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.

Joint aspiration is a useful tool during preoperative workup in suspected periprosthetic infection. The aim of this study was to review efficacy of joint aspiration in our unit and compare results with the published literature.

We undertook a retrospective review of 153 consecutive patients who underwent joint aspirations for suspected periprosthetic infection between 03/2011 and 10/2012 who were identified from the hospital electronic database. As per protocol, joint fluid was sent in an EDTA tube for cell count, Paediatric blood culture bottle and the remainder in a specimen pot.

105 (69%) were TKRs and 48 (31%) were THRs. Intraoperative samples were sent as per protocol in only 40 (26%) cases. The hit rate of positive cultures was 11/153 (7%) and specimens sent in paediatric culture bottles identified more positives than if it was omitted (10.5 Vs 5.5%).

In conclusion, the hit rate of positive cultures is low in this study compared to the literature (7% Vs 33%) and this is likely due to blanket aspiration of all patients who are undergoing revision. In addition, specimens sent in paediatric culture bottles seem to identify more positives. We recommend cases are selected for aspiration according to AAOS guidelines.

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.

Introduction: Infection is a serious complication of joint arthroplasty. Detection of low-grade prosthetic infection can be difficult, with major implications on the subsequent treatment, cost and patient morbidity. We evaluated the effectiveness of Polymerase Chain Reaction (PCR) in detecting infection in patients undergoing arthroplasty revision surgery.

Methods: Ninety-one consecutive patients (92 joints) undergoing revision THA or TKA were assessed prospectively. Preoperative assessment included clinical examination, blood tests and plain radiographs. At revision, tissue samples were sent for microbiology and histology. Cultures, using blood culture bottles, and PCR were performed on the synovial fluid. Diagnosis of infection relied on the surgeon’s opinion encompassing the clinical presentation, the results of various investigations and the intraoperative findings. Infected arthroplasties underwent a 2-stage revision. Post-operatively patients were followed up at regular intervals for a minimum of 2 years.

Results: Twelve (13%) joints were infected. Histology was positive for infection in 11 cases, tissue cultures were positive in 12 and PCR was positive in 32 cases. Intraoperative tissue cultures had sensitivity 0.75, specificity 0.96, positive predictive value 0.75 and negative predictive value 0.96; histology had sensitivity 0.92, specificity 1, positive predictive value 1 and negative predictive value 0.99 and PCR had a sensitivity 0.92, specificity 0.74, positive predictive value 0.34 and negative predictive value 0.98. At 2 years no patient showed evidence of infection.

Discussion: PCR is a sensitive method of diagnosing prosthetic infection but has poor specificity. False positive results may be due to contamination in theatre or in the laboratory. Positive results in apparently non-infected cases could be due to the detection of low virulence organisms, a small number of bacteria or a strong host immune response. Bacterial fragments and non-culturable forms of bacteria may also be responsible.

Conclusion: PCR was not helpful as a screening test for prosthetic infection. Cultures and histology combined with the surgeon’s clinical judgment remain the gold standard.

Objective: It has been observed in previous studies of autologous blood transfusion in total knee arthroplasty, that this technique is associated with a lower infection rate, though studies have not been sufficiently large to demonstrate a significant difference. We hypothesised that autologous salvage blood contained high levels of pro-inflammatory mediators which may prime or augment the patients’ inflammatory response, and, in particular, the function of the polymorphonuclear leukocyte (PMN).

Methods: Patients were randomised after consent to those receiving autologous transfusion and those having conventional treatment which was homologous transfusion only if clinically indicated. PMN were then isolated from the patients pre-admission immediately after the operation and 24 hours post-total knee arthroplasty. Three different aspects of PMN activity were measured: 1) The respiratory burst activity; 2) the ability to phagocytose microbes using radiolabelled staphylococcus epidermis; 3) and the ability to migrate across a collagen coated porous inserts.

