[Treatment of orthopedic implant-associated infections]

The Swedish National Guidelines for Bone and Joint Infections were revised during 2018. The work was carried out on behalf of the Swedish Society for Infectious Diseases. The study group consists of senior consultants in infectious diseases, supported by specialists in orthopedic surgery, clinical microbiology and allergology when needed. The study group emphasizes that implant associated infections are challenging and requires multidisciplinary cooperation, including, but not limited to, specialists in orthopedic surgery, infectious diseases, clinical microbiology and radiology for optimal treatment results. All aspects of the clinical management are equally important; selecting the optimal antibiotic prophylaxis in arthroplasty as well as fracture surgery, early diagnosis of infection, adequate treatment, follow-up, and finally a structured evaluation of outcome. Profound and updated knowledge of treatment of biofilm related infection is necessary to achieve optimal results in patients with implant-associated infections. Future challenges include improved decision support for combining surgical treatment with selection of proper antibiotics, as well as management of antibiotic resistance, drug-drug interactions and adverse effects of antibiotic treatment.

Cardiac device infections: definition, classification, differential diagnosis, and management

Cardiac device infections (CDIs) continue to be a serious clinical problem, with varying terminology and different classifications constituting one of the major diagnostic and therapeutic challenges in routine clinical practice. The problem invariably arises during an attempt to estimate the extent of the infection, which in consequence determines the choice of treatment strategy (duration of antibiotic therapy). The most serious form of CDI is lead-related infective endocarditis (LRIE). There are no clearly established diagnostic criteria for this disease; the available Duke University criteria are difficult to apply in patients with a suspicion of LRIE because of low sensitivity. As the treatment of LRIE is expensive and troublesome, there is a tendency to underdiagnose this condition and seek any intermediary forms between local pocket infection and definite LRIE. The present review includes suggestions for the systematization of CDIs with a clear definition of LRIE as a separate and most severe entity among CDIs.

[Periprosthetic joint infections: a practical overview for family physicians]

Periprosthetic joint infection is a rare but serious complication. Its management requires the collaboration between general practitioner, orthopaedic surgeon and infectious disease specialist. A delay in the diagnosis can result in complications, requiring complex surgical procedures. Identification of the causative pathogen and its susceptibility pattern is crucial, because it guides both the choice of antimicrobial treatment and the surgical strategy. Antimicrobial treatment without proper micro- biological sampling must be avoided. Swabs from open wounds are not helpful, because microorganisms belonging to the skin flora will grow. The target audience of this review article on periprosthetic joint infections is the general practitioner.

Classification of hip joint infections

Infections still remain one of the most devastating complications in hip joint surgery. Classification of these infections help the orthopaedic surgeon to identify the acuteness or chronicity of the infection, predict the complexity of the treatment procedure and ensure that all necessary device are available at the time of the revision surgery. The present article reviews the actual literature and provides an overview of clinical, arthroscopic, microbiological and radiological staging systems.

Antibiotic prophylaxis in dentistry: an update

Antibiotics are used in dentistry to treat an existing infection therapeutically or to prevent an infection prophylactically. To prevent a perioperative infection (primary prophylaxis), prophylactic antibiotics may be administered when a surgical device, such as a prosthetic cardiac valve, is placed. They also may be administered to patients who have an existing medical condition or have received a previously placed device to reduce the risk of infection from a bacteremia (secondary prophylaxis). Although it is common to prescribe secondary prophylaxis for many dental conditions, there is a general lack of scientific evidence of its effectiveness and accumulating evidence suggests that such prescriptions may be unnecessary. In the past, antibiotic prophylaxis has been used for conditions with no proven benefit. Risks associated with antibiotics include allergic reactions (for example, anaphylaxis), development of antibiotic-resistant bacteria, development of superinfections, pseudomembranous colitis, cross-reactions with other drugs, and death. The costs involved with the use of antibiotics can be significant as well. This article reviews the current status of secondary antibiotic prophylaxis use in dentistry.

