-antibiotic loaded cement group (adjusted odds ratio 1·43; 95% CI 0·87-2·35; p=0·16).

INTERPRETATION

In this trial, the use of high-dose dual-antibiotic loaded cement did not reduce the rate of deep surgical site deep infection among people aged 60 years or older receiving a hemiarthroplasty for intracapsular fracture of the hip.

FUNDING

Heraeus Medical. Supported by the UK National Institute for Health and Care Research Oxford Biomedical Research Centre.

The Prophylactic Effect of Single vs. Dual Antibiotic-Loaded Bone Cement against Periprosthetic Joint Infection Following Hip Arthroplasty for Femoral Neck Fracture: An Analysis of the German Arthroplasty Registry

BACKGROUND

Antibiotic-loaded bone cement in arthroplasties is currently experiencing increased usage. Therefore, single and double antibiotic-loaded bone cements are commercially available and used in orthopedic surgery. The aim of this investigation was to compare the clinical use of single compared to dual antibiotic-loaded bone cement for implant fixation after femoral neck fracture. Further infection rates were to be compared in (partial) arthroplasty for the treatment of femoral neck fracture for both treatment options.

METHODS

On the basis of the German Arthroplasty Registry (EPRD), all cases of femoral neck fracture treated with hemiarthroplasty (HA), or total hip arthroplasty (THA) with single and dual antibiotic-loaded bone cement, were included into the data analysis. The infection risk was compared using Kaplan-Meier estimates.

RESULTS

In total, 26,845 cases (HA 76.3%-THA: 23.7%) with femoral neck fracture were included. Within recent years, an increasing usage of dual antibiotic-loaded cement in Germany, with a current proportion of 7.30% in arthroplasty procedures for femoral neck fracture treatment, has been observed. In patients treated with HA, the proportion of dual antibiotic-loaded cement was 7.86%, while in those treated with THA, 5.46% of all prostheses were fixated with a two antibiotic component cement. For all arthroplasty procedures using single antibiotic-loaded bone cement after six months 1.8%, after one year 1.9%, and after five years 2.3%, of the cases failed due to periprosthetic joint infection (PJI), while in the same time period, in cases with dual antibiotic-loaded bone cement 1.5%, 1.5% and 1.5% suffered from infection (p = 0.34). A infection rate of 1.1% after HA with dual antibiotic-loaded bone cement was reported, compared to a 2.1% infection rate whilst using single antibiotic-loaded bone cement after five years (p = 0.098). The number required for treatment when using HA was 91.

CONCLUSIONS

The use of dual antibiotic-loaded bone cement is increasingly used in arthroplasty procedures after femoral neck fractures. It demonstrates a reduction of PJI after HA and seems, therefore, to be a useful method for the prevention of infection, especially in patients with increased risk factors for PJI.

Antimicrobials in polymethylmethacrylate: from prevention to prosthetic joint infection treatment: basic principles and risk of resistance

BACKGROUND

Excellent revisions about antibiotic-loaded bone cement (ALBC) have been recently published. In the present article, we review the principles and limitations of local antibiotic delivery in the context of recent advances in the pathogenesis of prosthetic joint infections (PJI), with particular attention paid to the potential association between ALBC and antimicrobial resistance.

MAIN BODY

Recalcitrance of PJI is related to the ability of pathogens to adapt to particular environments present in bone tissue and protect themselves from host immunity in different ways. Accordingly, delivery of high local antimicrobial concentrations using ALBC is needed. Most relevant clinical data showing the efficacy of ALBC for PJI prophylaxis and treatment are reviewed, and we dissected the limitations on the basis of the recent findings from animal models and suggested that aminoglycosides, in particular, could not be the best option. One of the major concerns associated with ALBC is the emergence of resistance because of theoretical prolonged exposure to low antibiotic concentrations. We summarize the mechanisms for the selection of resistant microorganisms, and we critically reviewed the evidence from animal models and clinical data from observational and registry studies and concluded that there is no evidence to support this association.

