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

Acute bone and joint infections in children are serious, and misdiagnosis can threaten limb and life. Most young children who present acutely with pain, limping, and/or loss of function have transient synovitis, which will resolve spontaneously within a few days. A minority will have a bone or joint infection. Clinicians are faced with a diagnostic challenge: children with transient synovitis can safely be sent home, but children with bone and joint infection require urgent treatment to avoid complications. Clinicians often respond to this challenge by using a series of rudimentary decision support tools, based on clinical, haematological, and biochemical parameters, to differentiate childhood osteoarticular infection from other diagnoses. However, these tools were developed without methodological expertise in diagnostic accuracy and do not consider the importance of imaging (ultrasound scan and MRI). There is wide variation in clinical practice with regard to the indications, choice, sequence, and timing of imaging. This variation is most likely due to the lack of evidence concerning the role of imaging in acute bone and joint infection in children. We describe the first steps of a large UK multicentre study, funded by the National Institute for Health Research, which seeks to integrate definitively the role of imaging into a decision support tool, developed with the assistance of individuals with expertise in the development of clinical prediction tools. Cite this article: Bone Joint J 2023;105-B(3):227–229

Aims. Gram-negative infections are associated with comorbid patients, but outcomes are less well understood. This study reviewed diagnosis, management, and treatment for a cohort treated in a tertiary spinal centre. Methods. A retrospective review was performed of all gram-negative spinal infections (n = 32; median age 71 years; interquartile range 60 to 78), excluding surgical site infections, at a single centre between 2015 to 2020 with two- to six-year follow-up. Information regarding organism identification, antibiotic regime, and treatment outcomes (including clinical, radiological, and biochemical) were collected from clinical notes. Results. All patients had comorbidities and/or non-spinal procedures within the previous year. Most infections affected lumbar segments (20/32), with Escherichia coli the commonest organism (17/32). Causative organisms were identified by blood culture (23/32), biopsy/aspiration (7/32), or intraoperative samples (2/32). There were 56 different antibiotic regimes, with oral (PO) ciprofloxacin being the most prevalent (13/56; 17.6%). Multilevel, contiguous infections were common (8/32; 25%), usually resulting in bone destruction and collapse. Epidural collections were seen in 13/32 (40.6%). In total, five patients required surgery, three for neurological deterioration. Overall, 24 patients improved or recovered with a mean halving of CRP at 8.5 days (SD 6). At the time of review (two to six years post-diagnosis), 16 patients (50%) were deceased. Conclusion. This is the largest published cohort of gram-negative spinal infections. In older patients with comorbidities and/or previous interventions in the last year, a high level of suspicion must be given to gram-negative infection with blood cultures and biopsy essential. Early organism identification permits targeted treatment and good initial clinical outcomes; however, mortality is 50% in this cohort at a mean of 4.2 years (2 to 6) after diagnosis. Cite this article: Bone Jt Open 2024;5(5):435–443

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. The purpose of this study was to compare the clinical outcomes, mortalities, implant survival rates, and complications of total knee arthroplasty (TKA) in patients with or without hepatitis B virus (HBV) infection over at least ten years of follow-up. Methods. From January 2008 to December 2010, 266 TKAs were performed in 169 patients with HBV (HBV group). A total of 169 propensity score–matched patients without HBV were chosen for the control group in a one-to-one ratio. Then, the clinical outcomes, mortalities, implant survival rates, and complications of TKA in the two groups were compared. The mean follow-up periods were 11.7 years (10.5 to 13.4) in the HBV group and 11.8 years (11.5 to 12.4) in the control group. Results. The mean Knee Society scores in the HBV and control groups improved from 37.1 (SD 5.6) and 38.4 (SD 5.4) points preoperatively to 78.1 (SD 10.8) and 81.7 (SD 10.2) points at final follow-up (p = 0.314), while the mean function scores in the HBV and control groups improved from 36.2 and 37.3 points preoperatively to 77.8 and 83.2 points at final follow-up (p = 0.137). Nine knees in the HBV group required revision surgery, including seven due to septic loosening and two due to aseptic loosening. Four knees in the control group required revision surgery, including three due to septic loosening and one due to aseptic loosening. Kaplan–Meier survivorship analysis with the revision of either component as an endpoint in the HBV and control groups estimated 96.6% and 98.5% chances of survival for ten years, respectively (p = 0.160). Conclusion. TKA in patients with HBV infection resulted in good clinical outcomes and survivorship. However, there was a higher revision rate over a minimum ten-year follow-up period compared to TKA in patients without HBV infection. Cite this article: Bone Jt Open 2022;3(6):470–474

Aims. Hand trauma accounts for one in five of emergency department attendances, with a UK incidence of over five million injuries/year and 250,000 operations/year. Surgical site infection (SSI) in hand trauma surgery leads to further interventions, poor outcomes, and prolonged recovery, but has been poorly researched. Antimicrobial sutures have been recognized by both the World Health Organization and the National Institute for Clinical Excellence as potentially effective for reducing SSI. They have never been studied in hand trauma surgery: a completely different patient group and clinical pathway to previous randomized clinical trials (RCTs) of these sutures. Antimicrobial sutures are expensive, and further research in hand trauma is warranted before they become standard of care. The aim of this protocol is to conduct a feasibility study of antimicrobial sutures in patients undergoing hand trauma surgery to establish acceptability, compliance, and retention for a definitive trial. Methods. A two-arm, multicentre feasibility RCT of 116 adult participants with hand and wrist injuries, randomized to either antimicrobial sutures or standard sutures. Study participants and outcome assessors will be blinded to treatment allocation. Outcome measures will be recorded at baseline (preoperatively), 30 days, 90 days, and six months, and will include SSI, patient-reported outcome measures, and return to work. Conclusion. This will inform a definitive trial of antimicrobial sutures in the hand and wrist, and will help to inform future upper limb trauma trials. The results of this research will be shared with the medical community through high impact publication and presentation. Cite this article: Bone Jt Open 2022;3(7):529–535

Aims. To evaluate the impact of negative pressure wound therapy (NPWT) on the odds of having deep infections and health-related quality of life (HRQoL) following open fractures. Methods. Patients from the Fluid Lavage in Open Fracture Wounds (FLOW) trial with Gustilo-Anderson grade II or III open fractures within the lower limb were included in this secondary analysis. Using mixed effects logistic regression, we assessed the impact of NPWT on deep wound infection requiring surgical intervention within 12 months post-injury. Using multilevel model analyses, we evaluated the impact of NPWT on the Physical Component Summary (PCS) of the 12-Item Short-Form Health Survey (SF-12) at 12 months post-injury. Results. After applying inverse probability treatment weighting to adjust for the influence of injury characteristics on type of dressing used, 1,322 participants were assessed. The odds of developing a deep infection requiring operative management within 12 months of initial surgery was 4.52-times higher in patients who received NPWT compared to those who received a standard wound dressing (95% confidence interval (CI) 1.84 to 11.12; p = 0.001). Overall, 1,040 participants were included in our HRQoL analysis, and those treated with NPWT had statistically significantly lower mean SF-12 PCS post-fracture (p < 0.001). These differences did not reach the minimally important difference for the SF-12 PCS. Conclusion. Our analysis found that patients treated with NPWT had higher odds of developing a deep infection requiring operative management within 12 months post-fracture. Due to possible residual confounding with the worst cases being treated with NPWT, we are unable to determine if NPWT has a negative effect or is simply a marker of worse injuries or poor access to early soft-tissue coverage. Regardless, our results suggest that the use of this treatment requires further evaluation. Cite this article: Bone Jt Open 2022;3(3):189–195

Aims. Surgical site infection (SSI) after soft-tissue sarcoma (STS) resection is a serious complication. The purpose of this retrospective study was to investigate the risk factors for SSI after STS resection, and to develop a nomogram that allows patient-specific risk assessment. Methods. A total of 547 patients with STS who underwent tumour resection between 2005 and 2021 were divided into a development cohort and a validation cohort. In the development cohort of 402 patients, the least absolute shrinkage and selection operator (LASSO) regression model was used to screen possible risk factors of SSI. To select risk factors and construct the prediction nomogram, multivariate logistic regression was used. The predictive power of the nomogram was evaluated by receiver operating curve (ROC) analysis in the validation cohort of 145 patients. Results. LASSO regression analysis selected possible risk factors for SSI, including age, diabetes, operating time, skin graft or flap, resected tumour size, smoking, and radiation therapy. Multivariate analysis revealed that age, diabetes, smoking during the previous year, operating time, and radiation therapy were independent risk factors for SSI. A nomogram was developed based on the results of multivariate logistic regression analysis. In the development cohort, the incidence of SSI was 4.5% in the low-risk group (risk score < 6.89) and 26.6% in the high-risk group (risk score ≥ 6.89; p < 0.001). In the validation cohort, the incidence of SSI was 2.0% in the low-risk group and 15.9% in the high-risk group (p = 0.004). Conclusion. Our nomogram will enable surgeons to assess the risk of SSI in patients with STS. In patients with high risk of SSI, frequent monitoring and aggressive interventions should be considered to prevent this. Cite this article: Bone Joint J 2024;106-B(5):492–500

Aims. Accurate diagnosis of chronic periprosthetic joint infection (PJI) presents a significant challenge for hip surgeons. Preoperative diagnosis is not always easy to establish, making the intraoperative decision-making process crucial in deciding between one- and two-stage revision total hip arthroplasty (THA). Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJI. We aimed to evaluate the utility of intraoperative calprotectin lateral flow immunoassay (LFI) in THA patients with suspected chronic PJI. Methods. The study included 48 THAs in 48 patients with a clinical suspicion of PJI, but who did not meet European Bone and Joint Infection Society (EBJIS) PJI criteria preoperatively, out of 105 patients undergoing revision THA at our institution for possible PJI between November 2020 and December 2022. Intraoperatively, synovial fluid calprotectin was measured with LFI. Cases with calprotectin levels ≥ 50 mg/l were considered infected and treated with two-stage revision THA; in negative cases, one-stage revision was performed. At least five tissue cultures were obtained; the implants removed were sent for sonication. Results. Calprotectin was positive (≥ 50 mg/l) in 27 cases; out of these, 25 had positive tissue cultures and/or sonication. Calprotectin was negative in 21 cases. There was one false negative case, which had positive tissue cultures. Calprotectin showed an area under the curve of 0.917, sensitivity of 96.2%, specificity of 90.9%, positive predictive value of 92.6%, negative predictive value of 95.2%, positive likelihood ratio of 10.6, and negative likelihood ratio of 0.04. Overall, 45/48 patients were correctly diagnosed and treated by our algorithm, which included intraoperative calprotectin measurement. This yielded a 93.8% concordance with postoperatively assessed EBJIS criteria. Conclusion. Calprotectin can be a valuable tool in facilitating the intraoperative decision-making process for cases in which chronic PJI is suspected and diagnosis cannot be established preoperatively. Cite this article: Bone Joint J 2024;106-B(5 Supple B):118–124

Aims. Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP. Methods. This was a retrospective cohort study of 11,550 primary TKAs performed at an orthopaedic hospital between 2013 and 2019. The primary outcome was PJI occurring within 90 days of surgery. Patients were stratified into two groups (cefazolin vs non-cephalosporin) based on their preoperative antibiotic. All patients also received the VIP protocol at wound closure. Bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify the odds ratio of PJI. Results. In all, 10,484 knees (90.8%) received cefazolin, while 1,066 knees (9.2%) received a non-cephalosporin agent (either vancomycin or clindamycin) as preoperative prophylaxis. The rate of PJI in the cefazolin group (0.5%; 48/10,484) was significantly lower than the rate of PJI in the non-cephalosporin group (1.0%; 11/1,066) (p = 0.012). After controlling for confounding variables, the odds ratio (OR) of developing a PJI was increased in the non-cephalosporin cohort compared to the cefazolin cohort (OR 2.389; 1.2 to 4.6); p = 0.01). Conclusion. Despite the use of topical irrigant solutions and addition of local antimicrobial agents, the use of a non-cephalosporin perioperative antibiotic continues to be associated with a greater risk of TKA PJI compared to cefazolin. Strategies that increase the proportion of patients receiving cefazolin rather than non-cephalosporin alternatives must be emphasized. Cite this article: Bone Jt Open 2022;3(1):35–41

Aims. In cases of severe periprosthetic joint infection (PJI) of the knee, salvage procedures such as knee arthrodesis (KA) or above-knee amputation (AKA) must be considered. As both treatments result in limitations in quality of life (QoL), we aimed to compare outcomes and factors influencing complication rates, mortality, and mobility. Methods. Patients with PJI of the knee and subsequent KA or AKA between June 2011 and May 2021 were included. Demographic data, comorbidities, and patient history were analyzed. Functional outcomes and QoL were prospectively assessed in both groups with additional treatment-specific scores after AKA. Outcomes, complications, and mortality were evaluated. Results. A total of 98 patients were included, 52 treated with arthrodesis and 47 with AKA. The mean number of revision surgeries between primary arthroplasty and arthrodesis or AKA was 7.85 (SD 5.39). Mean follow-up was 77.7 months (SD 30.9), with a minimum follow-up of two years. Complications requiring further revision surgery occurred in 11.5% of patients after arthrodesis and in 37.0% of AKA patients. Positive intraoperative tissue cultures obtained during AKA was significantly associated with the risk of further surgical revision. Two-year mortality rate of arthrodesis was significantly lower compared to AKA (3.8% vs 28.3%), with age as an independent risk factor in the AKA group. Functional outcomes and QoL were better after arthrodesis compared to AKA. Neuropathic pain was reported by 19 patients after AKA, and only 45.7% of patients were fitted or were intended to be fitted with a prosthesis. One-year infection-free survival after arthrodesis was 88.5%, compared to 78.5% after AKA. Conclusion. Above-knee amputation in PJI results in high complication and mortality rates and poorer functional outcome compared to arthrodesis. Mortality rates after AKA depend on patient age and mobility, with most patients not able to be fitted with a prosthesis. Therefore, arthrodesis should be preferred whenever possible if salvage procedures are indicated. Cite this article: Bone Joint J 2024;106-B(7):669–679

External fixation is widely used in orthopaedic and trauma surgery. Infections around pin or wire sites, which are usually localised, non-invasive, and are easily managed, are common. Occasionally, more serious invasive complications such as necrotising fasciitis (NF) and toxic shock syndrome (TSS) may occur. . We retrospectively reviewed all patients who underwent external fixation between 1997 and 2012 in our limb lengthening and reconstruction programme. A total of eight patients (seven female and one male) with a mean age of 20 years (5 to 45) in which pin/wire track infections became limb- or life-threatening were identified. Of these, four were due to TSS and four to NF. Their management is described. A satisfactory outcome was obtained with early diagnosis and aggressive medical and surgical treatment. . Clinicians caring for patients who have external fixation and in whom infection has developed should be aware of the possibility of these more serious complications. Early diagnosis and aggressive treatment are required in order to obtain a satisfactory outcome. Cite this article: Bone Joint J 2015;97-B:1296–1300

Aims. The aim of this investigation was to compare risk of infection in both cemented and uncemented hemiarthroplasty (HA) as well as in total hip arthroplasty (THA) following femoral neck fracture. Methods. Data collection was performed using the German Arthroplasty Registry (EPRD). In HA and THA following femoral neck fracture, fixation method was divided into cemented and uncemented prostheses and paired according to age, sex, BMI, and the Elixhauser Comorbidity Index using Mahalanobis distance matching. Results. Overall in 13,612 cases of intracapsular femoral neck fracture, 9,110 (66.9%) HAs and 4,502 (33.1%) THAs were analyzed. Infection rate in HA was significantly reduced in cases with use of antibiotic-loaded cement compared with uncemented fixated prosthesis (p = 0.013). In patients with THA no statistical difference between cemented and uncemented prosthesis was registered, however after one year 2.4% of infections were detected in uncemented and 2.1% in cemented THA. In the subpopulation of HA after one year, 1.9% of infections were registered in cemented and 2.8% in uncemented HA. BMI (p = 0.001) and Elixhauser Comorbidity Index (p < 0.003) were identified as risk factors of periprosthetic joint infection (PJI), while in THA cemented prosthesis also demonstrated an increased risk within the first 30 days (hazard ratio (HR) = 2.73; p = 0.010). Conclusion. The rate of infection after intracapsular femoral neck fracture was statistically significantly reduced in patients treated by antibiotic-loaded cemented HA. Particularly for patients with multiple risk factors for the development of a PJI, the usage of antibiotic-loaded bone cement seems to be a reasonable procedure for prevention of infection. Cite this article: Bone Joint Res 2023;12(5):331–338

