Systemic antibiotics reduce infection in open fractures. Local delivery of antibiotics can provide higher doses to wounds without toxic systemic effects. This study investigated the effect on infection of combining systemic with local antibiotics via polymethylmethacrylate (PMMA) beads or gel delivery. An established Staphylococcus aureus contaminated fracture model in rats was used. Wounds were debrided and irrigated six hours after contamination and animals assigned to one of three groups, all of which received systemic antibiotics. One group had local delivery via antibiotic gel, another PMMA beads and the control group received no local antibiotics. After two weeks, bacterial levels were quantified. . Combined local and systemic antibiotics were superior to systemic antibiotics alone at reducing the quantity of bacteria recoverable from each group (p = 0.002 for gel; p = 0.032 for beads). There was no difference in the bacterial counts between bead and gel delivery (p = 0.62). . These results suggest that local antibiotics augment the antimicrobial effect of systemic antibiotics. Although no significant difference was found between vehicles, gel delivery offers technical advantages with its biodegradable nature, ability to conform to wound shape and to deliver increased doses. Further study is required to see if the gel delivery system has a clinical role. Cite this article: Bone Joint J 2015;97-B:1423–7

Aims. The aims of this study were to characterize antibiotic choices for perioperative total knee arthroplasty (TKA) and total hip arthroplasty (THA) prophylaxis, assess antibiotic allergy testing efficacy, and determine rates of prosthetic joint infection (PJI) based on perioperative antibiotic regimen. Patients and Methods. We evaluated all patients undergoing primary TKA or THA at a single academic institution between January 2004 and May 2017, yielding 29 695 arthroplasties (22 705 patients), with 3411 arthroplasties in 2576 patients (11.5%) having undergone preoperative allergy testing. A series of institutional databases were combined to identify allergy consultation outcomes, perioperative antibiotic regimen, and infection-free survivorship until final follow-up. Results. Among 2576 allergy-tested patients, 2493 patients (97%) were cleared to use cephalosporins. For the entire cohort, 28 174 arthroplasties (94.9%) received cefazolin and 1521 (5.1%) received non-cefazolin antibiotics. Infection-free survivorship was significantly higher among arthroplasties receiving cefazolin compared with non-cefazolin antibiotics, with 0.06% higher survival free of infection at one month, 0.56% at two months, 0.61% at one year, and 1.19% at ten years (p < 0.001). Overall, the risk of PJI was 32% lower in patients treated with cefazolin after adjusting for the American Society of Anesthesiologists (ASA) classification, joint arthroplasty (TKA or THA), and body mass index (BMI; p < 0.001). The number needed to treat with cefazolin to prevent one PJI was 164 patients at one year and 84 patients at ten years. Therefore, potentially 6098 PJIs could be prevented by one year and 11 905 by ten years in a cohort of 1 000 000 primary TKA and THA patients. Conclusion. PJI rates are significantly higher when non-cefazolin antibiotics are used for perioperative TKA and THA prophylaxis, highlighting the positive impact of preoperative antibiotic allergy testing to increase cefazolin usage. Given the low rate of true penicillin allergy positivity, and the readily modifiable risk factor that antibiotic choice provides, we recommend perioperative testing and clearance for all patients presenting with penicillin and cephalosporin allergies. Cite this article: Bone Joint J 2019;101-B(6 Supple B):9–15

