Staphylococcus aureus prosthetic joint infection treated with debridement and prosthesis retention

The Effect of Retained Hardware on Failure Among Prosthetic Joint Infections of the Knee in the Presence and Absence of Staphylococcus aureus

Background

The risk of failure associated with different surgical strategies for prosthetic joint infections (PJIs) among patients with and without Staphylococcus aureus is uncertain. The purpose of this study was to assess whether S. aureus modifies the association between retained hardware and failure following revision surgery for PJI of the knee.

Methods

This was a single-center retrospective cohort study of 106 first PJIs of the knee between 2016 and 2020 at a rural academic medical center. The exposure was retained hardware following revision surgery for PJI, and the outcomes were recurrent infection, any infection, and a composite outcome including any infection, unplanned revision, failure to undergo reimplantation, amputation, or death within 2 years of revision. We used negative binomial regression to quantify the association between the exposure and outcome and to assess the presence of S. aureus as an effect modifier.

Results

Retained hardware was significantly associated with failure when defined as recurrent infection among S. aureus PJI (adjusted risk difference [aRD], 0.38; 95% CI, 0.12-0.64) but not in the absence of S. aureus (aRD, -0.02; 95% CI, -0.17 to 0.13), and S. aureus was an effect modifier (P interaction = .01).

Conclusions

We report a significant association between the presence of retained hardware and recurrent infection among S. aureus PJI of the knee, but not for non-S. aureus PJI. This could help inform the surgical management of PJI of the knee in cases where the microbiology is known before surgery.

KLIC Score Does Not Predict Failure After Early Prosthetic Joint Infection: An External Validation With 153 Knees and 130 Hips

BACKGROUND

A preoperative risk score, the KLIC score (chronic renal failure [K], liver cirrhosis [L], indication of the index surgery [I], cemented prosthesis [C], and C-reactive protein >115 mg/L), has been developed to predict the risk of treatment failure after early prosthetic joint infection (PJI). This study aimed to validate the KLIC score for the debridement, antibiotics, and implant retention (DAIR) procedure and one-stage revisions in a Northern European cohort.

METHODS

Revisions due to early PJI of the hip or knee between January 1, 2008, and September 12, 2021, were identified retrospectively. The primary outcome was early failure, which was considered when the patient needed an unscheduled surgery, the patient died, or the patient was prescribed long-term suppressive antibiotics. To examine the association between KLIC score and failure risk, univariable logistic regression with area under the curve (AUC) was used. In addition, models were calibrated to assess prognostic ability and clinical utility was examined with decision-curve analyses.

RESULTS

An increase in KLIC score had a moderate predictive value for early failure after DAIR (odds ratio [OR] 1.45; confidence interval [CI] 1.13 to 1.90). For one-stage revision, it was only slightly predictive of failure (OR 1.20; CI 0.93 to 1.56). After 60 days, the AUC for DAIR was 0.63 (CI 0.55 to 0.72) and 0.56 (CI 0.46 to 0.66) for one-stage revisions, indicating poor discriminative ability. The decision-curve analyses revealed that the model did not offer a remarkable net benefit across a range of threshold probabilities.

CONCLUSIONS

We demonstrated that the KLIC score is not a reliable predictor of early failure after early PJI in a Northern European cohort. Using the model to guide treatment decisions does not provide any additional clinical utility beyond the baseline strategies.

Appropriate Duration of Antimicrobial Treatment for Prosthetic Joint Infections: A Narrative Review

Prosthetic joint infections are considered difficult to treat they needing aggressive surgery and long antimicrobial treatments. However, the exact duration of these therapies has been established empirically. In the last years, several studies have explored the possibility of reducing the length of treatment in this setting, with conflicting results. In this narrative review, we critically appraise the published evidence, considering the different surgical approaches (implant retention [DAIR] and one-step and two-step exchange procedures) separately. In patients managed with DAIR, usually treated for at least 12 weeks, a large, randomized trial failed to show that 6 weeks were non-inferior. However, another randomized clinical trial supports the use of 8 weeks, as long as the surgical conditions are favorable and antibiotics with good antibiofilm activity can be administered. In patients managed with a two-step exchange procedure, usually treated during 6 weeks, a randomized clinical trial showed the efficacy of a 4-week course of antimicrobials. Also, the use of local antibiotics may allow the use of even shorter treatments. Finally, in the case of one-step exchange procedures, there is a trend towards reducing the length of therapy, and the largest randomized clinical trial supports the use of 6 weeks of therapy.

Debridement, antibiotics, and implant retention (DAIR) for the early prosthetic joint infection of total knee and hip arthroplasties: a systematic review

PURPOSE

Early periprosthetic joint infection (PJI) represents one of the most fearsome complications of joint replacement. No international consensus has been reached regarding the best approach for early prosthetic knee and hip infections. The aim of this updated systematic review is to assess whether debridement, antibiotics, and implant retention (DAIR) is an effective choice of treatment in early postoperative and acute hematogenous PJI.

METHODS

This systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The diagnostic criteria defining a PJI, the most present pathogen, and the days between the index procedure and the onset of the PJI were extracted from the selected articles. Additionally, the mean follow-up, antibiotic regimen, and success rate of the treatment were also reported.

RESULTS

The articles included provided a cohort of 970 patients. Ten studies specified the joint of their cohort in PJIs regarding either hip prostheses or knee prostheses, resulting in 454 total knees and 460 total hips. The age of the patients ranged from 18 to 92 years old. Success rates for the DAIR treatments in the following cohort ranged from 55.5% up to a maximum of 90% (mean value of 71%).

CONCLUSION

Even though the DAIR procedure is quite limited, it is still considered an effective option for patients developing an early post-operative or acute hematogenous PJI. However, there is a lack of studies, in particular randomized control trials (RCTs), comparing DAIR with one-stage and two-stage revision protocols in the setting of early PJIs, reflecting the necessity to conduct further high-quality studies to face the burden of early PJI.

Antibody-antibiotic conjugate targeted therapy for orthopedic implant-associated intracellular S. aureus infections

INTRODUCTION

Treating orthopedic implant-associated infections, especially those caused by Staphylococcus aureus (S. aureus), remains a significant challenge. S. aureus has the ability to invade host cells, enabling it to evade both antibiotics and immune responses during infection, which may result in clinical treatment failures. Therefore, it is critical to identify the host cell type of implant-associated intracellular S. aureus infections and to develop a strategy for highly targeted delivery of antibiotics to the host cells.

OBJECTIVES

Introduced an antibody-antibiotic conjugate (AAC) for the targeted elimination of intracellular S. aureus.

METHODS

The AAC comprises of a human monoclonal antibody (M0662) directly recognizes the surface antigen of S. aureus, Staphylococcus protein A, which is conjugated with vancomycin through cathepsin-sensitive linkers that are cleavable in the proteolytic environment of the intracellular phagolysosome. AAC, vancomycin and vancomycin combined with AAC were used in vitro intracellular infection and mice implant infection models. We then tested the effect of AAC in vivo and in vivo by fluorescence imaging, in vivo imaging, bacterial quantitative analysis and bacterial biofilm imaging.

RESULTS

In vitro, it was observed that AAC captured extracellular S. aureus and co-entered the cells, and subsequently released vancomycin to induce rapid elimination of intracellular S. aureus. In the implant infection model, AAC significantly improved the bactericidal effect of vancomycin. Scanning electron microscopy showed that the application of AAC effectively blocked the formation of bacterial biofilm. Further histochemical and micro-CT analysis showed AAC significantly reduced the level of bone marrow density (BMD) and bone volume fraction (BV/TV) reduction caused by bacterial infection in the distal femur of mice compared to vancomycin treatment alone.

CONCLUSIONS

The application of AAC in an implant infection model showed that it significantly improved the bactericidal effects of vancomycin and effectively blocked the formation of bacterial biofilms, without apparent toxicity to the host.

Early Staphylococcal Periprosthetic Joint Infection (PJI) Treated with Debridement, Antibiotics, and Implant Retention (DAIR): Inferior Outcomes in Patients with Staphylococci Resistant to Rifampicin

It is unknown how rifampicin resistance in staphylococci causing a periprosthetic joint infection (PJI) affects outcomes after debridement, antibiotics, and implant retention (DAIR). We thus aimed to compare the risk of relapse in DAIR-treated early PJI caused by staphylococci with or without rifampicin resistance. In total, 81 patients affected by early PJI were included, and all patients were treated surgically with DAIR. This was repeated if needed. The endpoint of relapse-free survival was estimated using the Kaplan-Meier method, and Cox regression models were fitted to assess the risk of infection relapse for patients infected with rifampicin-resistant bacteria, adjusted for age, sex, type of joint, and type of index surgery. In patients with rifampicin-resistant staphylococci, relapse was seen in 80% after one DAIR procedure and in 70% after two DAIR procedures. In patients with rifampicin-sensitive bacteria, 51% had an infection relapse after one DAIR procedure and 33% had an infection relapse after two DAIR procedures. Patients with rifampicin-resistant staphylococcal PJI thus had an increased adjusted risk of infection relapse of 1.9 (95% CI: 1.1-3.6, p = 0.04) after one DAIR procedure compared to patients with rifampicin-sensitive bacteria and a 4.1-fold (95% CI: 1.2-14.1, p = 0.03) increase in risk of infection relapse after two DAIR procedures. Staphylococcal resistance to rifampicin is associated with inferior outcomes after DAIR. These findings suggest that DAIR may not be a useful strategy in early PJI caused by rifampicin-resistant staphylococci.