[Examination of granuloma of revised cemented or cementless total hip arthroplasties using inductively coupled plasma atomic emission spectrometry (ICP-OES)]

INTRODUCTION

Aseptic loosening is the most common problem in total hip arthroplasty (THA). One main aspect is inflammatory reaction against wear particles of the prosthesis materials. Analysing failure mechanisms in THA analysis of the particles and their element distribution of revised granulomatous tissue is essential to improve materials used in THA.

MATERIALS AND METHODS

23 granulomas of revised THA due to aseptic loosening, 13 of which with metal on metal bearing (M/M), were analysed using inductively coupled plasma atomic emission spectrometry (ICP-OES).

RESULTS

Elements Cr, Mn, Ni, Al, Cu, Zn, Cd, Ti, V, Zr, Nb and Fe could be detected. The maximum value of Cr was 23.88 ppb (parts per billion), Al 191.02 ppb, Ni 64.95 ppb and Zr 9.96 ppb. The highest value of Al could be found in cementless implants. The maximum value of the elements Cr and Ni could be detected in M/M. In cemented implants the highest value of Zr was found.

DISCUSSION

The origin of Zr was the used bone cement in cemented THA. The elements Cr and Ni were significantly higher in M/M bearings. The highest value of Al was detected in granulomas of revised corund rough blasted cementless implants. The histopathologic findings of the revised M/M bearings have been published recently. Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES) could not show any differences of the alloying constituents in cases with or without allergic reactions. ICP-OES analysis seems to be not useful examination of histologic sections using SEM with cryotransfer unit.

New strategies for the treatment of infections associated with prosthetic joints

Treatment of infections associated with orthopedic devices usually requires appropriate surgical intervention combined with a prolonged course of antimicrobial therapy. The choice of optimal management depends on duration and pathogenesis of infection, stability of the implant, antimicrobial susceptibility of the pathogen and condition of the soft tissue. The role of rifampin in combination with quinolones, minocycline, co-trimoxazole or fusidic acid in the treatment of staphylococcal infections is outlined in this review. Increasing antimicrobial resistance requires the use of alternative agents, such as quinupristin-dalfopristin, linezolid and daptomycin, but results of clinical trials are limited. Finally, agents with a potential for treatment or prophylaxis of device-associated infections, such as novel rifamycin derivatives, and compounds acting on bacterial quorum-sensing mechanisms are presented in this review.

Vascularised muscular flaps and arterial graft infection in the groin

The groin is the commonest site for graft infections in vascular surgery. This is a potentially catastrophic situation as limb loss or even death occurs in a large percentage of cases. Standard teaching for treatment of infected vascular grafts is removal and extra anatomical bypass grafting whilst commencing appropriate antibiotics. This review article suggests careful scrutiny of the wound, debridement and coverage of the graft with a vascularised muscular flap is appropriate in certain situations.

Localization and diagnosis of septic endoprosthesis infection by using 99mTc-HMPAO labelled leucocytes

The aim of this study was to evaluate, retrospectively, the diagnostic value of Tc hexamethylpropylene amine oxime (99mTc-HMPAO) labelled autologous leucocytes for the preferred septic localizations of the infection of the endoprosthesis. We retrospectively reviewed 67 patients with implanted endoprostheses. Diagnosis was found in 42/67 patients. In 25/67 patients we were able to negate an acute pathological process of infection of the endoprosthesis. Our patients were divided into three groups according to the type of endoprosthesis (hip joint, knee joint, shoulder joint). The localizations of the endoprosthesis disorders are shown. The preferred localizations of the acute infection of the hip endoprosthesis are the regio intertrochanterica and the middle part of the shaft of the prosthesis. The preferred localization of the acute infection of the knee endoprosthesis is the proximal shaft of the tibia. The preferred localization of the acute infection of the shoulder endoprosthesis is the distal end of the prosthesis in the proximal humerus. It is hoped that the knowledge of these preferred localizations of infection of endoprosthesis will help patients and doctors in diagnosis and treatment in the future.

