Infection after total knee arthroplasty and its gold standard surgical treatment: Spacers used in two-stage revision arthroplasty

Outcomes of Antibiotic-Impregnated Calcium Sulfate, Reamer-Irrigator-Aspirator, and Locked Intramedullary Static Spacer in the Treatment of Periprosthetic Joint Infection in the Multiply Revised and Infected Knee: A Single-Center Case Series

Background

Periprosthetic joint infection after total knee arthroplasty is commonly treated via 2-stage revision utilizing either articulating or static antibiotic cement spacers. While recent literature exhibits a slight functional advantage in favor of articulating spacers, those patients with a history of recurrent infection/multiple revision procedures are frequently excluded from these studies. The purpose of this study was to report infection eradication rates and efficacy of utilizing antibiotic-loaded locked intramedullary nail for infection for the multiply revised, infected total knee arthroplasty.

Methods

A retrospective review was performed of all consecutive patients receiving static spacers between 2017 and 2020 at an academic medical center. Surgical techniques for all patients included irrigation and debridement using a reamer-irrigator-aspirator, injection of antibiotic-loaded calcium sulfate into the intramedullary canal, and nail placement. Antibiotic-loaded cement is then used to create a spacer block in the joint space. A Cox proportional hazard regression was run to identify risk factors for reinfection.

Results

Forty-two knees in 39 patients were identified meeting inclusion criteria. Overall, there was an 68.8% infection eradication rate at an average of 46.9 months following spacer placement. The only risk factors identified on cox regression were increasing number of previous spacers, a surrogate for previous infections (hazards ratio = 14.818, P value = .021), and increasing operative time during spacer placement (hazards ratio = 1.014, P value = .039).

Conclusions

Use of static spacers, in conjunction with reamer-irrigator-aspirator and antibiotic-loaded calcium sulfate, can be effective in treating chronic, complex periprosthetic joint infections in the setting of bone loss and or soft-tissue compromise and produced similar results to more simple infection scenarios.

Antibiotic prophylaxis in alloplastic temporomandibular joint replacement surgery: A multi-national survey of temporomandibular joint surgeons

Temporomandibular disorders include a wide spectrum of extra-articular and intra-articular conditions affecting the temporomandibular joint (TMJ). In salvage cases involving intra-articular end-stage disease, alloplastic temporomandibular joint replacement (TMJR) is a management option which can be utilised to rehabilitate a disabled joint's function and form. Whilst post-TMJR infection is rare, it is one of the most serious complications. The principles governing TMJR surgery antibiotic prophylaxis have been based on those established in orthopaedic surgery literature. Antibiotic resistance due to antibiotic over-use is a significant concern, therefore antibiotic stewardship has been developed to deal with this world-wide public health concern. The TMJ's anatomical proximity to the external auditory canal and oral cavity creates the potential for bacterial contamination. The aim of this study was to explore the views of 39 sub-specialist TMJ surgeons across nine nations usual approach to antibiotic prophylaxis and their management of TMJR infection. To accomplish this, an international survey was developed and conducted using Google Forms. The results demonstrated that 97.4% of the respondents employ prophylactic antibiotics at TMJR surgery, 83.8% on discharge. Variability in antibiotic choice with additional antimicrobial perioperative practices were also reported. Opinions on the management of a TMJR infection also varied. This survey establishes there is an agreement on the use of antibiotic prophylaxis, However the variability in choice, timing, course, duration of antibiotic use as well as the management of a postoperative TMJR infection demonstrates the need for further study leading to development of standardised antibiotic prophylaxis and infection management protocols for TMJR surgery.

What Is the Most Effective Treatment for Periprosthetic Joint Infection After Total Joint Arthroplasty in Patients with Rheumatoid Arthritis?: A Systematic Review

BACKGROUND

Rheumatoid arthritis (RA) is a risk factor for periprosthetic joint infection (PJI) after total joint arthroplasty (TJA). The purpose of this study was to perform a systematic review comparing the failure rates of debridement, antibiotics, and implant retention (DAIR), one-stage exchange arthroplasty/revision (OSR), and 2-stage exchange arthroplasty/revision (TSR) for RA patients with PJI and identify risk factors in the RA population associated with increased treatment failure rate.

METHODS

PubMed, Ovid MEDLINE, and Ovid Embase databases were screened with the terms "rheumatoid arthritis," "total joint arthroplasty," "prosthetic joint infection," and "treatment for PJI" on August 29, 2021. Four hundred ninety-one studies were screened, of which 86 were evaluated. The primary outcome evaluated was failure of surgical treatment for PJI.

