High concentration and bioactivity of vancomycin and aztreonam eluted from Simplex cement spacers in two-stage revision of infected hip implants: a study of 46 patients at an average follow-up of 107 days

High Incidence of Acute Kidney Injury Following Antibiotic-Loaded Spacer Insertion for Periprosthetic Joint Infection: An Updated Review of the Literature

BACKGROUND

The use of antibiotic-impregnated cement during 2-stage revision arthroplasty for periprosthetic joint infection poses a risk of renal complications following spacer insertion. This systematic review aimed to investigate the rate of acute kidney injury (AKI) following antibiotic-loaded spacer insertion and to identify risk factors associated with this complication.

METHODS

A systematic review was performed using PubMed, Cochrane Central, and Scopus databases. All clinical studies that documented renal complications following antibiotic-loaded spacer insertion for periprosthetic knee (total knee arthroplasty [TKA]) or hip (total hip arthroplasty [THA]) infection were included. Articles that combined THA and TKA outcomes were also included and labeled "THA + TKA." Descriptive statistics were analyzed when data were available.

RESULTS

There were 24 studies (9 THA, 7 TKA, 8 THA + TKA) included. The mean incidences of spacer-related AKI across THA, TKA, and THA + TKA cohorts were 4.2 (range, 0 to 10%), 14 (range, 0 to 19%), and 27% (range, 0 to 35%), respectively. The most common patient-related risk factors for AKI were underlying chronic kidney disease or high baseline creatinine, low preoperative hemoglobin, and blood transfusion requirement. Spacer-related risk factors included high antibiotic dosage (>3.6 g/cement batch) and antibiotic type. While most recovered without complication, select patients required hemodialysis for acute management (2 THA, 18 THA + TKA) and/or developed chronic kidney disease (8 TKA, 8 THA).

CONCLUSION

The rate of AKI following spacer insertion was high and likely under-reported in the literature. Surgeons should be cognizant of this devastating complication and should closely monitor at-risk patients for AKI following antibiotic-loaded spacer insertion.

Therapeutic efficacy of vancomycin-loaded carbon fiber-reinforced polyetheretherketone hip stem for periprosthetic joint infection: A pilot study

A carbon fiber-reinforced polyetheretherketone (CFR/PEEK) hip stem with a special antibiotic elution mechanism is under development to treat periprosthetic joint infection (PJI). The antibiotic elution characteristics of intramedullary implants were experimentally investigated, and the efficacy of revision surgery using a therapeutic stem in treating ovine PJI was examined. To evaluate elution characteristics, the intramedullary vancomycin-loaded CFR/PEEK cylindrical implants were inserted in the distal femur of nine sheep, and the vancomycin elution rate was measured at 2, 7, and 21 days. To evaluate therapeutic efficacy, the PJI model with staphylococcus aureus was attempted to create for five sheep. Moreover, the therapeutic vancomycin-loaded CFR/PEEK stem was implanted during one-stage revision surgery. Three weeks after revision surgery, the treatment efficacy was evaluated based on bacterial cultures and wound findings. In addition, the vancomycin elution rate from the stem was measured. On average, the cylindrical implants eluted approximately 70% vancomycin in 21 days. Of the five sheep attempting to create a PJI model, three were successfully infected with S. aureus as intended for verification of treatment efficacy. In all three joints, negative bacterial cultures and no purulence were observed 3 weeks after revision surgery. The vancomycin elution rates from the stems were >70%. Efficient elution of vancomycin was confirmed by the experimental implant inserted into the bone marrow and the stem in actual PJI treatment. Using a novel therapeutic stem with an antibiotic elution mechanism in one-stage revision surgery, successful treatment was demonstrated in all S. aureus-induced PJIs.

Incidence, associated factors, and outcomes of acute kidney injury following placement of antibiotic bone cement spacers in two-stage exchange for periprosthetic joint infection: a comprehensive study

Background

Two-stage exchange with placement of antibiotic cement spacer (ACS) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI), but it could cause a high prevalence of acute kidney injury (AKI). However, the results of the current evidence on this topic are too mixed to effectively guide clinical practice.

Methods

We retrospectively identified 340 chronic PJI patients who underwent the first-stage exchange with placement of ACS. The Kidney Disease Improving Global Outcomes guideline was used to define postoperative AKI. Multivariate logistic analysis was performed to determine the potential factors associated with AKI. Furthermore, a systematic review and meta-analysis on this topic were conducted to summarize the knowledge in the current literature further.

Results

In our cohort, the incidence of AKI following first-stage exchange was 12.1%. Older age (per 10 years, OR= 1.509) and preoperative hypoalbuminemia (OR= 3.593) were independent predictors for postoperative AKI. Eight AKI patients progressed to chronic kidney disease after 90 days. A meta-analysis including a total of 2525 PJI patients showed the incidence of AKI was 16.6%, and AKI requiring acute dialysis was 1.4%. Besides, host characteristics, poor baseline liver function, factors contributing to acute renal blood flow injury, and the use of nephrotoxic drugs may be associated with the development of AKI. However, only a few studies supported an association between antibiotic dose and AKI.

Conclusion

AKI occurs in approximately one out of every six PJI patients undergoing first-stage exchange. The pathogenesis of AKI is multifactorial, with hypoalbuminemia could be an overlooked associated factor. Although the need for acute dialysis is uncommon, the fact that some AKI patients will develop CKD still needs to be taken into consideration.

Effectiveness of antibiotic-loaded bone cement in total joint arthroplasty at a tertiary medical center: A retrospective cohort study

Background

Data regarding the effectiveness of antibiotic-loaded bone cement (ALBC) in preventing prosthetic joint infections (PJI) after total joint arthroplasty (TJA) is inconsistent. The objective of this study was to evaluate if the routine use of ALBC influenced the risk of revision surgery due to PJI.

Methods

This is a retrospective cohort study performed between January 2018 and September 2020. Adult patients aged ≥ 18 years who underwent TJA (knee or hip) and received either ALBC or plain cement (PC) were included. The outcome of this study was the rate of revision due to PJI. Multivariate analysis using logistic regression was used to identify factors that may be associated with increased risk of PJI, using STATA 15.1 (StataCorp LP, College Station, Texas, USA).

Results

A total of 844 patients were screened and 319 patients were included. There were 247 patients in ALBC group and 72 patients in the PC group. Only vancomycin powder was used in all ALBC cases, with a 2 g dose in 50% of the cases (dose ranged between 1 g and 8 g). The status of the prosthetic joint was assessed and recorded up to 2 years of the TJA. Overall, the difference in the rates of PJI between the two groups after primary arthroplasty was not statistically significant (5.6% vs 1.4%; p = 0.173; OR, 4.2; 95% CI, 0.5-33).

Conclusion

ALBC was not associated with a reduction in PJI rates after primary TJA. More research is needed to further evaluate the effectiveness of ALBC in preventing PJI.

Antibiotic release from PMMA spacers and PMMA beads measured with ELISA: Assessment of in vitro samples and drain fluid samples of patients

For prosthetic joint infections, antibiotic loaded poly methyl methacrylate (PMMA) spacer or beads can be used to release high concentrations of antibiotics locally at the infection site, while minimizing systemic toxicity. The aim of this study is to determine in vitro and in vivo pharmacokinetic release profile of antibiotics from PMMA spacers and PMMA beads. For the in vitro experiment, the PMMA spacers or beads were submerged in phosphate-buffered saline and gentamicin concentrations were determined from collected specimen at several times points, measured with enzyme-linked immunosorbent assays (ELISA). To assess the in vivo antibiotic release profile of different spacers, wound drainage fluid samples were collected after implantation of a spacer over a period of maximum 14 days. After 48 h, the burst gentamicin concentration elution was 9862 ± 1782 ng/ml (mean ± SD) from spacers versus 38,394 ± 7071 ng/ml (mean ± SD) for beads. Over 35 days, spacers had eluted a cumulative mean concentration of 13,812 ± 3548 versus 55,048 ± 12,006 ng/ml for beads (p < 0.001). Clinical samples of patients with a Vancogenx® spacer showed higher gentamicin release than Refobacin™ spacers (p < 0.001). This is the first study that measured the release data of local antibiotics with ELISA. Compare to spacers, the exact release values of gentamicin from PMMA beads are more than 10 times higher and reached a maximum much later than spacers. This makes the use of PMMA beads more preferable to use for treatment of the infection itself.