CONCLUSION

While waiting for better evidence from well-designed clinical trials, ALBC shows a beneficial effect as a prophylaxis in arthroplasty, and to avoid the colonization of spacers used for two-stage revision in patients with PJI. Experimental models and clinical evidence suggest the need to achieve high local antimicrobial concentrations to obtain the highest prophylactic and therapeutic effect. The current evidence does not support the risk of increasing resistance with use of ALBC. In the future, it is necessary to evaluate new carriers and different antimicrobials to improve clinical outcomes.

Meropenem-loaded Cement Is Effective in Preventing Gram-negative Osteomyelitis in an Animal Model

BACKGROUND

Low-dose antibiotic-loaded acrylic cement is routinely used for preventing skeletal infection or reimplantation in patients with periprosthetic joint infections. However, few reports about the selection of antibiotics in acrylic cement for antigram-negative bacteria have been proposed.

QUESTIONS/PURPOSES

(1) Does the addition of antibiotics (tobramycin, meropenem, piperacillin, ceftazidime, ciprofloxacin, and aztreonam) to acrylic cement adversely affect compressive strength before and after elution? (2) Which antibiotics have the highest cumulative release within 28 days? (3) Which antibiotics showed antimicrobial activity within 28 days? (4) Does meropenem-loaded cement improve body weight, temperature, and other inflammatory markers compared with control unloaded cement?

METHODS

This is an in vitro study that assessed the mechanical strength, antibiotic elution, and antibacterial properties of antibiotic-loaded cement, combined with an animal study in a rat model that evaluated key endpoints from the animal study. In the in vitro study, we added 2 g of tobramycin (TOB), meropenem (MEM), piperacillin (PIP), ceftazidime (CAZ), ciprofloxacin (CIP), and aztreonam (ATM) to 40 g of acrylic cement. The compressive strength, elution, and in vitro antibacterial properties of the antibiotic-loaded cement were detected. Thirty male rats were randomly divided into two groups: CON (antibiotic-unloaded cement) and MEM (meropenem-loaded cement, which had the most stable antibacterial properties of the six tested antibiotic-loaded cements in vitro within 28 days). The right tibia of all rats underwent arthroplasty and was implanted with the cement, followed by inoculation with Pseudomonas aeruginosa in the knee. General status, serum biomarkers, radiology, microbiological assay, and histopathological tests were assessed over 14 days postoperatively.

RESULTS

The compressive strength of all tested antibiotic cement combinations exceeded the 70 MPa threshold (the requirement established in ISO 5833). The cumulative release proportions of the raw antibiotic in cement were 1182.8 ± 37.9 µg (TOB), 355.6 ± 16.2 µg (MEM), 721.2 ± 40.3 µg (PIP), 477.4 ± 37.1 µg (CAZ), 146.5 ± 11.3 µg (CIP), and 372.1 ± 14.5 µg (ATM) within 28 days. Over a 28-day period, meropenem cement demonstrated antimicrobial activities against the four tested gram-negative bacteria ( Escherichia coli , P. aeruginosa , Klebsiella pneumoniae , and Proteus vulgaris ). Ciprofloxacin cement inhibited E. coli growth, ceftazidime and aztreonam cement inhibited K. pneumonia growth, and tobramycin cement inhibited P. aeruginosa . Only meropenem demonstrated antimicrobial activity against all gram-negative bacteria on agar diffusion bioassay. Rats treated with meropenem cement showed improved body weight (control: 280.1 ± 4.2 g, MEM: 288.5 ± 6.6 g, mean difference 8.4 [95% CI 4.3 to 12.6]; p < 0.001), improved knee width (control: 13.5 ± 0.3 mm, MEM: 11.8± 0.4 mm, mean difference 1.7 [95% CI 1.4 to 2.0]; p < 0.001), decreased inflammatory marker (control: 316.7 ± 45.0 mm, MEM: 116.5 ± 21.8 mm, mean difference 200.2 [95% CI 162.3 to 238.2]; p < 0.001), decreased radiographic scores (control: 17.7 ± 2.0 mm, MEM: 10.7± 1.3 mm, mean difference 7.0 [95% CI 5.4 to 8.6]; p < 0.001), improved bone volume/total volume (control: 8.7 ± 3.0 mm, MEM: 28.5 ± 5 .5 mm, mean difference 19.8 [95% CI 13.3 to 26.2]; p < 0.001), decreased Rissing scale scores of the knee gross pathology (control: 3.3 ± 0.5, MEM: 1.1 ± 0.7, mean difference 2.2 [95% CI 1.7 to 2.7]; p < 0.001), decreased Petty scale scores of knee synovium (control: 2.9 ± 0.4 mm, MEM: 0.7 ± 0.7 mm, mean difference 2.1 [95% CI 1.7 to 2.5]; p < 0.001), and decreased bacterial counts of the bone and soft tissues and negative bacterial cultures of cement (p < 0.001, p < 0.001, p < 0.001, p < 0.001, respectively).

