One-stage vs two-stage exchange

Prosthetic Joint Infections: Biofilm Formation, Management, and the Potential of Mesoporous Bioactive Glass as a New Treatment Option

Infection of prosthetic joints is one of the biggest challenges to a successful replacement of the joint after a total joint arthroplasty. Such infections are caused by bacterial colonies that are difficult to treat by systemic delivery of antibiotics. Local delivery of antibiotics can prove to be the solution to such a devastating outcome that impacts patients' health and ability to regain function in their joints as well as costs the healthcare system millions of dollars every year. This review will discuss prosthetic joint infections in detail with a focus on the development, management, and diagnosis of the infections. Surgeons often opt to use polymethacrylate cement locally to deliver antibiotics; however, due to the rapid release of antibiotics, non-biodegradability, and high chance of reinfection, the search for alternatives is in high demand. One of the most researched alternatives to current treatments is the use of biodegradable and highly compatible bioactive glass. The novelty of this review lies in its focus on mesoporous bioactive glass as a potential alternative to current treatments for prosthetic joint infection. Mesoporous bioactive glass is the focus of this review because it has a higher capacity to deliver biomolecules, stimulate bone growth, and treat infections after prosthetic joint replacement surgeries. The review also examines different synthesis methods, compositions, and properties of mesoporous bioactive glass, highlighting its potential as a biomaterial for the treatment of joint infections.

Systemic antibiotics are not required for successful two-stage revision hip arthroplasty

The duration of systemic antibiotic treatment following first-stage revision surgery for periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is contentious. Our philosophy is to perform an aggressive debridement, and to use a high local concentration of targeted antibiotics in cement beads and systemic prophylactic antibiotics alone. The aim of this study was to assess the success of this philosophy in the management of PJI of the hip using our two-stage protocol. The study involved a retrospective review of our prospectively collected database from which we identified all patients who underwent an intended two-stage revision for PJI of the hip. All patients had a diagnosis of PJI according to the major criteria of the Musculoskeletal Infection Society (MSIS) 2013, a minimum five-year follow-up, and were assessed using the MSIS working group outcome-reporting tool. The outcomes were grouped into 'successful' or 'unsuccessful'. A total of 299 two-stage revision THAs in 289 patients met the inclusion criteria, of whom 258 (86%) proceeded to second-stage surgery. Their mean age was 68.1 years (28 to 92). The median follow-up was 10.7 years (interquartile range (IQR) 6.3 to 15.0). A 91% success rate was seen in those patients who underwent reimplantation, decreasing to 86% when including those who did not proceed to reimplantation. The median duration of postoperative systemic antibiotics following the first stage was five days (IQR 5 to 9). There was no significant difference in outcome between those patients who were treated with antibiotics for ≤ 48 hours (p = 0.961) or ≤ five days (p = 0.376) compared with those who were treated with longer courses. Greater success rates were seen for Gram-positive PJIs (87%) than for Gram-negative (84%) and mixed-Gram PJIs (72%; p = 0.098). Aggressive surgical debridement with a high local concentration of targeted antibiotics at the time of first-stage revision surgery for PJI of the hip, without prolonged systemic antibiotics, provides a high rate of success, responsible antibiotic stewardship, and reduced hospital costs.

Success of staged revision reverse total shoulder arthroplasty in eradication of periprosthetic joint infection

INTRODUCTION

Management of periprosthetic joint infection (PJI) in shoulder arthroplasty remains a challenge, with no established gold standard treatment. This study presents the unique experience of a high-volume single-surgeon, single-institution approach on staged revision reverse total shoulder arthroplasty (RTSA) for infection. The authors theorize that staged revision RTSA is an effective treatment for PJI.

MATERIALS AND METHODS

Between 2013 and 2018, 38 patients underwent a staged RTSA for treatment of PJI. Patient histories were collected and classified using Cierny-Mader classification. Infection workup for all patients included radiographs, laboratory indices, and computed tomographic aspiration arthrogram. PJI was identified based on high clinical and radiographic suspicion, elevated serologic markers, and/or aspirate culture results per 2018 International Consensus Meeting Shoulder guidelines on Orthopedic Infections. All patients underwent first stage with implant removal, irrigation and débridement, and antibiotic spacer placement. Next, intravenous antibiotics were administered by infectious disease consultants for a minimum of 6 weeks. Infection workup was then repeated and, if normalized, final-stage revision commenced with antibiotic spacer removal and revision to RTSA. If indices were persistently abnormal, an additional stage of débridement and spacer placement procedure was performed. Treatment failure was defined as recurrent periprosthetic infection after final prosthesis implantation or persistently elevated indices despite adequate débridement and spacer placement.

