Methicillin-resistant Staphylococcus aureus in TKA treated with revision and direct intra-articular antibiotic infusion

Local antibiotic delivery via intra-articular catheter infusion for the treatment of periprosthetic joint infection: a systematic review

INTRODUCTION

There is an increasing interest in the use of intra-articular (IA) antibiotic infusion as a stand-alone or adjuvant therapy to standard revision surgery for periprosthetic joint infection (PJI). The objective of this systematic review is to evaluate the evidence with respect to this up-and-coming treatment modality.

METHODS

A systematic review of studies published until April 2023 was conducted using PubMed, Embase, MEDLINE and Cochrane databases. Quality assessment was performed with the National Institute of Health quality assessment tool. Inclusion criteria were adult patients (≥ 18 years) with a mean follow-up of ≥ 11 months and a score ≥ 6 on the National Institute of Health quality assessment tool. Primary outcome was eradication of infection.

RESULTS

15 articles, encompassing 631 PJIs in 626 patients, were included in the final analysis, all level IV case series. The majority was treated with single-stage revision with adjuvant IA antibiotic infusion (79.1%). The remaining PJIs were treated with stand-alone IA antibiotic infusion (12.2%), DAIR (debridement, antibiotics and implant retention) with adjuvant IA antibiotic infusion (5.7%) or two-stage revision with adjuvant IA antibiotic infusion (3.0%). Mean duration of IA antibiotic infusion was 19 days (range 3-50). An overall failure rate of approximately 11% was found. In total 117 complications occurred, 71 were non-catheter-related and 46 were catheter-related. The most common catheter-related complications were premature loss of the catheter (18/46) and elevated blood urea nitrogen (BUN) and creatinine levels (12/46).

CONCLUSIONS

Due to the lack of comparative studies the (added) benefit of IA antibiotic infusion in the treatment of PJI remains uncertain. Based on the current evidence, we would advise against using it as a stand-alone treatment. A prospective randomized controlled trial using a well-described infusion protocol is needed to see if the potential benefits justify the increased costs and potential complications of this treatment modality.

Single-stage revision in the management of prosthetic joint infections after total knee arthroplasty - A review of current concepts

Introduction

Prosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA); and the gold standard surgical approach involves a two-staged, revision TKA (TSR). Owing to the newer, emerging evidence on this subject, there has been gradual shift towards a single-stage revision approach (SSR), with the purported benefits of mitigated patient morbidity, decreased complications and reduced costs. However, there is still substantial lacuna in the evidence regarding the safety and outcome of the two approaches in chronic PJI. This study aimed to comprehensively review of the literature on SSR; and evaluate its role within Revision TKA post PJI.

Methods

The narrative review involved a comprehensive search of the databases (Embase, Medline and Pubmed), conducted on 20th of January 2024 using specific key words. All the manuscripts discussing the use of SSR for the management of PJI after TKA were considered for the review. Among the screened manuscripts, opinion articles, letters to the editor and non-English manuscripts were excluded.

Results

The literature search yielded a total 232 studies. Following a detailed scrutiny of these manuscripts, 26 articles were finally selected. The overall success rate following SSR is reported to range from 73 % to 100 % (and is comparable to TSR). SSR is performed in PJI patients with bacteriologically-proven infection, adequate soft tissue cover, immuno-competent host and excellent tolerance to antibiotics. The main difference between SSR and TSR is that the interval between the 2 stages is only a few minutes instead of 6 weeks. Appropriate topical, intraoperative antibiotic therapy, followed by adequate postoperative systemic antibiotic cover are necessary to ascertain good outcome. Some of the major benefits of SSR over TSR include reduced morbidity, decreased complications (such as arthrofibrosis or anesthesia-associated adverse events), meliorated extremity function, earlier return to activities, mitigated mechanical (prosthesis-associated) complications and enhanced patient satisfaction.

Conclusion

SSR is a reliable approach for the management of chronic PJI. Based on our comprehensive review of the literature, it may be concluded that the right selection of patients, extensive debridement, sophisticated reconstruction strategy, identification of the pathogenic organism, initiation of appropriate antibiotic therapy and ensuring adequate follow-up are the key determinants of successful outcome. To achieve this will undoubtedly require an MDT approach to be taken on a case-by-case basis.

Intra-articular Vancomycin Reduces Prosthetic Infection in Primary Hip and Knee Arthroplasty

Background

Intravenous antibiotic infusion has been the standard prophylaxis for total joint arthroplasty surgery. However, infection rates still occur at 1%-2% in many series. Single-dose intra-articular antibiotics (IAAs) present a safe and potentially more effective prophylactic regime in total joint arthroplasty. This study aimed to assess the outcomes of a single-dose IAA injection on PJI rates in a single surgeon series of hip and knee arthroplasty.

Methods

We reviewed the data of all patients operated on for a primary hip or knee replacement from 2010 to 2021. From January 2018, 1 gm of vancomycin in 10 ml of saline was injected into every total joint replacement after fascial closure. A comparison was made with PJI referencing the Australian National Joint Replacement Registry data on revision for the 2 periods: 2010-2017 and 2018-2021.

Results

During the period without IAA (2010-2017) for TKR, 6 of 489 (1.2%), and for THR, 5 of 694 (0.7%) had PJI requiring revision surgery. In the period with IAA (2018-2021) for TKR, 0 of 214 (0%, P = .11), and for THR, 1 of 517 (0.2%, P = .19) PJI required revision surgery, but the overall incidence of PJI for TKR and THR was significantly reduced (P = .03).

Conclusions

A single dose of intra-articular vancomycin 1 gm injected into the total joint replacement following fascial closure reduced the incidence of deep PJI requiring a revision surgery in a single-surgeon series. These results demonstrate significant benefits to this technique which merit further larger trials.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Local Antibiotic Delivery Options in Prosthetic Joint Infection

Prosthetic Joint Infection (PJI) causes significant morbidity and mortality for patients globally. Delivery of antibiotics to the site of infection has potential to improve the treatment outcomes and enhance biofilm eradication. These antibiotics can be delivered using an intra-articular catheter or combined with a carrier substance to enhance pharmacokinetic properties. Carrier options include non-resorbable polymethylmethacrylate (PMMA) bone cement and resorbable calcium sulphate, hydroxyapatite, bioactive glass, and hydrogels. PMMA allows for creation of structural spacers used in multi-stage revision procedures, however it requires subsequent removal and antibiotic compatibility and the levels delivered are variable. Calcium sulphate is the most researched resorbable carrier in PJI, but is associated with wound leakage and hypercalcaemia, and clinical evidence for its effectiveness remains at the early stage. Hydrogels provide a versatile combability with antibiotics and adjustable elution profiles, but clinical usage is currently limited. Novel anti-biofilm therapies include bacteriophages which have been used successfully in small case series.