Diagnosis and treatment of periprosthetic infection after hip replacement (a review)

Introduction. The frequency of hip arthroplasty is steadily increasing throughout the world and, although this operation has become routine, the likelihood of postoperative complications reaches 4.3 % [1]. The most dangerous of them are infectious lesions in the area of the endoprosthesis and adjacent tissues. At the same time, in addition to the threat of generalization of the infectious process, there are functional disorders in the joint area and a general deterioration in the quality of life of the patient. Timely diagnosis and treatment of the infectious process and related disorders can minimize the adverse effects of infection.

Target. The purpose of this review is to analyze modern methods for diagnosing and treating periprosthetic infection resulting from hip replacement.

Materials and methods. The subject literature was searched using the PubMed and Google Sholar databases.

Results. The main methods for diagnosing periprosthetic infection include histological and bacteriological examination of the biopsy specimen, determination of sensitivity to antibiotics, blood, and synovial fluid analysis for the content of leukocytes, IL-6, CRP, PCR diagnostics of infectious agents. Treatment consists of re-intervention and/or antibiotic therapy.

Conclusion. The most optimal method for diagnosing periprosthetic infection is a bacteriological study of biopsy specimens taken intraoperatively. The preferred method of treatment is determined by the severity of the infection, the degree of involvement of tissues adjacent to the prosthesis, the comorbid background, the nature of the infectious agent, and includes repeated revision surgery.

Microbial resistance to nanotechnologies: An important but understudied consideration using antimicrobial nanotechnologies in orthopaedic implants

Microbial resistance to current antibiotics therapies is a major cause of implant failure and adverse clinical outcomes in orthopaedic surgery. Recent developments in advanced antimicrobial nanotechnologies provide numerous opportunities to effective remove resistant bacteria and prevent resistance from occurring through unique mechanisms. With tunable physicochemical properties, nanomaterials can be designed to be bactericidal, antifouling, immunomodulating, and capable of delivering antibacterial compounds to the infection region with spatiotemporal accuracy. Despite its substantial advancement, an important, but under-explored area, is potential microbial resistance to nanomaterials and how this can impact the clinical use of antimicrobial nanotechnologies. This review aims to provide a better understanding of nanomaterial-associated microbial resistance to accelerate bench-to-bedside translations of emerging nanotechnologies for effective control of implant associated infections.

The Fate of Periprosthetic Joint Infection With Corynebacterium striatum: A Rare but Catastrophic Causative Organism

BACKGROUND

The virulence and antibiotic resistance profile of an infecting organism have been shown to impact the outcomes of periprosthetic joint infection (PJI). However, there are no existing data on the outcomes of PJI caused by Corynebacterium striatum, a rare organism. Thus, our objective is to ascertain: (1) the treatment success of PJI caused by this rare organism and (2) patient characteristics in the setting of C striatum PJI.

METHODS

A retrospective review was conducted on 741 consecutive PJIs managed at 2 hospital facilities by 8 surgeons (February 4, 2015 to October 30, 2019). The inclusion criteria represented the presence of minimum 1 positive culture of C. striatum. After excluding 1 patient with no follow-up, 15 patients were finally analyzed (9 hips/6 knees). Out of 15 patients, 9 underwent explantation with spacer insertion, 5 underwent irrigation and debridement with polyexchange (I&D), and 1 underwent Girdlestone. Out of 9 explanted patients, only 6 cleared infection and were reimplanted. The clinical staging system for PJI was determined using McPherson classification. The mean follow-ups for I&D and explantation were 35 and 23.5 months, respectively. Success of reimplantation was determined using Delphi criteria.

RESULTS

Out of 5 I&D patients, 40% had to be reoperated because of persistent infection. Out of 6 explanted patients who were reimplanted, 67% failed. According to McPherson, 40% of I&D and 22.2% of explanted patients were significantly compromised hosts.

CONCLUSION

C. striatum PJI has a high-treatment failure rate in patient undergoing I&D or 2-stage revision surgery. Surgeons should be aware of the difficulty controlling this PJI and advise patients accordingly.

Iatrogenic Contamination With a Surgical Helmet System in Orthopedic Surgery

Surgical helmet systems (SHSs) have been used to decrease iatrogenic contamination to prevent periprosthetic joint infections. However, the use of SHSs has been controversial. Therefore, the purpose of this study was to investigate iatrogenic contamination of traditional surgical attire (TSA), SHSs, and SHSs with delayed ventilation (SHS-DV) (helmet fan not turned on until surgeon gowned and gloved). A total of 180 orthopedic surgical procedures were prospectively enrolled and randomized into one of three cohorts. The TSA cohort included any orthopedic procedures, while the SHS and SHS-DV cohorts included arthroplasty procedures. Cultures were obtained from bilateral forearms, axillae, the sternum, and face shields for SHS groups. There were 60 surgeries in each group. The rate of positive cultures was calculated for each cohort and stratified by location and type of microorganism. The positive culture rates were 15% in the TSA, 25% in the SHS, 18% in the SHS-DV cohorts. The positive swab culture rates were 6% in the TSA, 7% in the SHS, and 4% in the SHS-DV cohorts. The positive culture rate was highest from the forearms in the TSA cohort (10%), the face shield in the SHS cohort (20%), and the chest in the SHS-DV cohort (7%). Coagulase-negative Staphylococcus was the most common bacteria cultured. The overall bacterial contamination rates were similar between the TSA and the SHS cohorts, with a lower rate in the SHS-DV cohort. Waiting to initiate airflow in SHSs and treating the shields as contaminated may reduce iatrogenic contamination. [Orthopedics. 2021;44(6):e753-e756.].

Debridement, Antibiotics, and Implant Retention in Periprosthetic Joint Infection: What Predicts Success or Failure?

BACKGROUND

Debridement, antibiotics and implant retention (DAIR) is the treatment of choice for acute postoperative and acute hematogenous periprosthetic joint infection (PJI). There is limited literature on predictive prognostic factors for DAIR. We aim to report the outcomes of DAIR and investigate the predictive prognostic factors.

METHODS

We retrospectively reviewed 106 DAIRs. Failure was defined as requiring removal of TKA implants. Predictive factors that may influence success of DAIR treatment such as age, gender, body mass index, ethnicity, American Society of Anesthesiologists score, comorbidities, preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein, symptom duration, time between total knee arthroplasty and DAIR, cultures, rifampicin use, polyethylene liner change, and antibiotic duration were analyzed.

RESULTS

The success rate of DAIR was 69.8% (74/106 patients). For successes, mean time from DAIR-to-mortality was longer than failures (61.6 ± 42.7 vs 9.75 ± 9.60 months, P = .0150). Methicillin-susceptible Staphylococcus aureus PJI (odds ratio [OR] 3.64, confidence interval [CI] 1.30-10.2, P = .0140) was a significant predictor for failure of DAIR. Higher preoperative ESR correlated to failure (OR 1.02, CI 1.01-1.04, P = .008). In successes, mean ESR was 75.4 (66.1-84.6), whereas mean ESR in failures was 116 (88.3-143) (P = .011). An ESR > 107.5 predicted failure with a sensitivity of 51.5 and specificity of 85.2. ESR > 107.5 correlated to failure (OR 6.60, CI 2.29-19.0, P < .001). Repeat DAIRs were strongly correlated to failure (OR 5.27, CI 1.99-13.9, P < .01).

CONCLUSION

DAIR failure is associated with earlier time to mortality. Repeat DAIRs, elevated ESR > 107.5, and S aureus PJI are associated with treatment failure and 2-stage revision is recommended.