Wound infection in hip and knee arthroplasty

We have studied prospectively the outcome of wound discharge in patients after arthroplasty of the hip and knee. Over a period of 3.5 years 530 primary arthroplasties were carried out in one hospital. Postoperative wound infections developed in 82. At a mean follow-up of two years a comparison was made between these patients and 82 with healthy wounds, in terms of symptoms and signs of deep infection. There was an incidence of 1.1% of early deep infection, within six weeks in all cases. The rate of 'superficial' infection was 17.3% in the hips, 10.5% in the knees and 14.3% in total. At a mean follow-up of 26 months, there were no significant differences between the patients with infected wounds and a matched group of patients with healthy wounds in terms of the ESR, level of C-reactive protein, white cell count and radiological scores, but clinical scores were significantly worse in the patients with infected knees (p < 0.05). The length of stay was also significantly longer in this group (mean 14.6 days in the healthy wound group, 19 days in the problem group; p < 0.005). There was, however, no convincing evidence that these wound infections led to deep infection and early revision in the early to medium follow-up period. A larger and longer prospective trial would be necessary to shed more light on this potential problem.

Outcome of infected total knee utilizing a staging system for prosthetic joint infection

This study reviews, over a 5-year period, the records of 70 consecutive patients with prosthetic knee infection and evaluates outcomes as a function of a staging system for prosthetic joint infection. The staging system for prosthetic joint infection was divided into three main categories that include infection type, systemic host grade, and local extremity grade. Outcome indices analyzed included Knee Society Score (KSS), complication rate, amputation rate, and rate of permanent resection. We show that categorizing and stratifying data for patients with infected total knee arthroplasty are useful. A universally accepted staging system would allow for more objective comparisons of treatments and may eventually define particular treatment regimens for particular classes of patients.

Infected total knee arthroplasty. Two-stage reimplantation with a gastrocnemius rotational flap

This study reviews a consecutive series of 21 patients undergoing two-stage reimplantation total knee arthroplasty for late chronic infection. All 21 patients had late chronic infections, and 20 of 21 patients were compromised hosts. Seven different organisms were isolated at the time of prosthetic resection. Staphylococcus coagulase negative species was the most frequently isolated organism. At the time of reimplantation, a medial gastrocnemius rotational flap was rotated over the proximal tibia and knee for wound closure. The average explantation time was 25 weeks (range, 7-76 weeks), and no methylmethacrylate spacers were used. At an average 17-month followup (range, 5.1-33.1 months) all reimplanted total knee replacements remained in place with one patient having recurrent infection. At reimplantation, 11 patients had positive bacterial cultures from tissue specimens. Sixteen of the 33 (40%) positive cultures were from specimens taken from the medullary canal. At followup, the average Knee Society Score was 77.4 (range, 40-100). The lack of a methylmethacrylate spacer and a long explantation time were considered important factors in diminishing functional performance and determining the need for a gastrocnemius flap. A medial gastrocnemius rotational flap should be considered at the time of reimplantation total knee arthroplasty if the soft tissue envelope about the knee is compromised and cannot be closed without undue tension.

Prosthetic graft infection

This article outlines the tenets and basic data critical for the management of prosthetic graft infections. Diagnostic algorithms and treatment options appropriate for patients with symptoms and signs suggestive of graft infection are presented.

Diagnoses and staging. Osteomyelitis and prosthetic joint infections

The diagnoses of osteomyelitis and prosthetic joint infections are usually made on the basis of clinical, laboratory, and radiographic examination. The diagnostic studies presently employed to diagnosis and assess osteomyelitis and prosthetic joint infections are described. A universally applied classification system for stratifying osteomyelitis and prosthetic joint infection would provide a framework for the evaluation of medical and surgical treatment efficacy. Such a system would enable treatment results to be compared among institutions. Staging systems currently being used are described.

Diagnosis and treatment of biomaterial-associated vascular infections

Management of biomaterial-associated vascular infections requires an understanding of pathogenetic mechanisms, risk factors, and microbiologic characteristics. Staphylococci sp., especially slime-producing strains of S. epidermidis are the prevalent pathogens. Experimental and clinical studies have indicated in situ replacement, particularly with an antibiotic-bonded prosthesis, as effective treatment for infections caused by coagulase-negative staphylococci. When sepsis is a presenting sign, prompt intervention, total excision of the prosthesis, and antibiotic administration are required.