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.

Periprosthetic knee infection: treatment options

Infection is one of the most catastrophic complication following total knee arthroplasty (TKA) and represents the second most common cause of TKA failure. Treatment of a patient with periprosthetic joint infection (PJI) could require often costly and prolonged hospital stays, weeks or months of antibiotic therapy, and multiple surgical procedures. The best management is still highly debating, whereas many treatment options are available. These include suppressive antibiotics, arthroscopic irrigation and debridement, open debridement with insert exchange, single-stage reimplantation and two-stage reimplantation. The choice of the treatment depends on many variables, including integrity of implant, timing of the infection, host factors (age, health, immunologic status), virulence of the infecting organism and wishes of the patient. The aim of this review is to provide a comprehensive understaning of the different options for knee PJIs.

The role of antibiotic calcium sulfate beads in acute periprosthetic knee infection: a retrospective cohort study

Background

The study aimed to compare debridement, antibiotics, and implant retention (DAIR) vs. debridement antibiotic bead and retention of the implant (DABRI) in terms of infection-free success rate and treatment cost for acute periprosthetic joint infections after total knee arthroplasty (TKA).

Method

Between 2017 and 2020, 32 patients with acute periprosthetic joint infection who were treated by total knee arthroplasty were retrospectively reviewed. The patients were divided into a DAIR group (n=15) and a DABRI group (n=17). During the DABRI, additional calcium ulphate antibiotic beads were used. Patient age, the Musculoskeletal Infection Society score, microorganisms involved, and success rate were assessed.

Results

The mean age of DAIR group (n=15) was 69 years, with 7 being male, and 8 female. The mean follow-up period lasted 30 months. The success rate was 80% (12/15). The mean age of DABRI group (n=17) was 64 years, with 10 patients being male and 7 female. The mean follow-up period was 16 months. The success rate was 88% (15/17). There were no significant differences in patient age (P>0.05), the Musculoskeletal Infection Society score (P>0.05), and success rate (P>0.05). A significant difference was found in the follow-up period between the two groups (P<0.05).

Conclusion

Both DAIR and DABRI could be used to treat acute periprosthetic joint infections and the outcomes and treatment costs of the two procedures were comparable. Additional use of calcium sulfate beads was safe, but might not improve the treatment result. Randomized controlled studies are warranted for the routine use.

Inorganic nanosheets facilitate humoral immunity against medical implant infections by modulating immune co-stimulatory pathways

Strategies to manipulate immune cell co-inhibitory or co-activating signals have revolutionized immunotherapy. However, certain immunologically cold diseases, such as bacterial biofilm infections of medical implants are hard to target due to the complexity of the immune co-stimulatory pathways involved. Here we show that two-dimensional manganese chalcogenophosphates MnPSe₃ (MPS) nanosheets modified with polyvinylpyrrolidone (PVP) are capable of triggering a strong anti-bacterial biofilm humoral immunity in a mouse model of surgical implant infection via modulating antigen presentation and costimulatory molecule expression in the infectious microenvironment (IME). Mechanistically, the PVP-modified MPS (MPS-PVP) damages the structure of the biofilm which results in antigen exposure by generating reactive oxidative species, while changing the balance of immune-inhibitory (IL4I1 and CD206) and co-activator signals (CD40, CD80 and CD69). This leads to amplified APC priming and antigen presentation, resulting in biofilm-specific humoral immune and memory responses. In our work, we demonstrate that pre-surgical neoadjuvant immunotherapy utilizing MPS-PVP successfully mitigates residual and recurrent infections following removal of the infected implants. This study thus offers an alternative to replace antibiotics against hard-to-treat biofilm infections.

Intra-articular versus systemic vancomycin for the treatment of periprosthetic joint infection after debridement and spacer implantation in a rat model

Aims

Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.

Methods

Total knee arthroplasty (TKA), MRSA inoculation, debridement, and vancomycin-spacer implantation were performed successively in rats to mimic first-stage PJI during the two-stage revision arthroplasty procedure. Vancomycin was administered intraperitoneally or intra-articularly for two weeks to control the infection after debridement and spacer implantation.

Results

Rats receiving intra-articular vancomycin showed the best outcomes among the four treatment groups, with negative bacterial cultures, increased weight gain, increased capacity for weightbearing activities, increased residual bone volume preservation, and reduced inflammatory reactions in the joint tissues, indicating MRSA eradication in the knee. The vancomycin-spacer and/or systemic vancomycin failed to eliminate the MRSA infections following a two-week antibiotic course. Serum vancomycin levels did not reach nephrotoxic levels in any group. Mild renal histopathological changes, without changes in serum creatinine levels, were observed in the intraperitoneal vancomycin group compared with the intra-articular vancomycin group, but no changes in hepatic structure or serum alanine aminotransferase or aspartate aminotransferase levels were observed. No local complications were observed, such as sinus tract or non-healing surgical incisions.

Conclusion

Intra-articular vancomycin injection was effective and safe for PJI control following debridement and spacer implantation in a rat model during two-stage revision arthroplasties, with better outcomes than systemic vancomycin administration.

Cite this article: Bone Joint Res 2022;11(6):371–385.

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.

Intra-wound vancomycin powder for the eradication of periprosthetic joint infection after debridement and implant exchange: experimental study in a rat model

Background

Intra-wound vancomycin powder (VP) has been used in clinical practice to prevent periprosthetic joint infection (PJI) after primary knee/hip arthroplasty. The role of intra-wound VP in the setting of debridement and implant exchange after PJI remains undefined. This study aimed to explore the efficacy and safety of intra-wound VP in the control of methicillin-resistant S. aureus (MRSA) infection after debridement and implant exchange.

Methods

PJI modeling by knee prosthesis implantation and MRSA inoculation, debridement and implant exchange were performed in Wistar rats successively to mimic the one-stage exchange arthroplasty of PJI patients. Two weeks of systemic vancomycin (SV) or/and intraoperative intra-wound VP of single dosage were applied after revision surgery.

Results

No post-surgery deaths, incision complications and signs of drug toxicity were observed. The microbial counts of SV or intra-wound VP group were significantly reduced compared with the control group, while bacteria were still detected on the bone, soft-tissue and prosthesis. The elimination of bacterial counts, along with improvement of tissue inflammation and serum inflammatory markers, were observed in the rats with SV plus intra-wound VP. Serum levels of vancomycin in all groups were lower than that of causing nephrotoxicity, while no statistic difference was observed in the serum biochemical marker among the groups.

Conclusions

Intra-wound VP is effective after debridement and implant exchange in our current rat PJI model. Neither SV nor intra-wound VP alone could eradicate the bacteria within a two-weeks treatment course, while SV plus intra-wound VP could eliminate the MRSA infection, without notable hepatic or renal toxicity and any incision complications.