Delayed Rifampin Administration in the Antibiotic Treatment of Periprosthetic Joint Infections Significantly Reduces the Emergence of Rifampin Resistance

Rifampin is one of the most important biofilm-active antibiotics in the treatment of periprosthetic joint infection (PJI), and antibiotic regimens not involving rifampin were shown to have higher failure rates. Therefore, an emerging rifampin resistance can have a devastating effect on the outcome of PJI. The aim of this study was to compare the incidence of rifampin resistance between two groups of patients with a PJI treated with antibiotic regimens involving either immediate or delayed additional rifampin administration and to evaluate the effect of this resistance on the outcome. In this retrospective analysis of routinely collected data, all patients who presented with an acute/chronic PJI between 2018 and 2020 were recorded in the context of a single-center comparative cohort study. Two groups were formed: Group 1 included 25 patients with a PJI presenting in 2018-2019. These patients received additional rifampin only after pathogen detection in the intraoperative specimens. Group 2 included 37 patients presenting in 2019-2020. These patients were treated directly postoperatively with an empiric antibiotic therapy including rifampin. In all, 62 patients (32 females) with a mean age of 68 years and 322 operations were included. We found a rifampin-resistant organism in 16% of cases. Rifampin resistance increased significantly from 12% in Group 1 to 19% in Group 2 (p < 0.05). The treatment failure rate was 16% in Group 1 and 16.2% in Group 2 (p = 0.83). The most commonly isolated rifampin-resistant pathogen was Staphylococcus epidermidis (86%) (p < 0.05). The present study shows a significant association between the immediate start of rifampin after surgical revision in the treatment of PJI and the emergence of rifampin resistance, however with no significant effect on outcome.

Is Negative Pressure Wound Therapy with Instillation Suitable for the Treatment of Acute Periprosthetic Hip Joint Infection?

Background: Periprosthetic joint infection (PJI) can be devastating for the patient and demanding for the surgeon. In acute PJI, attempts are made to retain the prosthesis by debridement of the infected tissue, targeted antibiotic therapy and an exchange of modular components with implant retention (DAIR). There has been sparse research with adjunctive negative pressure wound treatment with wound irrigation (NPWTI) on the treatment outcome. Questions/purposes: The goal was to assess the efficacy of our protocol of DAIR with adjunctive NPWTI in acute PJI and to reduce the need for later additional DAIR and Irrigation and Debridement (I and D). Patients and Methods: Our cohort of 30 patients (31 hips) with acute PJI was divided into two groups based on symptom presentation up to 6 weeks or >6 weeks from prior (index) surgery (acute early or acute late groups, respectively). All received DAIR with an exchange of modular components and NPWTI with polyhexanide instillation, with the goal of bacterial elimination and biofilm elimination. Postoperatively, the patients were followed up clinically and radiographically for a mean of 4.3 years. Results: Of the 31 PJI hips, 19 were early acute and 12 were late acute. In total, 21 hips had no evidence of residual infection, 10 required further surgical revision: 1 due to dislocation and 9 due to infection. Of these nine, seven had a removal of all the components and two were treated with irrigation and debridement (I and D), with the demise of one patient from pneumonia shortly after the procedure. The Kaplan–Meier 60-month revision free implant survival from infection was 73.2% (CI: 58.9–91.0%) and at the final follow up, the mean Harris Hip Score (HHS) was 81.1 ± 11.8 and the mean WOMAC score was 33.3 ± 20.1. Conclusions: Our results are in line with those reported in prior studies. However, the utility of our protocol is inconclusive and needs further evaluation based on our small cohort and the lack of a control group. Level of Evidence: IV.

Low frequency of local findings in periprosthetic hip infection caused by low-virulent bacteria compared to periprosthetic knee infection

Periprosthetic joint infection (PJI) is suspected when local findings such as pain, swelling, hyperthermia, and sinus tract are present. However, the frequency of these findings and the difference between hip and knee are unclear. This study compared the positive rates of local findings in periprosthetic hip infection (PHI) with periprosthetic knee infection (PKI), and aimed to identify potential risk factors associated with the frequency. One hundred one PJI (46 hips and 55 knees) fulfilled the 2018 Musculoskeletal infection society criteria were analysed retrospectively to assess the positive rates of each local finding. Patients were categorized into two groups based on the presence or absence of each local finding, and the influence of two potential risk factors [body mass index (BMI) and C-reactive protein (CRP)] was investigated. Causative bacterial species were divided into high and low-virulent groups, and then culture negative cases were included in low-virulent group. PHI had significantly lower rates of pain, swelling and hyperthermia compared to PKI. Overall, up to one-third of PHI had pain as only symptom. High BMI and low-virulent bacteria were associated with lower frequency of swelling and hyperthermia in PHI. CRP had no impact on positive rates of local findings. PHI was oligosymptomatic in a significant percentage of cases. This is particularly important in obese patients and infection by low-virulent bacteria.

Debridement, Antibiotics, and Implant Retention Is a Viable Treatment Option for Early Periprosthetic Joint Infection Presenting More Than 4 Weeks After Index Arthroplasty

BACKGROUND

The success of debridement, antibiotics, and implant retention (DAIR) in early periprosthetic joint infection (PJI) largely depends on the presence of a mature biofilm. At what time point DAIR should be disrecommended is unknown. This multicenter study evaluated the outcome of DAIR in relation to the time after index arthroplasty.

METHODS

We retrospectively evaluated PJIs occurring within 90 days after surgery and treated with DAIR. Patients with bacteremia, arthroscopic debridements, and a follow-up <1 year were excluded. Treatment failure was defined as (1) any further surgical procedure related to infection; (2) PJI-related death; or (3) use of long-term suppressive antibiotics.

RESULTS

We included 769 patients. Treatment failure occurred in 294 patients (38%) and was similar between time intervals from index arthroplasty to DAIR: the failure rate for Week 1-2 was 42% (95/226), the rate for Week 3-4 was 38% (143/378), the rate for Week 5-6 was 29% (29/100), and the rate for Week 7-12 was 42% (27/65). An exchange of modular components was performed to a lesser extent in the early post-surgical course compared with the late course (41% vs 63%, respectively; P < .001). The causative microorganisms, comorbidities, and durations of symptoms were comparable between time intervals.

CONCLUSIONS

DAIR is a viable option in patients with early PJI presenting more than 4 weeks after index surgery, as long as DAIR is performed within at least 1 week after the onset of symptoms and modular components can be exchanged.

Controversy about the Role of Rifampin in Biofilm Infections: Is It Justified?

Rifampin is a potent antibiotic against staphylococcal implant-associated infections. In the absence of implants, current data suggest against the use of rifampin combinations. In the past decades, abundant preclinical and clinical evidence has accumulated supporting its role in biofilm-related infections.In the present article, experimental data from animal models of foreign-body infections and clinical trials are reviewed. The risk for emergence of rifampin resistance and multiple drug interactions are emphasized. A recent randomized controlled trial (RCT) showing no beneficial effect of rifampin in patients with acute staphylococcal periprosthetic joint infection treated with prosthesis retention is critically reviewed and data interpreted. Given the existing strong evidence demonstrating the benefit of rifampin, the conduction of an adequately powered RCT with appropriate definitions and interventions would probably not comply with ethical standards.

Methods and probability of success after early revision of prosthetic joint infections with debridement, antibiotics and implant retention

Prosthetic joint infection (PJI) is a rare-and dreaded-complication of arthroplasty requiring multidisciplinary care. Given the dual goal of treating the infection and maintaining satisfactory function, it is preferable to determine how and when the implanted components can be retained. Bacteria and fungi organize themselves into biofilms that shield them from antibiotics and the immune system. This biofilm is in place after 15 days of active infection. Some antibiotics have a better activity on biofilms. The following factors have a negative impact on the probability of a successful debridement, antibiotics and implant retention (DAIR) intervention: fracture or revision, use of cement, bacteremia, kidney and/or liver failure, immunosuppression and elevated CRP. Hematogenous infections have a worse prognosis than early postoperative infections. Using a decision algorithm increases the chances of DAIR being successful. The KLIC score applies to early postoperative infections (<4 weeks postoperative and<3 weeks from the first signs) while the CRIME-80 score applies to hematogenous infections (<3 weeks from the first signs). Arthroscopic treatments have no role here, whereas DAIR through an arthrotomy is well standardized. Wide spectrum antibiotic therapy, secondarily adapted to the causative microorganism, is indicated for a total of 3 months. The results against the infection are mixed, although following a decision algorithm resolves the infection in about 75% of cases. The functional outcomes and quality of life are close to those of patients who have undergone primary joint replacement. It is not recommended to carry out a second DAIR if the first one fails. It is logical to apply the principles set out for the hip and knee to other joint replacements, and to use the same algorithm. For the upper limb, and especially for reverse shoulder arthroplasty, one must be careful about Cutibacterium acnes infections as they are hard to diagnose. Surgeons should not hesitate to contact a referral center for any PJI, although it is preferable that early infections be treated at the facility that performed the implantation.