Aims. The Open-Fracture Patient Evaluation Nationwide (OPEN) study was performed to provide clarity in open fracture management previously skewed by small, specialist centre studies and large, unfocused registry investigations. We report the current management metrics of open fractures across the UK. Method. Patients admitted to hospital with an open fracture (excluding phalanges or isolated hand injuries) between 1 June 2021 and 30 September 2021 were included. Institutional information governance approval was obtained at the lead site and all data entered using Research Electronic Data Capture software. All domains of the British Orthopaedic Association Standard for Open Fracture Management were recorded. Results. Across 51 centres, 1,175 patients were analyzed. Antibiotics were given to 754 (69.0%) in the emergency department, 240 (22.0%) pre-hospital, and 99 (9.1%) as inpatients. Wounds were photographed in 848 (72.7%) cases. Median time to first surgery was 16 hrs 14 mins (interquartile range (IQR) 8 hrs 29 mins to 23 hrs 19 mins). Complex injuries were operated on sooner (median 12 hrs 51 mins (IQR 4 hrs 36 mins to 21 hrs 14 mins)). Of initial procedures, 1,053 (90.3%) occurred between 8am and 8pm. A consultant orthopaedic surgeon was present at 1,039 (89.2%) first procedures. In orthoplastic centres, a consultant plastic surgeon was present at 465 (45.1%) first procedures. Overall, 706 (60.8%) patients required a single operation. At primary debridement, 798 (65.0%) fractures were definitively fixed, while 734 (59.8%) fractures had fixation and coverage in one operation through direct closure or soft-tissue coverage. Negative pressure wound therapy was used in 235 (67.7%) staged procedures. Following wound closure or soft-tissue cover, 509 (47.0%) patients received antibiotics for a median of three days (IQR 1 to 7). Conclusion. OPEN provides an insight into care across the UK and different levels of hospital for open fractures. Patients are predominantly operated on promptly, in working hours, and at specialist centres. Areas for improvement include combined patient review and follow-up, scheduled operating, earlier definitive soft-tissue cover, and more robust antibiotic husbandry. Cite this article: Bone Joint J 2022;104-B(9):1073–1080

Aims. With the ageing population, fragility fractures have become one of the most common conditions. The objective of this study was to investigate whether microbiological outcomes and fracture-healing in osteoporotic bone is worse than normal bone with fracture-related infection (FRI). Methods. A total of 120 six-month-old Sprague-Dawley (SD) rats were randomized to six groups: Sham, sham + infection (Sham-Inf), sham with infection + antibiotics (Sham-Inf-A), ovariectomized (OVX), OVX + infection (OVX-Inf), and OVX + infection + antibiotics (OVX-Inf-A). Open femoral diaphysis fractures with Kirschner wire fixation were performed. Staphylococcus aureus at 4 × 10. 4. colony-forming units (CFU)/ml was inoculated. Rats were euthanized at four and eight weeks post-surgery. Radiography, micro-CT, haematoxylin-eosin, mechanical testing, immunohistochemistry (IHC), gram staining, agar plating, crystal violet staining, and scanning electron microscopy were performed. Results. Agar plating analysis revealed a higher bacterial load in bone (p = 0.002), and gram staining showed higher cortical bone colonization (p = 0.039) in OVX-Inf compared to Sham-Inf. OVX-Inf showed significantly increased callus area (p = 0.013), but decreased high-density bone volume (p = 0.023) compared to Sham-Inf. IHC staining showed a significantly increased expression of TNF-α in OVX-Inf compared to OVX (p = 0.049). Significantly reduced bacterial load on bone (p = 0.001), enhanced ultimate load (p = 0.001), and energy to failure were observed in Sham-Inf-A compared to Sham-Inf (p = 0.028), but not in OVX-Inf-A compared to OVX-Inf. Conclusion. In osteoporotic bone with FRI, infection was more severe with more bone lysis and higher bacterial load, and fracture-healing was further delayed. Systemic antibiotics significantly reduced bacterial load and enhanced callus quality and strength in normal bone with FRI, but not in osteoporotic bone. Cite this article: Bone Joint Res 2022;11(2):49–60

Objective. Clinical studies of patients with bone sarcomas have been challenged by insufficient numbers at individual centres to draw valid conclusions. Our objective was to assess the feasibility of conducting a definitive multi-centre randomised controlled trial (RCT) to determine whether a five-day regimen of post-operative antibiotics, in comparison to a 24-hour regimen, decreases surgical site infections in patients undergoing endoprosthetic reconstruction for lower extremity primary bone tumours. . Methods. We performed a pilot international multi-centre RCT. We used central randomisation to conceal treatment allocation and sham antibiotics to blind participants, surgeons, and data collectors. We determined feasibility by measuring patient enrolment, completeness of follow-up, and protocol deviations for the antibiotic regimens. . Results. We screened 96 patients and enrolled 60 participants (44 men and 16 women) across 21 sites from four countries over 24 months (mean 2.13 participants per site per year, standard deviation 2.14). One participant was lost to follow-up and one withdrew consent. Complete data were obtained for 98% of eligible patients at two weeks, 83% at six months, and 73% at one year (the remainder with partial data or pending queries). In total, 18 participants missed at least one dose of antibiotics or placebo post-operatively, but 93% of all post-operative doses were administered per protocol. . Conclusions. It is feasible to conduct a definitive multi-centre RCT of post-operative antibiotic regimens in patients with bone sarcomas, but further expansion of our collaborative network will be critical. We have demonstrated an ability to coordinate in multiple countries, enrol participants, maintain protocol adherence, and minimise losses to follow-up. Cite this article: Bone Joint Res;4:154–162