Results: 80 patients were studied, of whom 43 were in the autologous transfusion group and 37 in the first group. Of these 37, 6 had homologous transfusion. The study showed no significant difference between the phagocytic ability of the PMN from both groups. The main stimulus to transmigration is surgery itself. There was a significant increase in the production of reactive oxygen species by the PMN of those patients who received an autologous transfusion post-operatively.

Conclusions: Using molecular biology techniques to study the PMN directly, our study indicates that autologous transfusion alters the activity of PMN and this indicates a possible mechanism whereby the immune response to infection could be enhanced. This, in turn, would explain the observed differences in infection rate in previous studies.

Background. Just under 2% of the joint infection work performed over the last 10 years in our institution has involved organisms found in the oropharynx. The issue of antibiotic prophylaxis for dental work in the presence of a joint prosthesis is controversial. However, advanced dental sepsis requires detection and treatment prior to joint replacement. Methods. Patients from whom non B-haemolytic streptococcal were recovered from revisions of prosthetic joints over the period 1993–2003 were retrospectively reviewed for predisposing factors. Results. 9 patients had viridans streptococcal infection detected and confirmed by histology and culture at excision arthroplasty. There were 5 total hip joints, 3 knee arthroplasties and 1 shoulder affected. No patient had a history of endocarditis. Two of the patients had previously had multiple revisions. Mean interval in these patients since last surgery was 7.6 years. All patients underwent 2 stage revision procedures. All patients required multiple dental extractions in the interval between 1st and 2nd stage surgery. On reviewing the patients’ histories further: One patient had reported a broken tooth reported at the time of surgery and been given reassurancethat it was safe to proceed. One patient had an overt dental abscess ongoing for 15 years and one patient had an occult dental abscess revealed on radiology. Two other patients had extensive dental caries with blackened stumps as teeth. Follow-up after antibiotic treatment and revision arthroplasty is limited in these cases but results appear satisfactory at up to five years. Conclusion. Poor dental care is associated with an increased risk of arthroplasty infection. Looking in the mouth should be a routine part of pre-op assessment prior to primary joint replacement, just as it would be in a cardiac surgery unit. Patients referred from other centres for revision arthroplasty should receive a dental examination if excision arthroplasty cultures yield viridans streptococci

Preventing infections in joint replacements is a major ongoing challenge, with limited effective clinical technologies currently available for uncemented knee and hip prostheses. This research aims to develop a coating for titanium implants, consisting of a supported lipid bilayer (SLB) encapsulating an antimicrobial agent. The SLB will be robustly tethered to the titanium using self-assembled monolayers (SAMs) of octadecylphosphonic acid (ODPA). The chosen antimicrobial is Novobiocin, a coumarin-derived antibiotic known to be effective against resistant strains of Staphylococcus aureus. ODPA SAMs were deposited on TiO. 2. -coated quartz crystal microbalance (QCM) sensors using two environmentally friendly non-polar solvents (anisole and cyclopentyl methyl ether, CPME), two concentrations of ODPA (0.5mM and 1mM) and two processing temperatures (21°C and 60°C). QCM, water contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and temperature-programmed desorption mass spectrometry (TPD-MS) were used to characterise the ODPA SAM. A SLB with encapsulated Novobiocin was subsequently developed on the surface of the ODPA SAM using fluorescent lipids and a solvent assisted method. The prototype implant surface was tested for antimicrobial activity against S. aureus. A well-ordered, uniform ODPA SAM was rapidly formed using 0.5 mM ODPA in CPME at 21°C during 10 min, as confirmed by high Sauerbrey mass (≍285-290 ng/cm. 2. ), high atomic percentage phosphorus (detected using XPS) and high water contact angles (117.6±2.5°). QCM measurements combined with fluorescence microscopy provided evidence of complete planar lipid bilayer formation on the titanium surface using a solvent assisted method. Incorporation of Novobiocin into the SLB resulted in reduced attachment and viability of S. aureus. Key parameters were established for the rapid, robust and uniform formation of an ODPA SAM on titanium (solvent, temperature and concentration). This allowed the successful formation of an antimicrobial SLB, which demonstrated potential for reducing attachment and viability of pathogens associated with joint replacement infections