CONCLUSION

In this current study, MEM cement had the most stable in vitro antimicrobial activities, effective in vivo activity while having acceptable mechanical and elution characteristics, and it may be an effective prophylaxis against skeletal infection caused by gram-negative bacteria.

CLINICAL RELEVANCE

Meropenem-loaded acrylic cement is a potentially effective prevention measure for skeletal infection caused by gram-negative bacteria; however, more related clinical research is needed to further evaluate the safety and efficacy.

Study protocol: The DAICY trial-dual versus single-antibiotic impregnated cement in primary hemiarthroplasty for femoral neck fracture-a register-based cluster-randomized crossover-controlled trial

BACKGROUND AND PURPOSE

Older patients with a displaced femoral neck fracture (FNF) are often treated with a cemented primary hemiarthroplasty (HA). The DAICY trial investigates whether high-dose dual-impregnated antibioticloaded cement (DIAC) including gentamicin and clindamycin can reduce the risk of periprosthetic joint infection (PJI) in comparison with low-dose single-impregnated gentamicin antibiotic-loaded cement (SIAC), in patients ≥ 60 years treated with a cemented HA for a displaced FNF.

STUDY DESIGN

The trial is a national, multicenter, register-based, cluster-randomized, crossover trial. Patients ≥ 60 years with a non-pathological, displaced FNF (Type Garden 3-4/AO 31-B2 or B3) suitable for HA according to local guidelines are eligible for inclusion. Participating orthopedic departments will be randomized to start with either SIAC (control group) or DIAC treatment (intervention group) for 2 years. After 2 years, the study departments will then change to the other treatment arm for the remaining 2 years of the study. Approximately 7,000 patients will be included. The study is pragmatic in that the choice of implant brands, surgical approach and peri- and postoperative protocols follow the local routines of each participating department. All outcome variables will be retrieved after linkage of the study cohort to the following Swedish registers: the Fracture Register, the Arthroplasty Register, the National Patient Register and the Prescribed Drug Registry Outcome: The primary outcome will be periprosthetic joint infection of the index joint within 1 year after surgery. Secondary outcomes will be any reoperation on the index joint, mortality within 90 days and 1 year, resistance patterns of causative bacteria in cases of PJI, and health economics. Potential added value: This trial is designed to support or refute the efficacy of DIAC used in patients with a displaced FNF, potentially reducing PJI and resource allocation. Start of the trial and estimated duration - The DAICY trial started recruiting patients in January 2022 and will continue recruiting for approximately 4 years. Complete follow-up expected in 5 years.

Patients at a high risk of PJI: Can we reduce the incidence of infection using dual antibiotic-loaded bone cement?