RESULTS

Ten retrospective cohort studies were included after full-text screening, yielding 401 patients with RA. Additional demographic and PJI management data were obtained for 149 patients. Patients with RA who underwent TSR demonstrated a lower failure rate (26.8%) than both DAIR (60.1%) and OSR (39.2%) (χ2 = 37.463, p < 0.00001). Patients with RA who underwent DAIR had a 2.27 (95% CI, 1.66-3.10) times higher risk of experiencing treatment failure than those who underwent TSR. Among risk factors, there was a significant difference in the C-reactive protein of patients who did vs. did not experience treatment failure (p = 0.02).

CONCLUSION

TSR has a higher rate of success in the management of PJI patients with RA compared with DAIR and OSR. The complete removal of the infected prosthesis and delayed reimplantation may lower the treatment failure rate.

LEVEL OF EVIDENCE

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

Indications and techniques for non-articulating spacers in massive bone loss following prosthetic knee joint infection: a scoping review

INTRODUCTION

Prosthetic joint infection (PJI) is a destructive complication of knee replacement surgery (KR). In two-stage revision a spacer is required to maintain limb length and alignment and provide a stable limb on which to mobilise. Spacers may be articulating or static with the gold standard spacer yet to be defined. The aims of this scoping review were to summarise the types of static spacer used to treat PJI after KR, their indications for use and early complication rates.

METHODS

We conducted a scoping review based on the Joanna Briggs Institute's "JBI Manual for Evidence Synthesis" Scoping review reported following Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. MEDLINE, EMBASE and CINAHL were searched from 2005 to 2022 for studies on the use of static spacers for PJI after KR.

RESULTS

41 studies (1230 patients/knees) were identified describing 42 static spacer constructs. Twenty-three (23/42 [54.2%]) incorporated cement augmented with metalwork, while nineteen (19/42, [45.9%]) were made of cement alone. Spacers were most frequently anchored in the diaphysis (22/42, [53.3%]), particularly in the setting of extensive bone loss (mean AORI Type = F3/T3; 11/15 studies 78.3% diaphyseal anchoring). 7.1% (79 of 1117 knees) of static spacers had a complication requiring further surgery prior to planned second stage with the most common complication being infection (86.1%).

CONCLUSIONS

This study has summarised the large variety in static spacer constructs used for staged revision KR for PJI. Static spacers were associated with a high risk of complications and further work in this area is required to improve the quality of care in this vulnerable group.

Engineering 3D-Printed Advanced Healthcare Materials for Periprosthetic Joint Infections

The use of additive manufacturing or 3D printing in biomedicine has experienced fast growth in the last few years, becoming a promising tool in pharmaceutical development and manufacturing, especially in parenteral formulations and implantable drug delivery systems (IDDSs). Periprosthetic joint infections (PJIs) are a common complication in arthroplasties, with a prevalence of over 4%. There is still no treatment that fully covers the need for preventing and treating biofilm formation. However, 3D printing plays a major role in the development of novel therapies for PJIs. This review will provide a deep understanding of the different approaches based on 3D-printing techniques for the current management and prophylaxis of PJIs. The two main strategies are focused on IDDSs that are loaded or coated with antimicrobials, commonly in combination with bone regeneration agents and 3D-printed orthopedic implants with modified surfaces and antimicrobial properties. The wide variety of printing methods and materials have allowed for the manufacture of IDDSs that are perfectly adjusted to patients' physiognomy, with different drug release profiles, geometries, and inner and outer architectures, and are fully individualized, targeting specific pathogens. Although these novel treatments are demonstrating promising results, in vivo studies and clinical trials are required for their translation from the bench to the market.

Selecting a high-dose antibiotic-laden cement knee spacer

Prosthetic joint infection [PJI] after total knee arthroplasty (TKA) remains a common and challenging problem for joint replacement surgeons and patients. Once the diagnosis of PJI has been made, patient goals and characteristics as well as the infection timeline dictate treatment. Most commonly, this involves a two-stage procedure with the removal of all implants, debridement, and placement of a static or dynamic antibiotic spacer. Static spacers are commonly indicated for older, less healthy patients that would benefit from soft tissue rest after initial debridement. Mobile spacers are typically used in younger, healthier patients to improve quality of life and reduce soft-tissue contractures during antibiotic spacer treatment. Spacers are highly customizable with regard to antibiotic choice, cement variety, and spacer design, each with reported advantages, drawbacks, and indications that will be covered in this article. While no spacer is superior to any other, the modern arthroplasty surgeon must be familiar with the available modalities to optimize treatment for each patient. Here we propose a treatment algorithm to assist surgeons in deciding on treatment for PJI after TKA.

