Introduction. A proportion of patients with hip and knee prosthetic joint infection (PJI) undergo multiple revisions with the aim of eradicating infection and improving quality of life. The aim of this study was to describe the microbiology cultured from multiply revised hip and knee replacement procedures to guide antimicrobial therapy at the time of surgery. Patients and Methods. Consecutive patients were retrospectively identified from databases at two specialist orthopaedic centres in the United Kingdom between 2011 and 2019. Patient were included who had undergone repeat revision total knee replacement (TKR) or total hip replacement (THR) for infection, following an initial failed revision for infection. Results. 106 patients were identified, of which 74 underwent revision TKR and 32 underwent revision THR. Mean age at first revision was 67 years (SD 10). Charlson Comorbidity Index was <2 for 31 patients, 3–4 for 57 patients, and >5 for 18 patients. All patients underwent >2 revisions, 73 patients received 3, 47 patients received 4, 31 patients received 5, and 21 patients received >6. After six revisions, 90% of patients cultured different organisms than the initial revision, and 53% of organisms were multi-drug resistant species. The most frequent organisms at each revision were coagulase negative Staphylococcus (36%) and Staphylococcus aureus (19%). Fungus was cultured from 3% of revisions and 21% of infections were polymicrobial. Conclusion. Patients undergoing multiple revisions for PJI are highly likely to experience a change in organisms and sensitivities with each subsequent revision. It is important to administer empirical antibiotics at each subsequent revision, appreciating known drug resistance from previous cultures. Our results do not support routine use of empirical antifungals

INTRODUCTION. Peri-prosthetic fungal infection is generally considered more difficult to cure than a bacterial infection. Two-stage exchange is considered the gold standard of surgical treatment. A recent study, however, reported a favorable outcome after one stage exchange in selected cases where the fungus was identified prior to surgery. The routine one stage exchange policy for bacterial peri-prosthetic infection involves the risk of identifying a fungal infection mimicking bacterial infection solely on intraoperative samples, i.e. after reimplantation, realizing actually a one stage exchange for fungal infection without pre-operative identification of the responsible fungus, which is considered to have a poor prognosis. We report two such cases of prosthetic hip and knee fungal infection. Despite this negative characteristic, no recurrence of the fungal infection was observed. CASE N°1: A 78 year old patient was referred for loosening of a chronically infected total hip arthroplasty (Staphylococcus aureus and Streptococcus dysgalactiae). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Two fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at three year follow up. CASE N° 2: A 53-year-old patient was referred for loosening of a chronically infected total knee prosthesis (Staphylococcus aureus methicillin susceptible, Klebsiella pneumoniae and Staphylococcus epidermidis). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Five fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at two-year follow-up. DISCUSSION. This experience suggests that eradication of fungal infection of a total hip or knee arthroplasty may be possible after one stage exchange even in cases where the diagnosis of fungal infection was not known before surgery, when the fungus was not identified and its antifungal susceptibility has not been evaluated before surgery. It is however not possible to propose this strategy as a routine procedure. CONCLUSION. We suggest evaluating the results of one stage exchange for peri-prosthetic fungal infection on a larger scale

Aim. Bone and joint infections (BJI) are associated with a heavy morbidity and high health costs. Comorbidities, device associated infections and complicated journeys are associated with increased mortality, treatment failures and costs. For this reason, 24 referral centers (RC) have been created in 2009 in order to advise about management of “complex” BJI in weekly multidisciplinary meetings (MM). Since end of 2012, data from these meetings are gathered in a national database. We aimed to describe the data from this French registry of BJI and determine factors associated with the definition of “complex” BJI. Method. Demographic, clinical, microbiologic and therapeutic characteristics of patients are systematically recorded in the database. Data from the first presentation in RC for each adult patients are presented. Complexity of BJI is recorded after each meeting according to 4 criteria (first failure, complex antibiotic therapy, precarious underlying conditions or complex surgical procedure). Part of unavailable data have been completed by pattern extraction from text-encoded commentaries. Factors associated with complexity were determined by multivariate logistic regression. Results. From 2012 to 2016, 17.527 patients were included corresponding to 30.300 presentations in MM. Median age was 64 years (IQR 50–76) with masculine predominance (61.8%). Comorbidity was present in 50.3%, with at least 2 comorbidities in 26%. Prosthetic joint infection represented 41.4% of patients, followed by chronic osteitis with/without foreign material (24%). Definite microbiologic documentation was available in 68.8% of cases, mostly Staphylococcus aureus (43.9%) followed by Coagulase negative Staphylococci (28.6%) and enterobacteriaceae (23.1%), with 27.4% of polybacterial infections. Antibiotic treatment was proposed in 81.6% and surgery in 70% of cases. BJI were defined as complex in 55.4%, mostly because underlying conditions (50%), and in 57.6% with at least 2 complexity criteria. Factors positively associated with definition of complexity in MM were: background: number of comorbidities, immunodeficiency, neoplasia, liver or kidney failure, intra-cardiac device; microbiology: Mycobacteria, Fungus, MRSA, MSSA, MR-CoNS, MDR enterobacteria, non-fermentative BGN, and atypical pathogens (actinomycetes, nocardia, intra-cellular …); infection characteristics: prosthetic joint infection, osteitis, foreign material infection, arthritis and number of infected sites; surgical procedures: surgical flap, 2 stages prosthesis exchange, spacer, arthrodesis, and joint removal. Simple debridement was negatively associated with complex definition. Conclusions. This registry is the first national prospective database about management of BJI in France and provide many information about epidemiology and management of BJI in France, as well as a more precise definition of complexity

Implant-associated infection is a major source of morbidity in orthopaedic surgery. There has been extensive research into the development of materials that prevent biofilm formation, and hence, reduce the risk of infection. Silver nanoparticle technology is receiving much interest in the field of orthopaedics for its antimicrobial properties, and the results of studies to date are encouraging. Antimicrobial effects have been seen when silver nanoparticles are used in trauma implants, tumour prostheses, bone cement, and also when combined with hydroxyapatite coatings. Although there are promising results with in vitro and in vivo studies, the number of clinical studies remains small. Future studies will be required to explore further the possible side effects associated with silver nanoparticles, to ensure their use in an effective and biocompatible manner. Here we present a review of the current literature relating to the production of nanosilver for medical use, and its orthopaedic applications.

Cite this article: Bone Joint J 2015; 97-B:582–9.