Experiences during Switching from Two-Stage to One-Stage Revision Arthroplasty for Chronic Total Knee Arthroplasty Infection

The objective of this study was to evaluate our preliminary results after changing our surgical strategy from 2-stage revision arthroplasty to 1-stage revision arthroplasty for patients with chronic knee periprosthetic joint infection. We conducted a prospective study of knee arthroplasty patients that had been diagnosed with chronic infection and treated using a 1-stage revision regardless of the traditional criteria applied for indication thereof. We evaluated two main variables: infection control and economic costs. The definitive diagnosis of infection of the revision was determined by using the criteria proposed by the Musculoskeletal Infection Society. The costs were calculated as average costs in USD, as described by Srivastava (2019), for 1-stage or 2-stage revisions. Eighteen patients were included in the study, and infection was controlled in 17 patients. The total economic savings for our hospital from these 18 patients amounted to USD 291,152. This clinical success has led to major changes in how our hospital approaches the treatment of chronically infected knee replacements, in addition to substantial economic advantages for the hospital.

Total hip revision with custom-made spacer and prosthesis: A case report

BACKGROUND

Both periprosthetic joint infections (PJIs) and severe femoral segmental defects are catastrophic complications of total hip arthroplasty (THA), and both present a significant challenge in revisional surgery. There are limited data available to guide clinical decision making when both occur concurrently.

CASE SUMMARY

A 61-year-old woman presented with a 6-mo history of a sinus tract at the site of her original THA incision. Radiological imaging revealed a total hip joint implant with an ipsilateral segmental femoral defect. Based on histological, radiological, laboratory, and clinical features, a diagnosis of concurrent chronic PJI and segmental femoral defect (Type IIIB, Paprosky classification) was made. After multidisciplinary team discussion, three-dimensional (3D)-printed, custom-made antibiotic spacers were created that could be used to mold antibiotic-loaded cement spacer. These were placed following PJI debridement in the first stage of revision surgery. After the PJI was eliminated, a 3D-printed, custom-made, femoral prosthesis was created to repair the considerable femoral defect. After 20-mo follow-up, the patient had excellent functional outcomes with a near-normal range of hip movement. So far, neither evidence of recurrent infection nor loosening of the prosthesis has been observed.

CONCLUSION

We describe a case of “two-stage, custom-made” total hip revision to treat PJI with a concurrent segmental femoral defect. Use of a personalized, 3D-printed spacer and proximal femoral prosthesis led to satisfactory hip function and no early postoperative complications. Use of a customized implant provides surgeons with an alternative option for patients where no suitable spacer or implant is available. However, the long-term function, longevity, and cost-effectiveness of the use of custom-made prostheses have yet to be fully explored.

Intra-articular administration of antibiotics in horses: Justifications, risks, reconsideration of use and outcomes

Antibiotics have been injected intra-articularly by equine veterinarians for decades, either prophylactically when other drugs are administered for osteoarthritis or therapeutically to treat septic arthritis. This route of administration has also more recently gained attention in human orthopaedic clinical practice, particularly as an alternative to systemic antibiotic administration to treat infections following prosthetic arthroplasty. While the rationale for injecting antibiotics intra-articularly has been largely focused on achieving high local drug concentrations, there has been relatively little focus on pharmacokinetic parameters of antibiotics administered by this route, or on the potential for local toxicity. The increasing incidence of antibiotic resistance in veterinary and human medicine prompts reconsideration of off-label antibiotic usage and evaluation of evidence-based dosing strategies. The purpose of this review was to summarise the current literature describing intra-articular antibiotic usage, including specific studies where pharmacokinetics, potential safety and toxicity have been evaluated. This review will advance practitioners' understanding of the use of intra-articularly administered antibiotics, including the overall pros and cons of the approach.

Local Application of Vancomycin in One-Stage Revision of Prosthetic Joint Infection Caused by Methicillin-Resistant Staphylococcus aureus

The rate of eradication of periprosthetic joint infection (PJI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is still not satisfactory with systemic vancomycin administration after one-stage revision arthroplasty. This study aimed to explore the effectiveness and safety of intraarticular (IA) injection of vancomycin in the control of MRSA PJI after one-stage revision surgery in a rat model. Two weeks of intraperitoneal (IP) and/or IA injection of vancomycin was used to control the infection after one-stage revision surgery. The MRSA PJI rats treated with IA injection of vancomycin showed better outcomes in skin temperature, bacterial counts, biofilm on the prosthesis, serum α₁-acid glycoprotein levels, residual bone volume, and inflammatory reaction in the joint tissue, compared with those treated with IP vancomycin, while the rats treated with IP and IA administration showed the best outcomes. However, only the IP and IA administration of vancomycin could eradicate MRSA. Minimal changes in renal pathology were observed in the IP and IP plus IA groups but not in the IA group, while no obvious changes were observed in the liver or in levels of serum markers, including creatinine, alanine aminotransferase, and aspartate aminotransferase. Therefore, IA use of vancomycin is effective and safe in the MRSA PJI rat model and is better than systemic administration, while IA and systemic vancomycin treatment could eradicate the infection with a 2-week treatment course.

Serum and Synovial Vancomycin Concentrations in Patients with Prosthetic Joint Infection after Intra-articular Infusion

BACKGROUND AND OBJECTIVES

Vancomycin is one of the most commonly used antibiotics for intra-articular (IA) infusion in the treatment of prosthetic joint infection (PJI). This study aimed to preliminarily investigate the serum and synovial vancomycin concentrations in patients with PJI after IA infusion.

METHODS

In total, 16 patients who developed PJI were enrolled in this study; 14 of the patients were treated with IA infusion of vancomycin postoperatively, while the other 2 patients received intravenous (IV) infusion of vancomycin alone. Chemiluminescent immunoassay assay (CLIA) and high-performance liquid chromatography (HPLC) were used to determine the serum and synovial vancomycin concentrations, respectively.

RESULTS

Administration of vancomycin 0.5 g once daily (qd) IA maintained a high vancomycin trough concentration in synovial fluid before the next IA dose, regardless of whether it was given in combination with IV administration. The combination vancomycin 0.5 g qd IA + vancomycin 1 g every 12 h (q12h) IV yielded relatively good trough concentrations of vancomycin in both serum and synovial fluid. The mean trough serum vancomycin concentration of patients who used vancomycin 1 g q12h IV therapy was above 10 μg/mL; however, no vancomycin was detected in their synovial fluid.

CONCLUSIONS

The rational use of IA vancomycin infusion may help to achieve effective therapeutic concentrations of vancomycin in the serum and synovial fluid of patients with PJI.