Prosthetic joint infection caused by an imipenem-resistant Mycobacterium senegalense

Periprosthetic joint infection (PJI) remains one of the most common complications of total knee arthroplasty. Although mainly caused by Staphylococcus aureus and other Gram-positive microorganisms, occasionally, commensal or environmental bacteria are reported as causative agents of these infections. The present work aimed to report a case of PJI caused by an imipenem-resistant Mycobacterium senegalense strain. A bacterial strain isolated from the culture of intraoperative samples was observed by optical microscopy after Gram and Ziehl-Neelsen staining. The species identification was performed by mass spectrometry analysis and partial sequencing of the heat shock protein 65 (hsp65) gene. The antimicrobial profile of the clinical isolate was determined according to the Clinical and Laboratory Standards Institute. Mass spectrometry and gene sequencing analysis identified the bacterial isolate as Mycobacterium fortuitum complex and M. senegalense, respectively. The isolated was found exhibiting an imipenem-resistant profile. The accurate and timely identification, as well as investigation of the antimicrobial susceptibility profile, of fast-growing nontuberculous mycobacteria species are crucial for establishing the prompt and correct treatment of the infection, particularly in cases of patients at greater risk for opportunistic and severe infections.

Articulating spacers: what are available and how to utilize them?

Periprosthetic joint infection (PJI) is the most devastating complication following total joint arthroplasty (TJA) and is posing a global healthcare challenge as the demand for TJA mounts. Two-stage exchange arthroplasty with the placement of antibiotic-loaded spacers has been shown to be efficacious against chronic PJI. This study aimed to review the key concepts, types, and outcome evaluations of articulating spacers in the two-stage exchange for PJI. Previous studies indicated that articulating spacers have been widely used due to better functional improvement and a comparable infection control rate relative to static spacers. Several types of articulating spacers are reportedly available, including hand-made spacers, spacers fashioned from molds, commercially preformed spacers, spacers with additional metal or polyethylene elements, new or autoclaved prosthesis, custom-made articulating spacers, and 3D printing-assisted spacers. However, limited evidence suggested no significant difference in clinical outcomes among the different subtypes of articulating spacers. Surgeons should be familiar with different treatment strategies when using various spacers to know which is the most appropriate.

Results of revision knee arthroplasty with individual implants

The aim of the study was to evaluate the long-term results of surgical treatment of patients with extensive bone defects (2B и 3 according to AORI) of the proximal tibia and/or distal femur using custom-made implants for revision knee arthroplasty. Material and methods. A retrospective clinical study was conducted in 24 patients who underwent revision arthroplasty using individual implants (9 femoral and 18 tibial) made on a 3D printer in the period from 2017 to 2021. T3 defect according to AORI classification was diagnosed in 12 patients (50%), F3 defect - in 1 (4.17%), F2B - in 8 (33.3%), T2B - in 6 (25%). All patients before surgery and 3, 6, 12 months after surgery were subjected to a questionnaire survey using the international scales VAS, KSS, WOMAC and SF-36. Results. At the follow-up examination 12 months after the operation, 9 out of 24 patients (37.510%) moved without additional means of support, 10 out of 24 (41.710%) with a cane, 4 out of 24 (16, 78%), walkers 1 out of 24 (4.210%). There were no periprosthetic fractures during surgery and in the postoperative period. Conclusion. The use of individual implants made using additive 3D printing technologies in revision knee arthroplasty in the presence of extensive bone defects (2B and 3 according to AORI) allows performing an organ-preserving operation without loss of the statodynamic function of the lower limb.

Two-stage revision hip arthroplasty in the treatment of periprosthetic joint infection

Introduction. One of the rare complications following hip arthroplasty is periprosthetic joint infection (PJI). Two-stage revision arthroplasty is the gold standard in the treatment of deep periprosthetic infection of large joints, providing high probability of infection process resolution as well as functional recovery of the limb and elimination of pain syndrome.

Aim: to improve the treatment results of patients with periprosthetic infection after primary hip arthroplasty.

Materials and Methods. 121 patients (62 patients in the main group and 59 in the control group) after primary hip arthroplasty were included in the study. In the main group, treatment was performed using a two-stage technique with implantation of a preformed spacer and our proposed algorithm. In the control group, treatment was performed using a homemade spacer and without using the developed algorithm.

Results. When using our developed treatment algorithm, a good result in the treatment of UTI was achieved. The infectious process was controlled in 80.6 % of cases, as compared with 64.4 % in the control group, which is comparable with the data of domestic and foreign literature.

Conclusion. Treatment of patients with periprosthetic infection should be performed only in specialized centers that perform all stages of treatment, have all necessary instruments, an equipped operating room, necessary drugs in the hospital pharmacy, experienced staff and equipped bacteriological laboratory, as well as many years of experience of surgeons with these patients.