The aim of this study is to examine the differences in long-term mortality rates between infected and aseptic revision total hip arthroplasty (rTHA) in a single specialist centre over an 18-year period. Retrospective consecutive study of all patients who underwent rTHA at our tertiary centre between 2003 and 2020 was carried out. Revisions were classified as infected or aseptic. We identified patients’ age, gender, American Society of Anaesthesiologists grade (ASA) and body mass index (BMI). The primary outcome measure was all-cause mortality at 5 years, 10 years and over the whole study period at 18 years. Death was identified through both local hospital electronic databases and linked data for the National Joint Registry. Kaplan-Meier survival curves were used to estimate time to death. Where two-stage revision techniques were used of the management of infected cases, these were grouped as a single revision episode for the purpose of analysis. In total, 1138 consecutive hip revisions were performed on 1063 patients (56 bilateral revisions – aseptic, 10 Excision arthroplasties – infection, 9 – Debridement, Antibiotics, Implant retention (DAIR) with 893 aseptic revisions in 837 patients (78.7%) and 245 infected revisions in 226 patients (21.3%). Average age of the entire study cohort was 71.0 (24–101) with 527 female (49.6%). Average age of the infection and aseptic cohorts was 68.8 and 71.5 respectively. Revisions for infection had higher mortality rates throughout the three time points of analysis. Patients’ survivorship for infected vs aseptic revisions was; 77.8% vs 87.7% at 5 years, 62.8% vs 76.5% at 10 years and 62.4% vs 72.0% at 18 years. The unadjusted 10-year risk ratio of death after infected revision was 1.58 (95% confidence interval 1.28–1.95) compared to aseptic revisions. rTHA performed for infection is associated with significantly higher long-term mortality at all time points compared to aseptic revision surgery

Methicillin Resistant Staphylococcus Aureus (MRSA) screening has reduced rates of MRSA infection in primary total hip (THR) and total knee (TKR) replacements. There are reports of increasing methicillin resistance (MR) in Coagulase Negative Staphylococci (CNS) causing arthroplasty infections. We examined microbiological results of all 2-stage THR/TKR revisions in Tayside from 2001–2010. 72 revisions in 67 patients were included; 30 THRs and 42 TKRs. Mean ages at revision were 89 and 72 years respectively. Male: female ratio 1.4:1.2-year survivorship for all endpoints: 96% in THRs and 88% in TKRs. 5-year survival: 83% and 84% respectively. The most common organisms were SA (30%) and CNS (29%). Antibiotic resistance was more common amongst CNS. 72% of CNS were resistant to Methicillin versus 20% of SA. 80% of CNS were resistant to Gentamicin OR Methicillin versus 20% of SA. 32% (8/72 cases or 11% overall) of CNS were resistant to BOTH Gentamicin AND Methicillin, the primary arthroplasty antibiotic prophylaxis in our region, versus 4% of SA. Harris Hip Scores and Knee Society Scores were lower post primary, prior to symptoms of infection in patients who had MR organisms cultured compared with those who had methicillin sensitive organisms. One-year post revision both groups recovered to similar scores. Our data suggest MR-CNS cause significantly more arthroplasty infections than MRSA. Patients developing MR infections tend to have poorer post-primary knee and hip scores before symptoms of infection fully develop. 32% of CNS causing arthroplasty infections in our region are resistant to current routine primary antibiotic prophylaxis