Does the use of antibiotic spacer disrupt induced membrane function?

Treatment of large segmental bone defects has been a challenging and long process for both physicians and patients. At present, the induced membrane technique is one of the reconstruction techniques commonly utilized in treating large segmental bone defects. It consists of a two-step procedure. In the first one, after bone debridement, the defect is filled with bone cement. The aim at this stage is to support and protect the defective area with cement. A membrane is formed around the area where cement was inserted 4-6 weeks after the first surgical stage. This membrane secretes vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), as shown in the earliest studies. In the second step, the bone cement is removed, and the defect is filled with cancellous bone autograft. In the first stage, antibiotics can be added to the applied bone cement, depending on the infection. Still, the histological and micromolecular effects of the added antibiotic on the membrane are unknown.This study investigates the molecular and histological effects of antibiotics addition into bone cement on the induced membrane.In this study, conducted on 27 male New Zealand rabbits, the 2 cm long defects of a bone were created in the rabbit femurs. Three groups were formed by placing antibiotic-free, gentamicin, and vancomycin-containing cement in the defect area.These groups were followed for six weeks, and the membrane formed at the end of 6 weeks was examined histologically. As a result of this study, it found that the membrane quality markers (Von Willebrand factor (vwf), Interleukin 6-8 (IL), Transforming growth factor beta (TGF-β), Vascular endothelial growth factor (VEGF) were significantly higher in the antibiotic-free bone cement group. Our study has shown that antibiotics added to the cement have negative effects on the membrane. Based on the results we obtained, it would be a better choice to use antibiotic-free cement in aseptic nonunions. However, more data is needed to understand the effects of these changes on the cement on the membrane.

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.

One-stage revision using intra-articular carbapenem infusion effectively treats chronic periprosthetic joint infection caused by Gram-negative organisms

Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity. We retrospectively reviewed 32 patients (22 hips and 11 knees) who underwent single-stage revision combined with IA carbapenem infusion between November 2013 and March 2020. The IA and intravenous (IV) carbapenem infusions were administered for a single Gram-negative infection, and IV vancomycin combined with IA carbapenems and vancomycin was applied for polymicrobial infection including Gram-negative bacteria. The bacterial community distribution, drug sensitivity, infection control rate, functional recovery, and complications were evaluated. Reinfection or death caused by PJI was regarded as a treatment failure. Gram-negative PJI was mainly caused by Escherichia coli (8/34), Enterobacter cloacae (7/34), and Klebsiella pneumoniae (5/34). Seven cases (7/32) involved polymicrobial PJIs. The resistance rates of penicillin, cephalosporin, quinolones, and sulfonamides were > 10%, and all penicillin and partial cephalosporins (first and second generation) were > 30%. Of 32 cases, treatment failed to eradicate infection in only three cases (9.4%), at a mean follow-up of 55.1 months (SD 25 to 90). The mean postoperative Harris Hip Score and Hospital for Special Surgery knee score at the most recent follow-up were 81 (62 to 91) and 79 (56 to 89), respectively. One patient developed a fistula, and another presented with a local rash on an infected joint. The use of IA carbapenem delivered alongside one-stage revision effectively controlled Gram-negative infection and obtained acceptable clinical outcomes with few complications. Notably, first- and second-generation cephalosporins and penicillin should be administrated with caution, due to a high incidence of resistance.

Two-stage revision of infected hip prosthesis after post-operative antibiotic therapy: An observational study

Infection is a major threatening side effect after total hip arthroplasty (THA) that its management is so difficult and is accompanied by different complications. The aim of this study was to determine the outcomes of patients underwent 2-staged THA after a course of antibiotic therapy. It was an observational prospective study performed during 2009 and 2019. We managed 51 patients with infected THA using a method in which antibiotic prophylaxis was performed after THA. We followed the same protocol for treatment of patients included 2-staged revision: in first stage, removal of infected instruments were performed and insertion of a hand-made antibiotic-cement spacer was done until erythrocyte sedimentation rate and CRP were normalized. In second stage, an un-cemented prosthesis was re-implanted in femoral side and post-operative IV antibiotic were administered for a week. Patients were monitored for about 15 months. Data were analyzed. There were 3 patients developed recurrent infection required girdlestone due to the aging. One of them needed to remove implant and 2 other with 3 times of re-infection were treated by antibiotic therapy. Other 10 cases were treated first by re-changing the cement. The rate of successful treatment was 78.4% (40 of 51) after the primary surgery and antibiotic therapy. This rose to 92.1% (47 of 51) following more debridement and antibiotic therapy. The merging of staged surgical debridement, using spacer of cement-antibiotic and re-implant beside 1-week intravenous antibiotic therapy, leaded to appropriate early outcomes in this series.

Is long time to reimplantation a risk factor for reinfection in two-stage revision for periprosthetic infection? A systematic review of the literature

The two-stage revision arthroplasty is a common treatment option for chronic periprosthetic infection (PJI). The time to reimplantation (TTR) reported in the literature varies substantially from a few days to several hundred days. It is hypothesized that longer TTR could be associated with worse infection control after second stage. A systematic literature search was performed according to Preferred Reporting items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in Pubmed, Cochrane Library and Web of Science Core Collection in clinical studies published until January 2023. Eleven studies investigating TTR as a potential risk factor for reinfection met the inclusion criteria (ten retrospective and one prospective study, published 2012-2022). Study design and outcome measures differed notably. The cutoff points above which TTR was regarded as "long" ranged from 4 to 18 weeks. No study observed a benefit for long TTR. In all studies, similar or even better infection control was observed for short TTR. The optimal TTR, however, is not yet defined. Larger clinical studies with homogeneous patient populations and adjustment for confounding factors are needed.

Low dose vancomycin-loaded spacers for two-stage revision knee arthroplasty: High success, low toxicity

BACKGROUND

Two-stage revision arthroplasty is a widely used treatment method for infected knee arthroplasty. Loading high doses of antibiotics to spacer during the first stage is standard practice. However, there are reported systemic side effects attributed to antibiotic-loaded spacers. The aim of our study is to investigate the success rate and systemic toxicity following the first stage revision knee arthroplasty with low-dose vancomycin-loaded spacers.

METHOD

We included patients with infected knee arthroplasty eligible for two-stage revision arthroplasty from 2001 to 2020. One gram of vancomycin is added per pack of bone cement. Spacers were handmade in the operating theatre. Following the first stage, pre-operative and postoperative culture results, infection parameters, kidney and liver function tests, and functional scores were analyzed. Kaplan-Meier survival analysis was done to determine the success rate.

RESULTS

Fifty patients with a mean follow-up of 48 months (24-108) were included in the study. A five-year survival analysis showed an 88.5% success rate. Fourteen percent of the patients had acute kidney injury with creatinine levels between 1.12-2.80 mg/dl, and 8% had a mild drug-induced liver injury with elevated serum ALT levels between 223-540 U/L and total bilirubin levels between 0.59-1.23 mg/dl. None of the patients required dialysis. All of the systemic side effects were reversible.

CONCLUSION

Our results have suggested that low dose antibiotic-loaded spacers are comparable to the studies with high dose antibiotic loaded spacers regarding infection eradication and survival rates. They are less likely to cause severe systemic side effects. Therefore we suggest low dose antibiotic-loaded spacers should be considered when treating patients with vancomycin sensitive Staphylococcal species and culture negative infected knee arthroplasty.

First Metatarsophalangeal Arthrodesis for the Failed Hallux

Hallux metatarsophalangeal joint (MTPJ) arthrodesis was first described in 1894 by Clutton, who recommended ankylosing the MTPJ to treat painful hallux valgus (HV). He used ivory pegs to stabilize the MTP joint. Surgeons over the last century have modified the procedure and added indications, including hallux rigidus, rheumatoid arthritis, and revision of failed surgeries. This article addresses many common yet challenging clinical scenarios, and a few hot topics, related to hallux MTPJ arthrodesis, including matarsus primus elevatus, severe hallux valgus, avascular necrosis, and infections. The article provides a condensed evidence-based discussion on how to manage these challenges using MTPJ arthrodesis.