RESULTS

Mean age of the cohort was 68 (standard deviation [SD] 8.9) years and mean follow-up was 33 (SD 14) months with 34 Cierny-Mader C hosts and 4 B hosts. Patients underwent a mean of 2 (SD 1.1) previous surgeries. The staged revision protocol was successful in 34 (89.5%) patients for management of PJI. Four patients (10.5%) were considered failures with recurrent infections at a mean of 13 months (range 2-26 months) after the final RTSA implantation and underwent repeat staged revisions. Of the 34 patients who had successful infection eradication, 31 had 2-stage treatment and 3 had to undergo 3 stages. There were no treatment-associated mortalities and 10 major complications (26%), including permanent neuropathy, instability, and periprosthetic fractures. The most common cultured microorganism was Cutibacterium acnes (18%), with no polymicrobial infections detected.

DISCUSSION

Although there are multiple treatment options for PJI management, staged revision remains an effective means of treatment. Although there were several patients who required an additional stage of treatment, and a significant complication rate, staged revision RTSA proved successful in the ultimate eradication of the PJI.

Influence of the Type of Bone Cement Used in Two-Stage Exchange Arthroplasty for Chronic Periarticular Joint Infection on the Spacer Replacement and Reinfection Rate

BACKGROUND

Antibiotic-loaded bone cement (ALBC) spacers are used in the first stage when treating periprosthetic joint infection (PJI). This study aimed to investigate whether a spacer made from commercial ALBC or plain bone cement with additional antibiotics could affect the spacer exchange rate before reimplantation.

METHODS

Patients undergoing two-stage exchange arthroplasty due to chronic PJI from January 2014 to August 2021 were retrospectively reviewed. The exclusion criteria included arthroplasty in the setting of septic arthritis, megaprosthesis, atypical pathogen infection, spacer placement unrelated to PJI, and spacer exchange due to mechanical complications. The patient demographics, brand of cement, and microbiology were recorded manually. The primary outcome was the incidence of spacer exchange due to persistent infection and the secondary outcome was the incidence of reinfection after reimplantation. A multivariate logistic regression analysis and Chi-square test were conducted to identify the effect of cement type on the spacer exchange.

RESULTS

A total of 334 patients underwent two-stage exchange arthroplasty for PJI. The spacer exchange rates in the commercial and non-commercial ALBC groups were 6.4% and 25.1%, respectively (p = 0.004). After controlling for confounding factors, there were significant differences between the commercial group and non-commercial groups in the spacer exchange rate (adjusted OR = 0.25; 95% CI = 0.72-0.87, p = 0.029). The use of commercial ALBC was not associated with a lower reinfection rate after reimplantation (p = 0.160).

CONCLUSIONS

In a two-stage exchange arthroplasty scenario, the spacer comprised of commercial ALBC resulted in a lower spacer exchange rate than the plain bone cement, both of which had additional antibiotics. However, the use of commercial ALBC was not associated with a lower incidence of reinfection following reimplantation.

Microbiological Advantages of Open Incisional Biopsies for the Diagnosis of Suspected Periprosthetic Joint Infections

Background: Periprosthetic joint infection (PJI) represents a serious complication following total hip (THA) and knee arthroplasty (TKA). When preoperative synovial fluid cultures remain inconclusive, open incisional joint biopsy (OIB) can support causative microorganism identification. Objective: This study investigates the potential benefit of OIB in THA and TKA patients with suspected PJI and ambigious diagnostic results following synovial fluid aspiration. Methods: We retrospectively assessed all patients treated from 2016 to 2020 with suspected PJI. Comparing the microbiology of OIB and the following revision surgery, we calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the number needed to treat (NNT). Results: We examined the diagnostic validity of OIB in 38 patients (20 female) with a median age of 66.5 years. In THA patients (n = 10), sensitivity was 75%, specificity was 66.67%, PPV was 60%, NPV was 80%, and NNT was 2.5. In TKA patients (n = 28), sensitivity was 62.5%, specificity was 95.24%, PPV was 83.33%, NPV was 86.96%, and NNT was 1.42. Conclusions: Our results indicate that OIB represents an adequate diagnostic tool when previously assessed microbiological results remain inconclusive. Particularly in TKA patients, OIB showed an exceptionally high specificity, PPV, and NPV, whereas the predictive validity of the diagnosis of PJI in THA patients remained low.

