Komplikationsmanagement bei infizierter Osteosynthese: Therapiealgorithmus bei periimplantären Infektionen

Bacterial pathogens and in-hospital mortality in revision surgery for periprosthetic joint infection of the hip and knee: analysis of 346 patients

INTRODUCTION

The management of periprosthetic joint infections (PJI) of the lower limb is challenging, and evidence-based recommendations are lacking. The present clinical investigation characterized the pathogens diagnosed in patients who underwent revision surgery for  PJI of total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

The present study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). The institutional databases of the RWTH University Medical Centre of Aachen, Germany, were accessed. The OPS (operation and procedure codes) 5-823 and 5-821 and the ICD (International Statistical Classification of Diseases and Related Health Problems) codes T84.5, T84.7 or T84.8 were used. All patients with PJI of a previous THA and TKA who underwent revision surgery were retrieved and included for analysis.

RESULTS

Data from 346 patients were collected (181 THAs and 165 TKAs). 44% (152 of 346 patients) were women. Overall, the mean age at operation was 67.8 years, and the mean BMI was 29.2 kg/m2. The mean hospitalization length was 23.5 days. 38% (132 of 346) of patients presented a recurrent infection.

CONCLUSION

PJI remain a frequent cause for revisions after total hip and knee arthroplasty. Preoperative synovial fluid aspiration was positive in 37%, intraoperative microbiology was positive in 85%, and bacteraemia was present in 17% of patients. Septic shock was the major cause of in-hospital mortality. The most common cultured pathogens were Staph. epidermidis, Staph. aureus, Enterococcus faecalis, and Methicillin-resistant Staph aureus (MRSA). An improved understanding of PJI pathogens is important to plan treatment strategies and guide the choice of empirical antibiotic regimens in patients presenting with septic THAs and TKAs.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Fracture Related Infections and Their Risk Factors for Treatment Failure—A Major Trauma Centre Perspective

Fracture related infections (FRI) are debilitating and costly complications of musculoskeletal trauma surgery that can result in permanent functional loss or amputation. Surgical treatment can be unsuccessful, and it is necessary to determine the predictive variables associated with FRI treatment failure, allowing one to optimise them prior to treatment and identify patients at higher risk. The clinical database at a major trauma centre was retrospectively reviewed between January 2015 and January 2021. FRI treatment failure was defined by infection recurrence or amputation. A univariable logistic regression analysis was performed, followed by a multivariable regression analysis for significant outcomes between groups on univariable analysis, to determine risk factors for treatment failure. In total, 102 patients were identified with a FRI (35 open, 67 closed fractures). FRI treatment failure occurred in 24 patients (23.5%). Risk factors determined by our multivariate logistic regression model were obesity (OR 2.522; 95% CI, 0.259–4.816; p = 0.006), Gustilo Anderson type 3c (OR 4.683; 95% CI, 2.037–9.784; p = 0.004), and implant retention (OR 2.818; 95% CI, 1.588–7.928; p = 0.041). Given that FRI treatment in 24 patients (23.5%) ended up in failure, future management need to take into account the predictive variables analysed in this study, redirect efforts to improve management and incorporate adjuvant technologies for patients at higher risk of failure, and implement a multidisciplinary team approach to optimise risk factors such as diabetes and obesity.

[Management of suspected early infection after osteosynthesis]

The infection rate after fracture osteosynthesis depends on many factors. The postoperative infection rate after osteosynthesis (inpatient treatment) was between 1.15% and 2.04% for the years 2017-2019. The total number of postoperative wound infections was estimated at around 225,000 annually in 2018. Essential factors for reducing the infection rate after osteosynthesis are the favorable choice of the timing of the operation and the surgical procedure as well as the treatment of relevant secondary diseases. If a postoperative wound infection is suspected critical assessment of the wounds in the postoperative course is essential in order to be able to identify and treat this complication at an early stage. After osteosynthesis, early diagnosis of a peri-implant infection and differentiated surgical and antibiotic treatment are the prerequisites for the best possible treatment success.