Wound fluid ceftriaxone concentrations after local application with calcium sulphate as carrier material in the treatment of orthopaedic device-associated hip infections

Aims

There is a considerable challenge in treating bone infections and orthopaedic device-associated infection (ODAI), partly due to impaired penetration of systemically administrated antibiotics at the site of infection. This may be circumvented by local drug administration. Knowledge of the release kinetics from any carrier material is essential for proper application. Ceftriaxone shows a particular constant release from calcium sulphate (CaSO4) in vitro, and is particularly effective against streptococci and a large portion of Gram-negative bacteria. We present the clinical release kinetics of ceftriaxone-loaded CaSO4 applied locally to treat ODAI.

Methods

A total of 30 operations with ceftriaxone-loaded CaSO4 had been performed in 28 patients. Ceftriaxone was applied as a single local antibiotic in 21 operations and combined with vancomycin in eight operations, and in an additional operation with vancomycin and amphotericin B. Sampling of wound fluid was performed from drains or aspirations. Ceftriaxone concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS).

Results

A total of 37 wound fluid concentrations from 16 operations performed in 14 patients were collected. The ceftriaxone concentrations remained approximately within a range of 100 to 200 mg/l up to three weeks. The median concentration was 108.9 mg/l (interquartile range 98.8 to 142.5) within the first ten days. No systemic adverse reactions were observed.

Conclusion

Our study highlights new clinical data of locally administered ceftriaxone with CaSO4 as carrier material. The near-constant release of ceftriaxone from CaSO4 observed in vitro could be confirmed in vivo. The concentrations remained below known local toxicity thresholds. Cite this article: Bone Joint Res 2022;11(11):835–842.

The Incidence of Severe Hypercalcaemia-Induced Mental Status Changes in Patients Treated with Antibiotic-Loaded Calcium Sulphate Depot for Orthopaedic Infections

Local application of antibiotics with calcium-containing carrier materials (CCCM) might deliver large quantities of calcium, with some cases of hypercalcaemia reported. The incidence of symptomatic hypercalcaemia was estimated retrospectively in a consecutive, prospective series of patients treated between 10/2006 and 02/2019 with antibiotic-loaded CCCM for various orthopaedic infections. Risk factors were analysed. In the study period, 215 CCCM applications were performed. Two patients (0.9%) developed symptomatic hypercalcaemia. In one case, hypercalcaemia occurred 14 days after a second CCCM application during a staged septic hip revision. In the other case, hypercalcaemia became symptomatic six days after application of vancomycin-loaded CCCM in a component-retaining septic revision hip arthroplasty. In both cases, hypercalcemia was not imputable solely to the CCCM. Prolonged immobilization, renal impairment and other specific risk factors were present. Implantation of a CCCM for local application of antibiotics exposes the patient to large quantities of calcium during dissolution. This might induce symptomatic hypercalcaemia, a potentially life-threatening complication. The observed incidence of symptomatic hypercalcaemia remained rare (<1%). In some patients, compensatory mechanisms might be overwhelmed in the presence of other risk factors. Postoperative monitoring of calcaemia as well as elimination of risk factors is mandatory for all patients treated with CCCM.

High-Dose Antibiotic Cement Spacers Independently Increase the Risk of Acute Kidney Injury in Revision for Periprosthetic Joint Infection: A Prospective Randomized Controlled Clinical Trial

BACKGROUND

Standard treatment for periprosthetic joint infection (PJI) involves 2-stage exchange with placement of an antibiotic-impregnated cement spacer (ACS). Conflicting evidence exists on the role of ACS in development of acute kidney injury (AKI) after first-stage surgery. In this randomized clinical trial, we aimed to compare the incidence of AKI between the first-stage of a planned 2-stage exchange vs 1-stage exchange. This study design isolates the effect of the ACS in otherwise identical treatment groups.

METHODS

The primary outcome variable was AKI, defined as a creatinine ≥1.5 times baseline or an increase of ≥0.3 mg/dL. Risk factors for AKI were evaluated using bivariate statistical tests and multivariable logistic regression.

RESULTS

Patients who underwent the first stage of a planned 2-stage exchange were significantly more likely to develop AKI compared with the 1-stage exchange group (15 [22.7%] vs 4 [6.6%], P = .011). On multivariable regression analysis, ACS placement (odds ratio 7.48, 95% confidence limit 1.77-31.56) and chronic kidney disease (odds ratio 3.84, 95% confidence limit 1.22-12.08) were independent risk factors for AKI.

CONCLUSION

Our study provides evidence that high-dose antibiotic cement spacers for treatment of PJI are an independent risk factor for AKI. Therefore, efforts to minimize nephrotoxicity should be employed in revision for PJI when possible.

Periprosthetic Joint Infection (PJI)—Results of One-Stage Revision with Antibiotic-Impregnated Cancellous Allograft Bone—A Retrospective Cohort Study

Controversy exists regarding the optimal treatment of periprosthetic joint infection (PJI), considering control of infection, functional results as well as quality of life. Difficulties in treatment derive from the formation of biofilms within a few days after infection. Biofilms are tolerant to systemically applied antibiotics, requiring extreme concentrations for a prolonged period. Minimum biofilm eradicating concentrations (MBEC) are only feasible by the local application of antibiotics. One established approach is the use of allograft bone as a carrier, granting a sustained release of antibiotics in very high concentrations after appropriate impregnation. The purpose of this study was to determine the rate of reinfection after a one-stage revision of infected hip or knee prostheses, using antibiotic-impregnated allograft bone as the carrier and avoiding cement. Between 1 January 2004 and 31 January 2018, 87 patients with PJI, according to MSIS, underwent a one-stage revision with antibiotic-impregnated cancellous allograft bone. An amount of 17 patients had insufficient follow-ups. There were 70 remaining patients (34 male, 36 female) with a mean follow-up of 5.6 years (range 2–15.6) and with a mean age of 68.2 years (range 31.5–86.9). An amount of 38 hips and 11 knees were implanted without any cement; and 21 knees were implanted with moderate cementing at the articular surface with stems always being uncemented. Within 2 years after surgery, 6 out of 70 patients (8.6%, CI 2–15.1) showed reinfection and after more than 2 years, an additional 6 patients showed late-onset infection. Within 2 years after surgery, 11 out of 70 patients (15.7%, CI 7.2–24.2) had an implant failure for any reason (including infection) and after more than 2 years, an additional 7 patients had an implant failure. Using Kaplan-Meier analysis for all 87 patients, the estimated survival for reinfection was 93.9% (CI 88.8–99.1) at 1 year, 89.9% (CI 83.2–96.6) at 2 years and 81.5% (CI 72.1–90.9) at 5 years. The estimated survival for implant failure for any reason was 90.4% (CI 84.1–96.7) at 1 year, 80.9% (CI 72.2–89.7) at 2 years and 71.1% (CI 60.3–81.8) at 5 years. One-stage revision with antibiotic-impregnated cancellous allograft bone grants comparable results regarding infection control as with multiple stages, while shortening rehabilitation, improving quality of life for the patients and reducing costs for the health care system.

Local antibiotic treatment with calcium sulfate as carrier material improves the outcome of debridement, antibiotics, and implant retention procedures for periprosthetic joint infections after hip arthroplasty – a retrospective study

Abstract. Purpose: Debridement, antibiotics, and implant retention (DAIR) is an established treatment modality in periprosthetic joint infections (PJIs), but success rates vary. This study compared the success of DAIR for PJIs after a total hip arthroplasty (THA), with or without local antibiotic delivery with CaSO4 as the carrier material. Methods: A retrospective review of DAIR for PJIs after THA performed between 2010 and 2018, including 41 patients is conducted. A total of 27 patients were treated by DAIR with local antibiotics with CaSO4 as the carrier material, and 14 patients were treated by a standard DAIR. The endpoints were treatment failure, defined as the need for a reoperation, either a second DAIR or a prosthesis removal or exchange due to persistent or recurrent infection, the initiation of a long-term suppressive antibiotic treatment, or death related to infection. Results: Considering any reoperation as an outcome, 11 of 14 cases treated without AB-CaSO4 (79 %) and 4 of the 27 cases treated with AB-CaSO4 failed (15 %). Considering revision as an outcome, 9 out of 14 cases treated without AB-CaSO4 (64 %) and 4 of the 27 cases treated with AB-CaSO4 (15 %) failed. A Kaplan–Meier survival analysis showed that local antibiotic delivery with CaSO4 as the carrier material led to a significantly longer infection-free survival, considering any surgical revision (p<0.0001; hazard ratio 8.9 (95 % CI 2.8–28.2)) or revision with component exchange (p=0.0015; hazard ratio 5.6 (95 % CI 1.7–18.2)) as the endpoint. Conclusion: The addition of local antibiotics with CaSO4 as the carrier material to DAIR for PJIs after THA significantly increases success rates, such as infection-free survival, any reoperation, and revision with component exchange in particular.