Aim. Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Interestingly, we previously reported a difference in the distribution of the clades involved in spine versus hip or knee prosthetic infection. To date, no study has previously explored the direct impact and close relationship of P. acnes on bone cells according to their own genetic background. The aim of this study was to investigate this interaction of P. acnes clinical strains involved in spine material infections, arthroplasty infections and acne lesions with bone cells. Method. From a large collection of 88 P. acnes clinical isolates collected between January 2003 and December 2014, a subset of 11 isolates was studied. Four isolates were recovered from spine infections, two from prosthetic infections (knee and hip), three from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant-associated infections were confirmed according to Infectious Diseases Society of America guidelines for bone and joint infections. Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. PLoS ONE 2010. Bacterial internalization experiments with MG63 osteosarcoma cells were adapted from Crémet et al. Pathog Dis 2015. Results. Among the nine clinical isolates, three isolates belonged to clonal complexes (CCs) 18; three to CC28 and three to CC36. ATCC isolates belonged to CC18. Bacterial internalization experiments revealed that CC36 P. acnes strains were less invasive than CC18 and CC28 P. acnes strains towards osteoblasts (mean percentage of internalized bacteria (< 0.01% for the CC36 P. acnes strains versus more than 1% for the CC18 and CC28 P. acnes strains). Surprisingly, the ATCC11827 CC18 P. acnes strain exhibited invasiveness similar to CC36 isolates. Conclusions. Evasion mechanism observed for CC36 P. acnes isolates could allow this clade to leave the site of infection, disseminate into deeper tissue layers and beget arthroplasty infection. Inside the deeper tissue, close to the material, the local immune defect fosters the low-grade infections observed with P. acnes clinical strains. On the another hand, for CC18 et CC28 clades, mostly involved in spine infection, the internalization process observed could allow these clades to escape from the numerous immune cells located under the skin and generate an infection locally, favored by the spine instrumentation close to the skin, especially during long spine surgeries

Infection is a complication in hip arthroplasty. It increases mortality and morbidity and is a cause for patient's dissatisfaction. Previous Works report an infection rate between 0,4% e 1,5% in primary hip replacement and between 3,2% in revision hip replacement. The aim of this work was to access the infection rates in one hospital, compare them with the reported rates and investigate possible risk factors for infection. Electronic clinical records were consulted. Patients who underwent total hip arthroplasty (primary or revision) or hemiarthroplasty in one hospital, between the 1st February 2011 and 31st February 2013, were included. Two hundred and sixty one patients (267 surgeries) were included. Demographically, 57,5% were female patients and 42,5% were male patients with an average age of 77,1 years (± 12,3 years). Infection rate for hemiarthroplasty 3,1%, for primary total hip arthroplasty was 1,4% and for revision procedures 4,8%. A statistically significant relation was found between arthroplasty infection and superficial wound infection (p<0,001), wound dehiscence (p<0,001), and surgery performed during summer months (p<0,05). No relation was found with duration of the surgery or the hospital stay or the patient's comorbidities. The infection rate is similar to the rate reported in other clinical centres. Superficial wound complications are a good predictor for arthroplasty infection, so it is important to diagnose and start prompt appropriate management and vigilance. The increase in infection rates in summer months may be related to higher operating room temperature or less routined personal. We concluded, therefore, that infection is a complication in hip arthroplasty being prevention is a key feature when arthroplasty is performed, as well as clinical vigilance for infection signs

Protocols for processing of tissue from arthroplasty infections vary and might affect the recovery of bacteria. We compared homogenization, bead beating and enzymatic disruption for recovery of live bacteria from tissue samples. Suspensions of Staphylococcus aureus and Escherichia coli were prepared as controls. Three samples were taken from each and the first was bead beaten, the second homogenized, and Proteinase K was added for 10 and 30 minutes to the third sample before culturing. In addition, artificially inoculated pork tissue and known infected human tissue samples were processed by either homogenization or bead beating prior to cultures and results were compared. Number of cycles of bead beating and homogenization and duration of Proteinase K treatment had significant effects. Bead beating for 2 and 4 cycles reduced the yield of S.aureus to 52% and 20% of control, and E.coli to 33% and 8%. Homogenization for 2 and 4 cycles reduced S.aureus to 86% and 65% of control, and E.coli to 90% and 87%. Proteinase K for 10 minutes and 30 minutes reduced the yield of S.aureus to 75% and 33% of control, and E.coli to 91% and 49% respectively. Inoculated Pork tissue showed a reduction in S.aureus recovery of 90% for bead beating compared to homogenization, and 80% in the case of E.coli. Bead beating of infected human tissue samples reduced the yield by 58% compared to homogenization. Bead-beating is a common recommended method of processing tissue from arthroplasty cases. However, even though it produces a homogeneous sample, it does so at the cost of significant loss of viable bacteria. Homogenization and 10 minutes of Proteinase K incubation are almost equivalent, but the homogenizer is preferred being more controllable and cheaper. This should help to define guidelines for diagnosing infections using tissue samples