Prosthetic joint infection (PJI) is one of the most devastating complications of orthopedic surgery. However, not all patients are equally at the risk of severe infection. The incidences of PJI vary with the host and surgery-related risk factors. It is now generally accepted that some important medical comorbidities may predispose the patients to a high risk of PJI. Time-consuming and invasive surgical procedures, such as revision arthroplasties, are also associated with a high incidence of PJI, presumably due to the increased risk of surgical site contamination. Effective infection-preventing strategies should begin with identifying and optimizing the patients at a high risk of infection prior to surgery. Optimizing the operating room environment and antibiotic prophylaxis are also essential strategies that help minimize the overall incidence of infection in orthopedic surgery. The ideal antibiotic prophylaxis is still under debate, and discussions have emerged about whether variations or adjustments to the standard protocol are justified in patients at a high risk of infection. This also includes evaluating the possible benefits and risks of using high-dose dual antibiotic-loaded bone cement instead of low-dose single antibiotic-loaded bone cement in arthroplasty. This review summarizes the evidence showing that the combination of two local antibiotics in bone cement exerts a strong and longer-lasting antimicrobial effect against PJI-associated pathogens. This conclusion is consistent with the preliminary clinical studies showing a low incidence of PJI in high-risk patients undergoing cemented hemiarthroplasty, cemented revision, and primary arthroplasty if dual ALBC is used. These results may encourage clinicians to consolidate this hypothesis in a wider clinical range.

Management of Periprosthetic Joint Infections After Hemiarthroplasty of the Hip: A Critical Analysis Review

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Periprosthetic joint infection (PJI) following hip hemiarthroplasty (HA) is a devastating complication, incurring immense health-care costs associated with its treatment and placing considerable burden on patients and their families. These patients often require multiple surgical procedures, extended hospitalization, and prolonged antimicrobial therapy.

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Notable risk factors include older age, higher American Society of Anesthesiologists (ASA) score, inadequate antibiotic prophylaxis, non-antibiotic-loaded cementation of the femoral implant, longer duration of the surgical procedure, and postoperative drainage and hematoma.

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Although the most frequent infecting organisms are gram-positive cocci such as Staphylococcus aureus, there is a higher proportion of patients with gram-negative and polymicrobial infections after hip HA compared with patients who underwent total hip arthroplasty.

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Several surgical strategies exist. Regardless of the preferred surgical treatment, successful management of these infections requires a comprehensive surgical debridement focused on eradicating the biofilm followed by appropriate antibiotic therapy.

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A multidisciplinary approach led by surgeons familiar with PJI treatment and infectious disease specialists is recommended for all cases of PJI after hip HA to increase the likelihood of treatment success.

Poly(DL-lactic acid) scaffolds as a bone targeting platform for the co-delivery of antimicrobial agents against S. aureus-C. albicans mixed biofilms

New strategies for the treatment of polymicrobial bone infections are required. In this study, the co-delivery of two antimicrobials by poly(D,L-lactic acid) (PDLLA) scaffolds was investigated in a polymicrobial biofilm model. PDLLA scaffolds were prepared by solvent casting/particulate leaching methodology, incorporating minocycline and voriconazole as clinically relevant antimicrobial agents. The scaffolds presented a sponge-like appearance, suitable to support cell proliferation and drug release. Single- and dual-species biofilm models of Staphylococcus aureus and Candida albicans were developed and characterized. S. aureus presented a higher ability to form single-species biofilms, compared to C. albicans. Minocycline and voriconazole-loaded PDLLA scaffolds showed activity against S. aureus and C. albicans single- and dual-biofilms. Ultimately, the cytocompatibility/functional activity of PDLLA scaffolds observed in human MG-63 osteosarcoma cells unveil their potential as a next-generation co-delivery system for antimicrobial therapy in bone infections.

Cement Loaded With High-Dose Gentamicin and Clindamycin Reduces the Risk of Subsequent Infection After One-Stage Hip or Knee Arthroplasty Exchange for Periprosthetic Infection: A Preliminary Study

BACKGROUND

The use of antibiotic-loaded acrylic cement for treating periprosthetic joint infections remains controversial. We hypothesized that the raw rate of surgical site infection (SSI) is lower after using cement loaded with high-dose gentamicin and clindamycin than after using cement loaded with standard-dose gentamicin for implant fixation during 1-stage hip and knee revision arthroplasty for infection.