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.

Major Shortening of the Patellar Tendon During Septic Two-Stage Knee Arthroplasty Revision Using Static Spacers

BACKGROUND

Two-stage septic revision knee arthroplasty (TKA) often results in inferior functional outcome after reimplantation, which might be due to impairments of the extensor mechanism. The aim of the current study was to elucidate possible alterations in extensor mechanisms during septic two-stage revision of TKA treated with a static spacer.

METHODS

This retrospective study included 87 patients (42 women, 45 men, age 64.5 ± 10.5; range, 29-85 years) undergoing septic two-stage TKA revision using a static spacer. The modified Insall Salvati ratio (mISR) was calculated via calibrated true lateral radiographs by two independent orthopedic surgeons before TKA explantation (G0), 6-8 days after TKA removal (G1), one day before TKA reimplantation (G2) and 6-8 days after TKA reimplantation (G3). Age, sex, body mass index (BMI), index C-reactive protein level, and number of previous surgeries were evaluated to identify the possible correlations.

RESULTS

Overall, mISR significantly decreased within the first 6 days after index surgery from 1.71 ± 0.41 to 1.63 ± 0.41 (G0 versus G1, P < .001) and showed a further decline within the next 6 weeks to 1.54 ± 0.39 (G1 versus G2, P = .002). Conversely, mISR increased after reimplantation of TKA to 1.6 ± 0.43 (G3 versus G2, P = .08), though it did not regain preoperative baseline levels (G0 versus G3, P < .001). The subgroup with mISR decrease ≥10% experienced patellar tendon shortening of 16% between G0 and G1, 19% between G0 and G2 and up to 20% between G0 and G3. There were weak correlations concerning age (r = -0.240, P = .038), preoperative C-reactive protein level (r = 0.239, P = .04) and patellar tendon shortening. Intraclass correlation coefficient (ICC)was 0.88 concerning radiographic measurement.

CONCLUSION

Septic two-stage TKA revision using static spacers leads to irreversible alterations of the extensor mechanism, specifically a major shortening of the patellar tendon, in one out of 3 patients.

LEVEL OF EVIDENCE

II.

Are Static Spacers Superior to Articulated Spacers in the Staged Treatment of Infected Primary Knee Arthroplasty? A Systematic Review and Meta-Analysis

In the treatment of knee periprosthetic joint infection with a two-stage protocol, static spacers allow for the local delivery of high doses of antibiotics and help to preserve soft tissue tension. Articulated spacers were introduced to better preserve flexion after the reimplantation. The aim of this systematic review is to provide a comprehensive data collection of the results of these different spacers. An in-depth search on the main clinical databases was performed concerning the studies reporting data on the topic. A total of 87 studies and 4250 spacers were included. No significant differences were found both in pooling data analysis and meta-analysis of comparative studies about infection recurrences, complications, and clinical scores. Mean active knee flexion at last follow-up after total knee reimplantation was found to be significantly higher using articulated spacers (91.6° ± 7° for static spacers vs. 100.3° ± 9.9° for articulated spacers; p < 0.001). Meta-analysis also recognized this strong significant difference (p < 0.001). This review has confirmed that articulated spacers do not appear to be inferior to static spacers regarding all clinical outcomes, while they are superior in terms of active flexion. However, the low quality of the studies and the risk for selection bias with complex patients preferentially treated with static spacers need to be accounted for.

Periprosthetic Knee Infection - Part 2: Treatment

Several treatment modalities are proposed for periprosthetic infections, with variable success rates. However, efficacy is related to the appropriate selection of cases for each type of treatment. Debridement with implant retention is indicated in acute infections with fixed implant, and its success depends on the type of infection, comorbidities of the host, and virulence of the etiological agent. One- or two-stage revision is required in cases in which biofilm is forming, or of implant loosening. The choice between performing the review in one or two stages depends on factors such as etiological agent identification, pathogen virulence, local and systemic host factors. Rescue procedures such as arthrodesis, amputation, resection arthroplasty or even antibiotic suppression are reserved for cases in which the infection has not been eradicated.

Outcomes of Modular Knee Arthrodesis for Challenging Periprosthetic Joint Infections

Background

Methods

Results

Discussion

Performance of alpha-defensin lateral flow test after synovial fluid centrifugation for diagnosis of periprosthetic knee infection

BACKGROUND

The quantitative alpha-defensin enzyme-linked immunosorbent assay (ELISA) demands a prior synovial fluid centrifugation, whereas this processing is not routinely required prior to the alpha-defensin lateral flow test.