Aim. The time to onset of symptoms after fracture fixation is still commonly used to classify fracture-related infections (FRI). Early infections (<2 weeks) can often be treated with debridement, systemic antibiotics, irrigation, and implant preservation (DAIR). Late infections (>10 weeks) typically require implant removal as mature, antibiotic-tolerant biofilms have formed. However, the recommendations for delayed infections (2–10 weeks) are not clearly defined. Here, infection healing and bone healing in early and delayed FRI is investigated in a rabbit model with a standardized DAIR procedure. Method. Staphylococcus aureus was inoculated into 17 rabbits after plate osteosynthesis in a humerus osteotomy. The infection developed either one week (early group, n=6) or four weeks (delayed group, n=6) before a standardized DAIR procedure and microbiological analysis were performed. Systemic antibiotics were administered for six weeks (two weeks: Nafcillin+Rifampin, four weeks: Levofloxacin+Rifampin). A control group (n=5) also underwent a revision operation (debridement and irrigation) after four weeks, but received no antibiotic treatment. Rabbits were euthanized seven weeks after the revision operation. Bone healing was assessed using a modified radiographic union score for tibial fractures (mRUST). After euthanasia, a quantitative microbiological examination of the entire humerus, adjacent soft tissues, and implants was performed. Results. All animals were infected at the time of revision surgery, with the bacterial load in the early group (especially in soft tissues) being greater than in the delayed group and control group. This indicates infiltration of bacteria into areas that are more difficult to reach after four weeks of debridement. The infection was eradicated in all animals in both the early and delayed groups at euthanasia, but not in the control group (CFU median (IQR): 2.1×10. 7. (1.3×10. 7. -2.6×10. 7. ). The osteotomy healed in the early group, while bone healing was significantly impaired in both the delayed group and control group (mRUST median (IQR): early group: 16 (14–16), delayed group: 7.5 (6–10), control: 7 (5.5–9); early vs. delayed: p=0.0411, early vs. control p=0.0065). Conclusion. The maturation of the infection between the first and fourth week does not affect the success of infection eradication in this rabbit FRI model. However, bone healing appears to be impaired with increasing duration of infection

Aims. Deep surgical site infection (SSI) remains an unsolved problem after hip fracture. Debridement, antibiotic, and implant retention (DAIR) has become a mainstream treatment in elective periprosthetic joint infection; however, evidence for DAIR after infected hip hemiarthroplaty is limited. Methods. Patients who underwent a hemiarthroplasty between March 2007 and August 2018 were reviewed. Multivariable binary logistic regression was performed to identify and adjust for risk factors for SSI, and to identify factors predicting a successful DAIR at one year. Results. A total of 3,966 patients were identified. The overall rate of SSI was 1.7% (51 patients (1.3%) with deep SSI, and 18 (0.45%) with superficial SSI). In all, 50 patients underwent revision surgery for infection (43 with DAIR, and seven with excision arthroplasty). After adjustment for other variables, only concurrent urinary tract infection (odds ratio (OR) 2.78, 95% confidence interval (CI) 1.57 to 4.92; p < 0.001) and increasing delay to theatre for treatment of the fracture (OR 1.31 per day, 95% CI 1.12 to 1.52; p < 0.001) were predictors of developing a SSI, while a cemented arthroplasty was protective (OR 0.54, 95% CI 0.31 to 0.96; p = 0.031). In all, nine patients (20.9%) were alive at one year with a functioning hemiarthroplasty following DAIR, 20 (46.5%) required multiple surgical debridements after an initial DAIR, and 18 were converted to an excision arthroplasty due to persistent infection, with six were alive at one year. The culture of any gram-negative organism reduced success rates to 12.5% (no cases were successful with methicillin-resistant Staphylococcus aureus or Pseudomonas infection). Favourable organisms included Citrobacter and Proteus (100% cure rate). The all-cause mortality at one year after deep SSI was 55.87% versus 24.9% without deep infection. Conclusion. Deep infection remains a devastating complication regardless of the treatment strategy employed. Success rates of DAIR are poor compared to total hip arthroplasty, and should be reserved for favourable organisms in patients able to tolerate multiple surgical procedures. Cite this article: Bone Jt Open 2021;2(11):958–965

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

Aims. Delayed postoperative inoculation of orthopaedic implants with persistent wound drainage or bacterial seeding of a haematoma can result in periprosthetic joint infection (PJI). The aim of this in vivo study was to compare the efficacy of vancomycin powder with vancomycin-eluting calcium sulphate beads in preventing PJI due to delayed inoculation. Methods. A mouse model of PJI of the knee was used. Mice were randomized into groups with intervention at the time of surgery (postoperative day (POD) 0): a sterile control (SC; n = 6); infected control (IC; n = 15); systemic vancomycin (SV; n = 9); vancomycin powder (VP; n = 21); and vancomycin bead (VB; n = 19) groups. Delayed inoculation was introduced during an arthrotomy on POD 7 with 1 × 10. 5. colony-forming units (CFUs) of a bioluminescent strain of Staphylococcus aureus. The bacterial burden was monitored using bioluminescence in vivo. All mice were killed on POD 21. Implants and soft-tissue were harvested and sonicated for analysis of the CFUs. Results. The mean in vivo bioluminescence in the VB group was significantly lower on POD 8 and POD 10 compared with the other groups. There was a significant 1.3-log. 10. (95%) and 1.5-log. 10. (97%) reduction in mean soft-tissue CFUs in the VB group compared with the VP and IC groups (3.6 × 10. 3. vs 7.0 × 10. 4. ; p = 0.022; 3.6 × 10. 3. vs 1.0 × 10. 5. ; p = 0.007, respectively) at POD 21. There was a significant 1.6-log. 10. (98%) reduction in mean implant CFUs in the VB group compared with the IC group (1.3 × 10. 0. vs 4.7 × 10. 1. , respectively; p = 0.038). Combined soft-tissue and implant infection was prevented in 10 of 19 mice (53%) in the VB group as opposed to 5 of 21 (24%) in the VP group, 3 of 15 (20%) in the IC group, and 0% in the SV group. Conclusion. In our in vivo mouse model, antibiotic-releasing calcium sulphate beads appeared to outperform vancomycin powder alone in lowering the bacterial burden and preventing soft-tissue and implant infections. Cite this article: Bone Joint J 2024;106-B(6):632–638

Aims. To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI). Methods. A retrospective cohort study of 50 chronic kPJI patients treated with two types of articulating spacers between January 2014 and March 2022 was conducted. The clinical outcomes and functional status of the different articulating spacers were compared. Overall, 17 patients were treated with prosthetic spacers (prosthetic group (PG)), and 33 patients were treated with cement spacers (cement group (CG)). The CG had a longer mean follow-up period (46.67 months (SD 26.61)) than the PG (24.82 months (SD 16.46); p = 0.001). Results. Infection was eradicated in 45 patients overall (90%). The PG had a better knee range of motion (ROM) and Knee Society Score (KSS) after the first-stage revision (p = 0.004; p = 0.002), while both groups had similar ROMs and KSSs at the last follow-up (p = 0.136; p = 0.895). The KSS in the CG was significantly better at the last follow-up (p = 0.013), while a larger percentage (10 in 17, 58.82%) of patients in the PG chose to retain the spacer (p = 0.008). Conclusion. Prosthetic spacers and cement spacers are both effective at treating chronic kPJI because they encourage infection control, and the former improved knee function status between stages. For some patients, prosthetic spacers may not require reimplantation. Cite this article: Bone Joint Res 2024;13(6):306–314

Aims. This study aimed to evaluate the BioFire Joint Infection (JI) Panel in cases of hip and knee periprosthetic joint infection (PJI) where conventional microbiology is unclear, and to assess its role as a complementary intraoperative diagnostic tool. Methods. Five groups representing common microbiological scenarios in hip and knee revision arthroplasty were selected from our arthroplasty registry, prospectively maintained PJI databases, and biobank: 1) unexpected-negative cultures (UNCs), 2) unexpected-positive cultures (UPCs), 3) single-positive intraoperative cultures (SPCs), and 4) clearly septic and 5) aseptic cases. In total, 268 archived synovial fluid samples from 195 patients who underwent acute/chronic revision total hip or knee arthroplasty were included. Cases were classified according to the International Consensus Meeting 2018 criteria. JI panel evaluation of synovial fluid was performed, and the results were compared with cultures. Results. The JI panel detected microorganisms in 7/48 (14.5%) and 15/67 (22.4%) cases related to UNCs and SPCs, respectively, but not in cases of UPCs. The correlation between JI panel detection and infection classification criteria for early/late acute and chronic PJI was 46.6%, 73%, and 40%, respectively. Overall, the JI panel identified 12.6% additional microorganisms and three new species. The JI panel pathogen identification showed a sensitivity and specificity of 41.4% (95% confidence interval (CI) 33.7 to 49.5) and 91.1% (95% CI 84.7 to 94.9), respectively. In total, 19/195 (9.7%) could have been managed differently and more accurately upon JI panel evaluation. Conclusion. Despite its microbial limitation, JI panel demonstrated clinical usefulness by complementing the traditional methods based on multiple cultures, particularly in PJI with unclear microbiological results. Cite this article: Bone Joint Res 2024;13(7):353–361

Aims. The principle strategies of fracture-related infection (FRI) treatment are debridement, antimicrobial therapy, and implant retention (DAIR) or debridement, antimicrobial therapy, and implant removal/exchange. Increasing the period between fracture fixation and FRI revision surgery is believed to be associated with higher failure rates after DAIR. However, a clear time-related cut-off has never been scientifically defined. This systematic review analyzed the influence of the interval between fracture fixation and FRI revision surgery on success rates after DAIR. Methods. A systematic literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in PubMed (including MEDLINE), Embase, and Web of Science Core Collection, investigating the outcome after DAIR procedures of long bone FRIs in clinical studies published until January 2020. Results. Six studies, comprising 276 patients, met the inclusion criteria. Data from this review showed that with a short duration of infection (up to three weeks) and under strict preconditions, retention of the implant is associated with high success rates of 86% to 100%. In delayed infections with a fracture fixation-FRI revision surgery interval of three to ten weeks, absence of recurrent infection was reported in 82% to 89%. Data on late FRIs, with a fracture fixation-FRI revision surgery interval of more than ten weeks, are scarce and a success rate of 67% was reported. Conclusion. Acute/early FRI, with a short duration of infection, can successfully be treated with DAIR up to ten weeks after osteosynthesis. The limited available data suggest that chronic/late onset FRI treated with DAIR may be associated with a higher rate of recurrence. Successful outcome is dependent on managing all aspects of the infection. Thus, time from fracture fixation is not the only factor that should be considered in treatment planning of FRI. Due to the heterogeneity of the available data, these conclusions have to be interpreted with caution. Cite this article: Bone Joint J 2021;103-B(2):213–221

Aim. The aim of this investigation was to compare risk of infection in both cemented and cementless hemiarthroplasty (HA) as well as total hip arthroplasty (THA) following femoral neck fracture. Methods. Data collection was performed using the German Arthroplasty Registry (EPRD) In HA and THA following femoral neck fracture fixation method was divided into cemented and cementless protheses and paired according to age, sex, body mass index (BMI), and the Elixhauser score using Mahalanobis distance matching. Results. Overall in 13,612 cases of intracapsular femoral neck fracture, with 9,110 (66.9 %) HAs and 4502 (33.1 %) THAs were analyzed. Infection rate in HA was significantly reduced in cases with use of antibiotic-loaded cement compared to cementless fixated prosthesis (p=0.013). In patients with THA no statistical difference between cemented and cementless prothesis was registered, however after one year 2.4 % of infections were detected in cementless and 2.1 % in cemented THA. In the subpopulation of HA after one year 1.9 % of infections were registered in cemented and 2.8 % in cementless HA. BMI (p=0.001) and Elixhauser-Comorbidity-Score (p<0.003) were identified as risk factors of PJI, while in THA also cemented prosthesis demonstrated within the first 30 days an increased risk (HR=2.728; p=0.010). Conclusion. The rate of infection after intracapsular femoral neck fracture was significantly reduced in patients treated by antibiotic-loaded cemented hemiarthroplasty. In particular for patients with multiple risk factors for the development of a PJI the usage of antibiotic-loaded bone cement seems to be a reasonable procedure for prevention of infection

Aim. The current antibiotic treatment of periprosthetic joint infection (PJI) is optimized by measuring concentrations in plasma. However, it remains unclear whether effective concentrations of the antibiotics are reached at the site of PJI. Nonetheless, adequate target site concentrations are important to achieve effective eradication of the micro-organism. In order to determine the efficacy of cefuroxime and flucloxacillin in synovial fluid, synovial tissue and bone tissue in relation to the minimal inhibitory concentration (MIC) of the pathogen causing the PJI, we perform a pharmacokinetic/pharmacodynamic (PK/PD) study. Therefore, we aimed to develop validated analytical methods for analysis of cefuroxime and flucloxacillin in synovial fluid, synovial tissue and bone tissue. Method. Blank samples of synovial fluid, synovial tissue and bone tissue were obtained by orthopedic surgeons during surgery. For validation the samples of each matrix were spiked with both cefuroxime and flucloxacillin. Synovial tissue and bone tissue was pulverized with a mikro-dismembrator. Samples were kept frozen at −20°C until analysis. After a sample preparation quantification of cefuroxime and flucloxacillin in each matrix was performed on the ultra-performance convergence chromatography-tandem mass spectrometry (UPC2-MS/MS). Stable-isotope-labeled meropenem-d6 served as internal standard. The linearity, limits of quantification, accuracy and precision and carry-over were determined for all methods separately. The methods were validated according to the European Medicine Agency (EMA) and Food and Drug Administration (FDA) guidelines on bioanalytical method validation. Results. These methods were successfully validated for cefuroxime and flucloxacillin quantification in all matrices according to the EMA and FDA guidelines. The limits of quantification were adequate to cover potential cefuroxime and flucloxacillin concentration in synovial fluid, synovial tissue and bone tissue as described in literature, with a range of 1–100mg/L for synovial fluid and 1–20 µg/g for synovial tissue and bone tissue (r >0.995). Accuracy and within-run precision were validated according to acceptance values (RSD <15%). Carry over was less than 20%. Matrix effects and recovery were investigated for synovial fluid. The results were within the range of 80–120%. Conclusions. The results of the validation fall within the limits of quantification according to the EMA and FDA guidelines. Therefore, these methods can be applied during a PK/PD study to discover the exposure of antibiotics in synovial fluid, synovial tissue and bone tissue at the site of infection in patients with a PJI

Aim. Accurate diagnosis is key in correctly managing prosthetic joint infection (PJI). Our aim is to compare the preoperative performance of three PJI definitions comparing it to definitive postoperative classification. Method. This is a multicenter retrospective study of patients who have undergone total hip or knee revision surgery in four different European institutions. For this specific study, cases with no preoperative synovial fluid differential leukocyte count and less than four intraoperative microbiology samples were excluded. Cases were classified using the 2021 EBJIS, the 2018 International Consensus Meeting (ICM) and the 2013 Musculoskeletal Infection Society (MSIS) PJI definitions. Preoperative classification was based on clinical features, inflammatory markers and synovial fluid leukocyte count and microbiology results. Results. Preoperative and definitive PJI classification status of the 384 patients included are presented in figure 1. EBJIS definition showed the highest agreement between preoperative and definitive classification (k=0.86, CI95% 0.81–0.90, p<0.001) compared to ICM 2018 (k=0.80, CI95% 0.75–0.84, p<0.001) or MSIS 2013 (k=0.70, CI95% 0.62–0.77, p<0.001). Compared to its respective definitive classification: EBJIS preoperative unlikely result shows 86.8% (95%CI 81.3%–91.2%) sensitivity and 87.7% (95%CI 83.3%–91.1%) negative predictive value (NPV); ICM 2018 preoperative not infected result shows 83.5% (95%CI 77.4%–88.5%) sensitivity and 86.2% (95%CI 81.9%–88.6%) NPV and; MSIS 2013 preoperative not infected result shows 63.9% (95%CI 55.0%–72.1%) sensitivity and 84.3% (95%CI 81.1%–87.1%) NPV. Around half of the preoperative EBJIS likely (45.8%) and ICM 2018 inconclusive (54.5%) turn out to be infected postoperatively. If we consider the more sensitive definition (EBJIS) as the gold standard: ICM 2018 preoperative not infected result shows 75.1% (95%CI 68.5%–81.0%) sensitivity and 78.3% (95%CI 73.9%–82.2%) NPV and; MSIS 2013 preoperative not infected result shows 42.1% (95% CI 35.2%–49.4%) sensitivity and 62.0% (59.2%–64.8) NPV. Conclusions. The EBJIS 2021 definition is not only the most sensitive definition as it was shown to be the most effective in preoperatively ruling out PJI when there is a negative result. For any tables or figures, please contact the authors directly