Debridement, antibiotics, and implant retention combined with direct intra-articular antibiotic infusion in patients with acute hematogenous periprosthetic joint infection of the knee

Background

Debridement, antibiotics, and implant retention (DAIR) is the recommended treatment for acute hematogenous periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). However, DAIR is associated with a high percentage of unsuccessful outcomes. Since 2007, direct intra-articular antibiotic infusion, which can provide a high concentration of intra-articular antibiotic, has been used in combination with DAIR to improve treatment outcomes among patients in our institution. This study aimed to assess the outcomes of DAIR combined with direct intra-articular antibiotic infusion in patients who presented with acute hematogenous PJI after TKA.

Methods

We reviewed the data of all patients diagnosed with acute hematogenous PJI after primary TKA (from 2008 to 2015) who received DAIR combined with direct intra-articular antibiotic infusion.

Results

In total, 15 knees in 12 patients were semi-urgently treated with this method. The mean follow-up time was 93.3 (minimum: 56) months, and the longest follow-up time was 11 years. Two patients (n = 3 knees) had a well-functioning, non-infected prosthesis 6 and 10 years after the procedure. Two patients (n = 2 knees) had re-infection 2 and 5 years after surgery, and they required two-stage revision. None of the patients were lost to follow-up. Finally, 13 (86.6%) of 15 infected knees were successfully treated with this method.

Conclusions

DAIR combined with direct intra-articular antibiotic infusion is an effective treatment for acute hematogenous PJI after TKA.

Single-Stage Revision of the Infected Total Knee Arthroplasty Is Associated With Improved Functional Outcomes: A Propensity Score-Matched Cohort Study

BACKGROUND

Single-stage revision is an alternative to the standard 2-stage revision, potentially minimizing morbidities and improving functional outcomes. This study aimed at comparing single-stage and 2-stage revision total knee arthroplasty (TKA) for chronic periprosthetic joint infection (PJI) with regard to patient-reported outcome measures (PROMs) and complication rates.

METHODS

A total of 185 consecutive revision TKA patients for chronic PJI with complete preoperative and postoperative PROMs were investigated. A total of 44 patients with single-stage revision TKA were matched to 88 patients following 2-stage revision TKA using propensity score matching, yielding a total of 132 propensity score-matched patients for analysis. Patient demographics and clinical information including reinfection and readmission rates were evaluated.

RESULTS

There was no significant difference in preoperative PROMs between propensity score-matched single-stage and 2-stage revision TKA cohorts. Postoperatively, significantly higher PROMs for single-stage revision TKA were observed for Knee disability and Osteoarthritis Outcome Score physical function (62.2 vs 51.9, P < .01), physical function short form 10A (42.8 vs 38.1, P < .01), PROMIS SF Physical (44.8 vs 41.0, P = .01), and PROMIS SF Mental (50.5 vs 47.1, P = .02). There was no difference between propensity score-matched single-stage and 2-stage revision TKA cohorts for clinical outcomes including reinfection rates (25.0% vs 27.2%, P = .78) and 90-day readmission rates (22.7% vs 25.0%, P = .77).

CONCLUSION

This study illustrated that single-stage revision TKA for chronic PJI may be associated with superior patient-reported outcomes compared to 2-stage revision for the infected TKA using a variety of PROMs. Improved PROMs were not accompanied by differences in complication rates between both cohorts, suggesting that single-stage revision TKA may provide an effective alternative to 2-stage revision in patients with chronic TKA PJI.

Systematic review of single stage revision for prosthetic joint infection

While advanced technology, increased medical knowledge and improved surgical technique has improved patient outcomes in total joint arthroplasty, prosthetic joint infection still remains one of the leading causes of increased healthcare costs, medical resources and societal burdens in orthopaedic care. Two stage arthroplasty revision remains the gold standard for treatment of prosthetic joint infection. Proponents of single stage revision arthroplasty for infection argue that it results in lower healthcare costs while improving patient reported functional outcomes and with equivalent success rates. Here we review the history of single stage revision arthroplasty, discuss the key principles, highlight the indications and contraindications, and review the reported outcomes with a focus on future developments of single stage revision arthroplasty for hip and knee periprosthetic joint infections.

Antibiotic Stewardship for Total Joint Arthroplasty in 2020

Projections indicate an increase in primary and revision total joint arthroplasties (TJAs). Periprosthetic joint infections (PJIs) are one of the most common and devastating causes of failure after TJA. Perioperative administration of systemic and/or local antibiotics is used for both prophylaxis and treatment of PJI. Antibiotic stewardship is a term that has been met with clinical acceptance and success in other specialties of medicine. Identifying antibiotic best practice use in the fight against PJI is limited by studies that are extremely heterogeneous in their design. Variations in studies include antibiotic selection and duration, surgical débridement steps, type of antibiotic delivery (intra-articular, local, intravenous, and prolonged oral), mix of primary and revision surgery cohorts, both hip and knee cohorts, infecting organisms, and definitions of treatment success/failure. This review highlights the current challenges of antibiotic stewardship in TJA.

Antimicrobial activity of mesenchymal stem cells against Staphylococcus aureus

Introduction

There have been limited advances in the treatment of bone and joint infections, which currently involves a combination of surgery and antibiotic administration. There is a timely need in orthopedics to develop more effective and less invasive forms of antimicrobial prophylaxis and treatment. The antibacterial effect of adult tissue-derived mesenchymal stem cells (MSCs) has recently been investigated against Escherichia coli and Staphylococcus aureus. The main mechanism of action is postulated to be via MSC production of the cationic antimicrobial peptide, LL-37.

Methods

This study examines the antimicrobial activity of adipose-derived human MSCs (ASCs) on S. aureus, specifically examining the role of LL-37 and regulation of its expression. Bacteria colony-forming unit (CFU) assay was used to assess antimicrobial activity.

Results

Our results showed that the ASC-conditioned medium significantly inhibited the growth of S. aureus under standard culture conditions with or without the continued presence of ASCs. Also, the treatment of ASCs with 1,25-dihydroxy vitamin D₃ elevated LL-37 expression and enhanced their antimicrobial activity. In support, treatment with the vitamin D receptor inhibitor, GW0742, blocked the antimicrobial activity of ASCs.

Conclusion

Our findings clearly demonstrate the antimicrobial activity of adult ASCs against S. aureus and implicate a key regulatory role for vitamin D. Further testing in in vivo models is being pursued to assess the potential application of ASCs as a biocompatible, adjunct treatment for musculoskeletal infections.