AIM

To evaluate whether a prior synovial fluid centrifugation could lead the lateral flow performance to achieve comparable results to ELISA during periprosthetic joint infection (PJI) diagnosis.

METHODS

Fifty-three cases were included in this study: 22 classified as PJI and 31 classified as aseptic cases, according to Musculoskeletal Infection Society 2013 criteria. Synovial fluid samples were submitted to centrifugation, and the supernatant was evaluated by ELISA and lateral flow tests. The sensitivity (SE), specificity (SP) and accuracy of each method were calculated as well as the agreement between those two methods.

RESULTS

In all of the 31 samples from aseptic patients, alpha-defensin ELISA and lateral flow tests showed negative results for infection. Regarding the 22 infected patients, the lateral flow test was positive in 19 cases (86.4%) and the ELISA was positive in 21 (95.5%). Sensibility, SP and accuracy were, respectively, 86.4% (95%CI: 65.1%-97.1%), 100% (95%CI: 88.8%-100%) and 93.2% (95%CI: 82.8%-98.3%) for the lateral flow test and 95.5% (95%CI: 77.2%-99.9%), 100% (95%CI: 88.8%-100%) and 98.1% (95%CI: 89.9%-100%) for ELISA. An agreement of 96.2% between those methods were observed. No statistical difference was found between them (P = 0.48).

CONCLUSION

Alpha-defensin lateral flow test showed high SE, SP and accuracy after a prior synovial fluid centrifugation, achieving comparable results to ELISA. Considering the lower complexity of the lateral flow and its equivalent performance obtained in this condition, a prior centrifugation might be added as a valuable step to enhance the PJI diagnosis.

Application of 3D Printing-Assisted Articulating Spacer in Two-Stage Revision Surgery for Periprosthetic Infection after Total Knee Arthroplasty: A Retrospective Observational Study

Background

Bone cement spacers are widely used in two-stage revision surgeries for periprosthetic joint infection (PJI) after total knee arthroplasty. Current spacer design results in insufficient release of drugs; therefore, current spacers have low efficacy. In this study, we explored a set of alternative articular spacer using 3D printing technology. This novel spacer will increase effectiveness of revision surgery for PJI.

Methods

The spacer was designed using CAD software and constructed on site using 3D-printed silicone mold during debridement surgery. We carried out a retrospective study among patients undergoing treatment using traditional static and new articular spacers. Infection control rate, bone loss, difficulty of revision surgery, knee joint range of motion, function evaluation, and subjective satisfaction of the patients in the two groups were compared.

Results

Forty-two patients undergoing knee revision surgery between Jan 2014 and Nov 2019 were included in this study. Twenty-two patients were treated with static antibiotic cement spacers, whereas the other twenty patients were with treated with 3D printing-assisted antibiotic loaded articulating spacers. Patients in the articular group showed significantly lower bone loss on the femur site and tibial site compared with patients in the static group. In addition, patients in the articular group showed significantly less operation time, intraoperative blood loss, and improved knee function and patient overall satisfaction compared with patients in the static group.

Conclusions

The 3D printing-assisted articular spacer provides satisfactory range of motion during the interim period, prevents bone loss, facilitates second-stage reimplantation and postoperative rehabilitation, and results in low reinfection and complication rates.

Low-dose vancomycin-loaded cement spacer for two-stage revision of infected total hip arthroplasty

OBJECTIVES

This study aims to evaluate the success rate in terms of eradication of infection and long-term outcomes of two- stage revision arthroplasty with spacers loaded with low-dose vancomycin alone for the treatment of an infected hip arthroplasty.

PATIENTS AND METHODS

The records of 42 two-stage exchange arthroplasty patients (16 males, 26 females; mean age 61 years; range, 30 to 80 years) treated between January 1999 and January 2009 were included in this retrospective study. In the first stage, following removal of the prosthesis and debridement, a spacer consisting of 1 g of vancomycin per 40 g of cement was placed in the infected joint space. Patients received six weeks of intravenous antibiotics according to intraoperative cultures. After cessation of systemic antibiotic treatment, with normal C-reactive protein and erythrocyte sedimentation rate levels, second stage surgery with cementless components was performed.

RESULTS

The mean follow-up duration was seven (range, 3 to 13) years. Two patients (4.7%) developed re-infection after two-stage reimplantation and one patient underwent a resection arthroplasty after repeated debridements. Five years of survival was 92.9% with Kaplan-Meier survival analysis.

CONCLUSION

For chronic infected total hip revisions, two-stage revision arthroplasty with low-dose vancomycin impregnated cement spacers have comparable re-infection and success rates. Low-dose vancomycin promotes effective infection control and reduces antibiotic toxicity.

