Periprosthetic joint infection (PJI) causes significant morbidity. Methicillin sensitive . Staphylococcus Aureus. (MSSA) is the most frequent organism, and the majority are endogenous. Nasal MSSA colonisation is a proven risk factor for S. aureus infection. Decolonisation reduces PJIs but there is a paucity of evidence comparing treatments. Aims; compare 3 nasal decolonisation treatments at (1) achieving MSSA decolonisation, (2) preventing PJI. Our hospital trust introduced MSSA screening and decolonisation prior to hip and knee arthroplasty in 2010. Data was prospectively collected since 2013, including all MSSA carriers, decolonisation treatment received, MSSA status at time of surgery and all PJIs. Prior to 2017 MSSA carriers received nasal mupirocin or neomycin, from August 2017 until August 2019 nasal octenidine was used. During the study period 15,958 primary hip and knee replacements were performed. 3,200 (20.1%) were MSSA positive at preoperative screening and received decolonisation treatment, 698 mupirocin, 1,210 neomycin and 1,221 octenidine. Mupirocin (89.1%) and neomycin (90.9%) were more effective at decolonisation than octenidine (50.0%, P<0.0001). There was no difference in S. aureus PJI rates (P=0.452). Of those negative at original screening 9.1% were positive on the day of surgery (1,164/12,758). MSSA decolonisation is an effective method to decrease PJI rates but there is little research into the best treatment. Both mupirocin and neomycin are more effective than octenidine at achieving MSSA decolonisation. There was poor correlation between the MSSA status after treatment and PJI rates. There is debate if treatment should be targeted by screening or if all patients she be treated without screening. Global decolonisation without screening is supported by the 26.7% of carriers that were negative at original screening in our study. Further research is needed comparing decolonisation treatments to reduce PJI rates and avoid the risk of drug resistance

We have analysed the management and clinical outcome of a series of consecutive patients who had a total hip replacement and developed post-operative surgical site infection (SSI) with methicillin-resistant Staphylococcus aureus. The incidence of this infection was 1% over a period of five years. We studied SSI in 15 patients (16 infections) with a mean age of 72.7 years (53 to 81). In all, 12 of the infections occurred early and half of the infections involved the prosthesis, resulting in an increase of 11-fold in the cumulative hospital stay. Methicillin-resistant Staph. aureus was successfully eradicated in all the patients after a mean follow-up of 53.6 months (25 to 88). Superficial incisional infections resolved after antibiotic therapy alone while deep infections required multiple operative debridements. Attempted retention of the implant in early organ space infections was successful in only one of five patients. Only three patients with implant-level infections obtained a pain-free, functional prosthesis while a further three required excision arthroplasty. We have formulated a protocol of treatment which may serve as a guide in the management of these infections

Bone ingrowth is desired with uncemented hip implants. Infection is clearly undesirable. We have worked on developing a nanofiber coating for implants that would enhance bone formation while inhibiting infection. Few studies have focused on developing an implant surface nanofiber (NF) coating to prevent infection and enhance osseointegration by local drug release. In this study, coaxial doxycycline (Doxy)-doped polycaprolactone/polyvinyl alcohol (PCL/PVA) Nanofibers were directly deposited on the titanium (Ti) implant surface during electrospinning.

The interaction of loaded Doxy with both PVA and PCL NFs was characterized by Raman spectroscopy. The bonding strength of Doxy-doped NF coating on Ti implants was confirmed by a stand single-pass scratch test. The improved implant osseointegration by PCL/PVA NF coatings in vivo was confirmed by scanning electron microscopy, histomorphometry and micro computed tomography at 2, 4 and 8 weeks after implantation. The bone contact surface (%) changes of NF coating group (80%) is significantly higher than that of no NF group (< 5%, p<0.05). Finally, we demonstrated that Doxy-doped NF coating effectively inhibited bacterial infection and enhanced osseointegration in an infected (Staphylococcus aureus) tibia implantation rat model. Doxy released from NF coating inhibited bacterial growth up to 8 weeks in vivo. The maximal push-in force of Doxy-NF coating (38 N) is much higher than that of NF coating group (6.5 N) 8 weeks after implantation (p<0.05), which was further confirmed by quantitative histological analysis and micro computed tomography.

These findings indicate that coaxial PCL/PVA NF coating doped with Doxy and/or other drugs have great potential in enhancing implant osseointegration and preventing infection.