Failure Analysis in Multiple TKA Revisions-Periprosthetic Infections Remain Surgeons' Nemesis

BACKGROUND

The aim of this study was to categorize reasons for failure and to analyze the survivorship of multiple total knee arthroplasty (TKA) revisions.

METHODS

The study retrospectively evaluated all multiple TKA revisions performed between 2005 and 2015 at the authors' institutions. Sixty-three patients (35 female, 28 male, age 64 ± 10 years, follow-up 55 ± 36 months) underwent a total of 157 re-revision TKA surgeries (range 2-5). The revision indications were divided up into main diagnoses. Survivorship was evaluated by mixed model analysis.

RESULTS

The main overall reason for re-revision was periprosthetic joint infection (PJI) (48%), followed by instability (12%), polyethylene wear (11%), malpositioning (8%), and aseptic loosening (8%). Survivorship shortened with an increasing number of revision surgeries (p = 0.003). While PJI was in 38% of all cases, the reason for the first revision, incidence increased constantly with the number of revisions (48% at second revision, 55% at third revision, 86% at fourth revision, and 100% at fifth revision, p = 0.022). If periprosthetic infection caused the first revision, patients showed an average of two more septic revisions at follow-up than patients with an aseptic first revision indication (p < 0.001). In 36% of cases, the reason for follow-up surgery in case of periprosthetic infection was again PJI.

CONCLUSION

The probability of survival of the implanted knee arthroplasty is significantly reduced with each subsequent revision. Periprosthetic infection is the main cause of multiple revisions.

Current Concepts on the Application, Pharmacokinetics and Complications of Antibiotic-Loaded Cement Spacers in the Treatment of Prosthetic Joint Infections

Prosthetic joint infection (PJI) is a devastating complication of total joint replacement surgery. It affects about 2% of primary total joint replacements. Treatment aims at infection eradication and restoration of patient's mobility. Two-stage revision arthroplasty with an interim application of an antibiotic-loaded cement spacer (ALCS) is the widely accepted treatment for PJI. Spacers are powerful local carriers of antibiotics at the site of infection, effective against biofilm-protected microbes. On the other hand, spacers permit some mobility of the patient and facilitate final prosthesis implantation. ALCS's are either commercially available or prepared intraoperatively on prefabricated or improvised molds. Antibiotic elution from the spacer depends on the amount of the antibiotic used for cement impregnation, at the expense of mechanical stiffness of the spacer. The antibiotic should not exceed 4g per 40g of bone cement to preserve the mechanical properties of the cement. Spacers are frequently accompanied by local or systemic complications. The spacer may break, dislocate and compress vessels or nerves of the limb. Systemic complications are the result of excess elution of antibiotic and include nephrotoxicity, hepatotoxicity, ototoxicity, allergic reactions or neutropenia. Elderly patients with comorbidities are at risk to present such complications. Microbial resistance is a potential risk of long-lasting spacer retention. Persisting infection may require multiple spacer replacements.

Effective Treatment of Single-Stage Revision Using Intra-Articular Antibiotic Infusion for Polymicrobial Periprosthetic Joint Infection

BACKGROUND

The treatment of polymicrobial periprosthetic joint infection (PJI) confronted distinct challenges. No reports have assessed the efficacy of local antibiotic delivery combined with 1-stage exchange in polymicrobial PJI.

METHODS

Between January 2013 and December 2018, we retrospectively analyzed the data of 126 patients, including 19 polymicrobial PJIs and 107 monomicrobial PJIs, who underwent single-stage revision using intra-articular antibiotic infusion. The risk factors, microbiology, infection control rate, and clinical outcomes were compared between the 2 groups.

RESULTS

Higher body mass index, presence of a sinus tract, and prior revisions were the risk factors for polymicrobial PJI. Isolation of Staphylococcus epidermidis, Streptococcus, Enterococcus, and Gram-negative pathogens was highly associated with polymicrobial PJI. Of the 19 polymicrobial PJIs, only 2 patients occurred infection recurrence, which is similar with the result of 6 of 107 patients in the monomicrobial PJI (P = .225). The Harris Hip Score of the polymicrobial group showed no difference from that of the monomicrobial group (78 vs 80; P = .181). Nevertheless, the polymicrobial group exhibited inferior Hospital for Special Surgery knee score relative to the monomicrobial group (77 vs 79; P = .017).

CONCLUSION

With rational and targeted use of antibiotics, single-stage revision can effectively control polymicrobial infections, and achieve favorable outcomes similar to that in monomicrobial patients. However, this regimen is still needed to be further confirmed, especially in the infections with different microbial species simultaneously. Additionally, obese patients with a sinus tract and those who had prior revisions had a greater risk of polymicrobial PJI.

Renal Toxicity Associated With Resection and Spacer Insertion for Chronic Hip PJI

BACKGROUND

Two-stage exchange arthroplasty with high-dose antibiotic-loaded bone cement spacer and intravenous (IV) antibiotics is the most common method of managing infected total hip arthroplasties. However, the contemporary incidence, risk factors, and outcomes of acute kidney injuries (AKIs) in this cohort are unknown.

METHODS

We identified 227 patients treated with 256 antibiotic-loaded bone cement spacers after resection of an infected primary total hip arthroplasty between 2000 and 2017. Mean age was 65 years, mean body mass index was 30 mg/kg², 55% were men, and 16% had pre-existing chronic kidney disease (CKD). Spacers were in situ for a mean of 15 weeks, concomitantly associated with IV or oral antibiotics for a mean of 6 weeks. AKI was defined as a creatinine ≥1.5X baseline or ≥0.3 mg/dL. Mean follow-up was 8 years.

RESULTS

AKI occurred in 13 patients without pre-existing CKD (7%) vs 10 patients with CKD (28%; OR 5; P = .0001). None required acute dialysis. Postoperative fluid depletion (β = 0.31; P = .0001), ICU requirement (β = 0.40; P = .0001), and acute atrial fibrillation (β = 0.43; P = .0001) were independent predictors for AKI in patients without pre-existing CKD. Duration of in situ spacer, mean antibiotic dose in cement, use of amphotericin B, and type of IV antibiotics were not significant risk factors. At last follow-up, 8 AKIs progressed to CKD, with one receiving dialysis 7 years later.

CONCLUSION

AKIs occurred in 7% of patients with normal renal function, with 5-fold greater risk in those with CKD, and 4% did develop CKD. Importantly, causes of acute renal blood flow impairment were independent predictors for AKI.

LEVEL OF EVIDENCE

Level III, comparative study.

Risk of reinfection after two- or multiple-stage knee revision surgery using superficial vancomycin coating and conventional spacers

This study investigates the effect of superficial vancomycin coating (SVC) in two- or more-stage exchange procedures of prosthetic knee joint infections. We hypothesized that spacer treatment with SVC result in lower reinfection rates than conventional spacers after prosthetic reimplantation. Our secondary aim was to determine the demographic and treatment factors associated with reinfection rates. This retrospective cohort study compromised 96 cases with prosthetic knee infections. Twenty-four cases were treated with a temporary SVC spacer and 72 cases with conventional spacers. Prosthetic reinfection occurred after a median observation period of 1.7 ± 4.0 years in 24 cases (25%). The prevalence of having a reinfection was not significantly different between the two treatment groups (13% [3 cases] in the SVC group vs. 29% [21 cases] in the conventional spacer group [p = .104]). In seven cases (7.3%), two in the SVC group (8.3%) and five (6.9%) in the conventional spacer group (p ≥ .999), histological, respectively microbiological evaluations from the intraoperative specimens revealed persistent infection at the second stage. Nevertheless, in all seven cases no significant higher risk of periprosthetic reinfection was observed during follow-up (p = .750). Our secondary investigation of cofactors revealed that spacers additionally stabilized by nails were significantly associated with a 3.9-fold higher hazard ratio of sustaining a reinfection of revision prosthesis (p = .005).