METHODS

One hundred seventy-one continuous patients operated by 2 experienced surgeons during a 2-year period were included in the study. All patients were followed for 24 months. The primary endpoint was the raw rate of SSI after 2 years of follow-up time.

RESULTS

The raw rate of SSI after 2 years of follow-up time was significantly lower in the study group (13%) than in the control group (26%) (P = .03) with an odds ratio of 0.42 (P = .03). These SSIs were new infections rather than a recurrence/persistence of the initial infection.

CONCLUSION

The cement used in the study group significantly reduced the risk of SSI relative to the cement used in the control group. Routine use of this high-dose dual antibiotic-loaded cement can be considered during 1-stage knee or hip revision arthroplasty for infection.

Properties of Orthopaedic Cements Biomechanically Little Affected by Exceptional Use of Liquid Antibiotics

OBJECTIVES

To specify the concentration of the liquid antibiotics to be added to polymethylmethacrylate (PMMA) and its impact on the quality of the spacer is the purpose of this study with liquid clindamycin added to different cements.

METHODS

In the present study, eight different cement mixtures were prepared and investigated. In the following, number 1 indicates the references, 2 all cements after liquid clindamycin was added to the liquid cement compound, 3 all cements after liquid clindamycin was added to the cement powder, and 4 all cements after liquid clindamycin was added to the cement dough. After curing, cements were filled into metal moulds and a pressure of 3 bar was maintained for 30 min. Mechanical investigations were carried out according to ISO 5833 (2002) and DIN 53435 (2007). For microbiological tests, standardized cylindrical mouldings (diameter: 25 mm, height: 10 mm) were produced and incubated in 10 ml buffer solution at room temperature for 24 h. All eluates were generated by spreading previously established suspensions of Staphylococcus aureus, Staphylococcus epidermidis, Cutibacterium acnes and methicillin-resistant Staphylococcus aureus (MRSA) with a 0.5 McFarland turbidity standard.

RESULTS

Apparently, we found that in all investigated cases, the admixture of liquid antibiotic negatively affected the mechanical characteristics of the cement mould. Among the various test groups, the influence on the ISO compression strength and ISO flexural modulus of the investigated test groups was only minimal when liquid clindamycin was added to cement liquid. Compared to admixing of liquid clindamycin into cement powder or dough ISO compression strength and ISO flexural modulus and flexural strength showed the maximum reduction. The efficacy against chosen germs was reduced as well when liquid antibiotic was admixed instead of powder. This admixture of liquid anti-infective agents resulted in a 234% enhanced elution after 10 days 29 a negative effect on the inhibition zones were detected during the previous period.

CONCLUSION

The admixture of powdery antibiotic is preferable to liquid antibiotics. If no powdery antibiotic is available, we can recommend the admixture of liquid antibiotic to liquid cement prior to dough production in case powdery antibiotics cannot be used. However, we discourage the admixture of liquid antibiotic to cement powder or cement dough during early low viscose phase.

Dual antibiotic loaded bone cement in patients at high infection risks in arthroplasty: Rationale of use for prophylaxis and scientific evidence

In view of the demographic changes and projected increase of arthroplasty procedures worldwide, the number of prosthetic joint infection cases will naturally grow. Therefore, in order to counteract this trend more rigid rules and a stricter implementation of effective preventive strategies is of highest importance. In the absence of a “miracle weapon” priorities should lie in evidence-based measures including preoperative optimization of patients at higher infection risks, the fulfilment of strict hygiene rules in the operating theatre and an effective antibiotic prophylaxis regimen. Instead of a “one size fits all” philosophy, it has been proposed to adjust the antibiotic prophylaxis protocol to major infection risks taking into account important patient- and procedure-related risk factors. A stronger focus on the local application mode via use of high dose dual antibiotic-loaded bone cement in such risk situations may have its advantages and is easy to apply in the theatre. The more potent antimicrobial growth inhibition in vitro and the strong reduction of the prosthetic joint infection rate in risk for infection patients with aid of dual antibiotic-loaded bone cement in clinical studies align with this hypothesis.