There is an increasing incidence of revision for periprosthetic joint infection. The addition of vancomycin to beta-lactam antimicrobial prophylaxis in joint arthroplasty may reduce surgical site infections, however, the efficacy and safety have not been established. This was a multicenter, double-blind, superiority, placebo-controlled trial. We randomized 4239 adult patients undergoing joint arthroplasty surgery to receive 1.5g vancomycin or normal saline placebo, in addition to standard cefazolin antimicrobial prophylaxis. The primary outcome was surgical site infection at 90-days from index surgery. Perioperative carriage of Staphylococcus species was also assessed. In the 4113 patients included in the modified intention-to-treat population, surgical site infections occurred in 72/2069 (3.5%) in the placebo group and 91/2044 (4. 5%) in the vancomycin group (risk ratio 1.28; 95% confidence interval 0.94 to 1.73; p value 0.11). No difference was observed between the two groups for primary hip arthroplasty procedures. A higher proportion of infections occurred in knee arthroplasty patients in the vancomycin group (63/1109 [4.7%]) compared with the placebo group (42/1124 [3.7%]; risk ratio 1.52; 95% confidence interval 1.04 to 2.23; p value 0.031). Hypersensitivity reactions occurred in 11 (0.5%) patients in the placebo group and 24 (1.2%) in the vancomycin group (risk ratio 2.20; 95% confidence interval 1.08, 4.49) and acute kidney injury in 74 (3.7%) patients in the placebo group and 42 (2.1%) in the vancomycin group (risk ratio 0.57; 95% confidence interval 0.39, 0.83). Perioperative Staphylococcus aureus carriage was detected in 1089/3748 (29.1%) of patients. This is the first randomized controlled trial examining the addition of a glycopeptide antimicrobial to standard beta-lactam surgical antimicrobial prophylaxis in joint arthroplasty. The addition of vancomycin to standard cefazolin prophylaxis was not superior to placebo for the prevention of surgical site infections in hip and knee arthroplasty surgery

No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Leukocyte esterase (LE) is a synovial marker that has proven utility in the diagnosis of PJI. The purpose of this prospective study was to (1) identify the optimal cutoff for the use of LE in the diagnosis of PJI and (2) determine whether performance of the LE strip test varied by infecting organism. This prospective study enrolled 1,015 patients undergoing hip or knee revision arthroplasty at a single institution from 2009 to September 2021. PJI was defined using a modified version of 2018 International Consensus Meeting (ICM) criteria that excluded LE when calculating the ICM score. Receiver operating characteristic curves were used to assess the utility of the LE strip test in the diagnosis of PJI. 973 patients were included in the analyses. 246 (25.4%) were classified as ICM-positive and 727 (74.6%) were classified as ICM-negative. An LE cutoff of “1+” (AUC 0.819, sensitivity 73.2%, specificity 90.6%) had superior accuracy to an LE cutoff of “2+” (AUC 0.713, sensitivity 43.9%, specificity 98.8%) in the overall diagnosis of PJI (p<0.001). When stratifying by organism type, an LE cutoff of “1+” had the best diagnostic utility for PJI caused by methicillin resistant Staphylococcus aureus (AUC 0.888, sensitivity 87.0%, n=23) followed by Streptococcus spp. (AUC 0.882, sensitivity 85.7%, n=28), coagulase negative Staphylococci (AUC 0.836, sensitivity 76.6%, n=47), methicillin sensitive Staphylococcus aureus (AUC 0.806, sensitivity 70.6%, n=34), culture negative (AUC 0.793, sensitivity 67.9%, n=56), and gram negative rods (AUC 0.763, sensitivity 61.9%, n=21). To our knowledge, this is the largest study evaluating the utility of the LE strip test in the diagnosis of PJI. Based on our findings, it appears that a “1+” cutoff has higher diagnostic utility than a cutoff of “2+”