Sonication fluid culture of antibiotic-loaded bone cement spacer has high accuracy to confirm eradication of infection before reimplantation of new prostheses

BACKGROUND

Sonication fluid culture of antibiotic-loaded bone cement spacer has been used to predict reinfection of two-stage revision, but its value remains disputable. This study aims to evaluate the association between the culture result of the sonicated spacer and the status of patients with periprosthetic joint infection receiving two-stage revision.

MATERIALS AND METHODS

A comprehensive electronic literature search was performed through four databases including PubMed, Embase/Ovid, and EBSCO, and the Cochrane Library to retrieve studies in which sonication fluid culture of the antibiotic spacer was conducted before reimplantation. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated to assess the association between the culture result of sonicated spacer and prognosis of the two-stage revision.

RESULTS

Eleven eligible studies comprising 603 artificial joints with PJI (134 suffering a clinical failure of two-stage revision) were included in the quantitative analysis. The pooled incidences of positive culture of sonicated spacer and intraoperative tissue were 0.14 (95% confidence interval [CI] 0.08-0.21) and 0.14 (95% CI 0.08-0.20), respectively. A positive culture of sonicated antibiotic-loaded bone cement spacer illustrated moderate sensitivity (0.31, 95% CI 0.13-0.58) but high specificity (0.94, 95% CI 0.86-0.98) for the diagnosis of therapeutic failure of two-stage revision; the pooled DOR was 7.67 (95% CI, 3.63-16.22). Meanwhile, the pooled sensitivity, specificity, and DOR of intraoperative tissue culture during the two-stage revision to predict therapeutic failure were 0.32 (95% CI, 0.20-0.47), 0.96 (95% CI, 0.92-0.98), and 10.62 (95% CI, 4.90-23.01), respectively.

CONCLUSIONS

Sonication fluid culture of antibiotic-loaded bone cement spacer revealed high accuracy for confirming eradication of infection before reimplantation of new prostheses and therefore could be used as a supplement for assessing therapeutic effect for PJI. However, both sonication fluid culture and intraoperative tissue culture from antibiotic-loaded bone cement spacer showed restricted yield for the prediction of a septic failure after the two-stage revision of PJI. Large-scale, prospective studies are still needed to testify current findings.

Comparison of elution characteristics and mechanical properties of acrylic bone cements with and without superficial vancomycin coating (SVC) in the late phase of polymerization

INTRODUCTION

Antibiotic-loaded bone cements (ALBCs) are used as spacers in two-stage revision arthroplasty for periprosthetic joint infection. We previously described a new technique applying vancomycin powder coating to custom-made cements. To our best knowledge, this method of superficial vancomycin coating (SVC) has not been assessed before. We therefore performed an in-vitro study to determine: (1) whether manually applied SVC strengthened the cements' antibiotic effect; and (2) whether the mechanical requirements for the cements were fulfilled.

HYPOTHESIS

SVC increases the antibiotic effect of cement within the first 24hours.

METHODS

Cuboid blocks were produced from two commercially available acrylic ALBCs (Palacos R+G and Copal G+V) with and without SVC. Each block was eluted in phosphate-buffered saline at 37°C. Eluates obtained at 1, 2, 3, 4, 5, 10, 15, 30 and 60minutes and 3, 6 and 24hours were evaluated against Staphylococcus aureus (Palacos, Copal) and methicillin-resistant Staphylococcus aureus (MRSA) (Copal) using zone of inhibition tests. Mechanical test results (bending modulus, bending strength) were compared to ISO requirements (≥1800MPa, ≥50MPa).

RESULTS

Palacos with SVC produced significantly greater zones of inhibition against Staphylococcus aureus than Palacos without SVC (p=0.002). Copal with SVC showed greater zones of inhibition against both Staphylococcus aureus and MRSA (p=0.002). The antibiotic effect was enhanced by SVC in both cements at every time point within 24hours. The bending modulus and bending strength of Palacos with SVC (2089±166MPa, 60.8±2.6 MPA) and Copal with SVC (2283±195MPa, 56.9±2.4MPa) were significantly above ISO requirements.

CONCLUSION

SVC boosts the antibiotic effect of ALBCs in the first 24hours, while maintaining sufficient stability. These findings endorse SVC as a promising additive in septic revision surgery.

LEVEL OF EVIDENCE

III; case control study.

Influence of ceftriaxone on human bone cell viability and in vitro mineralization potential is concentration- and time-dependent

Aims

In orthopaedic and trauma surgery, implant-associated infections are increasingly treated with local application of antibiotics, which allows a high local drug concentration to be reached without eliciting systematic adverse effects. While ceftriaxone is a widely used antibiotic agent that has been shown to be effective against musculoskeletal infections, high local concentrations may harm the surrounding tissue. This study investigates the acute and subacute cytotoxicity of increasing ceftriaxone concentrations as well as their influence on the osteogenic differentiation of human bone progenitor cells.

Methods

Human preosteoblasts were cultured in presence of different concentrations of ceftriaxone for up to 28 days and potential cytotoxic effects, cell death, metabolic activity, cell proliferation, and osteogenic differentiation were studied.

Results

Ceftriaxone showed a cytotoxic effect on human bone progenitor cells at 24 h and 48 h at concentrations above 15,000 mg/l. With a longer incubation time of ten days, subtoxic effects could be observed at concentrations above 500 mg/l. Gene and protein expression of collagen, as well as mineralization levels of human bone progenitor cells, showed a continuous decrease with increasing ceftriaxone concentrations by days 14 and 28, respectively. Notably, mineralization was negatively affected already at concentrations above 250 mg/l.

Conclusion

This study demonstrates a concentration-dependent influence of ceftriaxone on the viability and mineralization potential of primary human bone progenitor cells. While local application of ceftriaxone is highly established in orthopaedic and trauma surgery, a therapeutic threshold of 250 mg/l or lower should diminish the risk of reduced osseointegration of prosthetic implants.

Cite this article: Bone Joint Res 2021;10(3):218–225.

Controlling Antibiotic Release from Polymethylmethacrylate Bone Cement

Bone cement is used as a mortar for securing bone implants, as bone void fillers or as spacers in orthopaedic surgery. Antibiotic-loaded bone cements (ALBCs) have been used to prevent and treat prosthetic joint infections by providing a high antibiotic concentration around the implanted prosthesis. High antibiotic concentrations are, on the other hand, often associated with tissue toxicity. Controlling antibiotic release from ALBCS is key to achieving effective infection control and promoting prosthesis integration with the surrounding bone tissue. However, current ALBCs still need significant improvement in regulating antibiotic release. In this review, we first provide a brief introduction to prosthetic joint infections, and the background concepts of therapeutic efficacy and toxicity in antibiotics. We then review the current state of ALBCs and their release characteristics before focusing on the research and development in controlling the antibiotic release and osteo-conductivity/inductivity. We then conclude by a discussion on the need for better in vitro experiment designs such that the release results can be extrapolated to predict better the local antibiotic concentrations in vivo.

Trends in the treatment of infected knee arthroplasty

Essential treatment methods for infected knee arthroplasty involve DAIR (debridement, antibiotics, and implant retention), and one and two-stage exchange arthroplasty.

Aggressive debridement with the removal of all avascular tissues and foreign materials that contain biofilm is mandatory for all surgical treatment modalities.

DAIR is a viable option with an acceptable success rate and can be used as a first surgical procedure for patients who have a well-fixed, functioning prosthesis without a sinus tract for acute-early or late-hematogenous acute infections with no more than four weeks (most favourable being < seven days) of symptoms. Surgeons must focus on the isolation of the causative organism with sensitivities to bactericidal treatment as using one-stage exchange.

One-stage exchange is indicated when the patients have:

minimal bone loss/soft tissue defect allowing primary wound closure,

easy to treat micro-organisms,

absence of systemic sepsis and

absence of extensive comorbidities.

There are no validated serum or synovial biomarkers to determine optimal timing of re-implantation for two-stage exchange.

Antibiotic-free waiting intervals and joint aspiration before the second stage are no longer recommended. The decision to perform aspiration should be made based on the index of suspicion for persistent infection.

Re-implantation can be performed when the treating medical team feels that the clinical signs of infection are under control and serological tests are trending downwards.

