We evaluated the effects of a serum protein coating on prosthetic infection in 29 adult male rabbits divided into three groups: control, albumin-coated and uncoated. We used 34 grit-blasted, commercially pure titanium implants. Eleven were coated with cross-linked albumin. All the implants were exposed to a suspension of Staphylococcus epidermidis before implantation. Our findings showed that albumin-coated implants had a much lower infection rate (27%) than the uncoated implants (62%). This may be a useful method of reducing the infection of prostheses

Introduction

Hip prosthetic joint infection (PJI) is a debilitating complication following joint replacement surgery, with significant impact on patients and healthcare systems. The INFection ORthopaedic Management: Evidence into Practice (INFORM: EP) study, builds upon the 6-year INFORM programme by developing evidence-based guidelines for the identification and management of hip PJI.

Prosthetic joint infection (PJI) is an uncommon but serious complication of hip replacement. Over 1,000 operations are performed annually in the United Kingdom for PJI following hip replacement, using either one- or two-stage revision arthroplasty. It is unclear which is preferred by patients and which has the best long-term outcome. This qualitative study aims to describe patient experiences of treatment and recovery following one- and two-stage revision arthroplasty for PJI within the context of a pragmatic randomised controlled trial comparing these two approaches. Semi-structured interviews were conducted with 32 patients undergoing one- or two-stage revision treatment for PJI as part of a UK multi-centre randomised controlled trial. Patients were recruited from 12 participating National Health Service (NHS) Orthopaedic Departments and were interviewed 2–4 months after their first revision surgery and again approximately 18 months later. Final sample size was justified on the basis of thematic saturation. All patients consented to the interview being audio-recorded, transcribed, anonymised and analysed using an inductive thematic approach. Ethical approval was provided by NRES Committee South-West Frenchay, 14/SW/116. Patients in both the one- and two-stage treatment groups described prolonged hospital stays, with burdensome antibiotics and brief physiotherapy treatment. However, following discharge home and during recovery, participants undergoing two-stage revision with an ‘empty hip' or with a spacer reported being physically restricted in almost every aspect of their daily life, resulting in inactivity and confinement to home. Mobility aids were not sufficiently available through the health service for these patients. A key difference is that those with a spacer reported more pain than those without. Approximately one year following their second-stage revision, participants described being more independent and active, but two directly attributed muscle weakness to the lengthy period without a hip and described resulting falls or dislocations that had complicated their recovery. In contrast, those undergoing one-stage revision and CUMARS appeared to be more alike, reporting better mobility, functionality and independence, although still limited. Participants in these groups also reported minimal or no pain following their revision. A key difference between CUMARS and one-stage revision was the uncertainty of whether a second operation was necessary, which participants described as “hanging over them”, while those in the two-stage empty hip or spacer group described a more positive anticipation of a second definitive operation as it marked an end to what was described as a detachment from life. Our findings highlight the differences between patient experiences of recovery following revision arthroplasty, and how this is influenced by the surgical approach and presence or lack of spacers. An understanding of lived experiences following one- and two-stage surgical interventions will complement knowledge about the clinical effectiveness of these different types of revision surgery.

Summary. There is little knowledge in surgeons about the guidelines for prophylactic antibiotics in patients with prosthetic joints when undergoing a dental procedure. This study confirms this and there is need for robust and universal guidelines given the disastrous nature of prosthetic infection. Introduction. Infection as an indication for revision has increased to 12 % of the total revisions (NJR 9. th. report). However, it is next to impossible to find out the cause for a delayed prosthetic infection. With increasing number of arthroplasty procedures, is there a need for prophylactic antibiotics in patients with prostheses?. Methods. At London Knee Meeting 2012, a total of 163 surgeons were asked to take part in a survey. This was to find out if they knew of any existing guidelines for prophylaxis for dental procedures, if there was a need to practice more uniformly, and if they recommend such prophylaxis to their patients routinely. The grade of the surgeon and their experience in years was also noted. Results. Among the 163 surgeons who participated, 102 (62.6%) were arthroplasty surgeons. Of these, 73 (71.5%) were consultants with 3 or more years of experience. For this study, responses from these 102 surgeons were taken into consideration. Out of the 102 surgeons, only 39 (38%) were aware of AAOS recommendations. However, only 26 (25.5%) felt the need for such prophylaxis, other 37 (36%) were not sure if such prophylaxis was necessary. The remaining 39 (38.5%) did not think the prophylaxis was necessary. There was no difference found in the responses between the consultant and non-consultant surgeons. Conclusions. From this survey, it is clear that there is no uniformity of the knowledge of existing recommendations for prophylaxis of such patients with prostheses. There is probably a need to develop robust guidelines for prophylaxis, given the devastating nature of an infected prosthesis