Improved treatment strategies can result in better outcomes following one-stage exchange surgery for MRSA periprosthetic joint infection

Introduction. Periprosthetic joint infections caused by methicillin-resistant Staphylococcus aureus (MRSA-PJIs) are rare, with only a few studies reporting the treatment outcomes and even fewer reporting outcomes with one-stage exchange.Aim. This study aims to analyse the outcomes of one-stage exchange in the management of MRSA-PJIs.Methodology. Patients with MRSA-PJI of the hip and knee, who were treated with a one-stage exchange between 2001 and 2018 were enrolled in this study. The final cohort comprised of 29 patients, which included 23 hips and six knees. The mean follow-up was 5.3 years (1-9 years). Reinfection and complications rates after the one-stage exchange were analysed.Results. Overall infection control could be achieved in 93.1 % (27 out of 29 patients). The overall revision rate was 31.0% (9 patients), with three patients requiring an in-hospital revision (10.3 %). Six patients had to be revised after hospital discharge (20.7 %). Of the two reinfections, one had a growth of MRSA while the other was of methicillin-sensitive Staphyloccocus epidermidis.Conclusion. One-stage exchange surgery using current techniques could improve surgical outcomes with excellent results in the management of MRSA-PJIs.

Vancomycin pre-soaking of the graft reduces postoperative infection rate without increasing risk of graft failure and arthrofibrosis in ACL reconstruction

PURPOSE

To investigate whether pre-soaking the graft in vancomycin during anterior cruciate ligament reconstruction (ACLR) reduces the postoperative infection rate and if this technique is associated with an increased rate of complications, including graft failure or arthrofibrosis.

METHODS

A retrospective review of a prospective database was performed in 1779 patients who underwent ACLR over a period of 5 years, analysing the rate of postoperative deep knee infection. Group 1 and 2 both received perioperative IV antibiotics, while only group 2 underwent ACLR with grafts pre-soaked in a 5 mg/ml vancomycin solution. To analyse possible side effects associated with vancomycin use, 500 patients out of the overall study population (100 patients per year) were randomly selected and retrospectively interviewed for further postoperative complications including graft failure and arthrofibrosis as well as subjective evaluation of their knee by completing the IKDC form with a minimum mean follow-up of 37 months.

RESULTS

In group 1, 22 out of 926 (2%) patients suffered a postoperative deep knee infection. In contrast, there were no postoperative infections in the second group of 853 patients (0%). 16 of 22 infections (73%) were caused by coagulase-negative Staphylococcus. Statistical analysis revealed a significantly reduced postoperative infection rate when bathing the autograft in vancomycin (p < 0.01). Analysis of the random sample revealed a significant decrease of graft failure with 8 reruptures in 257 patients (3%) in the vancomycin group compared to 16 cases of graft failure in 167 patients (10%) in the control group (p < 0.05). No differences were found in the rate of postoperative arthrofibrosis, Tegner or subjective outcome scores.

CONCLUSION

Prophylactic vancomycin pre-soaking of autografts during ACLR appears to be a viable, cost-effective and safe option to reduce the rate of deep infection compared to systemic antibiotics alone.

LEVEL OF EVIDENCE

III.

Single-Stage Revision Surgery in Infected Total Knee Arthroplasty: A PRISMA Systematic Review

Periprosthetic joint infection in total knee arthroplasty is a significant complication that is a common reason for revision surgery. The current standard of care is two-stage revision surgery. There is however increasing evidence to support the use of single-stage revision surgery. We conducted a PRISMA systematic review of the current evidence on the use of single-stage revision for infected total knee arthroplasty. Four databases (PubMed, Embase, Science Direct, and Cochrane Library) were systematically screened for eligible studies. The risk bias of each study was identified using ROBINS-I tool, and the quality of evidence was assessed using the GRADE criteria. Sixteen articles were retained after applying the inclusion and exclusion criteria that evaluated 3645 knee single-stage revision surgeries. Our review reveals satisfactory outcomes for single-stage revision in the management of infected total knee arthroplasty. The reinfection rates in the studies included in our review varied however the majority reported low reinfection rates and good functional outcomes. Although strict patient selection criteria have yielded successful results, good results were also reported when these criteria were not applied. The greater use of risk factors in identifying patients likely to have a successful outcome needs to be balanced with the practical benefits of performing a single stage procedure in higher risk patients. Future large clinical randomized control trials are required to confirm our results.

The Role of One-Stage Exchange for Prosthetic Joint Infection

PURPOSE OF REVIEW

In an era of increasing numbers of hip and knee replacements, strategies to manage prosthetic joint infection (PJI) that are effective at infection control with good patient-reported outcomes and cost containment for health systems are needed. Interest in single-stage exchange for PJI is rising and we assess evidence from the last 5 years related to this treatment strategy.

RECENT FINDINGS

Only five series for total knee replacement and ten series for total hip replacement have been reported in the last five years. More review articles and opinion pieces have been written. Reinfection rates in these recent studies range from 0 to 65%, but a meta-analysis and systematic review of all studies showed a reinfection rate of 7.6% (95% CI 3.4-13.1) and 8.8% (95% CI 7.2-10.6) for single-stage and two-stage revisions respectively. There is emerging evidence to support single-stage revision in the setting of significant bony deficiency and atypical PJIs such as fungal infections. Prospective randomised studies are recruiting and are necessary to guide the direction of single-stage revision selection criteria. The onus of surgical excellence in mechanical removal of implants, necrotic tissue, and biofilms lies with the arthroplasty surgeon and must remain the cornerstone of treatment. Single-stage revision may be considered the first-line treatment for all PJIs unless the organism is unknown, the patient is systemically septic, or there is a poor tissue envelope.

Successful treatment for acute prosthetic joint infection due to MRSA and Candida albicans: a case report and literature review

Methicillin-resistant Staphylococcus aureus (MRSA) and Candidal prosthetic joint infections (PJIs) are very rare, and the optimal management for these patients is still unknown. A 54-year-old man with traumatic arthritis due to previous electric injury successfully retained the implant despite the successive infection with MRSA and Candida albicans after total knee arthroplasty (TKA). Continuous lavage with vancomycin was used to control MRSA infection and repeated local washout plus oral swallow with voriconazole tablet were administered to eradicate C. albicans. Additional three reported cases were identified by the criteria of selecting patients with concomitant and/or successive MRSA and Candidal PJIs. Different methods were applied with variable outcomes. Therefore, several risk factors such as intra-articular corticosteroid injection, high frequency of door openings in the operating room, excessive blood loss and allogeneic red blood cell transfusions should be avoided. Debridement, antibiotics and implant retention (DAIR) can be an alternative in dedicated patients to control acute MRSA and Candidal PJIs. Particularly, repeated intra-articular washout with susceptible drugs and a prolonged duration of oral antibiotics was essential for microbial control.