Cite this article: EFORT Open Rev 2020;5:672-683. DOI: 10.1302/2058-5241.5.190069

Short-course versus long-course antibiotics in prosthetic joint infections: a systematic review and meta-analysis of one randomized controlled trial plus nine observational studies

BACKGROUND

Prosthetic joint infections (PJIs) often require long-course antibiotic therapy. However, recent studies argue against the current practice and raise concerns such as the development of antibiotic resistance, side effects of medications and medical costs.

OBJECTIVES

To review and compare the outcomes of short-course and long-course antibiotics in PJIs.

METHODS

We conducted a systemic review and meta-analysis using a predefined search term in PubMed and EMBASE databases. Studies that met the inclusion criteria from inception to June 2018 were included. The quality of the included studies was assessed.

RESULTS

A total of 10 articles and 856 patients were analysed, comprising 9 observational studies and 1 randomized controlled trial. Our meta-analysis showed no significant difference between short-course and long-course antibiotics (relative risk = 0.87, 95% CI = 0.62-1.22). Additionally, the older the studied group was, the more short-course antibiotics were favoured.

CONCLUSIONS

When treating PJI patients following debridement, antibiotics and implant retention, an 8 week course of antibiotic therapy for total hip arthroplasty and a 75 day course for total knee arthroplasty may be a safe approach. For two-stage exchange, a shorter duration of antibiotic treatment during implant-free periods is also generally safe with the usage of antibiotic-loaded cement spacers.

Toxic Effect of Vancomycin on Viability and Functionality of Different Cells Involved in Tissue Regeneration

To prevent infections local delivery of antibiotics is a useful tool. Especially in bone fractures, vancomycin impregnated bone cements are often used allowing high concentrations of antibiotics at the infection side without high serum concentrations. However, besides potential pathogens, cells involved in tissue regeneration may also be affected by the drug. We investigated the effect of vancomycin on the viability and functionality on osteoblasts, endothelial cells, fibroblasts and skeletal muscle cells. Our results show that the viability of all cells analyzed was reduced by vancomycin and that the observed effects were time and concentration dependent. The most pronounced toxic effect was detected on day three when even the lowest concentration of 0.01 mg/ml led to a significant decrease in proliferation compared to control. Functionality assays of osteoblasts and skeletal muscle cells revealed a sensitive reaction of the cells to the drug, indicating that vancomycin is toxic to these cells during the process of differentiation. These data suggest that the vancomycin administration is critical for cell survival and function. Therefore, the concentration of administered antibiotics needs to be carefully evaluated to find a balance between defense against pathogens and functionality of host cells and tissues.

Does the use of a closed-suction drain reduce the effectiveness of an antibiotic-loaded spacer in two-stage exchange Arthroplasty for Periprosthetic hip infection? A prospective, randomized, controlled study

Background

There is a concern regarding the use of a closed-suction drain (CSD) in two-stage exchange arthroplasty for periprosthetic joint infection as it may decrease the antibiotic concentrations in the joint fluids. The purpose of this study was to identify whether the use of a CSD could reduce local antibiotic concentrations following spacer implantation.

Methods

A prospective, randomized, controlled trial was conducted at our institution between January 2018 and November 2018. We enrolled 32 patients undergoing two-stage exchange arthroplasty for periprosthetic hip infection with an interim cement spacer containing 4-g vancomycin and 2-g meropenem per 40-g methyl-methacrylate cement polymer. Patients were randomized and evenly divided into the study group (non-CSD) and control group (CSD group) by sealed envelopes. Drainage samples of joint fluids (n = 160) were collected every 24 h for the first five days following spacer implantation. The antibiotic concentrations of drainage samples were measured by high-performance liquid chromatography, and the bioactivities of the drainage samples against methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) and E. coli were assessed.

Results

There was no significant difference in the decrease of vancomycin (study group vs. control group: 163.20 ± 77.05 vs. 162.39 ± 36.31; p = 0.917) and meropenem concentration (123.78 ± 21.04 vs. 117.27 ± 19.38; P = 0.548) between the two groups during the first five days following spacer implantation. All joint drainage samples in each group exhibited antibacterial activity against MSSA, MRSA and E. coli.

Conclusions

The use of CSD following the implantation of an antibiotic-loaded cement spacer does not reduce the effectiveness of such a spacer in two-stage exchange arthroplasty.

(Chinese Clinical Trial Registry, ChiCTR-INR-17014162. Registered 26 December 2017.)

Hip Spacers in Two-Stage Revision for Periprosthetic Joint Infection: A Review of Literature

Infection after total hip arthroplasty (THA) is a devastating complication with significant consequences for patients. In literature, single and two-stage revision, irrigation and debridement, Girdlestone resection arthroplasty, and arthrodesis and amputation are reported as possible treatments. Recently, two-stage revision has become popular as the gold standard treatment for chronic hip joint infections after THA. In this review, we evaluate the current literature about microbiology of periprosthetic joint infections and the use of antibiotic-loaded cement spacers. We aim to give an overview about indications, clinical results, and mechanical complications for spacers implantation, evaluating also selection criteria, pharmacokinetic properties, and systemic safety of the most frequently used antibiotics.

Antibiotic-Loaded Polymethylmethacrylate Beads and Spacers in Treatment of Orthopedic Infections and the Role of Biofilm Formation

Polymethylmethacrylate (PMMA) also referred as (acrylic) bone cement is a non-degradable biomaterial that has been used in clinical orthopedic practice for several decades. PMMA can be used in a plain formulation, but is often used in an antibiotic-loaded formulation in (primary and revision) arthroplasty and in treatment of orthopedic infections as prosthetic joint infections (PJI) and chronic osteomyelitis. In treatment of PJIs antibiotic-loaded PMMA is often used as a carrier material for local antibiotic delivery in addition to treatment with systemic antibiotics. In this case, the antibiotic-loaded PMMA is often used as a spacer or as a bead chain. Since the introduction of PMMA as an antibiotic carrier there is a tremendous amount of scientific and clinical papers published, which studied numerous different aspects of antibiotic-loaded PMMA. This paper will review the research regarding basic principles of antibiotic-loaded PMMA as mechanism of action, antibiotic-release capacities, choice of antibiotics and influences on mechanical properties of PMMA. Subsequently, concerns regarding the application of antibiotic-loaded PMMA, biofilm formation, antibiotic resistance and local or systemic toxicity will be discussed. In addition to these subjects, the role of antibiotic loaded PMMA in clinical treatment of PJIs and chronic osteomyelitis is discussed in the final part of this paper.

Nephrotoxicity After the Treatment of Periprosthetic Joint Infection With Antibiotic-Loaded Cement Spacers

BACKGROUND

Treatment of periprosthetic joint infections commonly involves insertion of an antibiotic-loaded cement spacer (ACS). The risk for acute kidney injury (AKI) related to use of antibiotic spacers has not been well defined. We aimed to identify the incidence of and risk factors for AKI after placement of an ACS.

METHODS

We performed a prospective cohort study of patients with an infected primary total hip or knee arthroplasty treated with ACSs with vancomycin, gentamicin, and tobramycin. Serum creatinine and glomerular filtration rate data were collected at baseline and weekly intervals for 8 weeks. Patients were classified into Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) stages to determine incidence of AKI. Risk factors for kidney injury were identified via regression analysis.

RESULTS

A total of 37 patients (20 total knee arthroplasty and 17 total hip arthroplasty) were included. During the 8 weeks after ACS placement, 10 patients (27%) fit RIFLE criteria for kidney injury and 2 patients (5%) fit RIFLE criteria for kidney failure. No baseline patient characteristics were associated with development of AKI.

CONCLUSION

Patients should be monitored closely for development of AKI after placement of ACSs for the treatment of periprosthetic joint infection. Further research into minimizing risk for AKI is warranted.

The levels of vancomycin in the blood and the wound after the local treatment of bone and soft-tissue infection with antibiotic-loaded calcium sulphate as carrier material

AIMS

Calcium sulphate (CaSO₄) is a resorbable material that can be used simultaneously as filler of a dead space and as a carrier for the local application of antibiotics. Our aim was to describe the systemic exposure and the wound fluid concentrations of vancomycin in patients treated with vancomycin-loaded CaSO₄ as an adjunct to the routine therapy of bone and joint infections.

PATIENTS AND METHODS

A total of 680 post-operative blood and 233 wound fluid samples were available for analysis from 94 implantations performed in 87 patients for various infective indications. Up to 6 g of vancomycin were used. Non-compartmental pharmacokinetic analysis was performed on the data from 37 patients treated for an infection of the hip.