Background. In the UK, over 160,000 total joint replacements are performed annually. About 1% of patients subsequently develop a deep bacterial infection and, if untreated, this can result in severe pain, disability, and death. Costs to the NHS are substantial. The INFORM (Infection Orthopaedic Management) programme aims to address gaps in knowledge relating to treatment of deep prosthetic joint infection through six work packages. The programme is supported by a patient forum and patient-partners working on oversight groups. Methods. Literature reviews and meta-analysis of individual patient data from cohort studies of patients treated for prosthetic hip infection. Analysis of the National Joint Registry to observe trends in infection rates, and identify risk markers for infection and effective treatments. Qualitative interviews with patients and health professionals exploring the impact of infection and its treatment. A multicentre randomised controlled trial to compare patient-centred outcomes after one- or two-stage revision for prosthetic hip infection. An economic evaluation to assess cost-effectiveness of treatments. A survey of patients to explore individuals’ preferences for treatments. Results. Individual patient data has been provided by UK and international centres. Data on over 1.4 million procedures is available from the National Joint Registry. Interviews conducted with 19 patients with prosthetic hip infection and 12 treating surgeons. Information has advised randomised controlled trial methodology. Seven major UK centres recruiting patients to the INFORM randomised controlled trial. Methods for assessment of costs from a health service and societal perspective developed for the randomised controlled trial. Qualitative studies have contributed to the design of a discrete choice questionnaire. Conclusions. Findings from INFORM will establish how patient care and outcomes can be optimised after prosthetic joint infection. Guidance on best clinical practice will be developed. Level of evidence 1–3. Funding statement This abstract presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this abstract are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

One of the most common bacteria in orthopaedic prosthetic infections is Staphylococcus Aureus. Infection causes implant failure due to biofilm production. Biofilms are produced by bacteria once they have adhered to a surface. Nanotopography has major effects on cell behaviour. Our research focuses on bacterial adhesion on nanofabricated materials. We hypothesise that surface nanotopography impacts the differential ability of staphylococci species to adhere via altered metabolomics and may reduce orthopaedic implant infection rate. Bacteria were grown and growth conditions optimised. Polystyrene and titanium (Ti) nanosurfaces were studied. The polystyrene surfaces had different nanopit arrays, while the Ti surfaces expressed different nanowire structures. Adhesion analysis was performed using fluorescence imaging, quantitative PCR and bacterial percentage coverage calculations. Further substitution with ‘heavy’ labelled glucose into growth medium allowed for bacterial metabolomic analysis and identification of any up-regulated metabolites and pathways. Our data demonstrates reduced bacterial adhesion on specific nanopit polystyrene arrays, while nanowired titanium showed increased bacterial adhesion following qPCR (P<0.05) and percentage coverage calculations (P<0.001). Further metabolomic analysis identified significantly increased intensity counts of specific metabolites (Pyruvate, Aspartate, Alanine and Carbamoyl aspartate). Our study shows that by altering nanotopography, bacterial adhesion and therefore biofilm formation can be affected. Specific nanopatterned surfaces may reduce implant infection associated morbidity and mortality. The identification of metabolic pathways involved in adhesion may allow for a targeted approach to biofilm eradication in S. aureus. This is of significant benefit to both the patient and the surgeon, and may well extend far beyond the realms of orthopaedics

The most common bacteria in orthopaedic prosthetic infections are Staphylococcus, namely Staphylococcus Epidermidis (SE) and Staphylococcus Aureus (SA). Infection causes implant failure due to biofilm production. Biofilms are produced by bacteria once they have adhered to a surface. Nanotopography has major effects on cell behaviour. Our research focuses on bacterial adhesion and biofilm formation on nanofabricated materials. Bacteria studied were clinically relevant from an orthopaedic perspective, SA and SE. We hypothesise that that nanosurfaces can modulate bacterial adherence and biofilm formation and may reduce orthopaedic implant infection rate. Isolated bacteria were grown and growth conditions optimised. Bacterial concentrations were calculated by using qPCR. Statistical analysis allowed identification of optimal biofilm growth conditions. These were refined on standard, non-nanopatterned surfaces, and then control and nanopatterned polystyrene (nanopits) and titanium plates (nanowires). Adhesion analysis was performed using fluorescence imaging and quantitative PCR. 4 bacterial strains were isolated and cultured. Growth kinetics based on 24hr cultures allowed isolation of optimal media for biofilm conditions (Dulbecco's Modified Eagle Medium with additional supplements). Highest bacterial concentrations were found following 2hrs incubation with Lysozyme during qPCR. Bacterial concentration significantly increased between 30, 60 and 90 minutes incubation. Differences in percentage coverage on different polysyrene nanosurfaces (nanopits) were noted varying. This was confirmed by qPCR extractions that showed different bacterial concentrations on different nanopatterns. Titanium nanowire surfaces significantly increased bacterial adhesion (P<0.05). Our study cultured and quantified bacterial biofilm and suggests that by altering nanotopography, bacterial adhesion and therefore biofilm formation can be affected. Specific nanopatterned surfaces may reduce implant infection associated morbidity and mortality. Clearly this is of significant benefit to the patient, the surgeon and the NHS, and may well extend far beyond the realms of orthopaedics