We created TiO. 2. nanotubes (TNTs) on the surface of titanium (Ti) implants with subsequential loading with gentamicin and chitosan, acting as a control release agent, by electrophoretic deposition (EPD). We hypothesized femoral implants with TNTs loaded with gentamicin and chitosan would localize antibiotic to the implant and surgical site and prevent PJI in a mouse model. Ti-6Al-4V ELI wires underwent TNT surface modification by two-step anodization. EPD was then used to load gentamicin and chitosan onto the Ti wire with surface TNTs. Control Ti wires contained TNTs with EPD of chitosan only. 12-week-old male C57BL/6J mice underwent received a right femoral intramedullary implant followed by inoculation at the surgical site with 1×10. 3. CFUs of bioluminescent Xen36 Staphylococcus aureus (S. aureus). Mice were randomly divided into two implant groups: 1) Gentamicin + Chitosan Group (n=7; experimental group); 2) Chitosan Group (n=7; control group). Outcomes included: 1) Relative S. aureus abundance by bioluminescence imaging; 2) Quantification of S. aureus at the implant and surrounding tissue by colony forming unit (CFU) analysis; 3) Scanning electron microscopy (SEM) for implant bacterial biofilm; 4) Radiographic signs of PJI. Over 14 days assessment following wire implantation and inoculation with S. aureus, the experimental group had no evidence of infection based on i) no increased Xen36 S. aureus bioluminescence signal and ii) no CFUs present. All control had increased bioluminescence signal, above baseline, at all time-points and presence of CFUs. Ti femoral implants modified with surface TNTs and coated with gentamicin and chitosan through EPD prevented PJI in all mice through 14 days. In comparison, all control mice demonstrated evidence of PJI over 14 days. Implants with TNTs and EPD of gentamicin were highly effective in this mouse PJI model

Aims. The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. Methods. Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Staphylococcus aureus Xen36 was monitored with in vivo photoluminescent imaging in real-time. Pre- and postoperative gait analyses were performed and compared. Postmortem micro (m) CT was used to assess implant integration; field emission scanning electron microscopy (FE-SEM) was used to assess biofilm formation on prosthetic surfaces. Results. All animals tolerated surgery well, with preservation of gait mechanics and weightbearing in control individuals. Postoperative in vivo imaging demonstrated predictable evolution of infection with logarithmic signal decay coinciding with abscess formation. Postmortem mCT qualitative volumetric analysis showed high contact area and both cement-bone and cement-implant interdigitation. FE-SEM revealed biofilm formation on the prosthetic head. Conclusion. This study demonstrates the utility of a new, high-fidelity model of in vivo PJI using cemented hip hemiarthroplasty in rats. Inoculation with bioluminescent bacteria allows for non-invasive, real-time monitoring of infection. Cite this article: Bone Joint J 2021;103-B(7 Supple B):9–16

Aims. The purpose of this study was to evaluate unexpected positive cultures in total hip arthroplasty (THA) revisions for presumed aseptic loosening, to assess the prevalence of low-grade infection using two definition criteria, and to analyze its impact on implant survival after revision. Methods. A total of 274 THA revisions performed for presumed aseptic loosening from 2012 to 2016 were reviewed. In addition to obtaining intraoperative tissue cultures from all patients, synovial and sonication fluid samples of the removed implant were obtained in 215 cases (79%) and 101 cases (37%), respectively. Histopathological analysis was performed in 250 cases (91%). Patients were classified as having low-grade infections according to institutional criteria and Musculoskeletal Infection Society (MSIS) International Consensus Meeting (ICM) 2013 criteria. Low-grade infections according to institutional criteria were treated with targeted antibiotics for six weeks postoperatively. Implant failure was defined as the need for re-revision resulting from periprosthetic joint infection (PJI) and aseptic reasons. The mean follow-up was 68 months (26 to 95). Results. Unexpected positive intraoperative samples were found in 77 revisions (28%). Low-grade infection was diagnosed in 36 cases (13%) using institutional criteria and in nine cases (3%) using MSIS ICM 2013 criteria. In all, 41 patients (15%) had single specimen growth of a low-virulent pathogen and were deemed contaminated. Coagulase-negative Staphylococcus and anaerobes were the most commonly isolated bacteria. Implant failure for PJI was higher in revisions with presumed contaminants (5/41, 12%) compared to those with low-grade infections (2/36, 6%) and those with negative samples (5/197, 3%) (p = 0.021). The rate of all-cause re-revision was similar in patients diagnosed with low-grade infections (5/36, 14%) and those with presumed contaminants (6/41, 15%) and negative samples (21/197, 11%) (p = 0.699). Conclusion. Our findings suggest that the presumption of culture contamination in aseptic revision hip arthroplasty may increase the detection of PJI. In this cohort, the presence of low-grade infection did not increase the risk of re-revision. Further studies are needed to assess the relevance of single specimen growth and the benefits of specific postoperative antibiotic regimens. Cite this article: Bone Joint J 2021;103-B(6):1070–1077