RESULTS

The overall systemic exposure remained within a safe range, even in patients with post-operative renal failure, none requiring removal of the pellets. Local concentrations were approximately ten times higher than with polymethylmethacrylate (PMMA) as a carrier, but remained below reported cell toxicity thresholds. Decreasing concentrations in wound fluid were observed over several weeks, but remained above the common minimum inhibitory concentrations for Staphylococcus up to three months post-operatively.

CONCLUSION

This study provides the first pharmacokinetic description of the local application of vancomycin with CaSO₄ as a carrier, documenting slow release, systemic safety and a release profile far more interesting than from PMMA. In particular, considering in vitro data, concentrations of vancomycin active against staphylococcal biofilm were seen for several weeks. Cite this article: Bone Joint J 2017;99-B:1537-44.

Effect of Sonication on the Elution of Antibiotics from Polymethyl Methacrylate (PMMA)

Background: In the setting of prosthetic joint infections treated with a two-stage procedure, spacers can be sonicated after removal. We hypothesize that the sonication process may cause an increased elution of antibiotics from the spacer, leading to elevated concentrations of antibiotics in the sonication fluid inhibiting bacterial growth. We aimed to evaluate in vitro the influence of sonication on the elution of antibiotics from polymethyl methacrylate (PMMA) over time and to determine whether these concentrations are above the minimum inhibitory concentrations (MIC) for microorganisms relevant in prosthetic joint infections. Methods: PMMA blocks impregnated with vancomycin, fosfomycin, gentamicin or daptomycin were incubated in phosphate-buffered saline (PBS) at 37°C for up to 6 weeks. PBS was changed once a week. Concentrations were determined from samples of each antibiotic every week, and after 5 minutes of sonication at 2, 4 and 6 weeks. Results: With sonication there was a trend toward an increase of the elution of antibiotics. This increase was significant for vancomycin at 2 and 4 weeks (p=0.008 and 0.002 respectively) and for fosfomycin at 2 weeks (p=0.01). Conclusion: The effect of sonication could play a role in clinical results, especially for daptomycin and gentamicin for which the MIC is close to the concentration of antibiotics at 4 and 6 weeks. We conclude that elution of antibiotics from PMMA along with the effect of sonication could inhibit bacterial growth from spacers, resulting in false negative results in the setting of two-stage exchange procedures for prosthetic joint infections.

Antibiotic impregnated total femur spacers: a technical tip

Simultaneous prosthetic joint infection of ipsilateral hip and knee arthroplasties is often accompanied by significant bone loss and presents a challenging reconstructive problem. Two-stage reconstruction is favored and requires the placement of a total femur spacer, which is not a commercially available device. We describe a surgical technique, reporting on 2 cases in which a customized total femur antibiotic impregnated spacer was created by combining an articulating knee spacer and an articulating hip spacer with a reinforced cement dowel construct connecting the 2 spacers. Custom total femoral spacers are useful in the management of infected femoral megaprostheses and cases with ipsilateral injected hip and knee arthroplasties and severe femoral bone loss.

In vivo serum concentration of vancomycin in antibiotic-loaded acrylic cement for the treatment and prevention of periprosthetic hip infection

BACKGROUND

Although antibiotic-loaded acrylic cement (ALAC) is used to prevent and treat periprosthetic hip infection, it is unknown how much antibiotic is deposited in the body in vivo, how high the serum concentration rises, or how long its effects last. The aim of this study was firstly to determine the amount of vancomycin (VCM) deposited as ALAC in the body, and secondly to assess the safety and drug elution profile of VCM in ALAC.

METHODS

We administered VCM to prevent infection after total hip arthroplasty (THA) or to treat patients with methicillin-resistant Staphylococcus aureus. Patients were classified into two groups: a low-dose group (21 hips) that received primary THA for high-risk cases, revision THA without infection, or one-staged revision THA for infection; and a high-dose group (6 hips) that received cement beads during a two-staged revision THA. The amount of VCM placed as ALAC into the hip was calculated using the remaining ALAC. The serum concentrations of VCM and creatinine were evaluated at postoperative days 1, 4, 7, 14, and 28, and at 3 and 6 months.

RESULTS

The mean amount of VCM placed as ALAC into the hip was 0.9 g and 3.4 g for cemented THA and cement beads, respectively (P < 0.0001). The mean serum concentration of VCM from ALAC in the high-dose group was significantly increased compared with that in the low-dose group on postoperative days 1, 4, 7, 14, and 28 (P < 0.0001), but it remained within a clinically safe range. No significant differences were observed between the preoperative and postoperative serum creatinine levels of either group.

CONCLUSION

The average serum concentrations of VCM from ALAC were always less than the effective blood concentration, and were detectable until 6 months after surgery.

Superficial Vancomycin Coating of Bone Cement in Orthopedic Revision Surgery: A Safe Technique to Enhance Local Antibiotic Concentrations

BACKGROUND

The use of antibiotic-loaded cement has become a well-accepted method to develop high local antibiotic concentrations in revision surgery of infected arthroplasty. A new surgical technique has been established to further increase the local antibiotic concentration and thereby minimizes the risk of reinfection. Our study aim was to investigate the safety of additional superficial vancomycin coating (SVC) by analyzing postoperative joint and serum vancomycin concentrations, as well as the creatinine levels of patients with orthopedic revision surgery.

METHODS

A longitudinal case series was performed by reviewing collected data of patients who were treated by SVC during revision surgery (1- or 2-stage exchange) because of prosthetic joint infections. Vancomycin levels were obtained, local from drains and systemic from blood samples, on postoperative days 1 to 5. Furthermore, preoperative and postoperative serum creatinine levels were analyzed.

RESULTS

Highest median local vancomycin levels were documented on postoperative day 1 with 546.8 μg/mL (range, 44.4-1485 μg/mL) in the reimplantation group and 408.7 μg/mL (range, 24.7-1650 μg/mL) in the spacer group. Median serum vancomycin level was 4.4 μg/mL (range, <2.0-11.7 μg/mL) on the first postoperative day in the reimplantation group and <2.0 μg/mL (range, <2.0-3.9 μg/mL) in the spacer group, and lower than 2.0 μg/mL (range, <2.0-7.5 μg/mL) from postoperative day 2 to 5 in both groups. Neither an anaphylactic reaction nor other side effects to SVC were observed.

CONCLUSION

Our data showed that SVC of bone cement is an effective technique to enhance local concentrations of vancomycin without leading to systemic side effects.

Antibiotic stability over six weeks in aqueous solution at body temperature with and without heat treatment that mimics the curing of bone cement

OBJECTIVES

Thermal stability is a key property in determining the suitability of an antibiotic agent for local application in the treatment of orthopaedic infections. Despite the fact that long-term therapy is a stated goal of novel local delivery carriers, data describing thermal stability over a long period are scarce, and studies that avoid interference from specific carrier materials are absent from the orthopaedic literature.

METHODS

In this study, a total of 38 frequently used antibiotic agents were maintained at 37°C in saline solution, and degradation and antibacterial activity assessed over six weeks. The impact of an initial supplementary heat exposure mimicking exothermically curing bone cement was also tested as this material is commonly used as a local delivery vehicle. Antibiotic degradation was assessed by liquid chromatography coupled to mass spectrometry, or by immunoassays, as appropriate. Antibacterial activity over time was determined by the Kirby-Bauer disk diffusion assay.

RESULTS

The heat exposure mimicking curing bone cement had minimal effect on stability for most antibiotics, except for gentamicin which experienced approximately 25% degradation as measured by immunoassay. Beta-lactam antibiotics were found to degrade quite rapidly at 37°C regardless of whether there was an initial heat exposure. Excellent long-term stability was observed for aminoglycosides, glycopeptides, tetracyclines and quinolones under both conditions.

CONCLUSIONS

This study provides a valuable dataset for orthopaedic surgeons considering local application of antibiotics, and for material scientists looking to develop next-generation controlled or extended-release antibiotic carriers.Cite this article: E. Samara, T. F. Moriarty, L. A. Decosterd, R. G. Richards, E. Gautier, P. Wahl. Antibiotic stability over six weeks in aqueous solution at body temperature with and without heat treatment that mimics the curing of bone cement. Bone Joint J 2017;6:296-306. DOI: 10.1302/2046-3758.65.BJR-2017-0276.R1.