Aim. There have been many attempts to define the criteria by which prosthetic joint infection (PJI) is diagnosed. Our aim is to validate the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI. Method. This is a multicenter retrospective study of patients who have undergone total hip or knee revision surgery in four different European institutions between 2013–2018. Cases with less than four intraoperative microbiology samples; no preoperative/intraoperative synovial fluid differential leukocyte count or intraoperative histology were excluded. Minimum follow-up of at least two years after revision surgery if no subsequent infection and/or the need for implant removal was also required. All cases were classified using the 2021 EBJIS, the 2018 International Consensus Meeting (ICM) and the 2013 Musculoskeletal Infection Society (MSIS) PJI definitions. Results. Definitive PJI classification according to the different definitions of the 507 patients included are presented in table 1. The EBJIS definition classifies 40.4%(205/507) of the cases as confirmed infections compared to 33.9%(p=0.038) and 29.4%(p<0.001) in 2018 ICM and 2013 MSIS classifications respectively. Compared to 2018 ICM classification it also offers significantly less undetermined cases – 5.0% vs. 11.4%(p<0.001). Free from infection Kaplan-Meyer survival curve shows significantly better outcome for EBJIS unlikely compared to confirmed subgroup(p=0.031). EBJIS likely subgroup survival is not significantly different from unlikely(p=0.529) or confirmed(p=0.717) cohorts. Among the MSIS not infected cohort the newly classified EBJIS confirmed/likely cases present higher subsequent infection rate (albeit not statistically significant) when compared to EBJIS infection unlikely cases − 16.0%(13/81) vs. 10.1%(28/277). This subsequent PJI rate is similar to the MSIS infected cohort. A similar trend is not obvious within ICM 2018 not infected subgroup. Conclusions. The EBJIS 2021 definition is shown to be the most sensitive definition while also offering a smaller number of undetermined cases. Newly diagnosed infections seem to have a similar prognosis as “classically” infected cases. For any tables or figures, please contact the authors directly

Aims. Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model. Methods. Staphylococcus aureus was inoculated into a humeral osteotomy in 17 rabbits after plate osteosynthesis. Infection developed for one week (early group, n = 6) or four weeks (delayed group, n = 6) before DAIR (systemic antibiotics: two weeks, nafcillin + rifampin; four weeks, levofloxacin + rifampin). A control group (n = 5) received revision surgery after four weeks without antibiotics. Bacteriology of humerus, soft-tissue, and implants was performed seven weeks after revision surgery. Bone healing was assessed using a modified radiological union scale in tibial fractures (mRUST). Results. Greater bacterial burden in the early group compared to the delayed and control groups at revision surgery indicates a retraction of the infection from one to four weeks. Infection was cleared in all animals in the early and delayed groups at euthanasia, but not in the control group. Osteotomies healed in the early group, but bone healing was significantly compromised in the delayed and control groups. Conclusion. The duration of the infection from one to four weeks does not impact the success of infection clearance in this model. Bone healing, however, is impaired as the duration of the infection increases. Cite this article: Bone Joint Res 2024;13(3):127–135

Aims. We aimed to report the mid- to long-term rates of septic and aseptic failure after two-stage revision surgery for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). Methods. We retrospectively reviewed 96 cases which met the Musculoskeletal Infection Society criteria for PJI. The mean follow-up was 90 months (SD 32). Septic failure was assessed using a Delphi-based consensus definition. Any further surgery undertaken for aseptic mechanical causes was considered as aseptic failure. The cumulative incidence with competing risk analysis was used to predict the risk of septic failure. A regression model was used to evaluate factors associated with septic failure. The cumulative incidence of aseptic failure was also analyzed. Results. There were 23 septic failures at final follow-up, with a cumulative incidence of 14% (95% confidence interval (CI) 8% to 22%) at one year, 18% (95% CI 11% to 27%) at two years, 22% (95% CI 14% to 31%) at five years, and 23% (95% CI 15% to 33%) at ten years. Having at least one positive culture (hazard ratio (HR) 2.38 (interquartile range (IQR) 1.19 to 4.74); p = 0.013), or a positive intraoperative frozen section (HR 2.55 (IQR 1.06 to 6.15); p = 0.037) was significantly associated with septic failure after reimplantation. With dislocation being the most common cause of aseptic revision (5.2%), the cumulative incidence of aseptic failure was 1% (95% CI 0% to 5%) at one year, 6% (95% CI 1% to 8%) at five years, and 8% (95%CI 3% to 17%) at ten years. Conclusion. If there is no recurrent infection in the five years following reimplantation, the chances of further infection thereafter are remote. While the results of a frozen section may be a reliable guide to the timing of reimplantation, intraoperative culture has, currently, only prognostic value. Surgeons should be aware that instability remains a potential indication for further revision surgery. Cite this article: Bone Joint J 2021;103-B(1):79–86

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. Methods. We identified 33 patients who underwent treatment for PJIs of the hip between January 2010 and December 2019 using our institutional joint registry. Mean age was 82 years (80 to 90), with 19 females (57%) and a mean BMI of 26 kg/m. 2. (17 to 41). Mean American Society of Anesthesiologists (ASA) grade was 3 (1 to 4) and mean Charlson Comorbidity Index was 6 (4 to 10). Leading pathogens included coagulase-negative Staphylococci (45%) and Enterococcus faecalis (9%). Two-stage exchange was performed in 30 joints and permanent resection arthroplasty in three. Kaplan-Meier survivorship analyses were performed. Mean follow-up was five years (3 to 7). Results. The two-year survivorship free of any recurrent PJI was 72% (95% confidence interval (CI) 56 to 89; 18 patients at risk). There were a total of nine recurrent PJIs at a mean of one year (16 days to eight years), one for the same pathogen as at index infection. One additional surgical site infection was noted at two weeks, resulting in a 69% (95% CI 52 to 86; 17 patients at risk) survivorship free of any infection at two years. There were two additional revisions for dislocations at one month each. As such, the two-year survivorship free of any revision was 61% (95% CI 42 to 80; 12 patients at risk). In addition to the aforementioned revisions, there was one additional skin grafting for a decubitus ulcer, resulting in a survivorship free of any reoperation of 54% (95% CI 35 to 73; ten patients at risk) at two years. Mean Clavien-Dindo score of perioperative complications was two out of five, with one case of perioperative death noted at six days. Conclusion. Octogenarians undergoing surgery for PJI of the hip are at low risk of acute mortality, but are at moderate risk of other perioperative complications. One in two patients will undergo a reoperation within two years, with 70% attributable to recurrent infections. Cite this article: Bone Joint J 2023;105-B(2):135–139

Aims. Despite numerous studies focusing on periprosthetic joint infections (PJIs), there are no robust data on the risk factors and timing of metachronous infections. Metachronous PJIs are PJIs that can arise in the same or other artificial joints after a period of time, in patients who have previously had PJI. Methods. Between January 2010 and December 2018, 661 patients with multiple joint prostheses in situ were treated for PJI at our institution. Of these, 73 patients (11%) developed a metachronous PJI (periprosthetic infection in patients who have previously had PJI in another joint, after a lag period) after a mean time interval of 49.5 months (SD 30.24; 7 to 82.9). To identify patient-related risk factors for a metachronous PJI, the following parameters were analyzed: sex; age; BMI; and pre-existing comorbidity. Metachronous infections were divided into three groups: Group 1, metachronous infections in ipsilateral joints; Group 2, metachronous infections of the contralateral lower limb; and Group 3, metachronous infections of the lower and upper limb. Results. We identified a total of 73 metachronous PJIs: 32 PJIs in Group 1, 38 in Group 2, and one in Group 3. The rate of metachronous infection was 11% (73 out 661 cases) at a mean of four years following first infection. Diabetes mellitus incidence was found significantly more frequently in the metachronous infection group than in non-metachronous infection group. The rate of infection in Group 1 (21.1%) was significantly higher (p = 0.049) compared to Groups 2 (6.2%) and 3 (3%). The time interval of metachronous infection development was shorter in adjacent joint infections. Concordance between the bacterium of the first PJI and that of the metachronous PJI in Group 1 (21/34) was significantly higher than Group 2 (13/38; p = 0.001). Conclusion. The findings of this study suggest that metachronous PJI occurs in more than one in ten patients with an index PJI. Female patients, diabetic patients, and patients with a polymicrobial index PJI are at significantly higher risk for developing a metachronous PJI. Furthermore, metachronous PJIs are significantly more likely to occur in an adjacent joint (e.g. ipsilateral hip and knee) as opposed to a more remote site (i.e. contralateral or upper vs lower limb). Additionally, adjacent joint PJIs occur significantly earlier and are more likely to be caused by the same bacteria as the index PJI. Cite this article: Bone Joint J 2023;105-B(3):294–300

Aims. This study evaluated the definitions developed by the European Bone and Joint Infection Society (EBJIS) 2021, the International Consensus Meeting (ICM) 2018, and the Infectious Diseases Society of America (IDSA) 2013, for the diagnosis of periprosthetic joint infection (PJI). Methods. In this single-centre, retrospective analysis of prospectively collected data, patients with an indicated revision surgery after a total hip or knee arthroplasty were included between 2015 and 2020. A standardized diagnostic workup was performed, identifying the components of the EBJIS, ICM, and IDSA criteria in each patient. Results. Of 206 included patients, 101 (49%) were diagnosed with PJI with the EBJIS definition. IDSA and ICM diagnosed 99 (48%) and 86 (42%) as infected, respectively. A total of 84 cases (41%) had an infection based on all three criteria. In 15 cases (n = 15/206; 7%), PJI was present when applying only the IDSA and EBJIS criteria. No infection was detected by one definition alone. Inconclusive diagnoses occurred more frequently with the ICM criteria (n = 30/206; 15%) compared to EBJIS (likely infections: n = 16/206; 8%) (p = 0.029). A better preoperative performance of the EBJIS definition was seen compared with the ICM and IDSA definitions (p < 0.001). Conclusion. The novel EBJIS definition identified all PJIs diagnosed by any other criteria. Use of the EBJIS definition significantly reduced the number of uncertain diagnoses, allowing easier clinical decision-making. Cite this article: Bone Joint Res 2022;11(9):608–618

The June 2023 Research Roundup. 360. looks at: Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee; Predicted waiting times for orthopaedic surgery: an urgent need to address the deficit in capacity; Vascular impulse technology versus elevation for reducing the swelling of upper and lower limb joint fractures; Desperate patients will accept higher risks; How long does it take to find a positive culture in periprosthetic joint infection?

Aim. Synovial fluid investigation is the best alternative to diagnose prosthetic joint infection (PJI) before adequate microbiological/histology sampling during revision surgery. Although accurate preoperative diagnosis is certainly recommended, puncturing every patient before revision arthroplasty raises concerns about safety and feasibility issues especially in difficult to access joint (e.g., hip), that often require OR time and fluoroscopy/ultrasound guidance. Currently there is no clear guidelines regarding optimal indications to perform preoperative joint aspiration to diagnose PJI before revision surgery. The main goal of this study is to determine the accuracy of our institutional criteria using the new European Bone and Joint Infection Society (EBJIS) PJI definition. Method. We retrospectively evaluated every single- or first-stage for presumed aseptic or known infected revision total hip/knee arthroplasty procedures between 2013–2020. Preoperative clinical and laboratory features were systematically scrutinized. Cases with insufficient information for accurate final PJI diagnosis (i.e., no perioperative synovial fluid examination or no multiple cultures including sonication of removed implant) were excluded. Preoperative joint aspiration is recommended in our institution if any of the following criteria are met: 1) elevated CRP and/or ESR; 2) early failure (<2 years) or repeat failure; 3) high clinical suspicion/risk factors are present. Performance of such criteria were compared against final postoperative EBJIS definition PJI diagnosis. Results. A total of 364 revision THAs or TKAs were performed during the study period. After excluding 258 cases with insufficient information, a total of 106 patients were ultimately included. 38 (35,8 %) were classified as confirmed infections, 10 (9.4 %) as likely infected and 58 (54.7%) as infection unlikely. Of those, 37 confirmed infection cases, 9 likely infected cases and 32 infection unlikely cases did have indication for preoperative synovial fluid collection before revision surgery. Institutional criteria showed 95.8 % Sensitivity, 44.83 % Specificity, 92.9 % Negative Predictive Value (NPV) and 59 % Positive Predictive Value (PPV). Conclusions. Sensitivity and NPV of the aforementioned institutional criteria are very high even with the use of the more sensitive EBJIS PJI definition. As such they seem to be a valid alternative in selecting patients that should be punctured before revision arthroplasty. They identify the vast majority of infected patients while saving a significant number of patients from unnecessary procedures

Aims. Musculoskeletal infection is a devastating complication in both trauma and elective orthopaedic surgeries that can result in significant morbidity. Aim of this study was to assess the effectiveness and complications of local antibiotic impregnated dissolvable synthetic calcium sulphate beads (Stimulan Rapid Cure) in the hands of different surgeons from multiple centres in surgically managed bone and joint infections. Methods. Between January 2019 and December 2022, 106 patients with bone and joint infections were treated by five surgeons in five hospitals. Surgical debridement and calcium sulphate bead insertion was performed for local elution of antibiotics in high concentration. In all, 100 patients were available for follow-up at regular intervals. Choice of antibiotic was tailor made for each patient in consultation with microbiologist based on the organism grown on culture and the sensitivity. In majority of our cases, we used a combination of vancomycin and culture sensitive heat stable antibiotic after a thorough debridement of the site. Primary wound closure was achieved in 99 patients and a split skin graft closure was done in one patient. Mean follow-up was 20 months (12 to 30). Results. Overall, six out of 106 patients (5.6%) presented with sepsis and poorly controlled comorbid conditions, and died in the hospital within few days of index surgery. Out of the remaining 100 patients, control of infection was achieved in 95 patients (95%). Persistence of infection was noted in five (5%) patients. Out of these 95 patients that had good control of infection, four patients (4.2%) with gap nonunion needed Masquelet procedure to achieve union. Conclusion. Our multicentre experience confirmed that surgical debridement along with calcium sulphate bead insertion was effective in treating bone and joint infections without any side effects and complications. Cite this article: Bone Jt Open 2023;4(7):516–522

Aims. There is a paucity of long-term studies analyzing risk factors for failure after single-stage revision for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). We report the mid- to long-term septic and non-septic failure rate of single-stage revision for PJI after THA. Methods. We retrospectively reviewed 88 cases which met the Musculoskeletal Infection Society (MSIS) criteria for PJI. Mean follow-up was seven years (1 to 14). Septic failure was diagnosed with a Delphi-based consensus definition. Any reoperation for mechanical causes in the absence of evidence of infection was considered as non-septic failure. A competing risk regression model was used to evaluate factors associated with septic and non-septic failures. A Kaplan-Meier estimate was used to analyze mortality. Results. The cumulative incidence of septic failure was 8% (95% confidence interval (CI) 3.5 to 15) at one year, 13.8% (95% CI 7.6 to 22) at two years, and 19.7% (95% CI 12 to 28.6) at five and ten years of follow-up. A femoral bone defect worse than Paprosky IIIA (hazard ratio (HR) 13.58 (95% CI 4.86 to 37.93); p < 0.001) and obesity (BMI ≥ 30 kg/m. 2. ; HR 3.88 (95% CI 1.49 to 10.09); p = 0.005) were significantly associated with septic failure. Instability and periprosthetic fracture were the most common reasons for mechanical failure (5.7% and 4.5%, respectively). The cumulative incidence of aseptic failure was 2% (95% CI 0.4 to 7) at two years, 9% (95% CI 4 to 17) at five years, and 12% (95% CI 5 to 22) at ten years. A previous revision to treat PJI was significantly associated with non-septic failure (HR 9.93 (95% CI 1.77 to 55.46); p = 0.009). At the five-year timepoint, 93% of the patients were alive (95% CI 84% to 96%), which fell to 86% (95% CI 75% to 92%) at ten-year follow-up. Conclusion. Massive femoral bone loss was associated with greater chances of developing a further septic failure. All septic failures occurred within the first five years following the one-stage exchange. Surgeons should be aware of instability and periprosthetic fracture being potential causes of further aseptic revision surgery. Cite this article: Bone Joint J 2021;103-B(7):1247–1253

Aims. With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases. Methods. A retrospective review of 25 patients who underwent PFA for non-neoplastic indications between January 2009 and December 2015 was undertaken. Their clinical and radiological outcome, complication rates, and survival were recorded. All patients had the Stanmore Implant – Modular Endo-prosthetic Tumour System (METS). Results. At mean follow-up of 5.9 years, there were no periprosthetic fractures. Clearance of infection was achieved in 63.6% of cases. One hip was re-revised to pseudo arthroplasty for deep infection. Instability was noted in eight of the hips (32%), of which seven needed further surgery. Out of these eight hips with instability, five had preoperative infection. Deep infection was noted in five of the hips (20%), of which four were primarily revised for infection. One patient had aseptic loosening of the femoral component and awaits revision surgery. The Kaplan-Meier survivorship free of revision of any component for any reason was 72% (95% confidence interval (CI) 51.3% to 92.7%), and for revisions of only femoral component for any reason was 96% (95% CI 86.3% to 105.7%) at five years. Conclusion. Dislocation and infection remain the major cause for failure, particularly in patients with pre-existing infection. The use of dual mobility cups, silver-coated implants, and less aggressive postoperative rehabilitation regimens would possibly aid in the reduction of complications. PFA performed in patients with periprosthetic fracture seem to fair better. This study supports the judicious use of PFA in non-oncological revision hip arthroplasties, and that they be performed by experienced revision arthroplasty surgeons. Cite this article: Bone Jt Open 2022;3(3):229–235