Introduction: Papers about high-virulence infections are not usual, results contradictory, and orthopaedic outcomes not described. Purpose: to compare infectious and orthopaedic results after late arthroplasty infections by single vs. polymicrobial isolates, low vs. high-virulence, and Gram-positive vs. Gram-negative organisms, when treated by exchange surgery plus long cycles of combined oral antibiotics. Patients and Methods: A late arthroplasty infection was diagnosed in 68 consecutive patients (48 female) of 72.2(+/−10.2) years (37 hips/31 knees). Cultures were polymicrobial in 22 cases and by Gram-positive in 55 (80.9%). Highly-resistant organisms: methicillin-resistant Staphylococcus (36 patients) and ESBL-producing Enterobacteriaceae (2 patients). “Problematic-treatment”: Enterococcus (6 patients), Pseudomonas (3 patients), non-fermenting Gram-negative (2), moulds (1). Oral antibiotic selection: according to bacterial sensitivity, biofilm and intracellular effectiveness. Protocolized surgery: two-stage exchange. Average follow-up: 4.7+/−2.7 years (1–11). Healing of infection is diagnosed if absence of clinical, serological and radiological signs of infection during the whole follow-up. Orthopaedic outcome is evaluated by HHS for hips and by KSCRS for knees. Results: Surgery was not possible in 7 infections (rejected by patients), and reimplantation in 17 additional cases (patients died shortly after first surgery, rejected 2nd surgery, or was contraindicated because of medical reasons). Healing of infection: 59/68 patients (86.8%), 32/37 hips (86.5%) and 27/31 knees (87.1%). Infection not healed: 7/68 cases (10.3%) (4/37 hips, 3/31 knees) (5 by highly-resistant and 1 by “problematic-treatment” bacteria). There are no differences between hips and knees (p=0.55). Orthopaedic Results: HHS averages 80.5+/−16.2 (81+/−16 in healed infection, 56+/−23.5 in persistent infection). KSCRS averages 77.2/58.1 +/− 19.8/24.5 in healed infections, 32.6/0+/−25.8/0 in persistent infections. Infective and orthopaedic results present a strong statistical correlation in hips (p=0.016) and knees (p=0.0001). Statistically significant differences are not found when comparing subgroups according to Gram stain (p=0.43), multiple vs single bacteria (p=0.47 infective, p=0.71 orthopaedic), highly-resistant bacteria (p=0.2 infective, p=0.1/0.5 orthopaedic), or “problematic-treatment” (p=0.68). Conclusions:. A strong statistical correlation appears between infective and orthopedic results after late arthroplasty infections. With the number of cases presented significant differences in infective or in orthopaedic results are not found when comparing single vs. polymicrobial, gram-negative vs. gram-positive, high vs. low antimicrobial resistance and “problematic-treatment” infections

The December 2012 Hip & Pelvis Roundup. 360 . looks at: swimming against the tide with resurfacing; hip impingement surgery; the relationship between obesity and co-morbidities and joint replacement infection; cemented hips; cross-linked polyethylene notching; whether cement is necessary in oncological arthroplasty; and how total hip replacement may result in weight gain