Risk factors for failure after cementless femoral revision THA: a consecutive series of 105 cases

INTRODUCTION

Cementless femoral revision total hip arthroplasty (RTHA) after periprosthetic fracture, aseptic loosening or infection is a challenging surgical procedure. The aim of this study was to evaluate the incidence and reasons for failure after two-stage septic revision, periprosthetic fracture or aseptic loosening that may reveal a rationale for cementless RTHA in two-stage revisions.

MATERIALS AND METHODS

A consecutive series of 105 cases using cementless femoral revision prostheses were evaluated retrospectively. Indications for revision were 39 two-stage revisions after infection, 49 aseptic loosenings, and 17 periprosthetic fractures. A Kaplan-Meier analysis was performed using infection with or without removal of the implant as an endpoint.

RESULTS

Incidence of infection with or without implant removal was significantly higher in patients treated for periprosthetic fractures compared to two-stage revisions or aseptic loosening (log-rank P < 0.0001). The mean follow-up period was 6.4 (2.0-13.7) years. Using infection with or without implant removal as the endpoint, 12 patients were diagnosed after the index operation resulting in a cumulative risk after 13.7 years of 29.9% (95% CI 0-61.2).

CONCLUSION

Cementless revision using a modular tapered device is reliable with respect to reinfection risk in two-stage procedures.

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.

Positive frozen section during reimplantation increases the risk of treatment failure in two-stage exchange arthroplasty even in patients with normal ESR and CRP

AIMS

It can be extremely challenging to determine whether to perform reimplantation in patients who have contradictory serum inflammatory markers and frozen section results. We investigated whether patients with a positive frozen section at reimplantation were at a higher risk of reinfection despite normal ESR and CRP.

METHODS

We retrospectively reviewed 163 consecutive patients with periprosthetic joint infections (PJIs) who had normal ESR and CRP results pre-reimplantation in our hospital from 2014 to 2018. Of these patients, 26 had positive frozen sections at reimplantation. The minimum follow-up time was two years unless reinfection occurred within this period. Univariable and multivariable logistic regression analyses were performed to identify the association between positive frozen sections and treatment failure.

RESULTS

Treatment failure occurred in eight (30.77%) of the 26 PJI patients with positive frozen sections at reimplantation, compared with 13 (9.49%) of 137 patients with negative results. In the multivariate analysis, positive frozen section increased the risk of failure (odds ratio 4.70; 95% confidence interval (CI) 1.64 to 13.45). The mean number of months to reinfection was lower in the positive frozen section group than in the control group (p = 0.041). While there were nine (34.62%) patients with positive frozen section and 25 (18.25%) patients with negative frozen section who had prolonged antibiotic use (p = 0.042), the mean duration of antibiotic use was comparable in two groups. Synovial white blood cell count (p = 0.137) and polymorphonuclear leucocyte percentage (p = 0.454) were not associated with treatment failure in logistic regression model.

CONCLUSION

Positive frozen section at reimplantation was independently associated with subsequent failure and earlier reinfection, despite normal ESR and CRP levels pre-reimplantation. Surgeons should be aware of the risk of treatment failure in patients with positive frozen sections and carefully consider benefits of reimplantation. Cite this article: Bone Joint J 2021;103-B(5):916-922.

Use of antibiotic-impregnated hydroxyapatite for infection following total knee arthroplasty

OBJECTIVES

Antibiotic-impregnated hydroxyapatite (HA) is an emerging drug delivery system for the treatment of periprosthetic joint infection (PJI) of the knee. The aim of this study was to evaluate the clinical results of this treatment in patients with PJI following total knee arthroplasty (TKA).