Implant Removal in the Management of Prosthetic Joint Infection by Staphylococcus aureus: Outcome and Predictors of Failure in a Large Retrospective Multicenter Study

OBJECTIVES

To compare the characteristics and outcomes of cases with acute prosthetic joint infection (PJI; early post-surgical or hematogenous) by Staphylococcus aureus managed with implant removal (IRm) or debridement and retention (DAIR). To analyze the outcomes of all cases managed with IRm (initially or after DAIR failure).

METHODS

Retrospective, multicenter, cohort study of PJI by S. aureus (2003-2010). Overall failure included mortality within 60 days since surgery and local failure due to staphylococcal persistence/relapse.

RESULTS

499 cases, 338 initially managed with DAIR, 161 with IRm. Mortality was higher in acute PJI managed initially with IRm compared to DAIR, but not associated with the surgical procedure, after propensity score matching. Underlying conditions, hemiarthroplasty, and methicillin-resistant S. aureus were risk factors for mortality. Finally, 249 cases underwent IRm (88 after DAIR failure); overall failure was 15.6%. Local failure (9.3%) was slightly higher in cases with several comorbidities, but independent of previous DAIR, type of IRm, and rifampin treatment.

CONCLUSIONS

In a large multicenter study of S. aureus PJI managed with IRm, failure was low, but mortality significant, especially in cases with acute PJI and underlying conditions, but not associated with the IRm itself. Rifampin efficacy was limited in this setting.

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.

The Double DAIR: A 2-Stage Debridement with Prosthesis-Retention Protocol for Acute Periprosthetic Joint Infections

BACKGROUND

Debridement and implant retention (DAIR) has variable success as a treatment for acute periprosthetic joint infection (PJI), with generally poor outcomes reported in the literature1. Because of the unacceptably high failure rate of DAIR, we implemented a 2-stage debridement protocol that includes the use of high-dose antibiotic beads between stages for the treatment of acute PJI. In 2 previous studies, with an average follow-up of 3.5 years in each study, we reported overall infection-control rates of 87% and 90%2,3.

DESCRIPTION

Following exposure of the joint, cultures are obtained, and all modular components are removed, scrubbed, and soaked in an antiseptic solution. A thorough irrigation and debridement with complete synovectomy is performed, followed by temporary reinsertion of the original modular parts. High-dose antibiotic cement beads are inserted into the joint, and the joint is closed. Approximately 5 to 6 days later, a second debridement is performed, the beads are removed, and the new modular, sterile components are implanted. The patient is placed on a course of intravenous and, later, oral antibiotics, in addition to a standard postoperative rehabilitation protocol.

ALTERNATIVES

Long-term suppressive antibiotic therapy.One-stage DAIR.One-stage exchange arthroplasty.Two-stage exchange arthroplasty.Resection arthroplasty.Amputation.

RATIONALE

The treatment of acute PJI has historically consisted of a single irrigation and debridement, with exchange of modular parts and retention of the components, followed by intravenous antibiotic therapy. Despite having lower rates of patient morbidity compared with a 2-stage exchange arthroplasty, this more traditional procedure also has a higher rate of failure, with reported rates as high as 60% to 84%4-12. The utility of component retention continues to be a topic of debate13. Alternatives to component retention include both 1- and 2-stage exchange procedures. Although these modalities offer potentially higher rates of infection control, they are associated with substantial patient morbidity, particularly in patients with well-fixed implants14-16. Furthermore, exchange procedures may result in substantial iatrogenic bone loss, which can be problematic in revision total joint arthroplasty procedures, in which bone stock may already be limited. The double-DAIR protocol offers infection-control rates that are comparable with those of component-exchange procedures, but with the lower patient morbidity associated with component-retention procedures. Furthermore, the double-DAIR procedure provides the added benefit of retaining important bone stock.

EXPECTED OUTCOMES

The success rate for the double-DAIR procedure has been reproducible, with infection-control rates of 87% and 90% reported in 2 studies from a single cohort at our institution2,3. These rates represent a substantial improvement compared with a single irrigation and debridement1, and are on par with those reported for 2-stage exchange arthroplasty procedures17-21. The infection-control rates of the double-DAIR procedure did not significantly vary depending on whether infection occurred following a total knee or total hip arthroplasty. However, not surprisingly, patients who underwent debridement following a revision procedure had a lower rate of success (77.1% successful infection control) compared with patients debrided following a primary procedure (93.8% successful infection control). We could not demonstrate an association with organism and success or failure of treatment.Although not significant, there was a trend toward an association between the time from symptom onset to initial treatment and infection control (p = 0.07)2. Patients with successful infection control underwent the initial debridement an average of 6.2 days after symptom onset, compared with 10.7 days in patients in whom treatment had failed. Several other studies have demonstrated that successful infection control is associated with earlier initial irrigation and debridement22-27. We strongly support that, in the setting of confirmed acute PJI, prompt initiation of treatment optimizes the chances for successful infection control.

IMPORTANT TIPS

Thorough debridement is key to successful infection control of infection.Antibiotic-loaded bone cement has repeatedly been demonstrated to be safe, and we recommend its use28-31.Extended oral antibiotics following debridement with component retention can increase infection-free survivorship32.

A decision analysis of treatment strategies for acute periprosthetic joint infection: Early irrigation and debridement versus delayed treatment based on organism

OBJECTIVE

The purpose of this study was to investigate whether immediate or delayed tailored DAIR treatment based on microbial species is the optimal treatment for acute post-operative periprosthetic joint infection (PJI).

METHODS

A multicenter retrospective study was conducted to identify patients who underwent debridement, antibiotics, and implant retention (DAIR) for PJI. Decision analysis modeling was employed to determine the treatment strategy that yielded the greatest patient outcome.

RESULTS

316 patients who underwent DAIR for PJI were identified.

CONCLUSION

The decision analysis model determined that the optimal treatment strategy is to perform an immediate DAIR to achieve the greatest QALY outcomes in TKA and THA patients with acute PJI.

2020 Frank Stinchfield Award: Identifying who will fail following irrigation and debridement for prosthetic joint infection

AIMS

Failure of irrigation and debridement (I&D) for prosthetic joint infection (PJI) is influenced by numerous host, surgical, and pathogen-related factors. We aimed to develop and validate a practical, easy-to-use tool based on machine learning that may accurately predict outcome following I&D surgery taking into account the influence of numerous factors.

METHODS

This was an international, multicentre retrospective study of 1,174 revision total hip (THA) and knee arthroplasties (TKA) undergoing I&D for PJI between January 2005 and December 2017. PJI was defined using the Musculoskeletal Infection Society (MSIS) criteria. A total of 52 variables including demographics, comorbidities, and clinical and laboratory findings were evaluated using random forest machine learning analysis. The algorithm was then verified through cross-validation.

RESULTS

Of the 1,174 patients that were included in the study, 405 patients (34.5%) failed treatment. Using random forest analysis, an algorithm that provides the probability for failure for each specific patient was created. By order of importance, the ten most important variables associated with failure of I&D were serum CRP levels, positive blood cultures, indication for index arthroplasty other than osteoarthritis, not exchanging the modular components, use of immunosuppressive medication, late acute (haematogenous) infections, methicillin-resistant Staphylococcus aureus infection, overlying skin infection, polymicrobial infection, and older age. The algorithm had good discriminatory capability (area under the curve = 0.74). Cross-validation showed similar probabilities comparing predicted and observed failures indicating high accuracy of the model.

CONCLUSION

This is the first study in the orthopaedic literature to use machine learning as a tool for predicting outcomes following I&D surgery. The developed algorithm provides the medical profession with a tool that can be employed in clinical decision-making and improve patient care. Future studies should aid in further validating this tool on additional cohorts. Cite this article: Bone Joint J 2020;102-B(7 Supple B):11-19.

Irrigation, Débridement, and Implant Retention for Recurrence of Periprosthetic Joint Infection Following Two-Stage Revision Total Knee Arthroplasty: A Matched Cohort Study

BACKGROUND

We investigated clinical/functional outcomes and implant survivorship in patients who underwent 2-stage revision total knee arthroplasty (TKA) after periprosthetic joint infection (PJI), experienced acute PJI recurrence, and underwent irrigation, débridement, and polyethylene exchange (IDPE) with retention of stable implant.

METHODS

Twenty-four patients (24 knees) were identified who underwent 2-stage revision TKA for PJI, experienced acute PJI recurrence, and then underwent IDPE between 2005 and 2016 (minimum 2-year follow-up). After IDPE, intravenous antibiotics (6 weeks) and oral suppression therapy (minimum 6 months) were administered. Data were compared with 1:2 matched control group that underwent 2-stage revision TKA for chronic PJI and did not receive IDPE.