Treatment of Prosthetic Joint Infection with Debridement, Antibiotics and Irrigation with Implant Retention - a Narrative Review

Prosthetic joint infection usually requires combined medical and surgical therapy. While revision surgery is widely considered to be the gold standard surgical procedure, debridement, antibiotics and irrigation with implant retention is a very appealing alternative. There is however great controversy regarding its real worth with success rates ranging from 0% to over 90%. A number of different patient and host related variables as well as specific aspects of surgical and medical management have been described as relevant for the final outcome. Along this paper, the authors will provide the readers with a critical narrative review of the currently available literature while trying to provide concise and practical treatment recommendations regarding adequate patient selection criteria, proper surgical technique and optimal antibiotic therapy.

Management of radiation induced, bilateral Primary THA loosening with an aseptic Paprosky Type IIB acetabular defect and a contralateral septic Type IIIB acetabular defect: A case report and review of literature

INTRODUCTION

Primary THA in an irradiated hip poses risk for early loosening and inadequate ingrowth.Adverse effects such as decreased vascularity and increased infection risk pose a threat.

CASE PRESENTATION

Our patient was a case of post-irradiation (for cervical cancer) bilateral THA loosening causing aseptic acetabular loosening on one side and catastrophic septic loosening with a Paprosky type IIIB acetabular defect with pelvic discontinuity on the contralateral side.

DISCUSSION

There have been various studies documenting deleterious effects of irradiation on osseointegration and provide a challenge for long-term implant stability in THA patients.

CONCLUSION

A meticulous treatment protocol with contemporary implant technology and staged bilateral stepwise management can lead to satisfactory clinical outcomes.This case report highlights on such specific nuances and principles.

Management of Prosthetic Joint Infection

Although uncommon, prosthetic joint infection is a devastating complication. This challenging condition requires a coordinated management approach to achieve good patient outcomes. This review details the general principles to consider when managing patients with prosthetic joint infection. The different medical/surgical treatment strategies and how to appropriately select a strategy are discussed. The data to support each strategy are presented, along with discussion of antimicrobial strategies in specific situations.

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.

Prosthetic knee infection by resistant bacteria: the worst-case scenario

PURPOSE

The aim of the present paper was to determine (1) the incidence of failure (defined as the persistence or the recurrence of the infection), (2) the incidence of prosthesis (or even limb) loss (defined as the final need for an arthrodesis, resection arthroplasty or amputation) and (3) what factors could influence the failure in patients treated with a two-stage reimplantation for periprosthetic knee infections caused by resistant bacteria.

METHODS

The authors retrospectively reviewed 29 total knee arthroplasties infected by resistant bacteria in 29 patients who underwent a two-stage revision. Between the stages, intravenous-targeted antibiotics were administered for a median period of 8 (range 6-12) weeks. Median follow-up was 10 (range 7-14) years.

RESULTS

The authors found that failure occurred in 5 of 29 patients (17.2 %). When methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) were involved, failure rate was 10 % (2 of 20). When vancomycin-resistant enterococcus (VRE), multidrug-resistant (MDR) Acinetobacter baumannii and MDR Pseudomonas aeruginosa were involved, the failure rate was 33.3 % (3 of 9). Of those five patients, two underwent amputations, one chronic suppressive antibiotic therapy, one arthrodesis and one resection arthroplasty; among them, three lost the limb (10.3 % of the overall group). Timing of reimplantation and patient comorbidities did not significantly influence the failure.

CONCLUSIONS

Two-stage protocol resulted in a viable option for patients with infections by some resistant organisms (MRSA and MR-CoNS). However, when highly resistant organisms were involved (VRE, MDR Acinetobacter Baumannii and MDR Pseudomonas aeruginosa), the failure rate was much higher. In all cases of failure of the two-stage reimplantation, prosthesis (or even limb) loss occurred. Consequently, patients should be counselled that when highly resistant bacteria are involved, two-stage reimplantation could not be successful, with high final risk of prosthesis (or even limb) loss.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Is the prognosis the same for periprosthetic joint infections due to Staphylococcus aureus versus coagulase-negative staphylococci? A retrospective study of 101 patients with 2-year minimum follow-up

BACKGROUND

Staphylococcus aureus (SA) and Coagulase-negative staphylococci (CoNS) are often responsible for infections of total hip arthroplasty (THA) and total knee arthroplasty (TKA). One of the main differences between these two microorganisms is their virulence, with SA presumed to be more virulent; however, few studies have specifically investigated the impact of this virulence. This inspired us to carry out a retrospective study to evaluate whether the healing rate differed between SA and CoNS infections.

HYPOTHESIS

We hypothesised that the healing rate is lower for SA prosthetic joint infections.

MATERIALS AND METHODS

This was a retrospective study of 101 consecutive Staphylococcus infection cases that occurred between 2007 and 2011. There were 56 men and 45 women with an average age of 69 years (range 23-95). The infection was associated with TKA in 38 cases and THA in 63 cases. Thirty-two percent of patients had one or more comorbidities with infectious potential. In our cohort, there were 32 SA infections (31.7 %) and 69 CoNS infections (68.3 %) with 58 of the infections being methicillin-resistant (15 SA and 43 CoNS); there were 27 polymicrobial infections (26.7 %).

RESULTS

With a minimum 24-month follow-up after the end of antibiotic treatment, the healing rate was 70.3 % overall (71 patients). The healing rate was 75 % in the SA group (24 patients) versus 68.1 % (47 patients) in the CoNS group (P = 0.42).

CONCLUSION

Our hypothesis was not confirmed: the healing rate of SA prosthetic joint infections was not lower than that of CoNS infections.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Elution profiles of tobramycin and vancomycin from high-purity calcium sulphate beads incubated in a range of simulated body fluids

The aim of this study was to characterise the elution profiles of antibiotics in combination with pharmaceutical grade calcium sulphate beads in phosphate buffered saline and other physiological solutions which more closely mimic the in vivo environment. Synthetic recrystallised calcium sulphate was combined with vancomycin hydrochloride powder and tobramycin sulphate solution and the paste was formed into 3 mm diameter hemispherical beads. Then 2 g of beads were immersed in 2 ml of either phosphate buffered saline, Dulbecco's Modified Eagle Medium or Hartmann's solution and incubated at 37℃ for up to 21 days. At a range of time points, eluent was removed for analysis by liquid chromatography-mass spectrometry (LC-MS). Tobramycin sulphate and vancomycin hydrochloride release was successfully quantified against standard curves from solutions eluted in all three physiological media (phosphate buffered saline, Dulbecco's Modified Eagle Medium and Hartmann's solution) during incubation with calcium sulphate beads. One hour eluate concentrations were high, up to 2602 µg/ml for tobramycin in phosphate buffered saline and 7417 µg/ml for vancomycin, whereas in DMEM, the levels of tobramycin were 2458 µg/ml and 4401 µg/ml for vancomycin. The levels in HRT were 2354 µg/ml for tobramycin and 5948 µg/ml for vancomycin. The results show highest levels of antibiotic elution over the first 24 h, which gradually diminish over the following 21 days.