Aims. This work aimed at answering the following research questions: 1) What is the rate of mechanical complications, nonunion and infection for head/neck femoral fractures, intertrochanteric fractures, and subtrochanteric fractures in the elderly USA population? and 2) Which factors influence adverse outcomes?. Methods. Proximal femoral fractures occurred between 1 January 2009 and 31 December 2019 were identified from the Medicare Physician Service Records Data Base. The Kaplan-Meier method with Fine and Gray sub-distribution adaptation was used to determine rates for nonunion, infection, and mechanical complications. Semiparametric Cox regression model was applied incorporating 23 measures as covariates to identify risk factors. Results. Union failure occured in 0.89% (95% confidence interval (CI) 0.83 to 0.95) after head/neck fracturs, in 0.92% (95% CI 0.84 to 1.01) after intertrochanteric fracture and in 1.99% (95% CI 1.69 to 2.33) after subtrochanteric fractures within 24 months. A fracture-related infection was more likely to occur after subtrochanteric fractures than after head/neck fractures (1.64% vs 1.59%, hazard ratio (HR) 1.01 (95% CI 0.87 to 1.17); p < 0.001) as well as after intertrochanteric fractures (1.64% vs 1.13%, HR 1.31 (95% CI 1.12 to 1.52); p < 0.001). Anticoagulant use, cerebrovascular disease, a concomitant fracture, diabetes mellitus, hypertension, obesity, open fracture, and rheumatoid disease was identified as risk factors. Mechanical complications after 24 months were most common after head/neck fractures with 3.52% (95% CI 3.41 to 3.64; currently at risk: 48,282). Conclusion. The determination of complication rates for each fracture type can be useful for informed patient-clinician communication. Risk factors for complications could be identified for distinct proximal femur fractures in elderly patients, which are accessible for therapeutical treatment in the management. Cite this article: Bone Jt Open 2023;4(10):801–807

Aims. Uncemented implants are now commonly used at reimplantation of a two-stage revision total hip arthoplasty (THA) following periprosthetic joint infection (PJI). However, there is a paucity of data on the performance of the most commonly used uncemented femoral implants – modular fluted tapered (MFT) femoral components – in this setting. This study evaluated implant survival, radiological results, and clinical outcomes in a large cohort of reimplantation THAs using MFT components. Methods. We identified 236 reimplantation THAs from a single tertiary care academic institution from September 2000 to September 2020. Two designs of MFT femoral components were used as part of an established two-stage exchange protocol for the treatment of PJI. Mean age at reimplantation was 65 years (SD 11), mean BMI was 32 kg/m. 2. (SD 7), and 46% (n = 109) were female. Mean follow-up was seven years (SD 4). A competing risk model accounting for death was used. Results. The 15-year cumulative incidence of any revision was 24%. There were 48 revisions, with the most common reasons being dislocation (n = 25) and infection (n = 16). The 15-year cumulative incidence of any reoperation was 28%. Only 13 revisions involved the fluted tapered component (FTC), for a 15-year cumulative incidence of any FTC revision of 8%. Only two FTCs were revised for aseptic loosening, resulting in a 15-year cumulative incidence of FTC revision for aseptic loosening of 1%. Stem subsidence ≥ 5 mm occurred in 2% of unrevised cases. All stems were radiologically stable at most recent follow-up. Mean Harris Hip Score was 69 (SD 20) at most recent follow-up. Conclusion. This series demonstrated that MFT components were durable and reliable in the setting of two-stage reimplantation THA for infection. While the incidence of aseptic loosening was very low, the incidence of any revision was 24% at 15 years, primarily due to dislocation and recurrent PJI. Cite this article: Bone Joint J 2024;106-B(5 Supple B):125–132

The April 2023 Spine Roundup. 360. looks at: Percutaneous transforaminal endoscopic discectomy versus microendoscopic discectomy; Spine surgical site infections: a single debridement is not enough; Lenke type 5, anterior, or posterior: systematic review and meta-analysis; Epidural steroid injections and postoperative infection in lumbar decompression or fusion; Noninferiority of posterior cervical foraminotomy versus anterior cervical discectomy; Identifying delays to surgical treatment for metastatic disease; Cervical disc replacement and adjacent segment disease: the NECK trial; Predicting complication in adult spine deformity surgery

Aims. Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models. Methods. Literature research was performed on PubMed and Embase databases. Keywords used for search criteria were “bone AND biofilm”. Information on the species of the animal model, bacterial strain, evaluation of biofilm and bone infection, complications, key findings on observations, prevention, and treatment of biofilm were extracted. Results. A total of 43 studies were included. Animal models used included fracture-related infections (ten studies), periprosthetic joint infections (five studies), spinal infections (three studies), other implant-associated infections, and osteomyelitis. The most common bacteria were Staphylococcus species. Biofilm was most often observed with scanning electron microscopy. The natural history of biofilm revealed that the process of bacteria attachment, proliferation, maturation, and dispersal would take 14 days. For systemic mono-antibiotic therapy, only two of six studies using vancomycin reported significant biofilm reduction, and none reported eradication. Ten studies showed that combined systemic and topical antibiotics are needed to achieve higher biofilm reduction or eradication, and the effect is decreased with delayed treatment. Overall, 13 studies showed promising therapeutic potential with surface coating and antibiotic loading techniques. Conclusion. Combined topical and systemic application of antimicrobial agents effectively reduces biofilm at early stages. Future studies with sustained release of antimicrobial and biofilm-dispersing agents tailored to specific pathogens are warranted to achieve biofilm eradication. Cite this article: Bone Joint Res 2022;11(10):700–714

Aims. Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors. Methods. We retrospectively included 125 patients with chronic hip PJI who underwent a staged THA revision performed between January 2013 and December 2019. All spacer complications were systematically collected, and risk factors were analyzed. Statistical evaluations were performed using the Student's t-test, Mann-Whitney U test, and Fisher's exact test. Results. Our staged exchange practice shows poor results, which means a 42% mechanical spacer failure rate, and a 20% recurrent infection rate over the two years average follow-up period. Moreover, we found a high rate of spacer dislocation (23%) and a low rate of spacer fracture (8%) compared to the previous literature. Our findings stress that the majority of spacer complications and failures is reflecting a population with high comorbid burden, highlighted by the American Society of Anesthesiology grade, Charlson Comorbidity Index, and Lee score associations, as well as the cardiac, pulmonary, kidney, or hepatic chronic conditions. Conclusion. Our experience of a two-stage hip exchange revision noted important complication rates associated with high failure rates of polymethylmethacrylate spacers. These findings must be interpreted in the light of the patient’s comorbidity profiles, as the elective population for staged exchange has an increasing comorbid burden leading to poor results. In order to provide better results for this specific population, our conclusion suggests that comparative strategy studies are required to improve our therapeutic indication. Cite this article: Bone Jt Open 2022;3(6):485–494

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. Methods. Patients undergoing one- or two-stage revision of a primary THA for PJI between January 2008 and January 2021 were identified. Age, sex, BMI, American Society of Anesthesiologists grade, Charlson Comorbidity Index (CCI), McPherson systemic host grade, and causative organism were collated for all patients. PJI was classified as ‘confirmed’, ‘likely’, or ‘unlikely’ according to the 2021 European Bone and Joint Infection Society criteria. Primary outcomes were complications, reoperation, re-revision, and successful treatment of PJI. A total of 37 patients aged 80 years or older and 120 patients aged under 80 years were identified. The octogenarian group had a significantly lower BMI and significantly higher CCI and McPherson systemic host grades compared to the younger cohort. Results. The majority of patients were planned to undergo two-stage revision, although a significantly higher proportion of the octogenarians did not proceed with the second stage (38.7% (n = 12) vs 14.8% (n = 16); p = 0.003). Although there was some evidence of a lower complication rate in the younger cohort, this did not reach statistical significance (p = 0.065). No significant difference in reoperation (21.6% (n = 8) vs 25.0% (n = 30); p = 0.675) or re-revision rate (8.1% (n = 3) vs 16.7% (n = 20); p = 0.288) was identified between the groups. There was no difference in treatment success between groups (octogenarian 89.2% (n = 33) vs control 82.5% (n = 99); p = 0.444). Conclusion. When compared to a younger cohort, octogenarians did not show a significant difference in complication, re-revision, or treatment success rates. However, given they are less likely to be eligible to proceed with second stage revision, consideration should be given to either single-stage revision or use of an articulated spacer to maximize functional outcomes. Cite this article: Bone Joint J 2024;106-B(8):802–807

Purpose. Fracture-related infection (FRI) is an important complication related to orthopaedic trauma. Although the scientific interest with respect to the diagnosis and treatment of FRI is increasing, data on the microbiological epidemiology remains limited. Therefore, the primary aim of this study was to evaluate the microbiological epidemiology related to FRI, including the association with clinical symptoms and antimicrobial susceptibility data. The secondary aim was to analyze whether there was a relationship between the time to onset of infection and the microbiological etiology of FRI. Methods. Over a five-year period, FRI patients treated at the University Hospitals of Leuven, Belgium, were retrospectively included. The microbiological etiology and antimicrobial susceptibility data were analyzed. Patients were classified as having an early (<2 weeks after implantation), delayed (2–10 weeks) or late-onset (> 10 weeks) FRI. Results. One hundred ninety-one patients with 194 FRIs, mainly involving the tibia (23.7%) and femur (18.6%), were included. Staphylococcus aureus was the most frequently isolated pathogen, regardless of time to onset (n=61; 31.4%), followed by S. epidermidis (n=50; 25.8%) and non-epidermidis coagulase-negative staphylococci (n=35; 18.0%). Polymicrobial infections (n=49; 25.3%), mainly involving Gram-negative bacilli (n=32; 65.3%), were less common than monomicrobial infections (n=138; 71.1%). Virulent pathogens in monomicrobial FRIs were more likely to cause pus or purulent discharge (n=45;54.9%; p=0.002) and fistulas (n=21;25.6%; p=0.030). Susceptibility to piperacillin/tazobactam for GNB was 75.9%. Vancomycin covered 100% of Gram-positive cocci. Conclusion. The high frequency of polymicrobial infections, including Enterobacterales and enterococci, should be considered when choosing an empirical regimen, especially for early FRI. However, since antibiotic stewardship is the cornerstone of good antibiotic practice, overuse and misuse of broad-spectrum empiric therapy should be avoided at all costs. Large multicenter prospective studies are necessary to gain more insight into the added value of (broad) empirical antibiotic therapy

Aims. We compared the risks of re-revision and mortality between two-stage revision surgery and single-stage revision surgery among patients with infected primary knee arthroplasty. Methods. Patients with a periprosthetic joint infection (PJI) of their primary knee arthroplasty, initially revised with a single-stage or a two-stage procedure in England and Wales between 2003 and 2014, were identified from the National Joint Registry. We used Poisson regression with restricted cubic splines to compute hazard ratios (HR) at different postoperative periods. The total number of revisions and re-revisions undergone by patients was compared between the two strategies. Results. A total of 489 primary knee arthroplasties were revised with single-stage procedure (1,390 person-years) and 2,377 with two-stage procedure (8,349 person-years). The adjusted incidence rates of all-cause re-revision and for infection were comparable between these strategies (HR overall five years, 1.15 (95% confidence interval (CI) 0.87 to 1.52), p = 0.308; HR overall five years, 0.99 (95% CI 0.70 to 1.39), p = 0.949, respectively). Patients initially managed with single-stage revision received fewer revision procedures overall than after two-stage revision (1.2 vs 2.2, p < 0.001). Mortality was lower for single-stage revision between six and 18 months postoperative (HR at six months, 0.51 (95% CI 0.25 to 1.00), p = 0.049 HR at 18 months, 0.33 (95% CI 0.12 to 0.99), p = 0.048) and comparable at other timepoints. Conclusion. The risk of re-revision was similar between single- and two-stage revision for infected primary knee arthroplasty. Single-stage group required fewer revisions overall, with lower or comparable mortality at specific postoperative periods. The single-stage revision is a safe and effective strategy to treat infected knee arthroplasties. There is potential for increased use to reduce the burden of knee PJI for patients, and for the healthcare system. Cite this article: Bone Joint Res 2022;11(10):690–699

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

Aim. One of the most severe complications of primary total knee arthroplasty (TKA) is periprosthetic joint infection (PJI). Nowadays, the use of antibiotic-loaded cement for prevention of infection is still controversial. The aim of the present study is to evaluate the use of an antibiotic-loaded cement to reduce the infection rate in primary total knee arthroplasty. Method. Prospective randomized study, with 2893 cemented total knee arthroplasties performed between 2005 and 2010 in our institution. Two different groups were formed depending on which bone cement was used, without antibiotic (the control group) or loaded with erythromycin and colistin (the study group). All patients received the same systemic prophylactic antibiotics. The patients were followed for a minimum of twelve months. The rate of infection was analyzed according to the criteria of the Centers for Disease Control and Prevention (CDC). Results. In 1452 patients the prosthetic components were fixed using bone cement without antibiotic and in 1441 patients bone cement loaded with erythromycin and colistin was used. There were no differences between both groups in terms of demographic data (age, sex and BMI), either in operating time (p>0,05). The rate of infection was similar in both groups, being 2,0% (n=29) in the control group and 1,7% in the study group (p=0,58) at 8,7 years (SD 5,1) of follow up. In terms of prosthetic revision due to any cause (infected or aseptic), there wasn't differences between groups, performing a total of 61 revision arthroplasties in control group and 68 in study group (p>0,05). Moreover, we analyzed the erythromycin resistance rate, being no differences between both groups (p=0.6). Conclusions. The use of erythromycin and colistin-loaded bone cement in total knee arthroplasty did not lead to a decrease in the rate of infection when systemic prophylactic antibiotics were used, a finding that suggests that its use would not be indicated in the general population

Aims. Despite numerous studies on periprosthetic joint infections (PJI), there are no robust data on the risk factors and timing of metachronous infections. This study was performed to answer the following questions: 1) Is there any difference of manifestation time of metachronous PJIs between different localizations of multiple artificial joints? 2) Can we identify any specific risk factor for metachronous PJIs for different localizations of multiple artificial joints?. Methods. Between January 2010 and December 2018, 661 patients with more than one prosthetic joint at the time of PJI surgical treatment were recruited. Seventy-one developed metachronous PJI after a mean time interval of 101.4 months (range 37.5 to 161.5 months). The remaining patients were chosen as control group. The diagnosis of the PJI, including the metachronous PJI, was made according to the Muscoloskeletal Infection Society (MSIS) criteria. The metachronous infections were divided in group 1: metachronous infections in the same extremity (e.g. right hip and right knee); group 2: metachronous infections of the other extremity (e.g. right knee and left hip); group 3: metachronous infections of the lower extremity and upper extremity (e.g. right knee and left shoulder). Results. We identified 32 PJI cases in group 1, 38 in group 2 and 1 in group 3. Diabetes mellitus was found higher in the metachronous infections (p<0.05). Rate of same side infection was significantly higher compared to contralateral and upper and lower infection (p<0.05). Time interval of metachrononous infection development was faster in same-side infections. Same bacteria sample rate between primary PJI and metachronous PJI in same side infections (21/32) was significantly higher than in the contralateral PJI group (13/38, p<0.05). Conclusions. The current study underlined that the risk of metachronous infections are relatively high, particularly in the cases of prostheses on the same side

Aim. In recent years, many studies on revision for infection after arthroplasty have been published. In national arthroplasty registers, revision for infection is defined as surgical debridement, with or without removal or exchange of the entire or parts of the prosthesis due to deep infection, and should be reported to the register immediately after surgery. The diagnosis of infection is made at the surgeon's discretion, based on pre- and perioperative assessment and evaluation, and is not to be corrected to the register based on peroperative bacterial cultures. Due to this lack of validation, the rate of revision for infection will only be an approximation of the true rate of periprosthetic joint infection (PJI). Our aim was to validate the reporting of infection after total hip arthroplasty, and to assess if revisions for infection actually represented true PJI. Methods. We investigated the reported revisions for infection and aseptic loosening after total hip arthroplasty from 12 hospitals, representing one region of the country, reported during the period 2010–2020. The electronic patient charts were investigated for information on surgical treatment, use of antibiotics, biochemistry and microbiology findings. PJI was defined as growth of at least two phenotypically identical microbes in perioperative tissue samples. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated. Results. 145 revisions for infection and 137 revisions for aseptic loosening were reported. Of the reported infections, there were 141/145 true positives and 4/145 false positives. Of the reported aseptic loosenings, there were 126/137 true negatives and 11/137 false negatives. This gives a positive predictive value of 0.97, negative predictive value of 0.92, sensitivity of 0.93, specificity of 0.97 and accuracy of 0.95. Interpretation. We found the reporting revision for infection after total hip arthroplasty to the national register accurate. There was high correlation between reported revision for infection and PJI. Studies on revision for infection from arthroplasty registers may therefore be considered as reliable as studies of true PJI