METHODS

Participants comprised 14 consecutive patients with PJI of the knee who were scheduled to undergo two-stage knee revision. In the first stage, all components were removed with thorough debridement, and antibiotic-impregnated HA was inserted in the bone and joint space. In the second stage, revision TKA was performed after the eradication of infection. The mean period from the removal of all components and treatment with antibiotic-impregnated HA to revision TKA was 3.4 months. Clinical and radiographic evaluations were performed after a mean follow-up of 6.1 years following revision TKA. Predictors of reinfection were evaluated.

RESULTS

Eleven patients had no recurrent infection, whereas 3 patients showed recurrent infection. Knee Society knee score and function score, as well as flexion angles, improved significantly postoperatively. No knees showed osteolysis or loosening after revision TKA. The present study identified no predictors of reinfection.

CONCLUSION

Antibiotic-impregnated HA could be effective in treating knee PJI.

Current actual success rate of the two-stage exchange arthroplasty strategy in chronic hip and knee periprosthetic joint infection

AIMS

The success rates of two-stage revision arthroplasty for infection have evolved since their early description. The implementation of internationally accepted outcome criteria led to the readjustment of such rates. However, patients who do not undergo reimplantation are usually set aside from these calculations. The aim of this study was to investigate the outcomes of two-stage revision arthroplasty when considering those who do not undergo reimplantation, and to investigate the characteristics of this subgroup.

METHODS

A retrospective cohort study was conducted. Patients with chronic hip or knee periprosthetic joint infection (PJI) treated with two-stage revision between January 2010 and October 2018, with a minimum follow-up of one year, were included. Variables including demography, morbidity, microbiology, and outcome were collected. The primary endpoint was the eradication of infection. Patients who did not undergo reimplantation were analyzed in order to characterize this subgroup better.

RESULTS

A total of 162 chronic PJIs were included in the study. After a mean follow-up of 57.3 months (12.1 to 115.7), 18 patients (11.1%) did not undergo reimplantation, due either to medical issues (10), the patient's choice (4), or death (4). When only considering those who underwent reimplantation, the success rate was 80.6%. However, when those who did not undergo reimplantation were included, the success rate dropped to 71.6%. Advanced age, American Society of Anesthesiologists grade ≥ III, McPherson's C host, and Gram-negative related PJI were independent risk factors for retention of the spacer. The mortality was higher in the non-reimplanted group.

CONCLUSION

The real success rate of two-stage revision may not be as high as previously reported. The exclusion of patients who do not undergo reimplantation resulted in a 9% overestimation of the success rate in this series. Many comorbidity-related risk factors for retention of the spacer were identified, as well as higher death rates in this group. Efforts should be made to optimize these patients medically in order to increase reimplantation and success rates, while decreasing mortality. Cite this article: Bone Joint J 2020;102-B(12):1682-1688.

A Low Percentage of Patients Satisfy Typical Indications for Single-stage Exchange Arthroplasty for Chronic Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection (PJI) is a leading cause of revision arthroplasty. Considerable controversy still exists whether single- or two-stage exchange is the better approach for patients with chronic PJI. Historically, single-stage exchange arthroplasty was thought to have an unacceptably high risk of reinfection compared with two-stage exchange but recent studies have demonstrated that this may not be the case. To be considered for single-stage exchange, patients should meet certain criteria including a preoperatively identified nonvirulent pathogen in an immunocompetent host with an uncompromised soft tissue envelope. It is unclear what proportion of patients with chronic PJI actually meet these criteria. Additionally, patients who meet the criteria for single-stage exchange are selected because, in principle, they may be more likely to be able to overcome the infection, but it is unknown what the reinfection risk is in patients undergoing two-stage exchange who might have met selection criteria for single-stage exchange.

QUESTIONS/PURPOSES

(1) What percentage of patients with chronic PJI treated at our institution met the International Consensus Meeting criteria for single-stage exchange arthroplasty? (2) Is the risk of persistent or recurrent infection lower for patients treated with two-stage exchange who met International Consensus Meeting criteria for single-stage exchange than it is among those who did not meet those inclusion criteria?