Antibiotic-tolerant Staphylococcus aureus Biofilm Persists on Arthroplasty Materials

BACKGROUND

The continued presence of biofilm may be one cause of the high risk of failure observed with irrigation and débridement with component retention in acute periprosthetic joint infection (PJI). There is a poor understanding of the role of biofilm antibiotic tolerance in PJI.

QUESTIONS/PURPOSES

(1) Do increasing doses of cefazolin result in decreased viable biofilm mass on arthroplasty materials? (2) Is cefazolin resistance phenotypic or genotypic? (3) Is biofilm viability a function of biofilm depth after treatment with cefazolin? (4) Is the toxin-antitoxin system, yoeB expression, associated with antibiotic stress?

METHODS

Methicillin-sensitive Staphylococcus aureus biofilm was cultured on total knee arthroplasty (TKA) materials and exposed to increasing doses of cefazolin (control, 0.5, 1.0, 10.0, 100.0 μg/mL). Quantitative confocal microscopy and quantitative culture were used to measure viable biofilm cell density. To determine if cefazolin resistance was phenotypic or genotypic, we measured minimum inhibitory concentration (MIC) after exposure to different cefazolin concentrations; changes in MIC would suggest genotypic features, whereas unchanged MIC would suggest phenotypic behavior. Finally, quantitative reverse transcription-polymerase chain reaction was used to quantify expression of yoeB levels between biofilm and planktonic bacteria after exposure to 1 μg/mL cefazolin for 3 hours.

RESULTS

Although live biofilm mass was reduced by exposure to cefazolin when compared with biofilm mass in controls (39.2 × 10(3) ± 26.4 × 10(3) pixels), where the level after 0.5 µg/mL exposure also showed reduced mass (20.3 × 10(3) ± 11.9 × 10(3) pixels), no further reduction was seen after higher doses (mass at 1.0 µg/mL: 5.0 × 10(3) pixels ± 1.1 × 10(3) pixels; at 10.0 µg/mL: 6.4 × 10(3) ± 9.6 × 10(3) pixels; at 100.0 µg/mL: 6.4 × 10(3) ± 3.9 × 10(3)). At the highest concentration tested (100 µg/mL), residual viable biofilm was present on all three materials, and there were no differences in percent biofilm survival among cobalt-chromium (18.5% ± 15.1%), polymethylmethacrylate (22.8% ± 20.2%), and polyethylene (14.7% ± 10.4%). We found that tolerance was a phenotypic phenomenon, because increasing cefazolin exposure did not result in changes in MIC as compared with controls (MIC in controls: 0.13 ± 0.02; at 0.5 µg/mL: 0.13 ± 0.001, p = 0.96; at 1.0 µg/m: 0.14 ± 0.04, p = 0.95; at 10.0 µg/m: 0.11 ± 0.016, p = 0.47; at 100.0 µg/m: 0.94 ± 0.047, p = 0.47). Expression of yoeB after 1 µg/mL cefazolin for 3 hours in biofilm cells was greater in biofilm but not in planktonic cells (biofilm: 62.3-fold change, planktonic cells: -78.8-fold change, p < 0.001).

CONCLUSIONS

Antibiotics are inadequate at complete removal of the biofilm from the surface of TKA materials. Results suggest that bacterial persisters are responsible for this phenotypic behavior allowing biofilm high tolerance to antibiotics.

CLINICAL RELEVANCE

Antibiotic-tolerant biofilm suggests a mechanism behind the poor results in irrigation and débridement for acute TKA PJI.

Intra-articular infusion

Bactericidal levels of antibiotics are difficult to achieve in infected total joint arthroplasty when intravenous antibiotics or antibiotic-loaded cement spacers are used, but intra-articular (IA) delivery of antibiotics has been effective in several studies. This paper describes a protocol for IA delivery of antibiotics in infected knee arthroplasty, and summarises the results of a pharmacokinetic study and two clinical follow-up studies of especially difficult groups: methicillin-resistant Staphylococcus aureus and failed two-stage revision. In the pharmacokinetic study, the mean synovial vancomycin peak level was 9242 (3956 to 32 150; sd 7608 μg/mL) among the 11 patients studied. Serum trough level ranged from 4.2 to 25.2 μg/mL (mean, 12.3 μg/mL; average of 9.6% of the joint trough value), which exceeded minimal inhibitory concentration. The success rate exceeded 95% in the two clinical groups. IA delivery of antibiotics is shown to be safe and effective, and is now the first option for treatment of infected total joint arthroplasty in our institution.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):31–6.

Characterization of hip and knee arthroplasties and factors associated with infection

OBJECTIVE

To characterize arthroplasty procedures, calculate the surgical infection rate and identify related risk factors.

METHODS

This was a retrospective cohort study. Data on operations performed between 2010 and 2012 were gathered from documental sources and were analyzed with the aid of statistical software, using Fisher's exact test, Student's t test and the nonparametric Mann-Whitney and Wilcoxon tests.

RESULTS

421 total arthroplasty procedures performed on 346 patients were analyzed, of which 208 were on the knee and 213 on the hip. It was found that 18 patients (4.3%) were infected. Among these, 15 (83.33%) were reoperated and 2 (15.74%) died. The prevalence of infection in primary total hip arthroplasty procedures was 3%; in primary total knee arthroplasty, 6.14%; and in revision of total knee arthroplasty, 3.45%. Staphylococcus aureus was prevalent. The length of the surgical procedure showed a tendency toward being a risk factor (p = 0.067).

CONCLUSION

The prevalence of infection in cases of primary total knee arthroplasty was greater than in other cases. No statistically significant risk factors for infection were identified.

Single Stage Knee Arthroplasty Revision Surgery: A Systematic Review of the Literature

Total Knee Arthroplasty is an increasingly common procedure and revision surgery, particularly for infection, is associated with significant morbidity and healthcare costs. The current gold standard is a two stage revision procedure but single stage revision is increasingly being used in some departments to improve patient outcomes. We conducted a systematic review of the literature to determine the up-to-date evidence underlying the use of a single stage knee approach in revision surgery. A total of 12 studies were included in this review amounting to 433 revision surgeries. This is the largest review of single stage knee revision surgery. The procedures described were heterogenous and included the 'two-in-one' technique as well as other single stage revision procedures. There were also differences in implants and antibiotic regimens. The mean re-infection rates described in 10 studies was 9.4% (range 0-19.2%) after a mean follow-up of 40.3 months (range 7-180 months). The re-infection rates in the studies published over the last 30 years are falling, and this is not accounted for by any significant change in duration of follow-up during this period. The outcome scores varied, but patients generally showed an improvement. The Knee Society Score and the Oxford Knee Score were the most commonly used in five and three studies respectively. We conclude that the current evidence for single stage revision is variable and there is a lack of good quality evidence to address whether single stage revisions is thorough enough to eradicate deep infection and is able to restore adequate function. There is a need for larger prospective studies with standardised procedures and protocol, and with adequate follow-up. Till then, patients considered for a single stage approach should be thoroughly assessed and the surgery should be performed by a senior surgeon with experience in single stage knee revisions.