RESULTS

Average IDPE group follow-up was 3.8 years (range, 2.4-7.2). Reinfection rate after IDPE was 29% (n = 7): 3 of 7 underwent second IDPE (2 of 3 had no infection recurrence) and 5 (one was patient who had recurrent infection after second IDPE) underwent another 2-stage revision TKA. Control group reinfection rate was 27% (n = 13) (P = .85). For IDPE group, mean time to reinfection after 2-stage revision TKA was 4.6 months (range, 1-8 months) (patients presented with acute symptoms less than 3 weeks duration). At latest follow-up, mean Knee Society Score was 70 (range, 35-85) in IDPE group and 75 (range, 30-85) in control group (P = .53).

CONCLUSION

IDPE for acute reinfection following 2-stage revision TKA with well-fixed implants had a 71% success rate. These patients had comparable functional outcome as patients with no IDPE after 2-stage revision TKA. IDPE followed by long-term suppression antibiotic therapy should be considered in patients with acute infection and stable components.

Two-Stage Debridement With Prosthesis Retention for Acute Periprosthetic Joint Infections

BACKGROUND

Historically, infection control rates with debridement and component retention have been poor in the management of acute prosthetic joint infections. We previously described a 2-stage debridement with prosthesis retention protocol for acute periprosthetic joint infection and reported a 90% success rate in a sample of 20 patients.

METHODS

A retrospective review of 83 patients who underwent a 2-stage debridement with implant retention with a minimum 1-year follow-up was performed. Patient data were primarily analyzed to determine infection control rates. Infections were considered controlled when patients had not undergone a reoperation for infection, and demonstrated lack of any clinical signs or symptoms of infection (a well healed wound, diminishing swelling and warmth, absence of erythema, improvement in baseline pain symptoms) A secondary goal of this study was to examine the effects of symptom duration on infection control rate.

RESULTS

Average patient follow-up was 41.8 months (range 12-171) for all patients. The overall protocol success rate was 86.7% (72/83): 82.9% in hips and 89.6% in knees. Additionally, protocol success was observed in 45 of 48 primary joints (93.8%) and 27 of 35 (77.1%) revision joints (P = .046). Average time from onset of symptoms to surgery was 6.2 days for successfully treated patients (range 0-27 days) compared to 10.7 days for those who failed treatment (range 1-28 days, P = .070).

CONCLUSION

This 2-stage retention protocol resulted in a higher likelihood of infection control compared to prior reports of single stage debridement and modular part exchange.

Increased Failure After Irrigation and Debridement for Acute Hematogenous Periprosthetic Joint Infection

BACKGROUND

Acute periprosthetic joint infection (PJI) is difficult to treat. In this study, we investigated the failure rates of irrigation and debridement (I&D) among patients with acute post-surgical and acute hematogenous PJI, and explored various host and organism-related risk factors that may be associated with treatment failure.

METHODS

We retrospectively reviewed the cases of 199 total joint arthroplasty patients who underwent I&D for acute post-surgical PJI (<3 months postoperatively) and acute hematogenous PJI (≥3 months postoperatively, with abrupt symptoms lasting <3 weeks) at a single center during the period of 2005 to 2016. Only patients meeting the Musculoskeletal Infection Society (MSIS) criteria for PJI were included. Patient demographics, comorbidities, physical examination findings, laboratory results, and organism profile were identified. Treatment failure, as defined by the Delphi criteria, was determined for 1-year follow-up. Primary statistical analysis involved univariate and multivariate regression.

RESULTS

The failure rate was 37.7% (75 of 199) at 1 year. Among the patients with acute hematogenous infections, the rate of failure (56%, 29 of 52) was almost 2 times higher than that of patients with acute post-surgical infections (31%, 46 of 147) (adjusted odds ratio [OR], 2.36; 95% confidence interval [CI], 1.16 to 4.81; p = 0.018). Host predictors of failure included prior revision surgery (adjusted OR, 2.55; 95% CI, 1.22 to 5.32; p = 0.013) and a higher Charlson Comorbidity Index (adjusted OR, 1.22; 95% CI, 1.01 to 1.51; p = 0.048). Specific comorbidities associated with failure included chronic obstructive pulmonary disease (p = 0.026), diabetes (p = 0.004), and a history of malignancy (p = 0.005). Patients with polymicrobial infections (adjusted OR, 2.40; 95% CI, 1.10 to 5.20; p = 0.028) were also more likely to experience failure of treatment after I&D. The clinical and laboratory risk factors associated with failure were the presence of intraoperative purulence (p = 0.05), elevated systolic blood pressure (p = 0.05), tachycardia (p = 0.06), and higher serum C-reactive protein level (p = 0.003).

CONCLUSIONS

This study revealed that I&D is associated with a high rate of failure for patients with an acute hematogenous PJI. The study also identified a number of risk factors for failure. The findings of this study may allow better decision-making by surgeons regarding the surgical management of patients with acute PJI.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Calcium Phosphate Spacers for the Local Delivery of Sitafloxacin and Rifampin to Treat Orthopedic Infections: Efficacy and Proof of Concept in a Mouse Model of Single-Stage Revision of Device-Associated Osteomyelitis

Osteomyelitis is a chronic bone infection that is often treated with adjuvant antibiotic-impregnated poly(methyl methacrylate) (PMMA) cement spacers in multi-staged revisions. However, failure rates remain substantial due to recurrence of infection, which is attributed to the poor performance of the PMMA cement as a drug release device. Hence, the objective of this study was to design and evaluate a bioresorbable calcium phosphate scaffold (CaPS) for sustained antimicrobial drug release and investigate its efficacy in a murine model of femoral implant-associated osteomyelitis. Incorporating rifampin and sitafloxacin, which are effective against bacterial phenotypes responsible for bacterial persistence, into 3D-printed CaPS coated with poly(lactic co-glycolic) acid, achieved controlled release for up to two weeks. Implantation into the murine infection model resulted in decreased bacterial colonization rates at 3- and 10-weeks post-revision for the 3D printed CaPS in comparison to gentamicin-laden PMMA. Furthermore, a significant increase in bone formation was observed for 3D printed CaPS incorporated with rifampin at 3 and 10 weeks. The results of this study demonstrate that osteoconductive 3D printed CaPS incorporated with antimicrobials demonstrate more efficacious bacterial colonization outcomes and bone growth in a single-stage revision in comparison to gentamicin-laden PMMA requiring a two-stage revision.

[Clinical research of debridement with prosthesis retention for periprosthetic joint infection after arthroplasty]

Objective

To investigate the mid-term effectiveness of debridement with prosthesis retention for periprosthetic joint infection (PJI) after total hip arthroplasty (THA) and total knee arthroplasty (TKA), and analyze the influence factors that affected the effectiveness.

Methods

A clinical data of 45 cases with PJI after THA (16 cases) and TKA (29 cases) that were treated with debridement with prosthesis retention between January 2011 and January 2015 were collected and analyzed. There were 19 males and 26 females with a mean age of 58.4 years (range, 23-78 years). PJI occurred after primary joint arthroplasty in 40 cases and after revision in 5 cases. The mean time interval between the performance of infection symptoms and the arthroplasty or revision was 15.5 months (range, 0.5-72.0 months). The time interval between the performance of infection symptoms and debridment was 35 days (range, 3-270 days). There were early postoperative infections in 13 cases, acute hematogenous infections in 24 cases, and late chronic infections in 8 cases. X-ray films showed that the location of prosthesis was good. The results of bacilli culture showed that 28 cases were positive and 17 were negative. Twelve cases had sinuses. Length of stay, Hospital for Special Surgery (HSS) score, and Harris score were recorded to evaluate risk factors by using a multivariate logistic regression.

Results

The mean length of stay was 22.6 days (range, 5-79 days). All patients were followed up 24-74 months (mean, 52 months). There were 33 cases that retained the prosthesis without further evidence of infection with the success rate was 73.3%. There were significant differences in Harris score and HSS score between pre- and post-operation ( P<0.05). The univariate analysis results showed that the failure of debridement with prosthesis retention had a significant correlation with sinus developing and duration of infection symptoms more than 14 days ( P<0.05). Multivariate logistic regression analysis results showed that sinus developing was an independent risk factor of failure ( P<0.05).

Conclusion

Debridement with prosthesis retention plays an important role in treating PJI after THA and TKA. These patients with sinus performing and duration of infection symptoms more than 14 days have higher risk to develop infection again.

Acceptable Success Rate in Patients With Periprosthetic Knee Joint Infection Treated With Debridement, Antibiotics, and Implant Retention

BACKGROUND

Acute periprosthetic joint infection (PJI) following primary total knee arthroplasty (TKA) surgery can be treated with debridement, antibiotics, and implant retention (DAIR). However, varying results have been reported in the literature and optimal timing of the procedure is still debated. In this retrospective cohort study, we investigate (a) success rate of DAIR for treating PJI following primary TKA surgery and (b) whether time after primary surgery until DAIR and (c) type of isolated microorganism influence outcome.