METHODS

Between 2012 and 2016, one referral center treated 120 patients with chronic PJI as determined by Musculoskeletal Infection Society (MSIS) criteria. During this time, we used single-stage exchange only rarely in patients with chronic PJI (3%; four of 120), and only in oncologic patients with mega-prosthesis implants; 7% (eight of 120) underwent other procedures (resection arthroplasty or arthrodesis). Of the remaining 108, 16% (17) were lost to follow-up; the remaining 91 were evaluated in this retrospective study. To answer our first question, we applied the International Consensus Meeting indications for single-stage exchange, which were a known nonvirulent preoperative organism, an immunocompetent host, and a healthy soft-tissue envelope without a sinus tract; we then calculated the percentage of patients who would have met those criteria. To answer our second question, we compared those who would and would not have met those criteria in terms of the proportion who were determined to be infection-free at 2 years using the MSIS criteria.

RESULTS

Only 19% (20 of 108) of patients met the International Consensus Meeting criteria for single-stage exchange. With the numbers available, there was no difference between those who met and did not meet those criteria in terms of the proportion of patients who had persistent or recurrent infection 2 years after treatment (three of 15 versus 32% [24 of 76]; p = 0.38).

CONCLUSIONS

We found that only a small proportion of patients who presented with chronic PJI to a referral center would have been suitable for single-stage direct exchange; with the numbers available, we found no difference in the reinfection risk after two-stage revision in those patients compared with those who would not have met those criteria. Consequently, it is possible that a small proportion of patients may benefit from single-stage exchange, but our small sample size may have missed important differences in reinfection risk, and so our findings on that question must be considered preliminary. Larger studies randomizing patients who meet single-stage criteria to either single- or two-stage exchange will better elucidate the true reinfection risk in this patient population.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Clinical Evaluation of Alpha Defensin Test Following Staged Treatment of Prosthetic Joint Infections

BACKGROUND

Diagnosing persistent infection following staged treatment of prosthetic joint infection (PJI) is challenging. The alpha defensin (AD) test has been shown to be an accurate diagnostic test for the primary diagnosis PJI but has limited evaluation for use following a staged treatment of PJI. The goal of this study was to evaluate the diagnostic accuracy of AD testing following staged treatment of PJI before reimplantation surgery and to determine if negative AD test predicted success following reimplantation using Delphi Criteria at time of last follow-up.

METHODS

Patients who underwent AD testing prior to reimplantation after staged treatment of PJI (n = 52) were reviewed. Preoperative data (AD result, synovial fluid [SF], C-reactive protein level [mg/L], SF culture, SF white blood cell count, % of polymorphonuclear lymphocytes, serum C-reactive protein/erythrocyte sedimentation rate) and intraoperative data (purulence and tissue culture) were reviewed and used to classify patients using 2018 Musculoskeletal Infectious Disease Society criteria for infection, which was then used as a gold standard test to calculate diagnostic accuracy. Chart review was used to determine if patients who underwent reimplantation surgery would go on to treatment failure as defined by Delphi Criteria.

RESULTS

The sensitivity and specificity of AD test result as compared with Musculoskeletal Infectious Disease Society criteria in diagnosing PJI was calculated to be 71% and 97.78%. Positive predictive value was calculated to be 83.3%, and negative predictive value was calculated to be 95.65%. Patients who underwent reimplantation (46/52 patients) all had negative AD test results, and 9/46 or 19.5% would have treatment failure as defined by the Delphi Criteria with an average follow-up of 588 days.

CONCLUSION

AD demonstrates high specificity and negative predictive value, with low sensitivity when utilized after staged treatment of PJI. Further investigation of this and other diagnostic tests following staged treatment of PJI is needed. Additionally, validated criteria used to identify persistent infection following staged treatment of PJI are required.

Outcomes of repeat two-stage exchange hip arthroplasty for prosthetic joint infection

Aims

The increasing infection burden after total hip arthroplasty (THA) has seen a rise in the use of two-stage exchange arthroplasty and the use of increasingly powerful antibiotics at the time of this procedure. As a result, there has been an increase in the number of failed two-stage revisions during the past decade. The aim of this study was to clarify the outcome of repeat two-stage revision THA following a failed two-stage exchange due to recurrent prosthetic joint infection (PJI).