General treatment principles for fracture-related infection: recommendations from an international expert group

Fracture-related infection (FRI) remains a challenging complication that creates a heavy burden for orthopaedic trauma patients, their families and treating physicians, as well as for healthcare systems. Standardization of the diagnosis of FRI has been poor, which made the undertaking and comparison of studies difficult. Recently, a consensus definition based on diagnostic criteria for FRI was published. As a well-established diagnosis is the first step in the treatment process of FRI, such a definition should not only improve the quality of published reports but also daily clinical practice. The FRI consensus group recently developed guidelines to standardize treatment pathways and outcome measures. At the center of these recommendations was the implementation of a multidisciplinary team (MDT) approach. If such a team is not available, it is recommended to refer complex cases to specialized centers where a MDT is available and physicians are experienced with the treatment of FRI. This should lead to appropriate use of antimicrobials and standardization of surgical strategies. Furthermore, an MDT could play an important role in host optimization. Overall two main surgical concepts are considered, based on the fact that fracture fixation devices primarily target fracture consolidation and can be removed after healing, in contrast to periprosthetic joint infection were the implant is permanent. The first concept consists of implant retention and the second consists of implant removal (healed fracture) or implant exchange (unhealed fracture). In both cases, deep tissue sampling for microbiological examination is mandatory. Key aspects of the surgical management of FRI are a thorough debridement, irrigation with normal saline, fracture stability, dead space management and adequate soft tissue coverage. The use of local antimicrobials needs to be strongly considered. In case of FRI, empiric broad-spectrum antibiotic therapy should be started after tissue sampling. Thereafter, this needs to be adapted according to culture results as soon as possible. Finally, a minimum follow-up of 12 months after cessation of therapy is recommended. Standardized patient outcome measures purely focusing on FRI are currently not available but the patient-reported outcomes measurement information system (PROMIS) seems to be the preferred tool to assess the patients' short and long-term outcome. This review summarizes the current general principles which should be considered during the whole treatment process of patients with FRI based on recommendations from the FRI Consensus Group.Level of evidence: Level V.

Calculated parenteral initial treatment of bacterial infections: Bone and joint infections

This is the 10^th chapter of the guideline “Calculated initial parenteral treatment of bacterial infections in adults – update 2018” in the 2^nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience.

This chapter deals with bacterial Infections of bones, joints and prosthetic joints. One of the most pressing points is that after an initial empirical therapy a targeted antimicrobial which penetrates well to the point of infection and is tolerated well over the usually long duration of the therapy is chosen.

Pathogenesis and management of fracture-related infection

BACKGROUND

Both fracture-related infections (FRIs) and periprosthetic joint infections (PJIs) include orthopaedic implant-associated infections. However, key aspects of management differ due to the bone and soft tissue damage in FRIs and the option of removing the implant after fracture healing. In contrast to PJIs, research and guidelines for diagnosis and treatment in FRIs are scarce.

OBJECTIVES

This narrative review aims to update clinical microbiologists, infectious disease specialists and surgeons on the management of FRIs.

SOURCES

A computerized search of PubMed was performed to identify relevant studies. Search terms included 'Fracture' and 'Infection'. The reference lists of all retrieved articles were checked for additional relevant references. In addition, when scientific evidence was lacking, recommendations are based on expert opinion.

CONTENT

Pathogenesis, prevention, diagnosis and treatment of FRIs are presented. Whenever available, specific data of patients with FRI are discussed.

IMPLICATIONS

Management of patients with FRI should take into account FRI-specific features. Treatment pathways should implement a multidisciplinary approach to achieve a good outcome. Recently, international consensus guidelines were developed to improve the quality of care for patients suffering from this severe complication, which are highlighted in this review.

Pin tract infection prophylaxis and treatment

Pin tract infection in external fixation (ExFix) is a frequent finding which can eventually lead to loosening, osteomyelitis and loss of fixation. Its diagnosis is based on high empiricism and low validity, although it is possible to distinguish between minor and major infection. The first is limited to soft tissues, whereas the latter includes bone involvement. The rate of infection after conversion of external fixation to intramedullary nailing (IMN) is not well known. Unfortunately, papers referring to infection after the conversion of ExFix to intramedullary nailing (IMN) are of evidence level IV or V. It is suggested that conversion of ExFix to IMN should be carried out in a 2 step regimen. The time interval of 2 step regimen is uncertain although some authors have recommended to occur within 9 days. There is no consensus as to which prophylaxis protocol should be applied prior to conversion. In order to throw more light into this important issue, registries capturing important related parameters to the development of infection should be established.