Embedded sensing package for temporary bone cement spacers in infected total knee arthroplasty

The re-infection rate of total knee arthroplasty (TKA) after two stage revision (15%) remains high as it can be challenging to determine whether the infection has been fully cleared between the first and second stage procedures. Temporary embedded sensor systems could be a potential solution to indicate whether the infection has been cleared. In this study a telemetric sensor system to integrate with a bone cement spacer and measure knee joint temperature was designed and evaluated. The sensor package precision, accuracy, hysteresis, and thermal equilibrium were empirically determined. Cadaveric testing was performed with the sensor package implanted inside the femoral notch alongside a pre-formed femoral and tibial bone cement spacer. The limb was tested though 30,000 cycles at 0.5 Hz under a 500 N load. Accuracy and precision of the sensing package were found to be ±0.24 °C and 0.09 °C respectively with negligible hysteresis. Thermal insulation caused by the implant itself was found to produce a thermal time constant of 263 ± 5 s, resulting in a 17 min rise time. Memory capacity enabled data logging every 20 s for a 6 week period before necessitating data transfer. Bluetooth was suitable for data transmission while the package was implanted. Following cyclic loading of the cadaveric specimen, imaging and debridement revealed no issues related to mechanical integrity of the bone cement spacer or encapsulated sensor package. While additional validation is required before use in patients, the concept of temporary embedded sensing technology to aid management of infection treatments is promising.

Severe adverse events during medical and surgical treatment of hip and knee prosthetic joint infections

INTRODUCTION

The management of prosthetic joint infection requires a complex treatment procedure and can be associated with complications. However, the occurrence of severe adverse events during this intervention has been poorly evaluated.

PATIENTS AND METHODS

A 5-year multicentric retrospective study including patients from 3 hospitals in the South-Western France referral center for complex bone and joint infections (Crioac GSO) and treated for hip or knee prosthetic joint infection with 1 or 2-stage implant exchanges. The objective was to describe grade≥3 adverse events, according to the CTCAE classification, occurring within 6 weeks after surgery and to identify their associated factors.

RESULTS

One hundred and eighteen patients were identified. We observed 71 severe events in 50 patients (42.3%; 95% confidence interval [CI95%]: 33.8-51.4%). Sixteen severe events were an evolution of the infection. The remaining 55 others (47 grade 3 and 8 grade 4) occurred in 41 patients (34.7%; CI95%: 26.8-43.7%). They were distributed as follows: 27 (49.1%) medical complications, 21 (38.2%) surgical complications and 7 (12.7%) antibiotic-related complications. The main identified risk factor was a two-stage prosthetic exchange with OR=3.6 (CI95% [1.11-11.94], P=0.032). Obesity was limit of significance with OR=3.3 (CI95% [0.9-12.51], P=0.071). Infection with coagulase negative Staphylococcus was a protective factor with OR=0.3 (CI95% [0.12-0.99], P=0.047).

CONCLUSION

Severe adverse events are frequent following prosthetic exchange for PJI (34.7%) and are related to the high frequency of comorbidities in this population and to the complex surgical procedures required. The risk factor significantly associated with these events was a two-stage exchange.

Aspirin administration might accelerate the subsidence of periprosthetic joint infection

Since the past decade, aspirin, a popular anti-inflammatory drug, has been increasingly studied for its potential antimicrobial and antibiofilm activity with promising results, but studies were limited to in vitro and in vivo investigations. Moreover, evidence concerning the beneficial effects of aspirin on the treatment of biofilm-related infections in real-world population is limited. Thus, this study aimed to investigate whether aspirin could promote infection control for patients with periprosthetic joint infections (PJIs). A single-center database was searched. Regular aspirin exposure was defined as a prescription of aspirin for > 6 months before diagnosis of PJIs and consecutive use during the PJI treatment course at a dose ≧ 100 mg/day. General data, treatment modalities, and recurrence status were collected from medical records by an independent orthopedic surgeon. From January 01, 2010, to February 17, 2019, 88 patients who met the PJI criteria were identified and included in this study. Of these patients, 12 were taking aspirin regularly during the infectious events. In the Cox proportional hazards model, multivariate analysis revealed that the aspirin group demonstrated significant benefit via superior resolution of PJIs (HR 2.200; 95% CI 1.018-4.757; p = 0.045). In this study, aspirin is beneficial for infection resolution when combined with the current standard of PJI treatment and conventional antibiotics in the management of PJIs.