METHODS

Sixty-seven patients with PJI following primary TKA surgery treated with DAIR were identified. Patients with insufficient data and patients who did not fulfill Musculoskeletal Infection Society PJI criteria were excluded, leaving 58 patients for analysis. Minimum follow-up was 2 years. A DAIR was considered a success if the patient was infection free after 2 years.

RESULTS

The overall success rate of PJI treated with DAIR was 84%. Median time until DAIR was 21 days (7-1092). Thirty-four patients (59%) were revised within 28 days, 42 patients (72%) within 42 days, while 10 patients (17%) were revised more than 90 days after primary TKA surgery. The success rates were 85%, 88%, and 60%, respectively. In the patients revised within 90 days, our success rate was 90% (43/48) regardless of the involved microorganism.

CONCLUSION

We find DAIR to be a viable and safe treatment option for PJI following primary TKA surgery, when performed early after primary surgery and with the addition of a relevant postrevision antibiotic regime.

Role of Rifampin against Staphylococcal Biofilm Infections In Vitro, in Animal Models, and in Orthopedic-Device-Related Infections

Rifampin has been used as an agent in combination therapy in orthopedic device-related infections (ODRI) for almost three decades. The aim of this review is to provide data regarding the role of rifampin against biofilm infection in vitro, in animal models, and in clinical ODRI. Available data are gathered in order to present the rational use of rifampin combinations in patients with periprosthetic joint infection (PJI). The role of rifampin is well defined in patients with PJI and is indicated in those who fulfill the Infectious Diseases Society of America criteria for debridement and implant retention or one-stage exchange. It should be used with care because of the danger of rapid emergence of resistance. Potential drug interactions should be considered.

Functional outcome of two-stage reimplantation in patients with periprosthetic joint infection after primary total knee arthroplasty

INTRODUCTION

Two-stage reimplantation in patients with chronic periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) with the use of either articulating or static antibiotic-loaded spacers during the first step is considered to be the golden standard in orthopaedics.

THE AIM OF THE STUDY

The aim of the study was to evaluate the correlation of spacer type with the infection elimination rate as well as functional outcomes after two-staged revision TKA in patients with PJI.

MATERIALS AND METHODS

The cohort comprised 161 patients who were treated for PJI after TKA during a period from January 2007 to December 2015. After the exclusion of patients with severe bone defects (AORI 2B or 3), 104 were left for the analysis: 72 patients with articulating and 32 with static spacers. The overall patient mean age was 62 years old (95% CI, 30-84): 73 for females, 31 for males. The outcomes were evaluated after three, six and 12 months using the American Knee Society Score (KSS) and EQ-5D. Only 92 patients were available for observation: 25 with static and 67 with articulating spacers.

RESULTS

One year after the surgery, patients with articulating spacers demonstrated significantly higher mean KSS and function scores in comparison to patients with static spacers (90.4, 77.3 and 78.5, 67.8, respectively (p < 0.05)). The range of motion was also significantly better in patients with articulating spacers: 104.9° in comparison to 93.9° (р < 0.0001). The final EQ-5D score was comparable in both groups (0.82, 73.1 in articulating and 0.82, 72.6 in static spacers).

CONCLUSION

The two-stage revision TKA for PJI using articulating spacers in comparison to the static ones provides better infection eradication rate as well as functional outcomes and improved quality of life.

Factors affecting failure of irrigation and debridement with liner exchange in total knee arthroplasty infection

BACKGROUND

We sought to determine if reoperation-free survival following irrigation and debridement with polyethylene liner exchange of acutely infected primary TKA is affected by: 1) postoperative antibiotic duration; 2) patient characteristics or surgical factors; 3) infecting organism; or 4) whether infection was acute postoperative versus hematogenous.

METHODS

Of revision TKAs from 2004 to 2012 (n = 1735), 76 underwent irrigation and debridement (I&D) with liner exchange after primary TKA with mean 3.5-year follow-up. We analyzed those requiring reoperation for infection (n = 21) versus those who did not (n = 55).

RESULTS

Increased duration of postoperative antibiotic therapy (p = 0.0163) decreased reoperation for infection. Atrial fibrillation (p = 0.0053), chronic obstructive pulmonary disease (COPD) (p = 0.0122), more than 15 cells per high powered field (HPF) (p = 0.0124), or higher preoperative C-reactive protein (p = 0.0025) increased reoperation for infection. Incidence of infection recurrence was highest with Methicillin resistant S. aureus (MRSA) and lowest with Gram negative organisms. There was no difference in reoperation-free survival between acute postoperative and hematogenous infections.

CONCLUSION

Reoperation-free survival following I&D with polyethylene liner exchange of acutely infected primary TKA: 1) improves with increased postoperative antibiotic therapy duration so chronic antibiotic suppression should be considered following TKA I&D with liner exchange; 2) is worse with atrial fibrillation, COPD, >15 cells/HPF, preoperative C-reactive protein >500 mg/L, or MRSA so two-stage revision may be favored in these patients; and 3) is equivalent in acute postoperative and hematogenous infections.

Assessment and management of infected total knee replacements

Infection following total knee replacement surgery is a challenging and devastating complication. Clinical assessment including history, examination, radiographs, blood tests and knee aspirations helps to establish the diagnosis. Revision surgery is typically required to eradicate infection and restore function. This has traditionally been performed through two-stage revision surgery, although single-stage revision surgery is gaining popularity with comparable results in carefully selected patients. This article reviews the clinical assessment and principles of surgical management of infected total knee replacements.

Short-term Complications After Revision Hip Arthroplasty for Prosthetic Joint Infection Are Increased Relative to Noninfectious Revisions

BACKGROUND

Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is associated with significant morbidity and cost. The purpose of this study was to determine how rates of perioperative complications, operative duration, and postoperative length of stay (LOS) in patients undergoing revision THA for PJI compare to primary THA and to revision THA for non-PJI.

METHODS

We used the National Surgical Quality Improvement Program registry from 2005 to 2015 to identify all patients who underwent primary and revision THA. Patients were placed into cohorts based on the surgical procedure and by indication, including (1) primary THA, (2) revision THA for PJI, and (3) revision THA for non-PJI. Differences in 30-day postoperative medical complications, hospital readmissions, operative duration, and LOS were compared using bivariate and multivariate analyses.

RESULTS

One lakh fourteen thousand five hundred five THA patients were identified, with 102,460 (89.5%) patients undergoing a primary THA and 12,045 (10.5%) undergoing a revision procedure. Of the 12,045 revision procedures, 10,777 (89.5%) were for non-PJI indications and 1268 (10.5%) were for PJI. Relative to primary THA, patients undergoing revision THA for PJI had an increased rate of total complications (odds ratio [OR] 3.96), sepsis (OR 13.15), deep surgical site infections (SSIs, OR 8.58), superficial SSI (OR 2.14, P = .002), nonhome discharge (OR 1.85), readmissions (OR 2.46), LOS (+3.0 days), and operative duration (+61 minutes). Compared with non-PJI revisions, PJI revisions had an increased rate of total complications (OR 2.42), sepsis (OR 5.51), deep SSI (OR 2.12), nonhome discharge (OR 1.47), and LOS (+1.8 days).

CONCLUSION

Revision THA for PJI is associated with increased postoperative complications, nonhome discharge, and LOS relative to non-PJI revision THA. Separate care pathways and reimbursement bundles should be considered for patients with PJI.

LEVEL OF EVIDENCE

III.

[Posttraumatic Osteomyelitis: Improvement in Outcome by Negative Pressure Wound Therapy with Instillation Technique]

Posttraumatic Osteomyelitis: Improvement in Outcome by Negative Pressure Wound Therapy with Instillation Technique Abstract. Surgical treatment of post-traumatic (fistula) osteomyelitis can be difficult and is associated with an increased risk of later recurrence. Very often osteomyelitis is accompanied by a soft tissue (defective) wound. After surgical debridement, the use of the vacuum sealing technique can stimulate wound healing and improve local blood circulation. In particular, the introduction of the innovative instillation technique for wound sponges can increase the effectiveness of the treatment of the infection. By regularly rinsing the sponges with an antiseptic polyhexanide solution, the duration of treatment, the number of operations, the in-patient stay and the recurrence rate in this patient group can be statistically significantly reduced.

Analysis Of The KLIC-score; An Outcome Predictor Tool For Prosthetic Joint Infections Treated With Debridement, Antibiotics And Implant Retention

Background: Debridement, antibiotics and implant retention (DAIR) forms the primary treatment modality for early prosthetic joint infection (PJI). The KLIC score has been proposed as a risk stratification tool for use in predicting outcome of prosthetic knee infections. Our aim was to determine the accuracy of this scoring system at an independent tertiary PJI centre in a typical DAIR population.