With an ever-increasing aging population, total hip and knee arthroplasty is projected to increase by 137% and 601%, respectively, between the period; 2005–2030. Prosthetic Join Infection (PJI) occurs in approximately 2% of total joint replacements (TJRs) in the U.S. PJI is primarily caused by adherence of bacteria to the surface of the prosthesis, ultimately forming an irreversibly attached community of sessile bacteria, known as a biofilm, highly tolerant to antibiotic treatment. Often the only resolution if the ensuing chronic infection is surgical removal of the implant – at high cost for the patient (increased morbidity), and for healthcare resources. Strategies to prevent bacterial adherence have significant potential for medical impact. Laser surface treatment using an automated continuous wave (CW) fiber laser system has shown promise in producing anti-adherent and bactericidal surfaces. Work presented here aims to investigate the effect of this approach on orthopaedic metals as a proof of concept, specifically Ti-6Al-4V (kindly supplied by Stryker Orthopaedics, Limerick). A coupon was surface treated using a laser (MLS-4030; Micro Lasersystems BV, Driel). Samples were incubated in Müller Hinton Broth (MHB) inoculated with methicillin resistant Staphylococcus aureus (MRSA; ATCC 43300) for 24h before Live/Dead staining (BacLight™ solution; Molecular Probes) and inspection by fluorescence microscopy (GXM-L3201 LED; GX Optical). Images were analysed using ImageJ software (NIH) and a significant reduction (p > 0.05, n=24) in total biofilm coverage and Live/Dead ratio was observed between the laser treated and as received surfaces. This data demonstrates the anti-adherent, and indeed bactericidal, effect of Laser-surface treatment

Background. The two-stage revision strategy has been claimed as being the “gold standard” for treating prosthetic joint infection. The one-stage revision strategy remains an attractive alternative option, however, its effectiveness in comparison to the two-stage strategy remains uncertain. A systematic review and meta-analysis was conducted to compare the effectiveness of one- and two-stage revision strategies to prevent re-infection after prosthetic hip infection. Methods. Cohort studies (prospective or retrospective) conducted in unselected patients with infection treated exclusively by one- or two-stage revision and reporting re-infection outcomes within two years of revision were retrieved from MEDLINE, EMBASE, Web of Science, Cochrane databases, manual search of bibliographies to March 2015, and email contact with investigators. Data were extracted by two independent investigators and a consensus was reached with involvement of a third. Rates of re-infection were aggregated using random-effect models after arcsine transformation, and were grouped by study and population level characteristics. Results. In 38 one-stage studies, the rate (95% confidence intervals) of re-infection was 8.2% (6.0–10.8). The corresponding re-infection rate for 60 two-stage studies was 7.9% (6.2–9.7). Re-infection rates remained generally similar when grouped by several study and population level characteristics. There was no evidence of publication bias among contributing studies. Conclusion. Among unselected populations, evidence from aggregate published data suggest similar re-infection rates after one- or two-stage revision. More detailed analyses under a broader range of circumstances and exploration of other sources of heterogeneity will require collaborative pooling of individual participant data, which is ongoing within our Global Infection Orthopaedic Management (INFORM) collaboration. Level of evidence. Level 2a - Systematic reviews of cohort studies. Funding statement. This abstract presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this abstract are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

Objectives

Vancomycin and fosfomycin are antibiotics commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA) infection. This study compares the in vitro inhibitory effects against MRSA of articulating cement spacers impregnated with either vancomycin or fosfomycin.

High-intensity narrow-spectrum (HINS) light is a novel violet-blue light inactivation technology which kills bacteria through a photodynamic process, and has been shown to have bactericidal activity against a wide range of species. Specimens from patients with infected hip and knee arthroplasties were collected over a one-year period (1 May 2009 to 30 April 2010). A range of these microbial isolates were tested for sensitivity to HINS-light. During testing, suspensions of the pathogens were exposed to increasing doses of HINS-light (of 123mW/cm² irradiance). Non-light exposed control samples were also used. The samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation (greater than 4-log₁₀ reduction) was achieved for all of the isolates. The typical inactivation curve showed a slow initial reaction followed by a rapid period of inactivation. The doses of HINS-light required ranged between 118 and 2214 J/cm². Gram-positive bacteria were generally found to be more susceptible than Gram-negative.

As HINS-light uses visible wavelengths, it can be safely used in the presence of patients and staff. This unique feature could lead to its possible use in the prevention of infection during surgery and post-operative dressing changes.

Cite this article: Bone Joint J 2015;97-B:283–8.