Patients and Methods

We identified 42 patients who underwent a two-stage revision THA having already undergone at least one previous two stage procedure for infection, between 2000 and 2015. There were 23 women and 19 men. Their mean age was 69.3 years (48 to 81). The outcome was analyzed at a minimum follow-up of two years.

Results

A satisfactory control of infection and successful outcome was seen in 26 patients (57%). There therefore remained persistent symptoms that either required further surgery or chronic antibiotic suppression in 16 patients (38%). One-third of patients had died by the time of two years’ follow-up.

Conclusion

The rate of failure and complication rate of repeat two-stage exchange THA for PJI is high and new methods of treatment including host optimization, immunomodulation, longer periods between stages, and new and more powerful forms of antimicrobial treatment should be investigated. Cite this article: Bone Joint J 2019;101-B(6 Supple B):110–115.

Tests for predicting reimplantation success of two-stage revision for periprosthetic joint infection: A systematic review and meta-analysis

BACKGROUND

Several tests are used before reimplantation to detect persistent infection in patients with periprosthetic joint infection (PJI) undergoing two-stage revision. However, there is no consensus as to the optimal tests for excluding persistent infection or predicting successful reimplantation by stage. We aimed to determine the accuracy of different tests used to detect persistent infection after the first stage, and/or predicting failure following reimplantation in patients with PJI.

METHODS

We conducted a systematic review and meta-analysis of PubMed, Embase and the Cochrane Library databases. Two reviewers independently conducted quality assessments and data extractions to estimate pooled sensitivity and specificity, diagnostic odds ratio and area under the receiver operating characteristic curves (AUSROC) for each test.

RESULTS

We included 24 studies published between May 1999 and September 2017. Synovial fluid polymorphonuclear neutrophils (PMN)% had the highest sensitivity of 0.70, followed by serum erythrocyte sedimentation rate (0.57) and spacer sonication fluid culture (0.53). Synovial fluid culture had the highest specificity of 0.97, followed by frozen section (0.93) and the Musculoskeletal Infection Society criteria (0.92). Spacer sonication fluid culture was the most accurate test with an AUSROC of 0.8089, followed by synovial fluid culture (0.7749) and frozen section (0.7819).

DISCUSSION

Spacer sonication fluid culture had a relatively high diagnostic accuracy. We emphasize that no test can be used alone to exclude persistent infection beyond the first stage and/or predict failed reimplantation beyond the second stage.

LEVEL OF EVIDENCE

II, systematic review and meta-analysis of level 2 to level 4 studies with inconsistent results.

Determining the Role and Duration of the "Antibiotic Holiday" Period in Periprosthetic Joint Infection

BACKGROUND

Two-stage exchange arthroplasty involves resection and reimplantation of new implants at a later stage. An antibiotic-free period is often advocated by surgeons before reimplantation. However, there is no conclusive evidence supporting the utility or duration of this practice. This study evaluated the utility and optimal duration of the antibiotic-free period before reimplantation.

METHODS

Electronic infection databases of 2 institutions were retrospectively reviewed from 2000 to 2014 to identify 785 patients who underwent 2-stage exchange arthroplasty, of which 409 were reimplanted without any surgeries between the first and second stage. Total joint arthroplasties that met the Musculoskeletal Infection Society criteria for periprosthetic joint infection (PJI) and had a minimum of 1-year follow-up were included. The antibiotic holiday period was defined as the time period off antibiotics before reimplantation. Treatment success was defined according to the Delphi consensus criteria. A multivariate analysis and Fisher exact test were performed.

RESULTS

The duration of the antibiotic-free period was not significantly associated with reinfection following reimplantation after controlling for potential confounders, including joint involvement, gender, institution, and comorbidities. However, the duration of spacer implantation was significantly associated with reinfection. Of the patients who failed treatment, 41.5% failed on antibiotics while 58.5% failed during the antibiotic-free period at a mean of 26.1 days.

CONCLUSION

The duration of an antibiotic-free period does not appear to significantly affect PJI rate after reimplantation. However, many patients fail during the antibiotic-free period. Further prospective studies are needed to determine the optimal timing of reimplantation for 2-stage exchange arthroplasty for PJI treatment.