Efficacy of Single-stage Revision with Aggressive Debridement Using Intra-articular Antibiotics in the Treatment of Infected Joint Prosthesis

Prosthetic joint infections (PJI) of the hip and knee are uncommon, but result in significant morbidity and mortality when they do occur. Current management consists of a combination of either single- or two-stage exchange of the prosthesis and/or exchange of polymer components with intravenous (IV) antibiotics (4–6 weeks) and intraoperative debridement of the joint prior to reimplantation. However, failure rate, morbidity, and expense associated with current management are high, especially if the infection involves resistant pathogens and/or osteomyelitis. Also, the current use of systemic antibiotics does not allow for high local concentrations of the drug and biofilm penetration of the infected prosthesis. To overcome these difficulties, we examined the outcomes of aggressive operative debridement of the infected prosthesis. This was achieved through the use of a single-stage revision and administration of high concentrations of local intra-articular antibiotics via Hickman catheters. We present 57 patients with PJI who were treated with intra-articular antibiotics and single-stage revisions. Minimal systemic toxicity was observed along with a 100% microbiologic cure rate and 89% without relapse at 11-month follow-up despite isolation of multidrug resistant pathogens. This is the largest study to date using this method in the treatment of PJI.

Recognizing and managing infections in total joint arthroplasty

Periprosthetic joint infections are a devastating complication of joint arthroplasty procedures, affecting 1% to 4% of patients. With the increasing demand for joint replacement, the clinical and financial burden of periprosthetic joint infections is challenging. This article reviews the diagnosis and treatment of periprosthetic joint infections.

Arthrodesis should be strongly considered after failed two-stage reimplantation TKA

BACKGROUND

A two-stage reimplantation procedure is a well-accepted procedure for management of first-time infected total knee arthroplasty (TKA). However, there is a lack of consensus on the treatment of subsequent reinfections.

QUESTIONS/PURPOSES

The purpose of this study was to perform a decision analysis to determine the treatment method likely to yield the highest quality of life for a patient after a failed two-stage reimplantation.

METHODS

We performed a systematic review to estimate the expected success rates of a two-stage reimplantation procedure, chronic suppression, arthrodesis, and amputation for treatment of infected TKA. To determine utility values of the various possible health states that could arise after two-stage revision, we used previously published values and methods to determine the utility and disutility tolls for each treatment option and performed a decision tree analysis using the TreeAgePro 2012 software suite (Williamstown, MA, USA). These values were subsequently varied to perform sensitivity analyses, determining thresholds at which different treatment options prevailed.

RESULTS

Overall, the composite success rate for two-stage reimplantation was 79.1% (range, 33.3%-100%). The utility (successful outcome) and disutility toll (cost for treatment) for two-stage reimplantation were determined to be 0.473 and 0.20, respectively; the toll for undergoing chronic suppression was set at 0.05; the utility for arthrodesis was 0.740 and for amputation 0.423. We set the utilities for subsequent two-stage revision and other surgical procedures by subtracting the disutility toll from the utility each time another procedure was performed. The two-way sensitivity analysis varied the utility status after an additional two-stage reimplantation (0.47-0.99) and chance of a successful two-stage reimplantation (45%-95%). The model was then extended to a three-way sensitivity analysis twice: once by setting the variable arthrodesis utility at a value of 0.47 and once more by setting utility of two-stage reimplantation at 0.05 over the same range of values on both axes. Knee arthrodesis emerged as the treatment most likely to yield the highest expected utility (quality of life) after initially failing a two-stage revision. For a repeat two-stage revision to be favored, the utility of that second two-stage revision had to substantially exceed the published utility of primary TKA of 0.84 and the probability of achieving infection control had to exceed 90%.

CONCLUSIONS

Based on best available evidence, knee arthrodesis should be strongly considered as the treatment of choice for patients who have persistent infected TKA after a failed two-stage reimplantation procedure. We recognize that particular circumstances such as severe bone loss can preclude or limit the applicability of fusion as an option and that individual clinical circumstances must always dictate the best treatment, but where arthrodesis is practical, our model supports it as the best approach.

Intraoperative intra-articular injection of gentamicin: will it decrease the risk of infection in total shoulder arthroplasty?

BACKGROUND

Deep infection is a debilitating complication after shoulder arthroplasty. Intra-articular injection of antibiotic can give a higher concentration compared with intravenous administration. We hypothesized that a group of patients given an intra-articular, intraoperative injection of gentamicin would report a lower infection rate than a group without local antibiotics.

METHODS

Between 2005 and 2011, the senior author performed 507 shoulder arthroplasties. We retrospectively reviewed all of those cases. All patients were administered systemic prophylactic antibiotics. Beginning in June 2007, patients were also injected with 160 mg of gentamicin in the glenohumeral joint at the end of their surgery. Patient records were examined for preexisting medical conditions, type of surgery, and presence of infection. Patients receiving surgery before 2007 were compared with those after to determine the effect of prophylactic gentamicin administration in preventing deep infection associated with surgery. All patients were observed for a minimum of 1 year.

RESULTS

Of the 507 surgeries, 164 were performed before 2007 (without intra-articular injection of gentamicin; group A) and 343 were performed with addition of gentamicin (group B). In group A, 5 patients presented with infection (3.0%) compared with 1 in group B (0.29%). The gender, mean age, mean body mass index, and prevalence of comorbidities were similar between the groups.

CONCLUSIONS

The data from this study support the conclusion that intra-articular intraoperative gentamicin administration may reduce postoperative infection.

Low-grade periprosthetic knee infection: diagnosis and management

Diagnosis and management of low-grade periprosthetic knee infection are still controversial and debatable. The diagnosis of low-grade infection after total knee arthroplasty is often complex, as clinical symptomatology and diagnostic studies are highly conflicting and knees often exhibit well-fixed components. Although the criterion standard for staged reimplantation is interim placement of an antibiotic-loaded spacer, less-invasive surgical procedures have been advocated for managing infections caused by low-virulence bacteria. Debridement with polyethylene exchange and single-stage reimplantation could offer advantages, such as fewer surgeries, reduced potential for intraoperative complications, and lower direct social costs. The aim of this narrative review was to analyze the literature to evaluate the effectiveness of different surgical procedures in managing low-grade periprosthetic knee infections. Additionally, the most reliable investigations for diagnosing total knee infection caused by low-virulence bacteria were reviewed.

Level of evidence Level V.