In bone and joint infections, several materials can be used for local antibiotic elution at site of infection. Polymethylmethacrylate (PMMA) cement is often used. Recently the use of antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 has been used as an alternative, due to several perceived advantages. We present our experience of using Calcium sulphate beads in infections involving the upper limb. From Jan 2012 to Jan 2015, we used Calcium sulphate beads in 7 complex upper limb infections including 1 elbow replacement, 2 infected non unions, 2 shoulder replacement, 1 wrist fusion and I ORIF elbow. We used combination of Vancomycin and Gentamicin in the beads, using manufacturer's mixing guide for optimum setting. Arthroplasty infections underwent explantation, addition of antibiotic impregnated calcium sulphate beads in the joint space, followed by a second stage, and systemic antibiotics. Fracture non-union cases had surgical debridement, calcium sulphate beads and systemic antibiotics. Follow up (6months to 2 years) indicate no recurrence of infection in any case. The most common organisms isolated were Coagulase negative staphylococcus and Staphylococcus aureus. Others included Group B Streptococcus, Serratia marscesens and Corynebacterium spp. In 2 of 7 cases there was significant drainage from the wound. This settled without further input. For fracture non-union fixation, there was no need to do second procedure to remove beads as they dissolve. In cases of staged revisions, the beads were inserted at first stage with microbiological clearance at 2nd stage. At present there are no reports in the literature of the use of this product in the upper limb. Our experience suggests use of dissolvable pure Calcium sulphate beads impregnated with selected antibiotics, is an effective adjunct to current treatments. Aseptic drainage has been reported and this was seen in some of our cases. It is postulated that the use of Calcium sulphate beads in more superficial joints may lead to more drainage. It may be necessary to avoid packing any beads in the subcutaneous spaces and using lower volumes in upper limb. Further work will include long-term follow up and any evidence of relapse or recurrence of infection

Bone and joint infections of the lower limbs cause significant morbidity for patients. Infection is a devastating complication for prosthetic joint replacements. In this large case series from a single centre in the NE of England, we present our experience of using antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 for local elution of antibiotics at the site of infection. At our centre, from August 2012 to Jan 2015, antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 was used for local elution of antibiotics in 45 patients with lower limb bone or joint infections. Tailored plans were made by Orthopedic surgeon and Microbiologist MDTs based on bacteria and sensitivities. Cases included 20 THR, 13 TKR, 5 Hemiarthroplasties, 4 tibial nonunions, 1 infected femoral plate and 2 paediatric osteomyelitis. Organisms isolated – Coagulase negative Staphs, Staph aureus, MRSA, E coli, Enterococcus, Enterobacter cloacae, Serratia and 1 Salmonella typhimurium!!. In our cases, a combination of Vancomycin and Gentamicin was added to Stimulan beads following manufacturer's mixing guide. In 2 cases, we added Ceftazidime to the beads and Daptomycin in 1 case. In bone infections, surgical debridement and systemic antibiotics were also needed. All arthroplasty infections underwent explantation with addition of antibiotic impregnated beads either at single stage or both stages of 2 stage revisions and systemic antibiotics. Follow up (ranging 9months to 2 years) indicates no failure so far. The beads caused no excessive wound drainage. There was no need to remove beads as they dissolve. In the cases where a staged revision was performed, the beads were inserted at first stage and there was microbiological clearance of infection at 2nd stage. Our series includes some experince in paediatric cases too. As far as we are aware, this is the largest series in the UK from a single centre reporting experience with Stimulan in infected bone and joints of the lower limbs. Our experience suggests use of dissolvable pure Calcium sulphate beads impregnated with carefully selected antibiotics, works as an effective adjunct to current treatments and offers flexibility with choice of antiobiotics that can be added locally. Acknowledgements. Biocomposites UK for supporting attendance at EBJIS. Authors control ownership of all data and analysis

Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Aim of this study was to investigate P. acnes phylogeny and to screen for virulence factors among a large collection of clinical isolates involved in spine material infections, arthroplasty infections and acne lesions. 88 P. acnes clinical isolates were collected between January 2003 and December 2014 at Nantes University Hospital (France). Fifty-eight isolates came from spine infections, 14 from prosthetic infections (knee, hip or shoulder), 14 from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant associated infections were confirmed using Infectious Diseases Society of America criteria for bone and joint infections. Phylotypes and Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. All isolates were tested by established PCR-based assays for 21 putative virulence factor genes characteristic of P. acnes. MLST analysis revealed an association between clonal complexes (CCs) and origin of P. acnes isolates (p = 0,027). Regarding CCs distribution between different origins, CC36 and phylotype II P. acnes isolates are more frequently observed in prosthetic joint infections. On the other hand, CC18 (IA) and CC28 (IB) P. acnes isolates are more frequently involved in spine infections and acne lesions. Among all virulence factors screened, hyaluronate lyase gene was only present in CC36 and phylotype II P acnes isolates. Other virulence factors were present in all isolates, whatever their origin or CC. Regarding molecular typing results, P. acnes involved in spine infections seem to have a skin origin (same CC as isolates from acne lesion). Interestingly, the origin of prosthetic joint infection isolates seems different and they all carry one more virulence factor. Hyaluronate lyase (Hyl) is a major surface protein of P. acnes with potential antigenetically variable properties that might be essential for P. acnes virulence. Increased tissue permeability caused by the action of hyaluronidase on the extracellular matrix appears to play a role in wound infections, pneumonia, and other sepsis such as bacteremia and meningitis. It could be also take a prominent part in P. acnes prosthetic joint infection pathogenesis

Objectives. To review the current best surgical practice and detail a multi-disciplinary approach that could further reduce joint replacement infection. Methods. Review of relevant literature indexed in PubMed. Results. Surgical site infection is a major complication following arthroplasty. Despite its rarity in contemporary orthopaedic practice, it remains difficult to treat and is costly in terms of both patient morbidity and long-term health care resources. Conclusions. Emphasis on education of patients and all members of the health-care team and raising awareness in how to participate in preventative efforts is imperative

I wish to present my experience with 521 patients with infection around hip arthroplasty and 262 with infected knee arthroplasty. The management in each case depends on circumstances such as the period since surgery, the patient’s symptoms, severity of illness and general health, and the condition of the remaining bone stock. One hundred and thirty hips and 94 knees were managed conservatively i.e. without surgery. Nine knees and 11 hips had debridement and irrigation without removing the arthroplasty. Infection persisted in 2 knees and 3 hips. Nine knees were exchanged in one stage. infection persisted in 5. Forty three hips were exchanged in one stage. Infection persisted in 18. Fifty knees were exchanged in two stages. Infection persisted in 11. One hundred and ninety eight hips were exchanged in two stages. Infection persisted in 28. Arthrodesis was performed in 77 of the more severely infected and destroyed knees. Infection persisted in 32. One hundred and eight of the more severely destroyed hips were left as excision arthroplasties. Ten remained infected but comfortable. Five patients required amputation above the knee and three through the hip. Two patients sustained serious vascular complications during surgery at the hip and one at the knee. Four patients in this series died during treatment

Introduction: Arthroplasty infection is both devastating for the individual and expensive for the healthcare system. Many measures are taken during a patient’s pathway to try and prevent this complication. Ring fencing beds is perceived to be beneficial in this struggle, but due to complexity it is difficult to identify the effect of ringfencing on infection rates; furthermore to date there is little published data to support it’s use. We present our data of infection rates before and after the introduction of a ringfence policy. The antibiotic prophylaxis regime was the only other variable to change. Methods: Two 24 month periods were selected before and after the introduction of a strict ringfence policy. In the first period (pre-ringfence period) patients were MRSA screened pre operatively but not placed in a ward with a ringfence policy. Cefuroxime was administered as prophylaxis. In the second period (ringfence period) screened patients were only admitted to a ward where all patients were known to be MRSA free. Tei-coplanin prophylaxis was administered. The hospital building, operating theatres, implants and surgeons were the same for both groups. Infections were identified retrospectively by analysing clinical notes and laboratory results. Statistical analysis was performed using Fisher’s exact test. Results: Both patient groups had similar demographics. More joints were performed in the ringfence period compared to the pre-ringfence period (870 vs 590), with a shorter average length of stay (7 vs 11 days). In the ring-fencing period there was an overall significant reduction in early infections (1.26% vs 3.05%, p< 0.05). MRSA was eliminated (2.2% vs 0%, p< 0.05). Conclusions: A combination of these two interventions led to a significant reduction in early infection rates and the elimination of MRSA in primary joint arthroplasty patients, even though the exact contribution of each intervention could not be established