Treatment of chronic orthopaedic infection

Chronic infections are one of the major challenges in orthopaedic surgery, both for surgeons and patients. They are characterised by obstinate persistency of the causing microorganisms and resulting long-term disablement of the patients, associated with remarkable costs for the health care system.

Difficulties derive from the biofilm-mode of living of pathogens with resistances against immunological defence and antimicrobial substances, and osseous defects resulting from the disease itself and surgical interventions.

Established techniques usually require multiple costly operations with extended periods of disablement and impairment of the patients, sometimes making the therapy worse than the disease.

Better understanding of the backgrounds of the conditions has led to new surgical techniques and differentiated application of antibiotics, aiming in improved quality of life for our patients.

Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160063. Originally published online at www.efortopenreviews.org

Allograft Bone as Antibiotic Carrier

The treatment of chronic bone and joint infections is characterized by obstinate persistency of the causing microorganisms and resulting long term disability to patients, associated with remarkable costs for the health care system. Difficulties derive from biofilm formed on dead bone and eventual implants, with resistance against immunological defences and antimicrobial substances. Biofilm embedded bacteria require up to 1000 times the antibiotic concentration of planktonic bacteria for elimination. Systemic antibiotic treatment alone cannot provide the concentrations required and surgical intervention is always prerequisite for potentially providing a cure. A second issue is that osseous defects are almost always present after surgical debridement, and it is difficult to address their reconstruction. One option is to use bone grafts, either from the patient´s own body or from foreign donors (allografts). Grafts are usually unvascularized and are prone to colonization with bacteria. Loading of allografts with antibiotics may not only protect grafts from bacterial adhesion but, using appropriate processing methods, may also provide high local antibiotic concentrations that may eliminate remaining sessile pathogens. For efficient action as antibiotic carriers, the release of antibiotics should be above the minimum biofilm eradication concentration (MBEC) for a prolonged period of time. Cleaning the bone from bone marrow opens a large reservoir for storage of antimicrobial substances that, after implantation, may be released to the surrounding in a sustained mode, possibly eliminating remaining biofilm remnants. Removal of bone marrow, leaving a pure matrix, provides increased safety and improved revascularization of the graft. Local provision of antibiotic concentrations above the MBEC may enable simultaneous internal fixation with osteosynthetic material and single stage exchange of infected endoprostheses, resulting in shorter hospital stays with reduced pain and faster rehabilitation of patients.

Positive Culture During Reimplantation Increases the Risk of Subsequent Failure in Two-Stage Exchange Arthroplasty

BACKGROUND

It is strongly recommended that tissue and synovial fluid culture samples be obtained during reimplantation performed as part of a 2-stage exchange arthroplasty. The rate of positive cultures during reimplantation and the influence of positive cultures on subsequent outcomes, to our knowledge, are unknown. This study was designed to determine the rate of positive cultures during reimplantation and to investigate the association between positive cultures at reimplantation and subsequent outcomes.

METHODS

We retrospectively reviewed the data of 259 patients who met the Musculoskeletal Infection Society criteria for periprosthetic joint infection (PJI) and who underwent both stages of 2-stage exchange arthroplasty at our institution from 1999 to 2013. Among these patients were 267 PJIs (186 knees and 81 hips); 33 (12.4%) had ≥1 positive culture result at reimplantation. Treatment failure was assessed according to the Delphi-based consensus definition. Logistic regression analysis was performed to assess the predictors of positive culture and risk factors for failure of 2-stage exchange arthroplasty.

RESULTS

Of the 33 cases with PJI, 15 (45.5%) had a subsequent failure of the 2-stage exchange arthroplasty compared with 49 (20.9%) of the cases that were culture-negative at reimplantation. When controlling for other variables using multivariate analyses, the risk of treatment failure was higher (odds ratio = 2.53; 95% confidence interval [CI] = 1.13 to 5.64) and reinfection occurred earlier (hazard ratio = 2.00; 95% CI = 1.05 to 3.82) for the cases with a positive culture during reimplantation. The treatment failure rate did not differ (p = 0.73) between cases with ≥2 positive cultures (36.4%) and 1 positive culture (50%).