Hip Spacers with a Metal-on-Cement Articulation Did Not Show Significant Surface Alterations of the Metal Femoral Head in Two-Stage Revision for Periprosthetic Joint Infection

Two-stage revision is considered the gold standard treatment for chronic periprosthetic joint infection (PJI). During the interim period, between explantation of the infected hip endoprosthesis and revision arthroplasty, individually formed articulating hip spacers made of polymethylmethacrylate (PMMA) bone cement can be used to provide better soft tissue preservation, local antibiotic release, and improved postoperative mobilization. If effective prevention from luxation is achieved, hip function and hence overall patient satisfaction is improved. Zirconium oxide particles inside conventional PMMA bone cement, however, are known to enhance third-body wear, which may cause alterations of the metal head in the articulating spacer and hence become a serious risk for the patient. Therefore, the aim of our study was to analyze whether the articular surface of cobalt-chrome (CoCr) femoral heads is significantly altered in the setting of a metal-on-cement articulation during the interim period of two-stage revision for PJI. We analyzed a consecutive series of 23 spacer cases and compared them with femoral heads from two series of conventional hip arthroplasty revisions with metal-on-polyethylene articulations and different time intervals in situ. To investigate metallic wear, the femoral heads were thoroughly examined, and their surface roughness was measured and analyzed. We found no significant differences between the two conventional hip arthroplasty groups, despite their very different times in situ. Furthermore, the individually different times in situ within the spacer group had no significant impact on surface roughness, either. Compared with the spacer group, the surface roughness of the metal femoral heads from both conventional hip arthroplasty groups were even higher. Within the spacer group, roughness parameters did not show significant differences regarding the five predefined locations on the metal head. We conclude that metal-on-cement articulations do not cause enhanced surface alterations of the metal femoral head and hence do not limit the application in articulating hip spacers in the setting of two-stage revision for PJI.

[Research progress of two-stage revision for periprosthetic joint infection after hip and knee arthroplasties]

Objective

To summarize the research progress of two-stage revision for periprosthetic joint infection (PJI) after hip and knee arthroplasties.

Methods

The related literature on two-stage revision for PJI was summarized, and the new progress in the choice of spacers, systemic antibiotic therapy, and risk factors were analyzed.

Results

Two-stage revision is a common way to treat infection after hip and knee arthroplasties. The types of spacers used in the one-stage operation are diverse and each has its own advantages and disadvantages. Non-articular spacers are mainly used for the patients with poor soft tissue conditions around the joints and severe bone defects. But the joint mobility is not good after the placement of the spacer. Articular spacers can restore the affected joint movement after operation, which is beneficial to the joint mobility after two-stage operation. The use of antibiotics is an indispensable part of the treatment process, and the effectiveness of short-term antibiotic treatment is similar to long-term treatment. Identifying the relevant risk factors that influence the prognosis of the two-stage revision can help preoperative management and reduce the recurrence rate of infection.

Conclusion

There are still controversies about the choice of spacers and systemic antibiotic therapy during the two-stage revision and treatment of PJI. The factors affecting the prognosis of the two-stage revision need to be explored and the further high-quality research is needed.

Immobilization-Enhanced Eradication of Bacterial Biofilms and in situ Antimicrobial Coating of Implant Material Surface - an in vitro Study

PURPOSE

The aim of this study was to investigate a new method of in situ biofilm treatment for infected prostheses that remove bacterial biofilm and prevent reinfection through the use of an immobilizing agent in combination with the actions of biofilm-lysing enzymes and bactericidal antimicrobials.

METHODS

We investigated the combination of self-immobilization chemistry of dopamine with a biofilm-lysing enzyme, α-amylase (Am), and an antimicrobial agent, silver nitrate (Ag), to treat model Staphylococcus aureus (S. aureus) biofilms formed on titanium. The efficacy of biofilm removal and bacterial treatment was analyzed by crystal violet, colony-forming unit assays, confocal laser scanning microscopy, and scanning electron microscopy (SEM). To confirm the in situ coating of the titanium surface with antimicrobial Ag as a strategy to prevent bacterial recolonization, SEM in secondary electron mode (SE), backscatter electron mode, (BSE) and energy-dispersive spectroscopy (EDX) were used. The antimicrobial activity of the coated surface was evaluated by optical density measurement and colony-forming unit assays.

RESULTS

Polydopamine (PDA)-assisted treatment showed approximately a 2 log reduction in recoverable CFU and a 15% increase in biofilm removal efficacy compared to treatments that had only Am or Ag. More importantly, PDA-assisted treatment was found to immobilize Ag on the surface after the treatment, rendering them resistant to bacterial recolonization.

CONCLUSION

Our in vitro findings suggested that this PDA-assisted treatment and the surface immobilization-enhanced treatment concept could be promising in the development of advanced treatment for implant retention surgery for an infected prosthesis.