A randomized clinical trial of low dose single antibiotic-loaded cement versus high dose dual antibiotic-loaded cement in patients receiving a hip hemiarthroplasty after fracture: A protocol for the WHiTE 8 COPAL study

AIMS

Patients receiving cemented hemiarthroplasties after hip fracture have a significant risk of deep surgical site infection (SSI). Standard UK practice to minimize the risk of SSI includes the use of antibiotic-loaded bone cement with no consensus regarding type, dose, or antibiotic content of the cement. This is the protocol for a randomized clinical trial to investigate the clinical and cost-effectiveness of high dose dual antibiotic-loaded cement in comparison to low dose single antibiotic-loaded cement in patients 60 years and over receiving a cemented hemiarthroplasty for an intracapsular hip fracture.

METHODS

The WHiTE 8 Copal Or Palacos Antibiotic Loaded bone cement trial (WHiTE 8 COPAL) is a multicentre, multi-surgeon, parallel, two-arm, randomized clinical trial. The pragmatic study will be embedded in the World Hip Trauma Evaluation (WHiTE) (ISRCTN 63982700). Participants, including those that lack capacity, will be allocated on a 1:1 basis stratified by recruitment centre to either a low dose single antibiotic-loaded bone cement or a high dose dual antibiotic-loaded bone cement. The primary analysis will compare the differences in deep SSI rate as defined by the Centers for Disease Control and Prevention within 90 days of surgery via medical record review and patient self-reported questionnaires. Secondary outcomes include UK Core Outcome Set for hip fractures, complications, rate of antibiotic prescription, resistance patterns of deep SSI, and resource use (more specifically, cost-effectiveness) up to four months post-randomization. A minimum of 4,920 patients will be recruited to obtain 90% power to detect an absolute difference of 1.5% in the rate of deep SSI at 90 days for the expected 3% deep SSI rate in the control group.

CONCLUSION

The results of this trial will provide evidence regarding clinical and cost-effectiveness between low dose single and high dose dual antibiotic-loaded bone cement, which will inform policy and practice guidelines such as the National Institute for Health and Care Excellence guidance on management of hip fractures. Cite this article: Bone Jt Open 2021;2(2):72-78.

Is Dual Antibiotic-Loaded Bone Cement More Effective and Cost-Efficient Than a Single Antibiotic-Loaded Bone Cement to Reduce the Risk of Prosthetic Joint Infection in Aseptic Revision Knee Arthroplasty?

BACKGROUND

Higher rates of prosthetic joint infections (PJIs) are related to patient risk factors and/or to special surgical procedures such as revision total knee arthroplasty (rTKA). Among the measures discussed to better protect those patients from the higher infection risks use of dual antibiotic-loaded bone cement has emerged as a further prophylactic option.

METHODS

This retrospective study included 246 patients undergoing strictly aseptic revision knee arthroplasty at our institution in the time period 2015-2018. Based on the type of bone cement used for the cementation of the revision prosthesis, 2 groups were defined. In total, 143 patients received the low-dose single antibiotic-loaded bone cement (SALBC) PALACOS R+G and 103 patients received the high-dose dual antibiotic-loaded bone cement (DALBC) COPAL G+C. The number of PJI cases in each group over a follow-up time of minimum 1 year was compared and the extra costs for the DALBC use calculated against the economic savings per each avoided PJI case on basis of 3 different assumptions (treatment costs and amount of cement use).

RESULTS

Use of DALBC in aseptic rTKA was associated with a significant reduction in PJI cases (relative risk = 57%, PJI rate in the SALBC group 4.1% vs 0% in the DALBC group, P = 0.035). The calculated total savings per patient was $1367. Depending on the economic assumptions the range of savings was between $1413 (less favorable calculation model) and $3661 (most favorable calculation model).

CONCLUSION

The use of DALBC in rTKA has been found to be more effective in preventing PJI and proved cost-efficient in all our cost-calculation models.