Aims. Pelvic discontinuity is a challenging acetabular defect without a consensus on surgical management. Cup-cage reconstruction is an increasingly used treatment strategy. The present study evaluated implant survival, clinical and radiological outcomes, and complications associated with the cup-cage construct. Methods. We included 53 cup-cage construct (51 patients) implants used for hip revision procedures for pelvic discontinuity between January 2003 and January 2022 in this retrospective review. Mean age at surgery was 71.8 years (50.0 to 92.0; SD 10.3), 43/53 (81.1%) were female, and mean follow-up was 6.4 years (0.02 to 20.0; SD 4.6). Patients were implanted with a Trabecular Metal Revision Shell with either a ZCA cage (n = 12) or a TMARS cage (n = 40, all Zimmer Biomet). Pelvic discontinuity was diagnosed on preoperative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed, with failure defined as revision of the cup-cage reconstruction. Results. The five-year all-cause survival for cup-cage reconstruction was 73.4% (95% confidence interval (CI) 61.4 to 85.4), while the ten- and 15-year survival was 63.7% (95% CI 46.8 to 80.6). Survival due to aseptic loosening was 93.4% (95% CI 86.2 to 100.0) at five, ten, and 15 years. The rate of revision for aseptic loosening, infection, and dislocation was 3/53 (5.7%), 7/53 (13.2%), and 6/53 (11.3%), respectively. The mean leg length discrepancy improved (p < 0.001) preoperatively from a mean of 18.2 mm (0 to 80; SD 15.8) to 7.0 mm (0 to 35; SD 9.8) at latest follow-up. The horizontal and vertical hip centres improved (p < 0.001) preoperatively from a mean of 9.2 cm (5.6 to 17.5; SD 2.3) to 10.1 cm (6.2 to 13.4; SD 2.1) and 9.3 cm (4.7 to 15.8; SD 2.5) to 8.0 cm (3.7 to 12.3; SD 1.7), respectively. Conclusion. Cup-cage reconstruction provides acceptable outcomes in the management of pelvic discontinuity. One in four constructs undergo revision within five years, most commonly for periprosthetic joint infection, dislocation, or aseptic loosening. Cite this article: Bone Joint J 2024;106-B(5 Supple B):66–73

To determine risk factors of infection in total knee arthroplasty. This descriptive study was conducted in the Department of Orthopedics for a duration of three years from January 2016 to January 2019. All patients undergoing primary total knee replacement were included in the study. Exclusion criteria were all patients operated in another hospital and revision total knee replacement. All patients were followed up at 2, 4, 8, 12 and 24 weeks post-operatively. Signs of inflammation and inflammatory markers such as total leukocyte count (TLC), C-reactive protein (CRP) and ESR were measured. Risk factors like age, body mass index (BMI), ASA, co-morbid conditions were also noted. A total of 78 patients underwent primary unilateral Total Knee Replacement (TKR) during the study period. Of these, 30 (34.09%) were male and 48 (61.54%) female patients. Mean age of patients was 68.32 ± 8.54 years. Average BMI 25.89 Kg/m2 .Osteoarthritis was the pre-dominant cause of total knee replacement (94.87%). Among co-morbid factors 33.33% were diabetic, 28.20% having ischemic heart disease and 12.82% with chronic lung disease. Upon anaesthesia fitness pre-operatively, 91.02% patients had an American society of anaesthesiologist score (ASA) between 0–2 while 07 (8.97%) between 3- 5. Average duration of surgery was 85.62± 4.11 minutes. 6.41% cases got infected. In majority of the infected cases (60%), Staphylococcus aureus was the infective organism. Diabetes Mellitus (p=0.01) and Obesity (p=0.02) had a significant relation to post-operative infection. Pre-operative risk evaluation and prevention strategies along with early recognition of infection and control can greatly reduce the risk of joint infection post-TKR which will not only improve the mobility of patient but also its morbidity and mortality as well. Key Words:. C-reactive protein (CRP), Erythrocyte Sedimentation Rate (ESR), Staphylococcus aureus, Total Knee Arthroplasty (TKA)

Aims. There are limited long-term studies reporting on outcomes of the Zimmer Modular Revision (ZMR) stem, and concerns remain regarding failure. Our primary aim was to determine long-term survival free from all-cause revision and stem-related failure for this modular revision stem in revision total hip arthroplasty (THA). Secondary aims included evaluating radiological and functional outcomes. Methods. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR system from January 2000 to December 2007. We included 106 patients (108 hips) with a mean follow-up of 14.5 years (2.3 to 22.3). Mean patient age was 69.2 years (37.0 to 89.4), and 51.9% were female (n = 55). Indications for index revision included aseptic loosening (73.1%), infection (16.7%), fracture (9.3%), and stem fracture (0.9%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. At most recent follow-up, Oxford Hip Scores (OHS) were collected, and radiological stem stability was determined using the Engh classification. Results. A total of 17 hips (15.7%) underwent re-revision of any component. Indications for re-revision were stem failure (35.3%; n = 6), infection (29.4%; n = 5), instability (29.4%; n = 5), and acetabular aseptic loosening (5.9%; n = 1). The five- and 15-year all-cause survival was 89.7% (95% confidence interval (CI) 86.7 to 92.7) and 83.3% (95% CI 79.6 to 87.0), respectively. There were six re-revisions (5.6%) for stem failure; five for stem fracture and one for aseptic loosening. The five- and 15-year survival free from stem-related failure was 97.2% (95% CI 95.6 to 98.8) and 94.0% (95% CI 91.6 to 96.4), respectively. At final follow-up, the mean OHS was 36.9 (8.0 to 48.0) and 95.7% (n = 66) of surviving modular revision stems were well-fixed in available radiographs. Conclusion. Femoral revision with the ZMR offers satisfactory long-term all-cause revision-free survival, good survival free of stem-related failure, and favourable clinical outcomes. Stem fracture was the most common reason for stem-related failure and occurred both early and late. This highlights the importance of both early and long-term surveillance for stem-related failure. Cite this article: Bone Joint J 2024;106-B(5 Supple B):112–117

Aim. Diagnosing periprosthetic joint infections (PJI) can be very challenging, especially infections caused by low virulence microorganisms. No single test with a 100% accuracy is available yet. Hence, different infection definitions were introduced to improve the diagnostic confidence and quality of research articles. Due to constant developments in this field, infection definitions are adopted continuously. The aim of our study was to find the most sensitive currently available infection definition among three currently used criteria (International Consensus Meeting – criteria 2018 (ICM), Infectious Diseases Society of America - criteria 2013 (IDSA), and European Bone and Joint Infection Society – criteria 2021 (EBJIS)) for the diagnosis of PJI. Method. Between 2015 and 2020, patients with an indicated revision surgery due to septic or aseptic failure after a total hip or knee replacement were included in this retrospective analysis of prospectively collected data. A standardized diagnostic workup was done in all patients. The components of the IDSA-, ICM-, and EBJIS- criteria for the diagnosis of PJI were identified in each patient. Results. Overall, 206 patients (hip: n=104 (50%); knee: n=102 (50%)) with a median age of 74 years (IQR 65 – 80y) were included. 101 patients (49%) were diagnosed with PJI when using the EBJIS- criteria. Based on the IDSA- and ICM- criteria, 99 patients (48%, IDSA) and 86 patients (42%, ICM) were classified as septic. Based on all three criteria, 84 cases (41%) had an infection. 15 septic cases (n=15/206; 7%) were only identified by the IDSA- and EBJIS- criteria. In 2 patients (n=2/206, 1%), an infection was present based on only the ICM and EBJIS criteria. No case was classified as infected by one infection definition alone. A statistically significant higher number of inconclusive cases was observed when the ICM criteria (n=30/206; 15%) were used in comparison to the EBJIS criteria (likely infections: n=16/206; 8%) (Fisher's exact test, p=0.041). The EBJIS definition showed a better preoperative performance in comparison to the other two definitions (p<0.0001). Conclusions. The most sensitive infection definition seems to be the novel EBJIS– criteria covering all infections diagnosed by the IDSA- and ICM-criteria without detecting any further infection. In addition, less inconclusive (infection likely) cases were detected by the EBJIS-criteria in comparison with the ICM-criteria reducing the so called ‘grey zone’ significantly which is of utmost importance in clinical routine

Aim. Treatment algorithms for fracture-related nonunion depend on the presence or absence of bacterial infection. However, the manifestation of septic nonunion varies. Low-grade infections, unlike manifest infections, lack clinical signs of infection and present similarly to aseptic nonunion. The clinical importance of low-grade infection in nonunion is not entirely clear. Therefore, the aim of this study was to evaluate the clinical relevance of low-grade infection in the development and management of femoral or tibial nonunion. Method. A prospective, multicenter clinical study enrolled patients with nonunion and regular healed fractures. Preoperatively, complete blood count without differential, C-reactive protein (CRP), and procalcitonin were obtained, clinical signs of infection were recorded, and a suspected septic or aseptic diagnosis was made based on history and clinical examination. During surgical nonunion revision or routine implant removal, tissue samples were collected for microbiology and histopathology, and osteosynthesis material for sonication. Nonunion patients were followed for 12 months. Definitive diagnosis of “septic” or “aseptic” nonunion was made according to diagnostic criteria for fracture-related infection, considering the results of any further revision surgery during follow-up. Results. 34 patients with regular healed fractures were included. 62 nonunion patients were diagnosed as aseptic, 22 with manifest, and 23 with low-grade infection. The positive predictive value was 88% and the negative predictive value 72% for the suspected diagnosis. The nonunion groups had significantly higher CRP levels than the regular healer group. Differentiation between septic and aseptic nonunion based on blood values was not possible. Low-grade infection demonstrated less frequently histopathologic signs of infection than manifest infection (22% vs. 50%, p=0.048), with 15% of regular healers having histopathologic signs of infection. Cutibacterium acnes was less present in manifest compared to low-grade infection (p=0.042). Healing rates for septic nonunion involving C. acnes were significantly lower for manifest infection (20%) than for low-grade infection (100%, p=0.002). Patients with low-grade infection were treated with systemic antibiotics less frequently than patients with manifest infection (p=0.026), with no significant difference in healing rate (83% vs. 64%), which was slightly lower for low-grade infection than for aseptic nonunion (90%). Conclusions. Low-grade infections play a significant role in nonunion development and are difficult to diagnose preoperatively due to the lack of clinical signs of infection and unremarkable blood counts. However, our results imply that for low-grade infections, antibiotic therapy may not always be mandatory to heal the nonunion. This study was supported by the German Social Accident Insurance (FF-FR0276)

Aims. The aim of this study was to perform the first population-based description of the epidemiological and health economic burden of fracture-related infection (FRI). Methods. This is a retrospective cohort study of operatively managed orthopaedic trauma patients from 1 January 2007 to 31 December 2016, performed in Queensland, Australia. Record linkage was used to develop a person-centric, population-based dataset incorporating routinely collected administrative, clinical, and health economic information. The FRI group consisted of patients with International Classification of Disease 10th Revision diagnosis codes for deep infection associated with an implanted device within two years following surgery, while all others were deemed not infected. Demographic and clinical variables, as well as healthcare utilization costs, were compared. Results. There were 111,402 patients operatively managed for orthopaedic trauma, with 2,775 of these (2.5%) complicated by FRI. The development of FRI had a statistically significant association with older age, male sex, residing in rural/remote areas, Aboriginal or Torres Strait Islander background, lower socioeconomic status, road traffic accident, work-related injuries, open fractures, anatomical region (lower limb, spine, pelvis), high injury severity, requiring soft-tissue coverage, and medical comorbidities (univariate analysis). Patients with FRI had an eight-times longer median inpatient length of stay (24 days vs 3 days), and a 2.8-times higher mean estimated inpatient hospitalization cost (AU$56,565 vs AU$19,773) compared with uninfected patients. The total estimated inpatient cost of the FRI cohort to the healthcare system was AU$156.9 million over the ten-year period. Conclusion. The results of this study advocate for improvements in trauma care and infection management, address social determinants of health, and highlight the upside potential to improve prevention and treatment strategies. Cite this article: Bone Joint J 2024;106-B(1):77–85

Background. Increasing evidence suggests a link between the bearing surface used in total hip arthroplasty (THA) and the occurrence of infection. It is postulated that polyethylene has immunomodulatory effects and may influence bacterial function and survival, thereby impacting the development of periprosthetic joint infection (PJI). This study aimed to investigate the association between polyethylene type and revision surgery for PJI in THA using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). We hypothesized that the use of XLPE would demonstrate a statistically significant reduction in revision rates due to PJI compared to N-XLPE. Methods. Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) spanning September 1, 1999, to December 31, 2021, were used to compare the infection revision rates between THA using N-XLPE and XLPE. We calculated the Cumulative Percentage Revision rate (CPR) and Hazard Ratio (HR) while controlling for factors like age, sex, body mass index (BMI), American Society of Anesthesiologists’ (ASA) grade, and head size. Results. From the total 361,083 primary THAs, 26,827 used N-XLPE and 334,256 used XLPE. Excluding data from the first 6 months post-surgery, 220 revisions occurred in the N-XLPE group and 1,055 in the XLPE group for PJI. The HR for infection revision was significantly higher in N-XLPE compared to XLPE, at 1.64 (95% CI, 1.41–1.90, p<0.001). Conclusions. This analysis provides evidence of an association between N-XLPE and revision for infection in THA. We suspect that polyethylene wear particles contribute to the susceptibility of THA to PJI, resulting in a significantly higher risk of revision for infection in N-XLPE hips compared to those with XLPE. Level of Evidence. Therapeutic Level III

The June 2023 Hip & Pelvis Roundup. 360. looks at: Machine learning to identify surgical candidates for hip and knee arthroplasty: a viable option?; Poor outcome after debridement and implant retention; Can you cement polyethylene liners into well-fixed acetabular shells in hip revision?; Revision stem in primary arthroplasties: the Exeter 44/0 125 mm stem; Depression and anxiety: could they be linked to infection?; Does where you live affect your outcomes after hip and knee arthroplasties?; Racial disparities in outcomes after total hip arthroplasty and total knee arthroplasty are substantially mediated by socioeconomic disadvantage both in black and white patients

Introduction. Accurate diagnosis of peri-prosthetic joint infection is critical to allow adequate treatment. Currently, the criteria of the Musculo-Skeletal Infection Society (MSIS) serve as a validated reference tool. More recently, these criteria have been modified for better accuracy. The goal of this study was to compare retrospectively the diagnostic accuracy of these two different tools in cases of known peri-prosthetic hip or knee infection or in aseptic cases and to analyze one additional criterion: presence of an early loosening (prior to 2 years after implantation). Material – Methods. All cases of hip or knee prosthesis exchange operated on at our department during the year 2017 have been selected. There were 130 cases in 127 patients: 67 men and 60 women, with a mean age of 69 years − 69 total hip (THA) and 61 total knee (TKA) arthroplasties. 74 cases were septic and 53 cases were aseptic. All criteria included in both classifications were collected: presence of a fistula, results of bacteriological samples, ESR and CRP levels, analysis of the joint fluid, histological analysis. Additionally, the presence of an early loosening was recorded. The diagnosis accuracy of the classical MSIS classification and of the 2018 modification were assessed and compared with a Chi-square test at a 0.05 level of significance. Results. The conventional MSIS classification correctly discriminated between infected and non-infected cases in 128/130 cases (98%). There were two failures by infected cases: one case was considered infected with no major criteria and only three minor criteria; one case was considered infected with no major criteria and only two minor criteria. There was no failure by non-infected cases. The new MSIS classification correctly discriminated between infected and non-infected cases in 129/130 cases (99%). There was one single failure by infected cases: one case was considered infected despite a score of 4 points. There was no significant difference between the diagnostic accuracy of both classifications. The presence of an early loosening had a high specificity (85%) but a low sensitivity (22%). Discussion. The conventional MSIS classification had a high diagnostic accuracy. The new MSIS classification offered only minor, non significant increase of this accuracy. As the new classification involves several additional biological assays, these results might question the cost-effectiveness of the new classification. The presence of an early loosening might be an interesting additional criterion at no additional cost