CONCLUSIONS

Positive intraoperative culture at the time of reimplantation, regardless of the number of positive samples, was independently associated with >2 times the risk of subsequent treatment failure and earlier reinfection. Surgeons should be aware that a positive culture at the time of reimplantation independently increases the risk of subsequent failure.

LEVEL OF EVIDENCE

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

One-stage exchange for prosthetic joint infection of the hip

Exchange arthroplasty remains the gold standard of treatment of established prosthetic joint infection. This can be achieved using a one or two stage approach. The ENDO-Klinik, in Hamburg, has pioneered the one-stage technique since 1970 utilising antibiotic loaded acrylic cement (ALAC). This editorial discusses the relevant literature and describes the indications and surgical technique employed by the ENDO-Klinik Hamburg.

One-Stage Revision for Infected Total Hip Arthroplasty

Prosthetic joint infection (PJI) is a challenging complication following total hip arthroplasty (THA). Two-stage exchange arthroplasty is preferred for treating chronic PJI of THA, although specialized centers have reported comparable outcomes with protocol-based, 1-stage exchange arthroplasty. A main requirement is presurgical determination of the infecting organism's sensitivity. The therapeutic goal is control of the infection and maintenance of joint function. It offers advantages, including a single operative procedure, fewer antibiotics, and reduced hospitalization time and relative overall costs.

Risk factors and a prognostic model of hip periprosthetic infection recurrence after surgical treatment using articulating and non-articulating spacers

PURPOSE

The purpose of this study was evaluation of the efficacy of the first step of a two-stage procedure for treatment of hip prosthetic joint infection (PJI) using articulating and non-articulating spacers as well as development of a prediction model and prognostic score for infection recurrence.

METHODS

In a cohort of 217 patients treated for PJI of the hip, demographic characteristics, clinical symptoms, body temperature, body mass index (BMI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cell count (WBC), microbiological cultures and the type of the spacer used were retrospectively analyzed for association with the recurrence of PJI.

RESULTS

Patients with infection recurrence had increased levels of ESR and CRP (P < 0.001) together with higher BMI and shorter infection manifestation period after previous surgery (P < 0.05). Among these patients, there was no significant difference of clinical characteristics between subjects with articulating and non-articulating spacers. Microbial associations were more often identified in patients with recurrent infection (50 %, P < 0.01) where Gram-negative bacteria were predominant (61.5 %, P < 0.01). These patients had higher percentage of Acinetobacter sp. and P. aeruginosa isolates (28.2 %, P < 0.01).

CONCLUSIONS

Efficacy of the first step of two-stage revision was 64.1 %. Placement of either articulating or non-articulating spacers did not influence recovery from PJI. Laboratory values of ESR, CRP, BMI and the type of previous surgery were identified as main factors that affect outcomes of the two-stage procedure. A prognostic model with the calculation of a total risk score for PJI recurrence was developed.

Single-Stage Hip and Knee Exchange for Periprosthetic Joint Infection

Periprosthetic joint infections following hip and knee arthroplasty are challenging complications for Orthopaedic surgeons to manage. The single-stage exchange procedure is becoming increasingly popular with promising results. At our Institute we have demonstrated favourable or similar outcomes compared to the 'gold-standard' two-stage exchange, and other published single-stage results. The aim of this study is to describe the patient selection criteria and perioperative steps in a single-stage exchange for hip and knee arthroplasty undertaken at our Institute. The outlined protocol can be performed using standard debridement, attention to detail and well-recognised reconstructive techniques.

Two-Stage Revision Protocol in Multidrug Resistant Periprosthetic Infection Following Total Hip Arthroplasty Using a Long Interval Between Stages

We retrospectively reviewed the medical records of 31 patients with periprosthetic hip infections attempting to evaluate the outcome of a two-stage revision protocol characterized by prolonged interim period (mean=9.2 months, range 8-12 months) prior to the final re-implantation. In 3 cases (9.6%) the 1st stage was repeated after a mean period of 12.3 weeks due to relapse of infection. Five spacer dislocations occurred, not affecting the final clinical outcome after reimplantation, as evaluated by the Harris Hip Score. No protrusions or additional acetabular bone loss was noticed. Our proposed protocol is a simple, safe, efficient and reproducible treatment approach that may be successfully utilized predominantly when dealing with multidrug resistant pathogens.