Insights into treatment and outcome of fracture-related infection: a systematic literature review

INTRODUCTION

Standardized guidelines for treatment of fracture-related infection (FRI) are lacking. Worldwide many treatment protocols are used with variable success rates. Awareness on the need of standardized, evidence-based guidelines has increased in recent years. This systematic literature review gives an overview of available diagnostic criteria, classifications, treatment protocols, and related outcome measurements for surgically treated FRI patients.

METHODS

A comprehensive search was performed in all scientific literature since 1990. Studies in English that described surgical patient series for treatment of FRI were included. Data were collected on diagnostic criteria for FRI, classifications used, surgical treatments, follow-up protocols, and overall outcome. A systematic review was performed according to the PRISMA statement. Proportions and weighted means were calculated.

RESULTS

The search yielded 2051 studies. Ninety-three studies were suitable for inclusion, describing 3701 patients (3711 fractures) with complex FRI. The population consisted predominantly of male patients (77%), with the tibia being the most commonly affected bone (64%), and a mean of three previous operations per patient. Forty-three (46%) studies described FRI at one specific location. Only one study (1%) used a standardized definition for infection. A total of nine different classifications were used to guide treatment protocols, of which Cierny and Mader was used most often (36%). Eighteen (19%) studies used a one-stage, 50 (54%) a two-stage, and seven (8%) a three-stage surgical treatment protocol. Ten studies (11%) used mixed protocols. Antibiotic protocols varied widely between studies. A multidisciplinary approach was mentioned in only 12 (13%) studies.

CONCLUSIONS

This extensive literature review shows a lack of standardized guidelines with respect to diagnosis and treatment of FRI, which mimics the situation for prosthetic joint infection identified many years ago. Internationally accepted guidelines are urgently required to improve the quality of care for patients suffering from this significant complication.

[Antibiotic strategies in trauma surgery : Treatment of implant-associated infections]

Implant-associated infections represent a serious complication following fracture management. Due to biofilm formation, an optimized treatment strategy is required to treat these infections. Interdisciplinary cooperation between trauma surgeon, infectious diseases specialist and microbiologist enables the deployment of a concerted surgical and antibiotic treatment concept, which significantly influences treatment success. Fracture healing and chronic osteomyelitis prevention are the primary treatment goals. In general, the eradication of infection is possible with surgical debridement, change or removal of the implant and adequate antibiotic therapy. In some cases, suppressive therapy until consolidation of fracture and later removal of the implant is an option.

Infection after fracture fixation: Current surgical and microbiological concepts

One of the most challenging complications in trauma surgery is infection after fracture fixation (IAFF). IAFF may result in permanent functional loss or even amputation of the affected limb in patients who may otherwise be expected to achieve complete, uneventful healing. Over the past decades, the problem of implant related bone infections has garnered increasing attention both in the clinical as well as preclinical arenas; however this has primarily been focused upon prosthetic joint infection (PJI), rather than on IAFF. Although IAFF shares many similarities with PJI, there are numerous critical differences in many facets including prevention, diagnosis and treatment. Admittedly, extrapolating data from PJI research to IAFF has been of value to the trauma surgeon, but we should also be aware of the unique challenges posed by IAFF that may not be accounted for in the PJI literature. This review summarizes the clinical approaches towards the diagnosis and treatment of IAFF with an emphasis on the unique aspects of fracture care that distinguish IAFF from PJI. Finally, recent developments in anti-infective technologies that may be particularly suitable or applicable for trauma patients in the future will be briefly discussed.