Comparison of infection eradication rate of using articulating spacers containing bio-inert materials versus all-cement articulating spacers in revision of infected TKA: a systematic review and meta-analysis

PURPOSE

To assess the infection eradication rate when using two types of articulating spacers (prosthetic articulating spacers and all-cement articulating spacers) in two-stage revision of infected total knee arthroplasty (TKA).

METHODS

We comprehensively searched PubMed, Embase, and the Cochrane Library databases and performed a systematic review and meta-analysis of retrospective comparative studies assessing two types of articulating spacers. A quality assessment of the included studies was performed following the STROBE statement.

RESULTS

Thirty retrospective studies, including a total of 821 knees, were identified. The pooled infection control rates in stage I were as follows: 0.98 (95% confidence interval [CI], 0.97 to 1.00) and 0.98 (95% CI, 0.96 to 0.99) for the prosthetic articulating spacer group and all-cement articulating spacer group, respectively. The pooled postoperative reinfection rate was 0.05 (95% CI, 0.03 to 0.08) for the prosthetic spacer group and 0.03 (95% CI, 0.01 to 0.06) for the all-cement spacer group. Results of the subgroup analyses showed that the weight of the antibiotic cement, antibiotic type, mean period of spacers in situ, postoperative antibiotic treatment period, and postoperative antibiotic treatment approach had no effect on the reinfection rates (p < 0.05).

CONCLUSIONS

Compared to all-cement articulating spacers, articulating spacers containing bio-inert materials have a similar infection control rate but a higher postoperative reinfection rate. Although the 95% CIs of reinfection rates in the two groups overlapped, our results indicate that articulating spacers containing bio-inert materials may be associated with higher reinfection rates and poorer clinical outcomes than all-cement articulating spacers.

Two-Stage Revision Arthroplasty for the Treatment of Prosthetic Joint Infection

PURPOSE OF REVIEW

To review the diagnosis and treatment of prosthetic joint infection (PJI) with a focus on two-stage revision arthroplasty. The text will discuss different spacer constructs in total knee and total hip arthroplasty and will present clinical outcome data for these various options.

RECENT FINDINGS

There is no appreciable difference in infection eradication between mobile and static antibiotic spacers. Mobile spacers have shown improved knee range of motion after second-stage re-implantation. Two-stage revision arthroplasty is the gold standard treatment for PJI. The first stage involves removal of all components, cement, and compromised soft tissues with placement of an antibiotic-impregnated spacer. Spacer options include both mobile and static spacers. Mobile spacers offer maintenance of ambulation and joint range of motion between staged procedures and have shown to be as effective in eradicating infection as static spacers.

Mid-term results of two-stage revision of total knee arthroplasty using a mobile (dynamic) cement spacer in the treatment of periprosthetic infections

Introduction: Infection of the knee joint after primary total knee arthroplasty is a serious complication. In this work, we would like to evaluate the mid-term results after two-stage revision of total knee replacement in periprosthetic infection using dynamic spacer, in particular with regard to the function of the knee joint after reimplantation.

Patients and methods: In this retrospective study, we included patients who were treated in our clinic between 2005 and 2013 due to infection of the knee after total knee arthroplasty. All patients included have had a mobile antibiotic-coated cement spacer implanted after surgical debridement and removal of the components of total knee replacement. Subsequently, reimplantation of total knee replacement was performed when no clinical or paraclinical signs of infection were found. We analyzed all included cases for potential reinfection, examined the range of motion of the knee joint and evaluated the Merle d’Aubigné-Postel score. Statistical evaluation was performed with SPSS 24.0.

Results: This study group contains 16 patients (9 women and 7 men) with an average age of 72.0 ± 8.3 years. All patients were followed up for at least 6 months with an average follow-up of 22.5 ± 16.6 months. In all patients a pathogen was isolated intraoperatively during the first-stage surgery (explantation of the knee). Staphylococci were detected in 94% of the cases, streptococci in only one patient. Reimplantation was carried out after 6.2 ± 5.2 months. The average knee flexion in the group of patients without relapse of infection was 103.3° ± 17.1°. Only 3 patients showed extension deficit of max. 20°. The Merle d’Aubigné-Postel Score was 14.4 ± 1.9.

Conclusion: Two-stage surgery of total knee replacement with the use of a mobile spacer has its high value in the treatment of periprosthetic infections. The mobile spacers contribute to an advantageous range of motion of the knee joint after reimplantation of a total knee endoprosthesis. However, further studies are required that compare the results after using mobile or static spacer, but with the inclusion of homogeneous patient collective.