Conservative medical therapy of prosthetic joint infections: retrospective analysis of an 8-year experience

Two stage revision knee arthroplasty for infection with massive bone loss. A technique to achieve spacer stability

We report a technique for the intra-operative production of an antibiotic-impregnated cement spacer, reinforced with an intramedullary nail. The spacer is designed for use in cases where significant bone loss and/or ligamentous instability prevent the formation of a stable joint when using a conventional spacer during a two-stage revision knee arthroplasty. This technique has been performed in eleven patients. Nine patients have subsequently undergone a second-stage procedure. Two patients died of unrelated causes before a second-stage could be performed. In all but one case, the infection has been successfully eradicated and patients remain infection free at a mean follow-up of 32 months (range 21-64 months). We believe that the described technique is an effective alternative to the traditional spacer, in patients with significant bone loss and/or ligamentous instability. It delivers antibiotics locally, while producing a mechanically stable joint, on which the patient can mobilise, maintaining leg length and tissue tensions.

Prosthetic joint infection: recent developments in diagnosis and management

Over the past years there has been a significant increase in the number of joint prosthesis replacements worldwide. The most serious complication of joint prosthesis is infection with an incidence of 1.5-2.5% for primary interventions and up to 20% for revision procedures. The mortality rate ranges between 1% and nearly 3%. The economic cost of this complication is up to $50,000 per patient and $250,000 million per year. A major issue in the management of prosthetic joint infection (PJI) is the relative difficulty in making a diagnosis so to cause a significant effect on the prognosis. Goals of the treatment are to eradicate infection, prevent its recurrence and preserve mechanical joint function. In this review we focus on the value of traditional and newer diagnostic tests and we discuss management and preventive strategies. European networks are needed to define the best diagnostic and treatment strategies in order to reduce future challenge posed by PJIs.

Consensus document on controversial issues in the diagnosis and treatment of prosthetic joint infections

BACKGROUND

Joint replacement surgery has been on the increase in recent decades and prosthesis infection remains the most critical complication. Many aspects of the primary prevention and clinical management of such prosthesis infections still need to be clarified.

CONTROVERSIAL ISSUES

The aim of this GISIG (Gruppo Italiano di Studio sulle Infezioni Gravi) working group - a panel of multidisciplinary experts - was to define recommendations for the following controversial issues: (1) Is a conservative surgical approach for the management of prosthetic joint infections effective? (2) Is the one-stage or the two-stage revision for the management of prosthetic joint infections more effective? (3) What is the most effective treatment for the management of prosthetic joint infections due to methicillin-resistant staphylococci? Results are presented and discussed in detail.

METHODS

A systematic literature search using the MEDLINE database for the period 1988 to 2008 of randomized controlled trials and/or non-randomized studies was performed. A matrix was created to extract evidence from original studies using the CONSORT method to evaluate randomized clinical trials and the Newcastle-Ottawa Quality Assessment Scale for case-control studies, longitudinal cohorts, and retrospective studies. The GRADE method for grading quality of evidence and strength of recommendation was applied.

A biofilm growth protocol and the design of a magnetic field exposure setup to be used in the study of magnetic fields as a means of controlling bacterial biofilms

The use of prosthetic implants is increasing both in the United States and around the world and there is a concomitant rise in cases of biofilm-based, persistent infections that are quite serious and virtually impervious to antibiotic treatment. The development of alternate therapies that do not involve long term use of high levels of antibiotics or surgical intervention is needed. Based on the success of using electric or magnetic fields to alter certain physiological processes, it is hypothesized that relatively low level magnetic fields, in conjunction with the appropriate antibiotic, may be able to help control and eventually clear bacterial biofilms on a prosthetic. In order to test this hypothesis, it is necessary to first develop a means of growing laboratory grade biofilms on specific materials in a way that is repeatable between experiments and that can be reproduced by other laboratories. Secondly, a means of applying controlled magnetic fields to the surfaces supporting the biofilms at a defined temperature must be developed. This article addresses both of these points.