Aims. To investigate the efficacy of ethylenediaminetetraacetic acid-normal saline (EDTA-NS) in dispersing biofilms and reducing bacterial infections. Methods. EDTA-NS solutions were irrigated at different durations (1, 5, 10, and 30 minutes) and concentrations (1, 2, 5, 10, and 50 mM) to disrupt Staphylococcus aureus biofilms on Matrigel-coated glass and two materials widely used in orthopaedic implants (Ti-6Al-4V and highly cross-linked polyethylene (HXLPE)). To assess the efficacy of biofilm dispersion, crystal violet staining biofilm assay and colony counting after sonification and culturing were performed. The results were further confirmed and visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). We then investigated the efficacies of EDTA-NS irrigation in vivo in rat and pig models of biofilm-associated infection. Results. When 10 mM or higher EDTA-NS concentrations were used for ten minutes, over 99% of S. aureus biofilm formed on all three types of materials was eradicated in terms of absorbance measured at 595 nm and colony-forming units (CFUs) after culturing. Consistently, SEM and CSLM scanning demonstrated that less adherence of S. aureus could be observed on all three types of materials after 10 mM EDTA-NS irrigation for ten minutes. In the rat model, compared with NS irrigation combined with rifampin (Ti-6Al-4V wire-implanted rats: 60% bacteria survived; HXLPE particle-implanted rats: 63.3% bacteria survived), EDTA-NS irrigation combined with rifampin produced the highest removal rate (Ti-6Al-4V wire-implanted rats: 3.33% bacteria survived; HXLPE particle-implanted rats: 6.67% bacteria survived). In the pig model, compared with NS irrigation combined with rifampin (Ti-6Al-4V plates: 75% bacteria survived; HXLPE bearings: 87.5% bacteria survived), we observed a similar level of biofilm disruption on Ti-6Al-4V plates (25% bacteria survived) and HXLPE bearings (37.5% bacteria survived) after EDTA-NS irrigation combined with rifampin. The in vivo study revealed that the biomass of S. aureus biofilm was significantly reduced when treated with rifampin following irrigation and debridement, as indicated by both the biofilm bacterial burden and crystal violet staining. EDTA-NS irrigation (10 mM/10 min) combined with rifampin effectively removes S. aureus biofilm-associated infections both in vitro and in vivo. Conclusion. EDTA-NS irrigation with or without antibiotics is effective in eradicating S. aureus biofilm-associated infection both ex and in vivo. Cite this article: Bone Joint Res 2024;13(1):40–51

The incidence of PJI in knee replacements is 2.8% and slightly lower with hip replacement surgery. PJI make up 15% (or even more) of knee revisions. To combat PJI, antibiotic laden bone cement has been used for many decades, but antibiotic stewardship dictates more prudent management of antimicrobials. Projected increase in infection rate, due to increased surgery and latent infection to be almost 5-fold up to 2035. Biofilm is a complex structure of bacteria and polysaccharide matrix and, is recognised as a major component in PJI and other orthopaedic infections. Biofilm is responsible for high incidence of resistance to antimicrobials and ineffective host immune response. Method. Stabilized hypochlorous acid has been reported to have a rapid kill rate on all pathogens, including MDR pathogens associated with chronic and acute wound infections. It destroys biofilm on contact, is not cytotoxic, reduces inflammation and stimulates wound healing. 0,038% of Hypochlorous acid was used as prophylaxis against infection and to treat PJI. We report on our experience with hypochlorous acid as a wound irrigation as prophylaxis against infection (more than 600 cases) and for PJI. We also report on a University study where a head to head analysis was done on the anti-biofilm efficacy between hypochlorous acid 0,038% (Trifectiv Surgical Wound Irrigation) and Product X (an industry-standard product for the prevention and treatment of biofilm infection. Hypochlorous acid offers a valuable addition to the armamentarium of wound antiseptics, with added anti-inflammatory value. An in vitro study demonstrated superior efficacy against biofilm when compared to Product X

The February 2023 Knee Roundup. 360. looks at: Machine-learning models: are all complications predictable?; Positive cultures can be safely ignored in revision arthroplasty patients that do not meet the 2018 International Consensus Meeting Criteria; Spinal versus general anaesthesia in contemporary primary total knee arthroplasty; Preoperative pain and early arthritis are associated with poor outcomes in total knee arthroplasty; Risk factors for infection and revision surgery following patellar tendon and quadriceps tendon repairs; Supervised versus unsupervised rehabilitation following total knee arthroplasty; Kinematic alignment has similar outcomes to mechanical alignment: a systematic review and meta-analysis; Lifetime risk of revision after knee arthroplasty influenced by age, sex, and indication; Risk factors for knee osteoarthritis after traumatic knee injury

Aim. Previous publications have suggested that the incidence of revisions due to infection after THA is increasing. We performed updated time-trend analyses of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004–2018. Methods. 569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 through 2018 were studied. We estimated adjusted hazard ratios (aHR) with 95% confidence interval by Cox regression with the first revision due to infection after primary THA as endpoint. The risk of revision was investigated. In addition, we explored changes in the time span from primary THA to revision due to infection. Results. 5,653 (1.0%) were revised due to infection. The risk of revision due to infection increased through the study period. Compared to the period 2004–2008, the aHRs were 1.4 (95%CI 1.3–1.5) for 2009–2013, and 1.9 (1.7–2.0) for 2014–2018. We found an increased risk in all four Nordic countries. Compared to 2004–2008, the aHR due to infection 0–30 days after THA was 2.5 (2.1–2.9) for 2009–2013 and 3.4 (3.0–3.9) for 2013–2018. The aHR of revision due to infection 31–90 days after THA was 1.5 (1.3–1.9) for 2009–2013 and 2.5 (2.1–3.0) for 2013–2018, compared to 2004–2008. Beyond 91 days after THA, the risk of revision due to infection was stable over the whole study period. Interpretation. The risk of revision due to deep infection after THA nearly doubled throughout the period 2004–2018. This increase was mainly due to an increased risk of early revisions. The cause for these changes may be multifactorial (patient selection, diagnostics, revision strategy, completeness of reporting, etc.), are not possible to disclose in the present study, and warrants further research

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

Aim. Debridement, Antibiotics, Irrigation, and implant Retention (DAIR) is a surgical treatment protocol suitable for some patients with fracture related infection (FRI). Clinically relevant pre-clinical models of DAIR are scarce and none have been developed in large animals. Therefore, this project aimed to develop a large animal model for FRI including a DAIR approach and compare outcomes after 2 or 5 weeks of infection. Method. Swiss Alpine sheep (n=8), (2–6 years, 50–80 kg) were included in this study. This study was approved by cantonal Ethical authorities in Chur, Switzerland. A 2 mm osteotomy was created in the tibia and fixed with a 10-hole 5.5 mm steel plate. Subsequently, 2.5 mL of saline solution containing 10. 6. CFU/mL of Staphylococcus aureus MSSA (ATCC 25923) was added over the plate. Sheep were observed for 2 (n=3) or 5 weeks (n=5) until revision surgery, during which visibly infected or necrotic tissues were removed, and the wound flushed with saline. All samples were collected for bacterial quantification. After revision surgery, the sheep were treated systemically for 2 weeks with flucloxacillin and for 4 weeks with rifampicin and cotrimoxazole. After 2 further weeks off antibiotics, the animals were euthanized. Bacteriological culture was performed at the end of the study. Bone cores were isolated from the osteotomy site and processed for Giemsa & Eosin and Brown and Brenn staining. A radiographical examination was performed every second week. Results. Bacteriological evaluation of the retrieved samples during revision surgery showed no significant difference between the 2 vs 5 weeks infection periods in term of total CFU counts. At the end of the study, radiographical examination showed callus formation over the osteotomy site in both groups, although the osteotomy was not completely healed in either group. At euthanasia, the 2 weeks infection group showed a higher soft tissue burden compared to the 5 weeks group, whereby the infection in the 5 weeks group was primarily located in the bone and bone marrow. Conclusions. The large animal model of FRI and DAIR was successfully established. Bacteriological outcomes highlight that the increasing duration of the infection does not change the outcome but the location of the infection from a predominantly soft tissue infection to a deeper bone and intramedullary (IM) channel infection. The debridement of the IM channel could potentially reduce the infection burden by eliminating those bacteria not easily reached by systemic antibiotics, though is not practical using conventional techniques

Aims. Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections. Methods. We retrospectively collected data from 226 patients (90 hips, 136 knees) with periprosthetic joint infection who underwent two-stage revision between August 2011 and September 2021, with a minimum follow-up of one year. Histology was assessed via the SLIM classification. First, we analyzed whether patients with positive permanent sections at reimplantation had higher reinfection rates than patients with negative histology. Further, we compared permanent and frozen section results, and assessed the influence of anatomical regions (knee versus hip), low- versus high-grade infections, as well as first revision versus multiple prior revisions on the histological result at reimplantation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), chi-squared tests, and Kaplan-Meier estimates were calculated. Results. Overall, the reinfection rate was 18%. A total of 14 out of 82 patients (17%) with positive permanent sections at reimplantation experienced reinfection, compared to 26 of 144 patients (18%) with negative results (p = 0.996). Neither permanent sections nor fresh frozen sections were significantly associated with reinfection, with a sensitivity of 0.35, specificity of 0.63, PPV of 0.17, NPV of 0.81, and accuracy of 58%. Histology was not significantly associated with reinfection or survival time for any of the analyzed sub-groups. Permanent and frozen section results were in agreement for 91% of cases. Conclusion. Permanent and fresh frozen sections at reimplantation in two-stage revision do not serve as a reliable predictor for reinfection. Cite this article: Bone Joint J 2024;106-B(4):372–379

Aims. The use of a porous metal shell supported by two augments with the ‘footing’ technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique. Methods. We undertook a retrospective, two-centre series of 39 hips in 39 patients (15 male, 24 female) treated with the ‘footing’ technique for Paprosky IIIB acetabular defects between 2007 and 2020. The median age at the time of surgery was 64.4 years (interquartile range (IQR) 54.4 to 71.0). The median follow-up was 3.9 years (IQR 3.1 to 7.0). Results. The cumulative medium-term survival of the acetabular construct was 89%. Two hips (5.1%) required further revision due to shell loosening, one hip (2.6%) due to shell dislocation, and one hip (2.6%) due to infection. The median Harris Hip Score improved significantly from 47 points (IQR 41.5 to 54.9) preoperatively to 80 points (IQR 73.5 to 88.6) at the latest follow-up (p < 0.001). Conclusion. The reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and two augments using the ‘footing’ technique showed excellent medium-term results. It is a viable option for treating these challenging defects. Cite this article: Bone Joint J 2024;106-B(5 Supple B):54–58

Introduction. The management of fracture-related infection has undergone radical progress following the development of international guidelines. However, there is limited consideration to the realities of healthcare in low-resource environments due to a lack of available evidence in the literature from these settings. Initial antimicrobial suppression to support fracture union is frequently used in low- and middle-income countries despite the lack of published clinical evidence to support its practice. This study aimed to evaluate the outcomes following initial antimicrobial suppression to support fracture union in the management of fracture-related infection. Materials & Methods. A retrospective review of consecutive patients treated with initial antimicrobial suppression to support fracture healing followed by definitive eradication surgery to manage fracture-related infections following intramedullary fixation was performed. Indications for this approach were; a soft tissue envelope not requiring reconstructive surgery, radiographic evidence of stable fixation with adequate alignment, and progression towards fracture union. Results. This approach was associated with successful treatment in 51/55 (93%) patients. Fracture union was achieved in 52/55 (95%) patients with antimicrobial suppression alone. Remission of infection was achieved in 54/55 (98%) patients following definitive infection eradication surgery. Following antibiotic suppression, 6/46 (13%) pathogens isolated from intra-operative samples demonstrated multi-drug resistance. Conclusions. Initial antimicrobial suppression to support fracture healing followed by definitive infection eradication surgery was associated with successful treatment in 93% of patients. The likelihood of remission of infection increases when eradication surgery is performed in a healed bone. This approach was not associated with an increased risk of developing multi-drug-resistant infections compared to contemporary bone infection cohorts in the published literature

There is no consensus on how to evaluate and grade pin site infection. A precise, objective and reliable pin site infectious score is warranted. The literature was reviewed for pin site infection classification systems, The Modified Gordon Score (MGS) grade 0-6 was used. The aim was to test the reliability of The Modified Gordon Infection Score. The observed agreement and inter-rater reliability were investigated between nurse and doctors. MGS was performed in the outpatient clinic at Aalborg University Hospital, Denmark on 1472 pin sites in 119 patients by one nurse and one of three orthopaedic surgeons blinded to each other's judgement. The data was stored in a Red Cap Database for further statistical analysis. The observed agreement between the nurse and the 3 orthopaedic surgeons was evaluated with a one-way random-effect model with interclass correlation with absolute agreement. Furthermore the observed agreement for each of the 3 surgeons with the nurse was calculated. The distribution of MGS infection grade in the 1472 pin sites was: Grade 0; n=1372, Grade 1; n=32, Grade 2; n=39, Grade 3; n=24, Grade 4; n=5, Grade 5; n=0, Grade 6; n=0. The observed agreement between the nurse and the surgeons was calculated as 98%. The ICC estimated between nurse and the surgeons was 0,8943 (ICC >0,85 = reliable). The grading was done by three different doctors with an agreement with the nurse as follows. Rater1 (n=416) =99,5 %, Rater2 (n=1440) =97,4%, Rater3 (n=1440) =96,6%. A limitation to this study is that the dataset represents mostly clean pin sites with MGS 0. Only 100 pin sites had signs of superficial infection MGS 1-4 none above 4. We found that the MGS infection score is highly reliable for low grade infections but we cannot conclude on reliability in severe infections

Aims. Staphylococcus aureus is a major cause of septic arthritis, and in vitro studies suggest α haemolysin (Hla) is responsible for chondrocyte death. We used an in vivo murine joint model to compare inoculation with wild type S. aureus 8325-4 with a Hla-deficient strain DU1090 on chondrocyte viability, tissue histology, and joint biomechanics. The aim was to compare the actions of S. aureus Hla alone with those of the animal’s immune response to infection. Methods. Adult male C57Bl/6 mice (n = 75) were randomized into three groups to receive 1.0 to 1.4 × 10. 7. colony-forming units (CFUs)/ml of 8325-4, DU1090, or saline into the right stifle joint. Chondrocyte death was assessed by confocal microscopy. Histological changes to inoculated joints were graded for inflammatory responses along with gait, weight changes, and limb swelling. Results. Chondrocyte death was greater with 8325-4 (96.2% (SD 5.5%); p < 0.001) than DU1090 (28.9% (SD 16.0%); p = 0.009) and both were higher than controls (3.8% (SD 1.2%)). Histology revealed cartilage/bone damage with 8325-4 or DU1090 compared to controls (p = 0.010). Both infected groups lost weight (p = 0.006 for both) and experienced limb swelling (p = 0.043 and p = 0.018, respectively). Joints inoculated with bacteria showed significant alterations in gait cycle with a decreased stance phase, increased swing phase, and a corresponding decrease in swing speed. Conclusion. Murine joints inoculated with Hla-producing 8325-4 experienced significantly more chondrocyte death than those with DU1090, which lack the toxin. This was despite similar immune responses, indicating that Hla was the major cause of chondrocyte death. Hla-deficient DU1090 also elevated chondrocyte death compared to controls, suggesting a smaller additional deleterious role of the immune system on cartilage. Cite this article: Bone Joint Res 2022;11(9):669–678

Open tibial fractures can be difficult to manage, with a range of factors that could affect treatment and outcome. We present a large cohort of patients, and analyse which factors have significant associations with infection outcome. Elucidation will allow clinicians to strive for treatment optimisation, and patients to be advised on likely complications. Open tibia fractures treated at a major trauma centre between 2015-2021 were included. Mean age at injury was 55.4 (range 13-102). Infection status was categorized into no infection, superficial infection, and osteomyelitis. Age, mode of injury, polytrauma, fibula status, Gustilo-Anderson (GA) classification, wound contamination, time from injury to: first procedure/definitive plastics procedure/definitive fixation, type of definitive fixation, smoking and diabetic status, and BMI, were collected. Multicollinearity was calculated, with highly correlated factors removed. Multinomial logistic regression was performed. Chi Squared testing, with Post Hoc Bonferroni correction was performed for complex categorical factors. Two hundred forty-four patients with open tibial fractures were included. Forty-five developed superficial infection (18.4%), and thirty-nine developed osteomyelitis (16.0%). Polytrauma, fibula status, and type of definitive fixation were excluded from the multivariate model due to strong multicollinearity with other variables. With reference to the non-infected outcome; superficial infection patients had higher BMI (p<0.01), higher GA grade (p<0.01), osteomyelitis patients had longer time to definitive fixation (p=0.049) and time to definitive plastics procedure (p=0.013), higher GA grade (p<0.01), and positive wound contamination(p=0.015). Poc hoc analysis showed “no infection” was positively associated with GA-I (p=0.029) and GA-II (p<0.01), and negatively associated with GA-IIIC (p<0.01). Osteomyelitis was positively associated with GA-IIIc (p<0.01). This study investigated the associations between the injury and presentation factors that may affect infection outcome. The variables highlighted are the factors clinicians should give extra consideration to when treating cases, and take preventative measures to optimize treatment and mitigate infection risk