Antibiotics and cement: what I need to know?

We conducted a systematic review about antibiotic-loaded bone cement (ALBC) with a focus on clinical evidence about ALBC in general, concerns about ALBC and ALBC cost.

Antibiotic Choice: The Synergistic Effect of Single vs Dual Antibiotics

INTRODUCTION

This review summarizes single vs dual antibiotic cement literature, evaluating for synergistic activity with dual antibiotics.

METHODS

A systematic review was performed for literature regarding dual antibiotics in cement, identifying 13 studies to include for review.

RESULTS

Many in vitro studies reported higher elution from cement and/or improved bacteria inhibition with dual antibiotics, typically at higher dosages with a manual mixing technique. Limited clinical data from hip hemiarthroplasties and spacers demonstrated that dual antibiotics were associated with improved infection prevention and higher intra-articular antibiotic concentrations.

CONCLUSION

In addition to broader pathogen coverage, several studies document synergy of elution and increased antibacterial activity when dual antibiotics are added to cement. Limited clinical evidence suggests that dual antibiotic cement may be associated with reduced infection rates.

Impact of Multi-Drug-Resistant Pneumonia on Outcomes of Critically Ill Trauma Patients

Background: Rates of infections with multi-drug-resistant organisms (MDROs) are increasing among critically ill patients. Among non-surgical patients, MDROs increase directly the risk of adverse secondary events including death. However, similar effects do not appear to occur among surgical patients. Specifically, among critically injured trauma patients, it is unknown whether degree of injury versus the presence of an MDRO increases the risk of death. Methods: This is a retrospective chart review of admitted adult trauma patients. Data included demographics, medical comorbidities, injury severity score, infections, occurrence of pneumonia including microbiology sensitivity profile, hospital course, and outcomes. Results: Patients requiring adminission to the intensive care unit (ICU) were more severely injured with greater degree of thoracic and head trauma and had a greater burden of pre-trauma medical comorbidities. Among those admitted to the ICU, 93 patients developed pneumonia. Patients who developed pneumonia were younger and more severely injured, with higher rates of thoracic and head injuries and higher rates of smoking. Development of pneumonia was associated with worse outcomes. However, among patients with pneumonia, comparing MDRO to pan-sensitive (PanSens) infections, PanSens infection occurred earlier and were more likely associated with pre-trauma smoking status. There was no difference in injury patterns, medical comorbidities, or outcomes. Conclusion: The development of pneumonia among trauma patients reflects degree of injury and underlying medical status. However, development of MDRO versus PanSens pneumonia did not affect trauma-related outcomes further. This information will guide family discussions and critical care decisions better among vulnerable trauma patients.

Antibiotic-loaded bone cement is associated with a lower risk of revision following primary cemented total knee arthroplasty: an analysis of 731,214 cases using National Joint Registry data

AIMS

Antibiotic-loaded bone cements (ALBCs) may offer early protection against the formation of bacterial biofilm after joint arthroplasty. Use in hip arthroplasty is widely accepted, but there is a lack of evidence in total knee arthroplasty (TKA). The objective of this study was to evaluate the use of ALBC in a large population of TKA patients.

MATERIALS AND METHODS

Data from the National Joint Registry (NJR) of England and Wales were obtained for all primary cemented TKAs between March 2003 and July 2016. Patient, implant, and surgical variables were analyzed. Cox proportional hazards models were used to assess the influence of ALBC on risk of revision. Body mass index (BMI) data were available in a subset of patients.

RESULTS

Of 731 214 TKAs, 15 295 (2.1%) were implanted with plain cement and 715 919 (97.9%) with ALBC. There were 13 391 revisions; 2391 were performed for infection. After adjusting for other variables, ALBC had a significantly lower risk of revision for any cause (hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77 to 0.93; p < 0.001). ALBC was associated with a lower risk of revision for all aseptic causes (HR 0.85, 95% CI 0.77 to 0.95; p < 0.001) and revisions for infection (HR 0.84, 95% CI 0.67 to 1.01; p = 0.06). The results were similar when BMI was added into the model, and in a subanalysis where surgeons using only ALBC over the entire study period were excluded. Prosthesis survival at ten years for TKAs implanted with ALBC was 96.3% (95% CI 96.3 to 96.4) compared with 95.5% (95% CI 95.0 to 95.9) in those implanted with plain cement. On a population level, where 100 000 TKAs are performed annually, this difference represents 870 fewer revisions at ten years in the ALBC group.