The microbiology of the infected knee arthroplasty

We describe the results of a retrospective analysis of patients with microbiologically proven infection, who underwent revision TKA between 1994 and 2008. Of the 121 patients included in the study, 61 (50%) were male and 60 (50%) were female. The mean age was 71 (range 42-88) years. The most common organisms identified were Coagulase negative Staphylococcus (CNS) (49%) and Staphylococcus aureus (SA) (13%). The prevalence of CNS appears to be increasing, while that of SA and other organisms is decreasing. Vancomycin and teicoplanin were the most effective antibiotics with overall sensitivity rates of 100% and 96%, respectively. The results of our theoretical model suggest that gentamicin combined with vancomycin is the most effective empirical regimen. Staphylococcal species are the most common organisms encountered in deep infection of the knee. Gentamicin combined with vancomycin offers the most comprehensive protection and potentially allows for infected knee arthoplasties to be treated with a one-stage procedure.

Risk factors associated with acute hip prosthetic joint infections and outcome of treatment with a rifampinbased regimen

BACKGROUND AND PURPOSE

Acute prosthetic infection is a serious problem. We report factors related to the incidence of acute infection and results of combined joint debridement and prolonged rifampicin-based antibiotic therapy.

PATIENTS AND METHODS

Between 1998 and 2004, 14 acute infections occurred after 819 primary hip arthroplasties. The association between patient-related and surgical factors and the risk of infection were analyzed. Infections were treated with multiple joint lavage, debridement, 2 weeks of antibiotic therapy, and then oral antibiotics for a minimum of 6 months.

RESULTS

There was a correlation between having a body mass index (BMI) of >or=30, and also more than 2 co-morbidities, and an increased risk of infection. Diabetes was a potential risk factor. Following our regime of treatment, 11 of 14 patients retained their prosthesis. 2 of 3 who required resection arthroplasty underwent successful staged revision, while the third patient had no further surgery because of being deemed unfit.

INTERPRETATION

Primary joint replacement was salvaged in 11 of 14 patients. When successful re-implantation was included, 13 of 14 patients had a mobile prosthetic joint without further infection.

Antibiotics in trauma and orthopedic surgery -- a primer of evidence-based recommendations

Systematic reviews and meta-analyses published in recent years have allowed drafting of evidence-based guidelines for antibiotic prophylaxis in orthopedic and trauma surgery. It is important to recognize the limitations of the recommendations derived from the available body of evidence. Since some of the most relevant randomized controlled clinical trials were performed more than 20 years ago, it is sometimes difficult to apply the data to today's clinical practice. In establishing consensus guidelines, it could prove difficult to identify areas for improvement through further research and better compliance. Although recommendations for optimized treatment of orthopedic implant infections are not currently based on first-class evidence, there are very promising new concepts emerging in this field, and we are awaiting more data and decisive conclusions from larger clinical trials.

Recent advances in the treatment of infections due to resistant Staphylococcus aureus

PURPOSE OF REVIEW

This paper reviews recent data on the treatment of infections caused by drug-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). This review will focus on new findings reported in the English-language medical literature from June 2003 to September 2004.

RECENT FINDINGS

Despite the emergence of resistant and multidrug-resistant S. aureus, we have three effective drugs in clinical use for which little resistance has been observed: quinupristin-dalfopristin, linezolid, and daptomycin. Linezolid looks particularly promising in the treatment of MRSA pneumonia. Daptomycin displays rapid bactericidal activity in vitro, but, so far, clinical trials have only been conducted for the treatment of skin and soft-tissue infections. There are three drugs with broad-spectrum activity against Gram-positive organisms at an advanced stage of testing: two new glycopeptides with potent bacteriocidal activity and long half-lives (oritavancin and dalbavancin), and tigecycline, a minocycline derivative. These drugs have also shown efficacy in the treatment of skin and soft-tissue infections.

SUMMARY

The promising data that have emerged in the last year indicate that we may have six available drugs to treat resistant S. aureus infections within the next few years. The next goal is to determine the appropriate indications and cost-effectiveness of each of these drugs in our treatment strategy against S. aureus and other Gram-positive pathogens.