Fracture-related infection: A consensus on definition from an international expert group

Fracture-related infection (FRI) is a common and serious complication in trauma surgery. Accurately estimating the impact of this complication has been hampered by the lack of a clear definition. The absence of a working definition of FRI renders existing studies difficult to evaluate or compare. In order to address this issue, an expert group comprised of a number of scientific and medical organizations has been convened, with the support of the AO Foundation, in order to develop a consensus definition. The process that led to this proposed definition started with a systematic literature review, which revealed that the majority of randomized controlled trials in fracture care do not use a standardized definition of FRI. In response to this conclusion, an international survey on the need for and key components of a definition of FRI was distributed amongst all registered AOTrauma users. Approximately 90% of the more than 2000 surgeons who responded suggested that a definition of FRI is required. As a final step, a consensus meeting was held with an expert panel. The outcome of this process led to a consensus definition of FRI. Two levels of certainty around diagnostic features were defined. Criteria could be confirmatory (infection definitely present) or suggestive. Four confirmatory criteria were defined: Fistula, sinus or wound breakdown; Purulent drainage from the wound or presence of pus during surgery; Phenotypically indistinguishable pathogens identified by culture from at least two separate deep tissue/implant specimens; Presence of microorganisms in deep tissue taken during an operative intervention, as confirmed by histopathological examination. Furthermore, a list of suggestive criteria was defined. These require further investigations in order to look for confirmatory criteria. In the current paper, an overview is provided of the proposed definition and a rationale for each component and decision. The intention of establishing this definition of FRI was to offer clinicians the opportunity to standardize clinical reports and improve the quality of published literature. It is important to note that the proposed definition was not designed to guide treatment of FRI and should be validated by prospective data collection in the future.

[Infected osteosynthesis]

BACKGROUND

Infections after osteosynthesis are a feared complication of the surgical treatment of fractures and should be dealt with by a multidisciplinary team. In addition to the surgeon, also included in this multidisciplinary team are a specialist for infectious diseases, a microbiologist, a radiologist and often a plastic surgeon. This review article describes the current knowledge on the pathogenesis, diagnostics, classification and treatment. The aim is to demonstrate some basic rules in the treatment of infections associated with implants and to show potential therpeutic approaches.

MATERIAL AND METHODS

The principles of diagnostics and combined surgical and antibiotic treatment are presented based on the current specialist literature.

RESULTS

With the help of a team approach the goals of treatment of an infected osteosynthesis, i.e. fracture healing, return to function and eradication of infection can be achieved. While the osteosynthesis material can usually be retained in acute infections, it is better to remove the infected hardware in chronic infections as eradication of the mature biofilm is no longer possible.

DISCUSSION

With adequate local wound débridement, the use of local and systemic antibiotics, as indicated by the specialist for infectious diseases and appropriate soft tissue coverage and wound closure, acute as well as chronic infections can be successfully treated. Nowadays, the surgeon has many different options for the management of bone defects. Depending on the anatomical location and the size of the defect a variety of techniques ranging from acute shortening to the Masquelet technique up to the Ilizarov distraction technique are available. These techniques should be combined with local bactericidal treatment.

Management of infections associated with neurosurgical implanted devices

INTRODUCTION

Neurosurgical devices are increasingly used. With it, neurosurgical device-related infections gain relevance. As biofilms are involved in implant-associated infections the diagnosis and treatment is challenging and requires specific anti-biofilm concepts and management algorithms. Areas covered: The literature concerning the management of neurosurgical device-associated infections is scarce and heterogeneous treatment concepts are discussed, but no standardized diagnostic and treatment procedures exist. Therefore, we emphasize extrapolating management strategies predominantly from orthopedic device-associated infections, where the concept is better established and clinically validated. This review covers infections associated with craniotomy fixation devices, cranioplasties, external ventricular and lumbar drainages, internal shunts and neurostimulators. Expert commentary: Sonication of the removed implants significantly improves microbiological diagnosis. A combined surgical and antimicrobial management is crucial for successful treatment: appropriate surgical intervention is combined with prolonged anti-biofilm therapy of usually 12 weeks. In selected patients, new treatment algorithms enable cure of neurosurgical device-associated infections without implant removal or with a one-stage implant exchange, considerably improving the quality of patient lives.