Aims. Local antibiotics are used in the surgical management of foot infection in diabetic patients. This systematic review analyzes the available evidence of the use of local antibiotic delivery systems as an adjunct to surgery. Materials and Methods. Databases were searched to identify eligible studies and 13 were identified for inclusion. Results. Overall, the quality of the studies was poor. A single trial suggested that wound healing is quicker when a gentamicin-impregnated collagen sponge was implanted at time of surgery, with no difference in length of stay or rate of amputation. Results from studies with high risk of bias indicated no change in wound healing when a gentamicin-impregnated sponge was implanted during transmetatarsal amputation, but a reduction in the incidence of wound breakdown (8% vs 25%, not statistically significant) was identified. A significant cost reduction was identified when using an antimicrobial gel to deliver antibiotics and anti-biofilm agents (quorum-sensing inhibitors) compared with routine dressings and systemic antibiotics. Analyses of case series identified 485 patients who were treated using local antibiotic delivery devices. The rates of wound healing, re-operation, and mortality were comparable to those that have been previously reported for the routine management of these infections. Conclusion. There is a lack of good-quality evidence to support the use of local antibiotic delivery devices in the treatment of foot infections in patients with diabetes. Cite this article: Bone Joint J 2018;100-B:1409–15

Objectives. We wanted to investigate regional variations in the organisms reported to be causing peri-prosthetic infections and to report on prophylaxis regimens currently in use across England. Methods. Analysis of data routinely collected by Public Health England’s (PHE) national surgical site infection database on elective primary hip and knee arthroplasty procedures between April 2010 and March 2013 to investigate regional variations in causative organisms. A separate national survey of 145 hospital Trusts (groups of hospitals under local management) in England routinely performing primary hip and/or knee arthroplasty was carried out by standard email questionnaire. Results. Analysis of 189 858 elective primary hip and knee arthroplasty procedures and 1116 surgical site infections found statistically significant variations for some causative organism between regions. There was a 100% response rate to the prophylaxis questionnaire that showed substantial variation between individual trust guidelines. A number of regimens currently in use are inconsistent with the best available evidence. Conclusions. The approach towards antibiotic prophylaxis in elective arthroplasty nationwide reveals substantial variation without clear justification. Only seven causative organisms are responsible for 89% of infections affecting primary hip and knee arthroplasty, which cannot justify such widespread variation between prophylactic antibiotic policies. Cite this article: Bone Joint Res 2015;4:181–189

The February 2024 Trauma Roundup. 360. looks at: Posterior malleolus fractures: what about medium-sized fragments?; Acute or delayed total hip arthroplasty after acetabular fracture fixation?; Intrawound antibiotics reduce the risk of deep infections in fracture fixation; Does the VANCO trial represent real world patients?; Can a restrictive transfusion protocol be effective beyond initial resuscitation?; What risk factors result in avascular necrosis of the talus?; Pre-existing anxiety and mood disorders have a role to play in complex regional pain syndrome; Three- and four-part proximal humeral fractures at ten years

The August 2023 Hip & Pelvis Roundup. 360. looks at: Using machine learning to predict venous thromboembolism and major bleeding events following total joint arthroplasty; Antibiotic length in revision total hip arthroplasty; Preoperative colonization and worse outcomes; Short stem cemented total hip arthroplasty; What are the outcomes of one- versus two-stage revisions in the UK?; To cement or not to cement? The best approach in hemiarthroplasty; Similar re-revisions in cemented and cementless femoral revisions for periprosthetic femoral fractures in total hip arthroplasty; Are hip precautions still needed?