Aims. Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment. Methods. The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load. Results. PlySs2 treatment reduced 99% more CFUs and 75% more biofilm compared with vancomycin in vitro. A combination of PlySs2 and vancomycin in vivo reduced the number of CFUs on the surface of implants by 92% and in the periprosthetic tissue by 88%. Conclusion. PlySs2 lysin was able to reduce biofilm, target planktonic bacteria, and work synergistically with vancomycin in our in vitro models. A combination of PlySs2 and vancomycin also reduced bacterial load in periprosthetic tissue and on the surface of implants in a murine model of DAIR treatment for established PJI. Cite this article: Bone Joint J 2020;102-B(7 Supple B):3–10

This trial aims to assess the effectiveness of quality improvement collaboratives as a technique to introduce large-scale change and improve outcomes for patients undergoing primary elective total hip or total knee arthroplasty. 41 NHS Trusts that did not have; a preoperative anaemia screening and optimisation pathways, or a methicillin sensitive Staphylococcus Aureus (MSSA) decolonisation pathway, in place were randomised to one of two parallel collaboratives in a two arm, cluster randomised controlled trial. Each collaborative focussed on implementing one of these two preoperative pathways. Collaboratives took place from May 2018 to November 2019. 27 Trusts completed the trial. Outcome data were collected for procedures between November 2018 and November 2019. Co-primary outcomes were perioperative blood transfusion (within 7 days of surgery) and deep surgical site infections (SSI) caused by MSSA (within 90 days) for the anaemia and MSSA arms respectively. Secondary outcomes include deep and superficial SSIs (any organism), length of stay, critical care admissions, and readmissions. Process measures include the proportion of patients receiving each preoperative initiative. 19,254 procedures from 27 Trusts are included. Process measures show both preoperative pathways were implemented to a high degree (75.3% compliance in MSSA arm; 61.2% anaemia arm), indicating that QICs can facilitate change in the NHS. However, there were no improvements in blood transfusions (2.9% v 2.3% adjusted-OR 1.20, 95% CI 0.52–2.75, p=0.67), MSSA deep SSIs (0.13% v 0.14% adjusted-OR 1.01, 95%CI 0.42–2.46, p=0.98), or any secondary outcome. Whilst no significant improvement in patient outcomes were seen, this trial shows quality improvement collaboratives can successfully support the implementation of new preoperative pathways in planned surgery in the NHS

Aims. Failure of irrigation and debridement (I&D) for prosthetic joint infection (PJI) is influenced by numerous host, surgical, and pathogen-related factors. We aimed to develop and validate a practical, easy-to-use tool based on machine learning that may accurately predict outcome following I&D surgery taking into account the influence of numerous factors. Methods. This was an international, multicentre retrospective study of 1,174 revision total hip (THA) and knee arthroplasties (TKA) undergoing I&D for PJI between January 2005 and December 2017. PJI was defined using the Musculoskeletal Infection Society (MSIS) criteria. A total of 52 variables including demographics, comorbidities, and clinical and laboratory findings were evaluated using random forest machine learning analysis. The algorithm was then verified through cross-validation. Results. Of the 1,174 patients that were included in the study, 405 patients (34.5%) failed treatment. Using random forest analysis, an algorithm that provides the probability for failure for each specific patient was created. By order of importance, the ten most important variables associated with failure of I&D were serum CRP levels, positive blood cultures, indication for index arthroplasty other than osteoarthritis, not exchanging the modular components, use of immunosuppressive medication, late acute (haematogenous) infections, methicillin-resistant Staphylococcus aureus infection, overlying skin infection, polymicrobial infection, and older age. The algorithm had good discriminatory capability (area under the curve = 0.74). Cross-validation showed similar probabilities comparing predicted and observed failures indicating high accuracy of the model. Conclusion. This is the first study in the orthopaedic literature to use machine learning as a tool for predicting outcomes following I&D surgery. The developed algorithm provides the medical profession with a tool that can be employed in clinical decision-making and improve patient care. Future studies should aid in further validating this tool on additional cohorts. Cite this article: Bone Joint J 2020;102-B(7 Supple B):11–19