Methods: Between 2008 and 2015, patients with infected knee prostheses treated with DAIR were identified. The patient notes and blood tests were reviewed retrospectively and the 'KLIC-score' was calculated and correlated with outcome. The end point for early failure was defined as: 1) the need for unscheduled surgery, 2) infection-related death ≤12 months from debridement or 3) the need for suppressive antibiotic treatment.

Results: 59 patients received DAIR procedures for knee PJI. Treatment was successful in 41 patients (69%) with early failure in 18 patients (31%). Patients deemed high-risk (KLIC-score ≥7) had notably higher failure rates (60%) than those scoring <7 (28%). No relationship can be drawn between KLIC-scores of <7 and failure rates.

Conclusions: The KLIC-score applied retrospectively was able to predict patients with the highest risk of early failure but provides little information in patients with scores of <7.

Topical adjuvants incompletely remove adherent Staphylococcus aureus from implant materials

Adjuvant treatments including Betadine, Dakin's solution (sodium hypochlorite), or hydrogen peroxide (H₂ O₂ ) have been attempted to eradicate prosthetic joint infection caused by biofilm or intracellular bacteria. The purpose of this study was to evaluate the in vitro abilities of chemical adjuvants to decrease Staphylococcus aureus (S. aureus) biofilm presence on orthopaedic implant grade materials, including titanium, stainless steel, and cobalt chrome. S. aureus biofilms were grown for 48 h and evaluated for baseline colony forming units/centimeter squared (CFU/cm² ) and compared to treatments with Betadine, Dakin's solution, H₂ O₂ , or 1% chlorine dioxide (ClO₂ ). Control discs (n = 18) across all metals had an average of 4.2 × 10⁷ CFU/cm² . All treatments had statistically significant reductions in CFU/cm² when compared to respective control discs (p < 0.05). For all metals combined, the most efficacious treatments were Betadine and H₂ O₂ , with an average 98% and 97% CFU/cm² reduction, respectively. There were no significant differences between reductions seen with Betadine and H₂ O₂ , but both groups had statistically greater reductions than Dakin's solution and ClO₂ . There was no change in antibiotic resistance patterns after treatment. Analysis of S. aureus biofilms demonstrated a statistically significant reduction in biofilm after a five-minute treatment with the modalities, with an average two log reduction in CFU/cm² . Statement of clinical significance: While statistically significant reductions in CFU/cm² were accomplished with chemical adjuvant treatments, the overall concentration of bacteria never fell below 10⁵ CFU/cm² , leading to questionable clinical significance. Further techniques to eradicate biofilm should be investigated. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1599-1604, 2018.

Prosthetic Joint Infections: an Update

PURPOSE OF REVIEW

Prosthetic joint infection (PJI) is a rare but serious complication that is frequently misdiagnosed. We aimed to highlight the nuances of PJI diagnosis and antimicrobial therapies and provide clarity in key areas of management.

RECENT FINDINGS

Current research in PJI centers on a potential role for diagnostic biomarkers, molecular techniques, and implant sonication to reduce culture-negativity rates. The optimal duration of antimicrobial therapy remains controversial. A high clinical index of suspicion for PJI combined with data from multiple preoperative and intraoperative tests enables timely diagnosis and treatment. Biomarkers, molecular methods, and implant sonication are currently adjunctive to traditional diagnostic techniques. Shorter courses of antimicrobial therapies as well as the role of chronic suppressive therapy need confirmation by randomized controlled trials. Existing practices for preoperative dental prophylaxis and treatment of asymptomatic bacteriuria warrant revision based on evidence arguing against risk for PJI.

A Multicenter Study of Irrigation and Debridement in Total Knee Arthroplasty Periprosthetic Joint Infection: Treatment Failure Is High

BACKGROUND

In total knee arthroplasty (TKA) periprosthetic joint infection (PJI), irrigation and debridement (I&D) with component retention is a treatment option with a wide variation in reported failure rates. The purpose of this study was to determine failure rates, outcomes, and factors that predict failure in I&D for TKA PJI.

METHODS

A multicenter observational study of patients with a TKA PJI and subsequently undergoing an I&D with retention of components was conducted. The primary outcome was failure rate of I&D, where failure was defined as any subsequent surgical procedures.

RESULTS

Two hundred sixteen cases of I&D with retention of components performed on 206 patients met inclusion criteria. The estimated long-term failure rate at 4 years was 57.4%. Time-to-event analyses revealed that the median survival time was 14.32 months. Five-year mortality was 19.9%. Multivariable modeling revealed that time symptomatic and organism were independent predictors of I&D failure. Culture-negative status had a higher hazard for failure than culture-positive patients. When primary organism and time symptomatic were selected to produce an optimized scenario for an I&D, the estimated failure rate was 39.6%.

CONCLUSION

I&D with retention of components has a high failure rate, and there is a high incidence of more complex procedures after this option is chosen. The patient comorbidities we investigated did not predict I&D success. Our results suggest that I&D has a limited ability to control infection in TKA and should be used selectively under optimum conditions.

Multidrug-Resistant Organisms in the Setting of Periprosthetic Joint Infection-Diagnosis, Prevention, and Treatment

BACKGROUND

Periprosthetic joint infection (PJI) is a rare yet challenging problem in total hip and knee arthroplasties. The management of PJI remains difficult primarily due to the evolution of resistance by the infecting organisms.

METHODS

This review profiles acquired mechanisms of bacterial resistance and summarizes established and emerging techniques in PJI diagnosis, prevention, and treatment.

RESULTS

New techniques in PJI diagnosis and prevention continue to be explored. Antibiotics combined with 1 or 2-stage revision are associated with the higher success rates and remain the mainstay of treatment.

CONCLUSION

With higher prevalence of antibiotic-resistant organisms, novel antibiotic implant and wound care materials, improved methods for organism identification, and well-defined organism-specific treatment algorithms are needed to optimize outcomes of PJI.

Viable bacteria persist on antibiotic spacers following two-stage revision for periprosthetic joint infection

Treatment in periprosthetic joint infection (PJI) remains challenging. The failure rate of two-stage revision and irrigation and debridement with component retention in PJI suggests that biofilm cells have a high tolerance to antibiotic chemotherapy. Previous work has demonstrated that biofilm cells have high antibiotic tolerance in vitro, but there is little clinical evidence to support these observations. The aim of this study was to determine if retrieved antibiotic spacers from two-stage revision total knee arthroplasty for PJI have evidence of remaining viable bacteria. Antibiotic poly (methyl methacrylate) (PMMA) spacers from two-stage revision total knee arthroplasty for PJI were prospectively collected and analyzed for bacterial 16s rRNA using polymerase chain reaction (PCR), reverse transcription (RT)-PCR, quantitative RT-PCR (qRT-PCR), and single genome analysis (SGA). PCR and RT-PCR identified bacterial species on 53.8% (7/13) of these samples. When initial culture negative cases are excluded, 68% (6/9) samples were identified with bacterial species. A more rigorous qRT-PCR analysis showed a strong positive signal for bacterial contamination in 30.7% (4/13) of cases. These patients did not show any clinical evidence of PJI recurrence after 15 months of follow-up. Because the half-life of bacterial rRNA is approximately a few days, the identification of bacteria rRNA on antibiotic PMMA spacers suggests that viable bacteria were present after conclusion of antibiotic therapy. This study provides evidence for the high tolerance of biofilm cells to antibiotics in vivo and the important role of bacterial persisters in PJI. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:452-458, 2018.

Irrigation and Debridement with Component Retention for Acute Infection After Hip Arthroplasty: Improved Results with Contemporary Management

BACKGROUND

There are conflicting data on the results of irrigation and debridement with component retention in patients with acute periprosthetic hip infections. The goals of this study were to examine contemporary results of irrigation and debridement with component retention for acute infection after primary hip arthroplasty and to identify host, organism, antibiotic, or implant factors that predict success or failure.

METHODS

Ninety hips (57 total hip arthroplasties and 33 hemiarthroplasties) were diagnosed with acute periprosthetic hip infection (using strict criteria) and were treated with irrigation and debridement and component retention between 2000 and 2012. The mean follow-up was 6 years. Patients were stratified on the basis of McPherson criteria. Hips were managed with irrigation and debridement and retention of well-fixed implants with modular head and liner exchange (70%) or irrigation and debridement alone (30%). Seventy-seven percent of patients were treated with chronic antibiotic suppression. Failure was defined as failure to eradicate infection, characterized by a wound fistula, drainage, intolerable pain, or infection recurrence caused by the same organism strain; subsequent removal of any component for infection; unplanned second wound debridement for ongoing deep infection; and/or occurrence of periprosthetic joint infection-related mortality.