Vancomycin displays time-dependent eradication of mature Staphylococcus aureus biofilms

This study was carried out to determine the time and concentration profile required to achieve vancomycin-mediated eradication of Staphylococcus aureus biofilm. This information is critical for the identification of performance targets for local antibiotic delivery vehicles that target biofilm infections. S. aureus UAMS-1 biofilms were grown for 7 days on titanium-aluminium-niobium discs in Mueller Hinton broth. After 7 days, the discs were then incubated in Mueller Hinton broth containing vancomycin at concentrations of 100, 200, 500, 1,000, and 2,000 mg/L. Biofilm eradication was assessed under both static and shaking conditions. Samples were retrieved at regular intervals for up to 28 days for quantification of residual biofilm. One additional disc was processed per time point for scanning electron microscopy. Progressive and significant reduction of viable bacteria was observed over time at all concentrations compared to unexposed controls. After 28 days under static conditions, the S. aureus biofilm was completely eradicated at 200 mg/L vancomycin and higher concentrations, but not at 100 mg/L. In contrast, bacterial biofilm could not be eradicated under shaking conditions at any concentration.

CLINICAL SIGNIFICANCE

The present study shows that it is possible to eradicate mature S. aureus biofilm from metal implants by vancomycin alone although the time concentration profile required cannot be achieved by systemic administration or any of the local delivery vehicles currently available. Identifying targets for antibiotic delivery is the first step in developing fit for purpose local antibiotic delivery vehicles that will successfully and predictably treat established biofilm infection. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:381-388, 2017.

One-stage Revision With Catheter Infusion of Intraarticular Antibiotics Successfully Treats Infected THA

BACKGROUND

Two-stage revision surgery for infected total hip arthroplasty (THA) is commonly advocated, but substantial morbidity and expense are associated with this technique. In certain cases of infected THA, treatment with one-stage revision surgery and intraarticular infusion of antibiotics may offer a reasonable alternative with the distinct advantage of providing a means of delivering the drug in high concentrations.

QUESTIONS/PURPOSES

We describe a protocol for intraarticular delivery of antibiotics to the hip through an indwelling catheter combined with one-stage revision surgery and examine (1) the success as judged by eradication of infection at 1 year when treating chronically infected cemented stems; (2) success in treating late-onset acute infections in well-ingrown cementless stems; and (3) what complications were associated with this approach in a small case series.

METHODS

Between January 2002 and July 2013, 30 patients (30 hips) presented to the senior author for treatment of infected THA. Of those, 21 patients (21 hips) with infected cemented THAs underwent débridement and single-stage revision to cementless total hip implants followed by catheter infusion of intraarticular antibiotics. Nine patients (nine hips) with late-onset acute infections in cementless THA had bone-ingrown implants. These patients were all more than 2 years from their original surgery and had acute symptoms of infection for 4 to 9 days. Seven had their original THA elsewhere, and two were the author's patients. All were symptom-free until the onset of their infection, and none had postoperative wound complications, fever, or prolonged pain suggestive of a more chronic process. They were treated with débridement and head and liner exchange, again followed by catheter infusion of intraarticular antibiotics. During this time period, this represented all infected THAs treated by the senior author, and all were treated with this protocol; no patient underwent two-stage exchange during this time, and no patients were lost to followup. At the time of the surgery, two Hickman catheters were placed in each hip to begin intraarticular delivery of antibiotics in the early postoperative period. Antibiotics were infused daily into the hip for 6 weeks with the tubes used for infusion only. Eleven of the single-stage revisions and four of the hips treated with débridement had methicillin-resistant Staphylococcus aureus. Patients were considered free of infection if they had no clinical signs of infection and had a normal C-reactive protein and erythrocyte sedimentation rate at 1 year. Complications were ascertained by chart review.

RESULTS

Twenty of 21 (95%) infections in patients who had single-stage revision for chronically infected cemented THA were apparently free from infection and remained so at a mean followup of 63 months (range, 25-157 months). One case grew Candida albicans in the operative cultures and remained free of signs of infection after rerevision followed by infusion of fluconazole. The nine cementless THAs treated with débridement and head/liner exchange all remained free of signs of infection at a mean followup of 74 months (range, 62-121 months). Few complications were associated with the technique. Four patients had elevated serum levels of vancomycin without renal function changes and two patients had transient blood urea nitrogen/creatinine elevations with normal vancomycin levels that resolved with dosage adjustments. No patient had evidence of permanent renal damage. None of the patients in this study developed a chronic fistula or had significant drainage from the catheter site.

CONCLUSIONS

Single-stage revision for chronically infected cemented THA and débridement of bone-ingrown cementless THA with late-onset acute infection followed with indwelling catheter antibiotic infusion can result in infection eradication even when resistant organisms are involved. Larger study groups would better assess this technique and prospective comparisons to more traditional one- and two-stage revision techniques for infected THA will likely require multi-institutional approaches.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Vancomycin and Ceftazidime in Bone Cement as a Potentially Effective Treatment for Knee Periprosthetic Joint Infection

BACKGROUND

The aim of this study was to determine the optimal formulation of antibiotic-loaded bone cement for knee periprosthetic joint infection. We used both in vitro and in vivo models incorporating various broad-spectrum antibiotics and tested their efficacy against gram-positive and gram-negative bacteria.

METHODS

Bone cement specimens loaded with 4 g of either vancomycin or teicoplanin and 4 g of ceftazidime, imipenem, or aztreonam were studied to measure their in vitro antibiotic release characteristics and antibacterial capacities against methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Bone cement spacers loaded with the antibiotics with the superior in vitro antibacterial capacity were then implanted into 8 patients (4 women and 4 men between 51 and 79 years of age) diagnosed with chronic knee periprosthetic joint infection. The antibiotic concentrations and antibacterial activities in the joint fluid at the site of the infection were measured following spacer implantation.

RESULTS

Cement samples loaded with vancomycin and ceftazidime exhibited in vitro antibacterial activity against the test microorganisms that lasted for as long as or longer than that of cement loaded with the other antibiotic combinations. Joint fluid samples exhibited activity against bacteria including American Type Culture Collection (ATCC) strains and clinically isolated strains.

CONCLUSIONS

Bone cement loaded with vancomycin and ceftazidime provided broad-spectrum antibacterial capacity both in vitro and in vivo and was shown to be a potentially effective therapeutic measure in the treatment of knee periprosthetic joint infections.

CLINICAL RELEVANCE

This study confirmed the potential effectiveness of drug delivery from bone cement spacers impregnated with vancomycin and ceftazidime.

Antibiotic Elution from Hip and Knee Acrylic Bone Cement Spacers: A Systematic Review

Knowledge about the elution from antibiotic-loaded cement spacers is an indispensable premise for guarantee of clinical success. A systematic literature search was performed through PubMed. Search terms were “antibiotic elution” and “antibiotic release” in combination with “spacer,” “hip spacer,” and “knee spacer,” respectively. A total of 11 studies could be identified. Seven studies reported on the release of antibiotics after spacer implantation, three studies at spacer removal, and one study on both time points. Seven studies reported on hip spacers, one study on knee spacers, and three studies on both. In eight studies, custom-made spacers have been implanted and in three prefabricated ones. In the majority of the studies, the cement has been loaded with an antibiotic combination, mostly consisting of aminoglycoside (either gentamicin or tobramycin) and vancomycin. Measured concentrations exceeded the minimal inhibitory concentration of the particular pathogen organisms in each case. However, large discrepancies were observed with regard to the height of the antibiotic concentration depending on the antibiotic combination and the antibiotic ratio used. Current literature data indicate a sufficient elution of antibiotics after spacer implantation and at spacer removal, respectively. Future studies are required to optimize the local antibiotic therapy at the site of spacer implantation.

Therapeutic Use of Antibiotic-loaded Bone Cement in the Treatment of Hip and Knee Joint Infections

The use of antibiotic-loaded cement spacers is an established method in the management of periprosthetic hip and knee joint infections. Despite inconsistencies among published studies, data shows that infection control rates exceed 90% with two-stage exchange arthroplasty. The present work reviews the current literature about antibiotic-loaded cement spacers and concentrates on the indications for spacer implantation, spacer production details, antibiotic impregnation, pharmacokinetic properties, clinical success, mechanical complications, and systemic safety.