Aims. Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint. Methods. For this non-randomized non-blinded study, 101 adult patients scheduled for hip or knee surgery were recruited. For each, four 3 mm dermal punch biopsies were collected after administration of anaesthesia, but prior to antibiotics. Prebiopsy skin preparation consisted of a standardized preoperative 2% chlorhexidine skin cleansing protocol and an additional 70% isopropyl alcohol mechanical skin scrub immediately prior to biopsy collection. Two skin samples 10 cm apart were collected from a location approximating a standard direct anterior skin incision, and two samples 10 cm apart were collected from a lateral skin incision (suitable for posterior, direct-lateral, or anterolateral approaches). Samples were cultured for two weeks using a protocol optimized for Cutibacterium. Results. A total of 23 out of 404 cultures (collected from 101 patients) were positive for a microorganism, with a total of 22 patients having a positive culture (22%). Overall, 15 of the cultures in 14 patients were positive for Cutibacterium sp. (65%), of which Cutibacterium acnes comprised the majority (n = 13; 87%). Other isolated microorganisms include coagulase-negative Staphylococcus (n = 6), Clostridium (n = 1), and Corynebacterium (n = 1). Of all positive cultures, 15 were obtained from the anterior location (65%), of which seven (60%) were from the most proximal biopsy location. However, these findings were not statistically significant (anterior vs lateral, p = 0.076; proximal vs distal, p =0.238). Conclusion. Approximately 14% (14/101) of the patients demonstrated a positive Cutibacterium colonization about the hip, the majority anteriorly. Given the high colonization rate of Cutibacterium, alternative skin preparations for total hip arthroplasty should be considered. Cite this article: Bone Joint J 2020;102-B(7 Supple B):52–56

Treatment of periprosthetic joint infection (PJI) can include local delivery of antibiotics. A frequently used medium is absorbable calcium sulphate beads. The aims of this study were to:. identify how often organisms in infected THRs are sensitive to the added antibiotics. establish the incidence of persistent wound discharge and hypercalcaemia. All patients who received an antibiotic loaded calcium sulphate carrier (Stimulan, Biocomposites, Keele, UK) for either confirmed infection, presumed infection or for prophylaxis between July 2015 and July 2020 were included. Stimulan use was at the discretion of the surgeon, and between 10 and 40cc was used. In the absence of a known organism we routinely used 1g vancomycin and 240mg gentamicin per 10 cc of calcium sulphate. Post-operative sensitivities for all organisms cultured were compared to the antibiotics delivered locally. Persistent wound drainage was defined as discharge beyond the third postoperative day. Patients had serum calcium measured if they developed symptoms consistent with hypercalcaemia (Ca >2.6 mmol/L) or the clinical team felt they were at high risk. 189 patients (mean age 66.9 years, mean BMI 28.9, 85 male, 104 female) were included. 11 patients had a native joint septic arthritis, 42 presented with acute PJI and 136 presented with chronic PJI. 133 patients grew an organism, of which 126 were sensitive to the added antibiotics. Of the seven patients with resistant growth five had vancomycin-resistent Enterococcus, one Pseudomonas and one multi-organism growth including coagulase negative Staphylococcus. 40 patients experienced persistent wound discharge, with eight requiring re-operation. All other cases settled with dressing management. 12 patients developed hypercalcaemia (3/64 10cc, 7/117 20cc, 0/2 30cc and 2/6 40cc). The peak calcium reading ranged between the second and twelfth post-operative day. The addition of vancomycin and gentamicin to absorbable calcium sulphate covers the majority of organisms found in culture positive infection in our cohort. It also appears safe, with an acceptable incidence of hypercalcaemia or wound discharge. Further work is required to identify patients at greatest risk of culturing resistant organisms or delayed wound healing

Aims

This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection.

Aims

Periprosthetic joint infection (PJI) in total hip arthroplasty in the elderly may occur but has been subject to limited investigation. This study analyzed infection characteristics, surgical outcomes, and perioperative complications of octogenarians undergoing treatment for PJI in a single university-based institution.

Aims

Current diagnostic tools are not always able to effectively identify periprosthetic joint infections (PJIs). Recent studies suggest that circulating microRNAs (miRNAs) undergo changes under pathological conditions such as infection. The aim of this study was to analyze miRNA expression in hip arthroplasty PJI patients.

Aims

The aims of this study were to determine the incidence and factors for developing periprosthetic joint infection (PJI) following hemiarthroplasty (HA) for hip fracture, and to evaluate treatment outcome and identify factors associated with treatment outcome.

Aims

A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach.

Aims

The number of revision arthroplasties being performed in the elderly is expected to rise, including revision for infection. The primary aim of this study was to measure the treatment success rate for octogenarians undergoing revision total hip arthroplasty (THA) for periprosthetic joint infection (PJI) compared to a younger cohort. Secondary outcomes were complications and mortality.

Aims

Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design.