RESULTS

Treatment failure occurred in 17% (15 of 90 hips), with component removal secondary to recurrent infection in 10% (9 of 90 hips). Treatment failure occurred in 15% (10 of 66 hips) after early postoperative infection and 21% (5 of 24 hips) after acute hematogenous infection (p = 0.7). Patients with McPherson host grade A had a treatment failure rate of 8%, compared with 16% (p = 0.04) in host grade B and 44% in host grade C (p = 0.006). Most treatment failures (12 of 15 failures) occurred within the initial 6 weeks of treatment; failures subsequent to 6 weeks occurred in 3% of those treated with chronic antibiotic suppression compared with 11% of those who were not treated with suppression (hazard ratio, 4.0; p = 0.3).

CONCLUSIONS

The success rate was higher in this contemporary series than in many previous series. Systemic host grade A was predictive of treatment success.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Outcomes following debridement, antibiotics and implant retention in the management of periprosthetic infections of the hip: a review of cohort studies

AIMS

The aims of the study were to review and analyse the reported series of debridement, antibiotics and implant retention (DAIR) in the management of infected total hip arthroplasties (THAs) to establish the overall success and the influencing factors.

PATIENTS AND METHODS

Using a standardised recognised study protocol, meta-analysis of observational studies in epidemiology guidelines, a comprehensive review and analysis of the literature was performed. The primary outcome measure was the success of treatment. The search strategy and inclusion criteria which involved an assessment of quality yielded 39 articles for analysis, which included 1296 patients.

RESULTS

The proportion of success following DAIR in the management of an infected THA appeared to improve after 2004 with a pooled mean proportion of success of 72.2%. For all reported series, from 1977 onwards, there was improved success with early debridement (< 7 days; 75.7%) and exchange of modular components (77.5%). There was a statistically non-significant improvement if debridement was performed within four weeks of the initial procedure (73.0%).

CONCLUSION

The reported success following DAIR has improved since 2004. The only determinants of outcome which we found were the timing of debridement after the onset of symptoms of infection and the exchange of modular components. Cite this article: Bone Joint J 2017;99-B:1488-66.

Cutibacterium (formerly Propionibacterium) acnes infections associated with implantable devices

INTRODUCTION

Cutibacterium acnes (C. acnes), a Gram-positive biofilm-forming rod implicated in acne vulgaris, is increasingly recognized for its role in implant-associated infections. The diagnosis of C. acnes implant-associated infections remains challenging. The optimal treatment is a combination of both surgical intervention and antibiotic therapy. Areas covered: In this review, we discuss the different types of implant-associated infections caused by C. acnes. We also highlight the clinical manifestations pertaining to the various sites of infection, and identify several risk factors previously reported in the literature. We then cover the diagnostic laboratory markers, such as IL-6 and AD-1, optimizing C. acnes recovery in culture, and the specific molecular techniques. Finally, we examine the various effective antibiotic regimens and identify some preventive methods against C. acnes infections. Expert commentary: Biomarkers such as IL-6 and AD-1 should be further investigated for the diagnosis of C. acnes implant-associated infections. The use of 16S rRNA gene sequencing and other molecular techniques should be further explored in this setting. Longer incubation periods should be requested whenever C. acnes infection is suspected. If the clinical suspicion is high, sonication of the excised implant should be encouraged. Research should focus on developing effective anti-biofilm agents. Finally, preventive methods such as hair removal prior to surgery should be further explored.

A Review of the Literature on Culture-Negative Periprosthetic Joint Infection: Epidemiology, Diagnosis and Treatment

Purpose

The prevalence of periprosthetic joint infection (PJI) has increased with the increasing incidence of arthroplasty surgery. Considering identification of causative microorganisms is crucial for treatment of PJI, culture-negative (CN) PJI is a significant clinical issue. The purpose of the present study is to describe epidemiology, diagnosis and treatment of CN PJI based on review of the literature to help prevent delayed diagnosis and improve clinical outcomes of CN PJI.

Methods

MEDLINE, EMBASE, Cochrane Library and Scopus databases were searched for articles on CN PJI. Only clinical studies written in English were included. Basic science studies, letters to the editor, case reports and review articles on PJI were excluded.

Results

Seven studies were included in this study. The prevalence of CN PJI ranged from 0% to 42.1%. The major risk factors for CN PJI were prior antibiotic use and presence of postoperative wound drainage. Vancomycin and cephalosporins were the most commonly used antibiotics for CN PJI. Two-stage revision arthroplasty followed by 6 weeks of antibiotic therapy produced the most successful treatment outcomes.

Conclusions

In most clinical studies on CN PJI, a definite diagnostic method for identifying causative microorganisms or optimal treatment strategy for CN PJI were not clearly described. Therefore, further studies are needed to establish standard diagnostic methods for identifying infecting organisms and treatment strategies for CN PJI.

Surgical Site Infections: An Update

Surgical site infections (SSIs) lead to adverse patient outcomes, including prolonged hospitalization and death. Wound contamination occurs with each incision, but proven strategies exist to decrease the risk of SSI. In particular, improved adherence to evidence-based preventative measures related to appropriate antimicrobial prophylaxis can decrease the rate of SSI. Aggressive surgical debridement and effective antimicrobial therapy are needed to optimize the treatment of SSI.

What is the Long-term Economic Societal Effect of Periprosthetic Infections After THA? A Markov Analysis

BACKGROUND

Current estimates for the direct costs of a single episode of care for periprosthetic joint infection (PJI) after THA are approximately USD 100,000. These estimates do not account for the costs of failed treatments and do not include indirect costs such as lost wages.

QUESTIONS/PURPOSES

The goal of this study was to estimate the long-term economic effect to society (direct and indirect costs) of a PJI after THA treated with contemporary standards of care in a hypothetical patient of working age (three scenarios, age 55, 60, and 65 years).

METHODS

We created a state-transition Markov model with health states defined by surgical treatment options including irrigation and débridement with modular exchange, single-stage revision, and two-stage revision. Reoperation rates attributable to septic and aseptic failure modes and indirect and direct costs were calculated estimates garnered via multiple systematic reviews of peer-reviewed orthopaedic and infectious disease journals and Medicare reimbursement data. We conducted an analysis over a hypothetical patient's lifetime from the societal perspective with costs discounted by 3% annually. We conducted sensitivity analysis to delineate the effects of uncertainty attributable to input variables.

RESULTS

The model found a base case cost of USD 390,806 per 65-year-old patient with an infected THA. One-way sensitivity analysis gives a range of USD 389,307 (65-year-old with a 3% reinfection rate) and USD 474,004 (55-year-old with a 12% reinfection rate). Indirect costs such as lost wages make up a considerable portion of the costs and increase considerably as age at the time of infection decreases.

CONCLUSIONS

The results of this study show that the overall treatment of a periprosthetic infection after a THA is markedly more expensive to society than previously estimated when accounting for the considerable failure rates of current treatment options and including indirect costs. These overall costs, combined with a large projected increase in THAs and a steady state of septic failures, should be taken into account when considering the total cost of THA. Further research is needed to adequately compare the clinical and economic effectiveness of alternative treatment pathways.

LEVEL OF EVIDENCE

Level II, economic and decision analysis.

The Not-So-Good Prognosis of Streptococcal Periprosthetic Joint Infection Managed by Implant Retention: The Results of a Large Multicenter Study

BACKGROUND.

Streptococci are not an infrequent cause of periprosthetic joint infection (PJI). Management by debridement, antibiotics, and implant retention (DAIR) is thought to produce a good prognosis, but little is known about the real likelihood of success.

METHODS.

A retrospective, observational, multicenter, international study was performed during 2003-2012. Eligible patients had a streptococcal PJI that was managed with DAIR. The primary endpoint was failure, defined as death related to infection, relapse/persistence of infection, or the need for salvage therapy.

RESULTS.

Overall, 462 cases were included (median age 72 years, 50% men). The most frequent species was Streptococcus agalactiae (34%), and 52% of all cases were hematogenous. Antibiotic treatment was primarily using β-lactams, and 37% of patients received rifampin. Outcomes were evaluable in 444 patients: failure occurred in 187 (42.1%; 95% confidence interval, 37.5%-46.7%) after a median of 62 days from debridement; patients without failure were followed up for a median of 802 days. Independent predictors (hazard ratios) of failure were rheumatoid arthritis (2.36), late post-surgical infection (2.20), and bacteremia (1.69). Independent predictors of success were exchange of removable components (0.60), early use of rifampin (0.98 per day of treatment within the first 30 days), and long treatments (≥21 days) with β-lactams, either as monotherapy (0.48) or in combination with rifampin (0.34).

CONCLUSIONS.

This is the largest series to our knowledge of streptococcal PJI managed by DAIR, showing a worse prognosis than previously reported. The beneficial effects of exchanging the removable components and of β-lactams are confirmed and maybe also a potential benefit from adding rifampin.