Aims. Continuous local antibiotic perfusion (CLAP) has recently attracted attention as a new drug delivery system for orthopaedic infections. CLAP is a direct continuous infusion of high-concentration gentamicin (1,200 μg/ml) into the bone marrow. As it is a new system, its influence on the bone marrow is unknown. This study aimed to examine the effects of high-concentration antibiotics on human bone tissue-derived cells. Methods. Cells were isolated from the bone tissue grafts collected from six patients using the Reamer-Irrigator-Aspirator system, and exposed to different gentamicin concentrations. Live cells rate, apoptosis rate, alkaline phosphatase (ALP) activity, expression of osteoblast-related genes, mineralization potential, and restoration of cell viability and ALP activity were examined by in vitro studies. Results. The live cells rate (the ratio of total number of cells in the well plate to the absorbance-measured number of live cells) was significantly decreased at ≥ 500 μg/ml of gentamicin on day 14; apoptosis rate was significantly increased at ≥ 750 μg/ml, and ALP activity was significantly decreased at ≥ 750 μg/ml. Real-time reverse transcription-polymerase chain reaction results showed no significant decrease in the ALP and activating transcription factor 4 transcript levels at ≥ 1,000 μg/ml on day 7. Mineralization potential was significantly decreased at all concentrations. Restoration of cell viability was significantly decreased at 750 and 1,000 μg/ml on day 21 and at 500 μg/ml on day 28, and ALP activity was significantly decreased at 500 μg/ml on day 28. Conclusion. Our findings suggest that the exposure concentration and duration of antibiotic administration during CLAP could affect cell functions. However, further in vivo studies are needed to determine the optimal dose in a clinical setting. Cite this article: Bone Joint Res 2024;13(3):91–100

Aims. The aim of this study was to report the incidence of implant-related complications, further operations, and their influence on the outcome in a series of patients who underwent primary reverse total shoulder arthroplasty (RTSA). Methods. The prospectively collected clinical and radiological data of 797 patients who underwent 854 primary RTSAs between January 2005 and August 2018 were analyzed. The hypothesis was that the presence of complications would adversely affect the outcome. Further procedures were defined as all necessary operations, including reoperations without change of components, and partial or total revisions. The clinical outcome was evaluated using the absolute and relative Constant Scores (aCS, rCS), the Subjective Shoulder Value (SSV) scores, range of motion, and pain. Results. The overall surgical site complication rate was 22% (188 complications) in 152 patients (156 RTSAs; 18%) at a mean follow-up of 46 months (0 to 169). The most common complications were acromial fracture (in 44 patients, 45 RTSAs; 5.3%), glenoid loosening (in 37 patients, 37 RTSAs; 4.3%), instability (in 23 patients, 23 RTSAs; 2.7%), humeral fracture or loosening of the humeral component (in 21 patients, 21 RTSAs; 2.5%), and periprosthetic infection (in 14 patients, 14 RTSAs; 1.6%). Further surgery was undertaken in 79 patients (82 RTSAs) requiring a total of 135 procedures (41% revision rate). The most common indications for further surgery were glenoid-related complications (in 23 patients, 23 RTSAs; 2.7%), instability (in 15 patients, 15 RTSAs; 1.8%), acromial fractures (in 11 patients, 11 RTSAs; 1.3%), pain and severe scarring (in 13 patients, 13 RTSAs; 1.5%), and infection (in 8 patients, 8 RTSAs; 0.9%). Patients who had a complication had significantly worse mean rCS scores (57% (SD 24%) vs 81% (SD 16%)) and SSV scores (53% (SD 27%) vs 80% (SD 20%)) compared with those without a complication. If revision surgery was necessary, the outcome was even further compromised (mean rCS score: 51% (SD 23%) vs 63% (SD 23%); SSV score: 4% (SD 25%) vs 61% (SD 27%). Conclusion. Although the indications for, and use of, a RTSA are increasing, it remains a demanding surgical procedure. We found that about one in five patients had a complication and one in ten required further surgery. Both adversely affected the outcome. Cite this article: Bone Joint J 2022;104-B(3):401–407

Aims. This study aims to identify the top unanswered research priorities in the field of knee surgery using consensus-based methodology. Methods. Initial research questions were generated using an online survey sent to all 680 members of the British Association for Surgery of the Knee (BASK). Duplicates were removed and a longlist was generated from this scoping exercise by a panel of 13 experts from across the UK who provided oversight of the process. A modified Delphi process was used to refine the questions and determine a final list. To rank the final list of questions, each question was scored between one (low importance) and ten (high importance) in order to produce the final list. Results. This consensus exercise took place between December 2020 and April 2022. A total of 286 clinicians from the BASK membership provided input for the initial scoping exercise, which generated a list of 105 distinct research questions. Following review and prioritization, a longlist of 51 questions was sent out for two rounds of the Delphi process. A total of 42 clinicians responded to the first round and 24 responded to the second round. A final list of 24 research questions was then ranked by 36 clinicians. The topics included arthroplasty, infection, meniscus, osteotomy, patellofemoral, cartilage, and ligament pathologies. The management of early osteoarthritis was the highest-ranking question. Conclusion. A Delphi exercise involving the BASK membership has identified the future research priorities in knee surgery. This list of questions will allow clinicians, researchers, and funders to collaborate in order to deliver high-quality research in knee surgery and further advance the care provided to patients with knee pathology. Cite this article: Bone Joint J 2024;106-B(7):662–668

Aims. In recent years, the use of a collared cementless femoral prosthesis has risen in popularity. The design intention of collared components is to transfer some load to the resected femoral calcar and prevent implant subsidence within the cancellous bone of the metaphysis. Conversely, the load transfer for a cemented femoral prosthesis depends on the cement-component and cement-bone interface interaction. The aim of our study was to compare the three most commonly used collared cementless components and the three most commonly used tapered polished cemented components in patients aged ≥ 75 years who have undergone a primary total hip arthroplasty (THA) for osteoarthritis (OA). Methods. Data from the Australian Orthopaedic Association National Joint Replacement Registry from 1 September 1999 to 31 December 2022 were analyzed. Collared cementless femoral components and cemented components were identified, and the three most commonly used components in each group were analyzed. We identified a total of 11,278 collared cementless components and 47,835 cemented components. Hazard ratios (HRs) from Cox proportional hazards models, adjusting for age and sex, were obtained to compare the revision rates between the groups. Results. From six months postoperatively onwards, patients aged ≥ 75 years undergoing primary THA with primary diagnosis of OA have a lower risk of all-cause revision with collared cementless components than with a polished tapered cemented component (HR 0.78 (95% confidence interval 0.64 to 0.96); p = 0.018). There is no difference in revision rate prior to six months. Conclusion. Patients aged ≥ 75 years with a primary diagnosis of OA have a significantly lower rate of revision with the most common collared cementless femoral component, compared with the most common polished tapered cemented components from six months postoperatively onwards. The lower revision rate is largely due to a reduction in revisions for fracture and infection. Cite this article: Bone Joint J 2024;106-B(3 Supple A):121–129

Aims. The aim of this study is to report the long-term outcomes of instrumented femoral revisions with impaction allograft bone grafting (IBG) using the X-change femoral revision system at 30 years after introduction of the technique. Methods. We updated the outcomes of our previous study, based on 208 consecutive revisions using IBG and the X-change femoral revision system in combination with a cemented polished stem, performed in our tertiary care institute between 1991 and 2007. Kaplan-Meier survival analyses were used to determine the survival rate of the revisions with endpoint revision for any reason and aseptic loosening. Secondary outcomes were radiological loosening and patient-reported outcome measures. Results. Mean age at revision total hip arthroplasty (THA) was 64.9 years (30 to 86). The most prevalent diagnosis for the femoral revision was aseptic loosening. At review in May 2021, 81 patients (85 hips) were still alive and 118 patients (120 hips; 58%) had died. Three patients (3 hips; 1%) were lost to follow-up at 11, 15, and 16 years after surgery, respectively. Data of all deceased and lost patients were included until final follow-up. The mean follow-up was 13.4 years (0 to 28). During the follow-up, 22 re-revisions were performed. The most common reason for re-revision was infection (n = 12; 54%). The survival with endpoint re-revision for any reason was 86% (95% confidence interval (CI) 79 to 91) at 20 years and 74% (95% CI 43 to 89) at 25 years after surgery. The survival for endpoint re-revision for aseptic loosening was 97% (95% CI 91 to 99) after both 20 and 25 years. Conclusion. We conclude that femoral IBG is a valuable technique that can reconstitute femoral bone loss in the long term. After 25 years of follow-up, few re-revisions for aseptic loosening were required. Also, the overall revision rate is very acceptable at a long follow-up. This technique is especially attractive for younger patients facing femoral revisions with extensive bone loss. Cite this article: Bone Joint J 2022;104-B(9):1039–1046

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. Methods. A retrospective review was performed of consecutive patients treated for HA PJI at a tertiary referral centre with a mean 4.5 years’ follow-up (1.6 weeks to 12.9 years). Surgeries performed included debridement, antibiotics, and implant retention (DAIR) and single-stage revision. The effect of different factors on developing infection and treatment outcome was determined. Results. A total of 1,984 HAs were performed during the study period, and 44 sustained a PJI (2.2%). Multiple logistic regression analysis revealed that a higher CCI score (odds ratio (OR) 1.56 (95% confidence interval (CI) 1.117 to 2.187); p = 0.003), peripheral vascular disease (OR 11.34 (95% CI 1.897 to 67.810); p = 0.008), cerebrovascular disease (OR 65.32 (95% CI 22.783 to 187.278); p < 0.001), diabetes (OR 4.82 (95% CI 1.903 to 12.218); p < 0.001), moderate-to-severe renal disease (OR 5.84 (95% CI 1.116 to 30.589); p = 0.037), cancer without metastasis (OR 6.42 (95% CI 1.643 to 25.006); p = 0.007), and metastatic solid tumour (OR 15.64 (95% CI 1.499 to 163.087); p = 0.022) were associated with increasing PJI risk. Upon final follow-up, 17 patients (38.6%) failed initial treatment and required further surgery for HA PJI. One-year mortality was 22.7%. Factors associated with treatment outcome included lower preoperative Hgb level (97.9 g/l (SD 11.4) vs 107.0 g/l (SD 16.1); p = 0.009), elevated CRP level (99.1 mg/l (SD 63.4) vs 56.6 mg/l (SD 47.1); p = 0.030), and type of surgery. There was lower chance of success with DAIR (42.3%) compared to revision HA (66.7%) or revision with conversion to total hip arthroplasty (100%). Early-onset PJI (≤ six weeks) was associated with a higher likelihood of treatment failure (OR 3.5 (95% CI 1.2 to 10.6); p = 0.007) along with patients treated by a non-arthroplasty surgeon (OR 2.5 (95% CI 1.2 to 5.3); p = 0.014). Conclusion. HA PJI initially treated with DAIR is associated with poor chances of success and its value is limited. We strongly recommend consideration of a single-stage revision arthroplasty with cemented components. Cite this article: Bone Jt Open 2022;3(12):924–932

Aims. The purpose of this study is to report our updated results at a minimum follow-up of 30 years using a first generation uncemented tapered femoral component in primary total hip arthroplasty (THA). Methods. The original cohort consisted of 145 consecutive THAs performed by a single surgeon in 138 patients. A total of 37 patients (40 hips) survived a minimum of 30 years, and are the focus of this review. The femoral component used in all cases was a first-generation Taperloc with a non-modular 28 mm femoral head. Clinical follow-up at a minimum of 30 years was obtained on every living patient. Radiological follow-up at 30 years was obtained on all but four. Results. Seven femoral components (18%) required revision, and none for septic loosening. Four well fixed stems were removed during acetabular revision and three were revised for late infection. One femoral component (3%) was loose by radiological criteria. The mean Harris Hip Score improved from 47 points (SD 4.62) preoperatively to 83 points (SD 9.27) at final follow-up. With revision for any reason as the endpoint, survival of the femoral component was 80% (95% confidence interval (CI) 61% to 90%) at 32 years. With revision for aseptic loosing femoral component, survival was 99% (95% CI 93% to 99%). Conclusion. With regards to aseptic loosening, the Taperloc femoral component provides excellent fixation at a mean follow-up of 32 years. Cite this article: Bone Jt Open 2023;4(2):79–86

Aims. Fractures of the humeral shaft represent 3% to 5% of all fractures. The most common treatment for isolated humeral diaphysis fractures in the UK is non-operative using functional bracing, which carries a low risk of complications, but is associated with a longer healing time and a greater risk of nonunion than surgery. There is an increasing trend to surgical treatment, which may lead to quicker functional recovery and lower rates of fracture nonunion than functional bracing. However, surgery carries inherent risk, including infection, bleeding, and nerve damage. The aim of this trial is to evaluate the clinical and cost-effectiveness of functional bracing compared to surgical fixation for the treatment of humeral shaft fractures. Methods. The HUmeral SHaft (HUSH) fracture study is a multicentre, prospective randomized superiority trial of surgical versus non-surgical interventions for humeral shaft fractures in adult patients. Participants will be randomized to receive either functional bracing or surgery. With 334 participants, the trial will have 90% power to detect a clinically important difference for the Disabilities of the Arm, Shoulder and Hand questionnaire score, assuming 20% loss to follow-up. Secondary outcomes will include function, pain, quality of life, complications, cost-effectiveness, time off work, and ability to drive. Discussion. The results of this trial will provide evidence regarding clinical and cost-effectiveness between surgical and non-surgical treatment of humeral shaft fractures. Ethical approval has been obtained from East of England – Cambridge Central Research Ethics Committee. Publication is anticipated to occur in 2024. Cite this article: Bone Jt Open 2024;5(4):343–349

Aims. A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients. Methods. Episodes of knee or hip PJI (defined by the European Bone and Joint Infection Society criteria) treated at our institution between January 2015 and October 2020 were included in a retrospective PJI cohort. Episodes with a follow-up of > one year were stratified by route of infection into haematogenous and non-haematogenous PJI. Probability of failure-free survival was estimated using the Kaplan-Meier method, and compared between groups using log-rank test. Univariate and multivariate analysis was applied to assess risk factors for failure. Results. A total of 305 PJI episodes (174 hips, 131 knees) were allocated to the haematogenous (n = 146) or the non-haematogenous group (n = 159). Among monomicrobial infections, Staphylococcus aureus was the dominant pathogen in haematogenous PJI (76/140, 54%) and coagulase-negative staphylococci in non-haematogenous PJI (57/133, 43%). In both groups, multi-stage exchange (n = 55 (38%) in haematogenous and n = 73 (46%) in non-haematogenous PJI) and prosthesis retention (n = 70 (48%) in haematogenous and n = 48 (30%) in non-haematogenous PJI) were the most common surgical strategies. Median duration of antimicrobial treatment was 13.5 weeks (range, 0.5 to 218 weeks) and similar in both groups. After six years of follow-up, the probability of failure-free survival was significantly lower in haematogenous compared to non-haematogenous PJI (55% vs 74%; p = 0.021). Infection-related mortality was significantly higher in haematogenous than non-haematogenous PJI (7% vs 0% episodes; p = 0.001). Pathogenesis of failure was similar in both groups. Retention of the prosthesis was the only independent risk factor for failure in multivariate analysis in both groups. Conclusion. Treatment failure was significantly higher in haematogenous compared to non-haematogenous PJI. Retention of the prosthesis was the only independent risk factor for failure in both groups. Cite this article: Bone Joint J 2023;105-B(12):1294–1302

While pre-soaking grafts in vancomycin has demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain. The primary aim of this study was to determine the cost-effectiveness of vancomycin pre-soaking during primary ACLR to prevent post-operative joint infections. The secondary aims of the study were to establish the breakeven cost-effectiveness threshold of the technique. A Markov model was used to determine cost effectiveness and the incremental cost effectiveness ratio of additional vancomycin pre-soaking compared to intravenous antibiotic prophylaxis alone. A repeated meta-analysis of nine cohort studies (Level III evidence) was completed to determine the odds ratio of infection with vancomycin pre-soaking compared to intravenous antibiotics alone. Estimated costs and transitional probabilities for further surgery were obtained from the literature. Breakeven threshold analysis was performed. The vancomycin soaking technique provides an expected cost saving of $600AUD per patient. There was an improvement in the quality-adjusted life years of 0.007 compared to intravenous antibiotic prophylaxis alone (4.297 versus 4.290). If the infection rate is below 0.023% with intravenous antibiotics alone or the additional intervention cost more than $1000AUD, the vancomycin wrap would no longer be cost-effective. For $30AUD, the vancomycin soaking technique provides a $600AUD cost saving by both reducing the risk of ACLR related infection and economic burden of infection. Treating septic arthritis represents a mean cost per patient of 6 times compared to that of the primary surgery. There has been no previous cost-effectiveness study of the vancomycin wrap technique. The vancomycin pre-soaking technique is a highly cost-effective method to prevent post-operative septic arthritis following primary ACLR