The April 2024 Research Roundup. 360. looks at: Prevalence and characteristics of benign cartilaginous tumours of the shoulder joint; Is total-body MRI useful as a screening tool to rule out malignant progression in patients with multiple osteochondromas?; Effects of vancomycin and tobramycin on compressive and tensile strengths of antibiotic bone cement: a biomechanical study; Biomarkers for early detection of Charcot arthropathy; Strong association between growth hormone therapy and proximal tibial physeal avulsion fractures in children and adolescents; UK pregnancy in orthopaedics (UK-POP): a cross-sectional study of UK female trauma and orthopaedic surgeons and their experiences of pregnancy; Does preoperative weight loss change the risk of adverse outcomes in total knee arthroplasty by initial BMI classification?

Aims. The standard of wide tumour-like resection for chronic osteomyelitis (COM) has been challenged recently by adequate debridement. This paper reviews the evolution of surgical debridement for long bone COM, and presents the outcome of adequate debridement in a tertiary bone infection unit. Methods. We analyzed the retrospective record review from 2014 to 2020 of patients with long bone COM. All were managed by multidisciplinary infection team (MDT) protocol. Adequate debridement was employed for all cases, and no case of wide resection was included. Results. A total of 53 patients (54 bones) with median age of 45.5 years (interquartile range 31 to 55) and mean follow-up of 29 months (12 to 59) were included. In all, ten bones were Cierny-Mader type I, 39 were type III, and five were type IV. All patients were treated with single-staged management, except for one (planned two-stage stabilization). Positive microbial cultures grew in 75%. Overall, 46 cases (85%) had resolution of COM after index procedure, and 49 (90.7%) had resolution on last follow-up. Four patients (7%) underwent second surgical procedure and six patients (11%) had complications. Conclusion. We challenge the need for wide tumour-like resection in all cases of COM. Through detailed preoperative evaluation and planning with MDT approach, adequate debridement and local delivery of high concentration of antibiotic appears to provide comparable outcomes versus radical debridement. Cite this article: Bone Jt Open 2023;4(8):643–651

We used a goat model of a contaminated musculoskeletal defect to determine the effectiveness of rapidly-resorbing calcium-sulphate pellets containing amikacin to reduce the local bacterial count. Our findings showed that this treatment eradicated the bacteria quickly, performed as well as standard polymethylmethacrylate mixed with an antibiotic and had many advantages over the latter. The pellets were prepared before surgery and absorbed completely. They released all of the antibiotic and did not require a subsequent operation for their removal. Our study indicated that locally administered antibiotics reduced bacteria within the wound rapidly. This method of treatment may have an important role in decreasing the rate of infection in contaminated wounds

Aims. Periprosthetic hip-joint infection is a multifaceted and highly detrimental outcome for patients and clinicians. The incidence of prosthetic joint infection reported within two years of primary hip arthroplasty ranges from 0.8% to 2.1%. Costs of treatment are over five-times greater in people with periprosthetic hip joint infection than in those with no infection. Currently, there are no national evidence-based guidelines for treatment and management of this condition to guide clinical practice or to inform clinical study design. The aim of this study is to develop guidelines based on evidence from the six-year INFection and ORthopaedic Management (INFORM) research programme. Methods. We used a consensus process consisting of an evidence review to generate items for the guidelines and online consensus questionnaire and virtual face-to-face consensus meeting to draft the guidelines. Results. The consensus panel comprised 21 clinical experts in orthopaedics, primary care, rehabilitation, and healthcare commissioning. The final output from the consensus process was a 14-item guideline. The guidelines make recommendations regarding increased vigilance and monitoring of those at increased risk of infection; diagnosis including strategies to ensure the early recognition of prosthetic infection and referral to orthopaedic teams; treatment, including early use of DAIR and revision strategies; and postoperative management including appropriate physical and psychological support and antibiotic strategies. Conclusion. We believe the implementation of the INFORM guidelines will inform treatment protocols and clinical pathways to improve the treatment and management of periprosthetic hip infection. Cite this article: Bone Jt Open 2023;4(4):226–233