CONCLUSION

After adjusting for a range of variables, ALBC was associated with a significantly lower risk of revision in this registry-based study of an entire nation of primary cemented knee arthroplasties. Using ALBC does not appear to increase midterm implant failure rates. Cite this article: Bone Joint J 2019;101-B:1331-1347.

Risk assessment of antibiotic resistance development by antibiotic-loaded bone cements: is it a clinical concern?

Because of the risk of bacterial biofilm infections, prophylactic use of antibiotics in orthopaedic procedures involving the implantation of large prosthesis systems is considered mandatory.

A strategy based on the rationale that local antibiotics released from bone cement or other carriers establish a second antibacterial frontline in and around the prosthesis is considered complementary to the administration of systemic antibiotics.

Although less common as a consequence of the initially very high drug concentrations of local antibiotics in the tissues, a selection process of previous high resistance bacteria may occur, leading to antibiotic resistance.

The use of antibiotic combinations in bone cement is generally accepted to improve antibiotic efficacy and minimizes the treatment failure risk due to antibiotic resistance. This is important in septic revisions and/or in patients at particularly high risk of infection.

On an individual basis, the benefit of a lower infection probability with combined systemic and local antibiotic application should outweigh the risk of the selection of more resistant bacteria. Each prevented infection means that a complex and extended antibiotic therapy with risk of resistance development over time has been avoided.

On an epidemiological level there is no clinical evidence that the routine use of bone cement impregnated with appropriate bactericidal antibiotics promotes the widespread development of antibiotic resistance and thereby puts the successful treatment of a prosthetic joint infection at higher risk.

Cite this article: EFORT Open Rev 2019;4:576-584. DOI: 10.1302/2058-5241.4.180104

Activation of Pregnane X Receptor Sensitizes Mice to Hemorrhagic Shock-Induced Liver Injury

Hemorrhagic shock (HS) is a life-threatening condition associated with tissue hypoperfusion and often leads to injury of multiple organs including the liver. Pregnane X receptor (PXR) is a species-specific xenobiotic receptor that regulates the expression of drug-metabolizing enzymes (DMEs) such as the cytochrome P450 (CYP) 3A. Many clinical drugs, including those often prescribed to trauma patients, are known to activate PXR and induce CYP3A. The goal of this study is to determine whether PXR plays a role in the regulation of DMEs in the setting of HS and whether activation of PXR is beneficial or detrimental to HS-induced hepatic injury. PXR transgenic, knockout, and humanized mice were subject to HS, and the liver injury was assessed histologically and biochemically. The expression and/or activity of PXR and CYP3A were manipulated genetically or pharmacologically in order to determine their effects on HS-induced liver injury. Our results showed that genetic or pharmacological activation of PXR sensitized wild-type and hPXR/CYP3A4 humanized mice to HS-induced hepatic injury, whereas knockout of PXR protected mice from HS-induced liver injury. Mechanistically, the sensitizing effect of PXR activation was accounted for by PXR-responsive induction of CYP3A and increased oxidative stress in the liver. The sensitizing effect of PXR was attenuated by ablation or pharmacological inhibition of CYP3A, treatment with the antioxidant N-acetylcysteine amide, or treatment with a PXR antagonist. Conclusion: We have uncovered a function of PXR in HS-induced hepatic injury. Our results suggest that the unavoidable use of PXR-activating drugs in trauma patients has the potential to exacerbate HS-induced hepatic injury, which can be mitigated by the coadministration of antioxidative agents, CYP3A inhibitors, or PXR antagonists.