We reviewed systematically the published evidence on the effectiveness of antibiotic prophylaxis for the reduction of wound infection in patients undergoing total hip and total knee replacement. Publications were identified using the Cochrane Library, MEDLINE, EMBASE and CINAHL databases. We also contacted authors to identify unpublished trials. We included randomised controlled trials which compared any prophylaxis with none, the administration of systemic antibiotics with that of those in cement, cephalosporins with glycopeptides, cephalosporins with penicillin-derivatives, and second-generation with first-generation cephalosporins. A total of 26 studies (11 343 participants) met the inclusion criteria. Methodological quality was variable. In a meta-analysis of seven studies (3065 participants) antibiotic prophylaxis reduced the absolute risk of wound infection by 8% and the relative risk by 81% compared with no prophylaxis (p < 0.00001). No other comparison showed a significant difference in clinical effect. Antibiotic prophylaxis should be routine in joint replacement but the choice of agent should be made on the basis of cost and local availability

Aims. This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%). Methods. In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared. Results. The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI. Conclusion. SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly. Cite this article: Bone Joint Res 2023;12(2):113–120

Aims. This study aimed to investigate the clinical characteristics and outcomes associated with culture-negative limb osteomyelitis patients. Methods. A total of 1,047 limb osteomyelitis patients aged 18 years or older who underwent debridement and intraoperative culture at our clinic centre from 1 January 2011 to 31 December 2020 were included. Patient characteristics, infection eradication, and complications were analyzed between culture-negative and culture-positive cohorts. Results. Of these patients, 264 (25.2%) had negative cultures. Patients with a culture-negative compared with a culture-positive status were more likely to have the following characteristics: younger age (≤ 40 years) (113/264 (42.8%) vs 257/783 (32.8%); p = 0.004), a haematogenous aetiology (75/264 (28.4%) vs 150/783 (19.2%); p = 0.002), Cierny-Mader host A (79/264 (29.9%) vs 142/783 (18.1%); p < 0.001), antibiotic use before sampling (34/264 (12.9%) vs 41/783 (5.2%); p＜0.001), fewer taken samples (n＜3) (48/264 (18.2%) vs 60/783 (7.7%); p＜0.001), and less frequent presentation with a sinus (156/264 (59.1%) vs 665/783 (84.9%); p < 0.001). After initial treatments of first-debridement and antimicrobial, infection eradication was inferior in culture-positive osteomyelitis patients, with a 2.24-fold increase (odds ratio 2.24 (95% confidence interval 1.42 to 3.52)) in the redebridement rate following multivariate analysis. No statistically significant differences were found in long-term recurrence and complications within the two-year follow-up. Conclusion. We identified several factors being associated with the culture-negative result in osteomyelitis patients. In addition, the data also indicate that culture negativity is a positive prognostic factor in early infection eradication. These results constitute the basis of optimizing clinical management and patient consultations. Cite this article: Bone Joint J 2024;106-B(7):720–727

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. Methods. A group of eight patients revised due to a PJI with a previous lateral approach was compared with a group of 21 revised THAs without infection, performed using the same approach. The primary variables of the study were the fibril diameter, as seen in transmission electron microscopy (TEM), and the total degeneration score (TDS), as seen under the light microscope. An analysis of bacteriology, classification of infection, and antibiotic treatment was also performed. Results. Biopsy samples from the GMED from infected patients revealed a larger fibril diameter than control patients, as seen in the TEM (p < 0.001). Uninfected patients were slightly older and had their revisions performed significantly later than the infected patients. Histologically, samples from infected patients revealed significantly more vascularity (p < 0.001), the presence of glycosaminoglycans (p < 0.001), and a higher TDS (p = 0.003) than the control patients. The majority of patients had staphylococcal infections of various species. Conclusion. More histological degeneration in the GMED was found in patients undergoing THA revision surgery due to PJI than in patients undergoing THA revision surgery due to other reasons. Cite this article: Bone Jt Open 2023;4(8):628–635

Aims. Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity. Methods. We retrospectively reviewed 32 patients (22 hips and 11 knees) who underwent single-stage revision combined with IA carbapenem infusion between November 2013 and March 2020. The IA and intravenous (IV) carbapenem infusions were administered for a single Gram-negative infection, and IV vancomycin combined with IA carbapenems and vancomycin was applied for polymicrobial infection including Gram-negative bacteria. The bacterial community distribution, drug sensitivity, infection control rate, functional recovery, and complications were evaluated. Reinfection or death caused by PJI was regarded as a treatment failure. Results. Gram-negative PJI was mainly caused by Escherichia coli (8/34), Enterobacter cloacae (7/34), and Klebsiella pneumoniae (5/34). Seven cases (7/32) involved polymicrobial PJIs. The resistance rates of penicillin, cephalosporin, quinolones, and sulfonamides were > 10%, and all penicillin and partial cephalosporins (first and second generation) were > 30%. Of 32 cases, treatment failed to eradicate infection in only three cases (9.4%), at a mean follow-up of 55.1 months (SD 25 to 90). The mean postoperative Harris Hip Score and Hospital for Special Surgery knee score at the most recent follow-up were 81 (62 to 91) and 79 (56 to 89), respectively. One patient developed a fistula, and another presented with a local rash on an infected joint. Conclusion. The use of IA carbapenem delivered alongside one-stage revision effectively controlled Gram-negative infection and obtained acceptable clinical outcomes with few complications. Notably, first- and second-generation cephalosporins and penicillin should be administrated with caution, due to a high incidence of resistance. Cite this article: Bone Joint J 2023;105-B(3):284–293

Aims. Achievement of accurate microbiological diagnosis prior to revision is key to reducing the high rates of persistent infection after revision knee surgery. The effect of change in the microorganism between the first- and second-stage revision of total knee arthroplasty for periprosthetic joint infection (PJI) on the success of management is not clear. Methods. A two-centre retrospective cohort study was conducted to review the outcome of patients who have undergone two-stage revision for treatment of knee arthroplasty PJI, focusing specifically on isolated micro-organisms at both the first- and second-stage procedure. Patient demographics, medical, and orthopaedic history data, including postoperative outcomes and subsequent treatment, were obtained from the electronic records and medical notes. Results. The study cohort consisted of 84 patients, of whom 59.5% (n = 50) had successful eradication of their infection at a mean follow-up of 4.7 years. For the 34 patients who had recurrence of infection, 58.8% (n = 20) had a change in isolated organism, compared to 18% (n = 9) in the infection eradication group (p < 0.001). When adjusting for confound, there was no association when the growth on the second stage was the same as the first (odd ratio (OR) 2.50, 95% confidence interval (CI) 0.49 to 12.50; p = 0.269); however, when a different organism was identified at the second stage, this was independently associated with failure of treatment (OR 8.40, 95% CI 2.91 to 24.39; p < 0.001). There were no other significant differences between the two cohorts with regard to patient demographics or type of organisms isolated. Conclusion. Change in the identified microorganism between first- and second-stage revision for PJI was associated with failure of management. Identification of this change in the microorganism prior to commencement of the second stage may help target antibiotic management and could improve the success of surgery in these patients. Cite this article: Bone Jt Open 2023;4(9):720–727

Allograft bone is widely used in orthopaedic surgery, but peri-operative infection of the graft remains a common and disastrous complication. The efficacy of systemic prophylactic antibiotics is unproven, and since the graft is avascular it is likely that levels of antibiotic in the graft are low. Using an electrical potential to accelerate diffusion of antibiotics into allograft bone, high levels were achieved in specimens of both sheep and human allograft. In human bone these ranged from 187.1 mg/kg in endosteal (. sd. 15.7) to 124.6 (. sd. 46.2) in periosteal bone for gentamicin and 31.9 (. sd. 8.9) in endosteal and 2.9 (. sd. 1.1) in periosteal bone for flucloxacillin. The antibiotics remained active against bacteria in vitro after iontophoresis and continued to elute from the allograft for up to two weeks. Structural allograft can be supplemented directly with antibiotics using iontophoresis. The technique is simple and inexpensive and offers a potential means of reducing the rate of peri-operative infection in allograft surgery. Iontophoresis into allograft bone may also be applicable to other therapeutic compounds