Aims. The aim of this study was to report the long-term follow-up of cemented short Exeter femoral components when used in primary total hip arthroplasty (THA). Methods. We included all primary 394 THAs with a cemented short Exeter femoral component (≤ 125 mm) used in our tertiary referral centre between October 1993 and December 2021. A total of 83 patients (21%) were male. The median age of the patients at the time of surgery was 42 years (interquartile range (IQR) 30 to 55). The main indication for THA was a childhood hip disease (202; 51%). The median follow-up was 6.7 years (IQR 3.1 to 11.0). Kaplan-Meier survival analyses were performed to determine the rates of survival with femoral revision for any indication, for septic loosening, for fracture of the femoral component and for aseptic loosening as endpoints. The indications for revision were evaluated. Fractures of the femoral component were described in detail. Results. The 20-year rate of survival was 85.4% (95% confidence interval (CI) 73.9 to 92.0) with revision for any indication, 96.2% (95% CI 90.5 to 98.5) with revision for septic loosening and 92.7% (95% CI 78.5 to 97.6) with revision for fracture of the femoral component. No femoral components were revised for aseptic loosening. There were 21 revisions of the femoral component; most (seven) as part of a two-stage management of infection. Fracture of the femoral component occurred in four THAs (1.0%) at 6.6, 11.6, 16.5, and 18.2 years of follow-up, respectively. Three of these were transverse fractures and occurred at the level of the lesser trochanter. In one THA, there was a fracture of the neck of the component. Conclusion. THAs using cemented short Exeter femoral components showed acceptable rates of survival of the femoral component at long-term follow-up, in this young cohort of patients. Although fracture is a rare complication of these components, surgeons should be aware of their incidence and possible risk factors. Cite this article: Bone Joint J 2024;106-B(3 Supple A):137–142

Aims. Bacteriophages infect, replicate inside bacteria, and are released from the host through lysis. Here, we evaluate the effects of repetitive doses of the Staphylococcus aureus phage 191219 and gentamicin against haematogenous and early-stage biofilm implant-related infections in Galleria mellonella. Methods. For the haematogenous infection, G. mellonella larvae were implanted with a Kirschner wire (K-wire), infected with S. aureus, and subsequently phages and/or gentamicin were administered. For the early-stage biofilm implant infection, the K-wires were pre-incubated with S. aureus suspension before implantation. After 24 hours, the larvae received phages and/or gentamicin. In both models, the larvae also received daily doses of phages and/or gentamicin for up to five days. The effect was determined by survival analysis for five days and quantitative culture of bacteria after two days of repetitive doses. Results. In the haematogenous infection, a single combined dose of phages and gentamicin, and repetitive injections with gentamicin or in combination with phages, resulted in significantly improved survival rates. In the early-stage biofilm infection, only repetitive combined administration of phages and gentamicin led to a significantly increased survival. Additionally, a significant reduction in number of bacteria was observed in the larvae after receiving repetitive doses of phages and/or gentamicin in both infection models. Conclusion. Based on our results, a single dose of the combination of phages and gentamicin is sufficient to prevent a haematogenous S. aureus implant-related infection, whereas gentamicin needs to be administered daily for the same effect. To treat early-stage S. aureus implant-related infection, repetitive doses of the combination of phages and gentamicin are required. Cite this article: Bone Joint Res 2024;13(8):383–391

Abstract. Aim. To identify the difference in infection rates in ankle fracture surgery in Laminar and Non Laminar flow theatres. Background. The infection rates in ankle fracture surgery range between 1–8%. The risk factors include diabetes, alcoholism, smoking, open fractures, osteoporotic fractures in the elderly, and high BMI. Laminar flow has been shown to reduce infections in Arthroplasty surgeries. Therefore, it has become mandatory to use in those procedures. However, it's not the same with ankle fracture surgery. Materials and Methods. It was a retrospective study. The data was collected over a 5 year period between 2015 and 2020. It was collected from Blue spier, Panda, and theatre register. There were 536 cases in each group i.e. Laminar flow (LF) and Non-Laminar flow (NLF). The variables looked at were: 1. Superficial and deep infection rates in LF and NLF theatres, 2. The number of open fractures, 3. Type of ankle fractures (Bimalleolar, Trimalleolar), 4. The number of infected cases who had external fixation prior to ORIF, 5. The number of cases that had Plastics reconstructive procedures, and 6. The grade of the operating surgeon. Conclusions. Superficial infection rate between NLF and LF was not significantly different 11.5% vs 10.3%. The deep infection rate was statistically significant against NLF theatres at 6.34% vs 4.29%. The open fracture was a major contributing factor for deep SSI (14.7% vs 26%). The application of an external fixator in LF and NLF theatres did not alter the infection. rates. Bimalleolar fractures were associated with a higher infection rate

Aims. The diagnosis of periprosthetic joint infection (PJI) can be challenging as the symptoms are similar to other conditions, and the markers used for diagnosis have limited sensitivity and specificity. Recent research has suggested using blood cell ratios, such as platelet-to-volume ratio (PVR) and platelet-to-lymphocyte ratio (PLR), to improve diagnostic accuracy. The aim of the study was to further validate the effectiveness of PVR and PLR in diagnosing PJI. Methods. A retrospective review was conducted to assess the accuracy of different marker combinations for diagnosing chronic PJI. A total of 573 patients were included in the study, of which 124 knees and 122 hips had a diagnosis of chronic PJI. Complete blood count and synovial fluid analysis were collected. Recently published blood cell ratio cut-off points were applied to receiver operating characteristic curves for all markers and combinations. The area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values were calculated. Results. The results of the analysis showed that the combination of ESR, CRP, synovial white blood cell count (Syn. WBC), and polymorphonuclear neutrophil percentage (PMN%) with PVR had the highest AUC of 0.99 for knees, with sensitivity of 97.73% and specificity of 100%. Similarly, for hips, this combination had an AUC of 0.98, sensitivity of 96.15%, and specificity of 100.00%. Conclusion. This study supports the use of PVR calculated from readily available complete blood counts, combined with established markers, to improve the accuracy in diagnosing chronic PJI in both total hip and knee arthroplasties. Cite this article: Bone Jt Open 2023;4(11):881–888

Research into COVID-19 has been rapid in response to the dynamic global situation, which has resulted in heterogeneity of methodology and the communication of information. Adherence to reporting standards would improve the quality of evidence presented in future studies, and may ensure that findings could be interpreted in the context of the wider literature. The COVID-19 pandemic remains a dynamic situation, requiring continued assessment of the disease incidence and monitoring for the emergence of viral variants and their transmissibility, virulence, and susceptibility to vaccine-induced immunity. More work is needed to assess the long-term impact of COVID-19 infection on patients who sustain a hip fracture. The International Multicentre Project Auditing COVID-19 in Trauma & Orthopaedics (IMPACT) formed the largest multicentre collaborative audit conducted in orthopaedics in order to provide an emergency response to a global pandemic, but this was in the context of many vital established audit services being disrupted at an early stage, and it is crucial that these resources are protected during future health crises. Rapid data-sharing between regions should be developed, with wider adoption of the revised 2022 Fragility Fracture Network Minimum Common Data Set for Hip Fracture Audit, and a pragmatic approach to information governance processes in order to facilitate cooperation and meta-audit. This editorial aims to: 1) identify issues related to COVID-19 that require further research; 2) suggest reporting standards for studies of COVID-19 and other communicable diseases; 3) consider the requirement of new risk scores for hip fracture patients; and 4) present the lessons learned from IMPACT in order to inform future collaborative studies. Cite this article: Bone Joint Res 2022;11(6):342–345

Periprosthetic joint infection (PJI) remains an extremely challenging complication. We have focused on this issue more over the last decade than previously, but there are still many unanswered questions. We now have a workable definition that everyone should align to, but we need to continue to focus on identifying the organisms involved. Surgical strategies are evolving and care is becoming more patient-centred. There are some good studies under way. There are, however, still numerous problems to resolve, and the challenge of PJI remains a major one for the orthopaedic community. This annotation provides some up-to-date thoughts about where we are, and the way forward. There is still scope for plenty of research in this area. Cite this article: Bone Joint J 2022;104-B(11):1193–1195

Aim. The number of operatively treated clavicle fractures has increased over the past decades. Consequently, this has led to an increase in secondary procedures required to treat complications such as fracture-related infection (FRI). The primary objective of this study was to assess the clinical and functional outcome of patients treated for FRI of the clavicle. The secondary objectives were to evaluate the healthcare costs and propose a standardized protocol for the surgical management of this complication. Method. All patients with a clavicle fracture who underwent open reduction and internal fixation (ORIF) between 1 January 2015 and 1 March 2022 were retrospectively evaluated. This study included patients with an FRI who were diagnosed and treated according to the recommendations of a multidisciplinary team at the University Hospitals Leuven, Belgium. Results. We evaluated 626 patients with 630 clavicle fractures who underwent ORIF. In total, 28 patients were diagnosed with an FRI. Of these, eight (29%) underwent definitive implant removal, five (18%) underwent debridement, antimicrobial treatment and implant retention, and fourteen patients (50%) had their implant exchanged in either a single-stage procedure, a two-stage procedure or after multiple revisions. One patient (3.6%) underwent resection of the clavicle. Twelve patients (43%) underwent autologous bone grafting (tricortical iliac crest bone graft (n=6), free vascularized fibular graft (n=5), cancellous bone graft (n=1)) to reconstruct the bone defect. The median follow-up was 32.3 (P. 25. -P. 75. : 23.9–51.1) months. Two patients (7.1%) experienced a recurrence of infection. The functional outcome was satisfactory, with 26 out of 28 patients (93%) having full range of motion. The median healthcare cost was € 11.506 (P. 25. -P. 75. : € 7.953–23.798) per patient. Conclusion. FRI is a serious complication that can occur after the surgical treatment of clavicle fractures. Overall, the outcome of patients treated for FRI of the clavicle is good, when management of this complication is performed by using a multidisciplinary team approach. The median healthcare costs of these patients are up to 3.5 times higher compared to non-infected operatively treated clavicle fractures. Expert opinion considers factors such as the size of the bone defect, the condition of the soft tissue, and patient demand to guide surgical decision making

Aims. Adverse spinal motion or balance (spine mobility) and adverse pelvic mobility, in combination, are often referred to as adverse spinopelvic mobility (SPM). A stiff lumbar spine, large posterior standing pelvic tilt, and severe sagittal spinal deformity have been identified as risk factors for increased hip instability. Adverse SPM can create functional malposition of the acetabular components and hence is an instability risk. Adverse pelvic mobility is often, but not always, associated with abnormal spinal motion parameters. Dislocation rates for dual-mobility articulations (DMAs) have been reported to be between 0% and 1.1%. The aim of this study was to determine the early survivorship from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) of patients with adverse SPM who received a DMA. Methods. A multicentre study was performed using data from 227 patients undergoing primary total hip arthroplasty (THA), enrolled consecutively. All the patients who had one or more adverse spine or pelvic mobility parameter had a DMA inserted at the time of their surgery. The mean age was 76 years (22 to 93) and 63% were female (n = 145). At a mean of 14 months (5 to 31) postoperatively, the AOANJRR was analyzed for follow-up information. Reasons for revision and types of revision were identified. Results. The AOANJRR reported two revisions: one due to infection, and the second due to femoral component loosening. No revisions for dislocation were reported. One patient died with the prosthesis in situ. Kaplan-Meier survival rate was 99.1% (95% confidence interval 98.3 to 100) at 14 months (number at risk 104). Conclusion. In our cohort of patients undergoing primary THA with one or more factor associated with adverse SPM, DM bearings conferred stability at two years’ follow-up. Cite this article: Bone Joint J 2022;104-B(7):820–825

Aim. Serum parameters continue to be a focus of research in diagnosing periprosthetic joint infections (PJI). Several workgroups have recently proposed serum Albumin-Globulin-Ratio (AGR) as a potential new biomarker. Due to controversies in the literature, its usability in clinical practice remains uncertain. The aim of this study was to assess the value of serum AGR in diagnosing PJI preoperatively, especially in comparison with the well-established marker C-reactive Protein (CRP). Method. From January 2015 to June 2022, patients with indicated revision hip (rTHA) and knee (rTKA) arthroplasty were included in this retrospective cohort study of prospectively collected data. A standardized diagnostic workup was performed using the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI, excluding CRP. Diagnostic accuracies of serum AGR and CRP were calculated by receiver operating characteristic curve (ROC) analysis. A z-test was used to compare the area under the curves (AUC). Results. A total of 275 patients with rTHA and rTKA were included, 144 joints (52.4%) were identified as septic. Decreased AGR and elevated CRP were strongly associated with PJI, optimal diagnostic thresholds were calculated with 1.253 and 9.4 mg/L, respectively. Sensitivities were 62.5% (95%-confidence interval: 54.3–70.0) and 73.6% (65.8–80.1), and specificities 84.7% (77.5–89.9) and 87.8% (80.9–92.4), respectively. CRP showed a significantly higher AUC than AGR (0.807 (0.761–0.853) and 0.736 (0.686–0.786); p<0.0001). Subgroup analysis of acute versus chronic infections yielded significantly higher diagnostic accuracies in acute PJI for both parameters (p<0.0001). Similar results were observed when focusing on the causative microorganism; a better diagnostic performance was observed in high-virulence PJI compared to low-virulence PJI (p≤0.005). Furthermore, higher AUCs were calculated in knee PJI compared with hip PJI, with a significant difference for AGR (p=0.043). Conclusions. Due to its limited diagnostic accuracy, serum AGR cannot be recommended as an additional marker for diagnosing PJI. Serum parameters are generally unspecific and can be influenced by comorbidities and other foci of infection. Additionally, parameters may remain within normal levels in low-grade PJI. Evaluating AGR, further possible pitfalls must be considered, for example an increased latency until bottom values are reached and the impact of malnutrition

The documentation of deep infection rates in joint replacement is fraught with multiple difficulties. Deep infections acquired in theatre may present late, but some later presenting deep infections are clearly haematogenous, and not related to surgical management. The effect of Ultra Clean Air on infection rates was published by Charnley in 1972 (CORR,87:167–187). The data is valuable because large numbers of THRs were performed in standard and Ultra Clean theatres, and detailed microbiology of the air was also recorded. No IV antibiotics were used, so only the effect of air quality was studied. We extracted the data on theatre type and numbers from Table 3, and numbers and intervals from surgery of deep infections from Table 7. Theatre types with 300 air changes per hour and 3.5 CFU/M. 3. were classified as Ultra Clean. A logistic regression model was used to examine the effect of theatre type and time elapsed after procedure on the probability of becoming infected. The model suggests that, controlling for time period, Ultra Clean Air is associated with a significantly lower probability of infection, with an OR of 0.30, p = 2.74 × 10. −6. The effect is larger earlier post-surgery, but it does persist. The results are best reviewed as a graphic, which shows that Ultra Clean Air clearly affects the deep infection rate for up to four years post-surgery. Ultra Clean Air reduces infection rates for up to four years post-surgery, so it is safe to assume that infections presenting after this are haematogenous. Ultra Clean Air does not eliminate early deep infection, so some early infections are not related to air quality. It is not practical to undertake widespread detailed retrospective analyses of cases. When monitoring infection rates there needs to be a balance between failing to record infections related to surgical technique and waiting many years to record low numbers of very late presenting problems. We suggest that registries should regard infections documented within three years of surgery as treatment complications. For any figures or tables, please contact the authors directly

Aims. The aim of this study was to determine the consensus best practice approach for the investigation and management of children (aged 0 to 15 years) in the UK with musculoskeletal infection (including septic arthritis, osteomyelitis, pyomyositis, tenosynovitis, fasciitis, and discitis). This consensus can then be used to ensure consistent, safe care for children in UK hospitals and those elsewhere with similar healthcare systems. Methods. A Delphi approach was used to determine consensus in three core aspects of care: 1) assessment, investigation, and diagnosis; 2) treatment; and 3) service, pathways, and networks. A steering group of paediatric orthopaedic surgeons created statements which were then evaluated through a two-round Delphi survey sent to all members of the British Society for Children’s Orthopaedic Surgery (BSCOS). Statements were only included (‘consensus in’) in the final agreed consensus if at least 75% of respondents scored the statement as critical for inclusion. Statements were discarded (‘consensus out’) if at least 75% of respondents scored them as not important for inclusion. Reporting these results followed the Appraisal Guidelines for Research and Evaluation. Results. A total of 133 children’s orthopaedic surgeons completed the first survey, and 109 the second. Out of 43 proposed statements included in the initial Delphi, 32 reached ‘consensus in’, 0 ‘consensus out’, and 11 ‘no consensus’. These 11 statements were then reworded, amalgamated, or deleted before the second Delphi round of eight statements. All eight were accepted as ‘consensus in’, resulting in a total of 40 approved statements. Conclusion. In the many aspects of medicine where relevant evidence is not available for clinicians to base their practice, a Delphi consensus can provide a strong body of opinion that acts as a benchmark for good quality clinical care. We would recommend clinicians managing children with musculoskeletal infection follow the guidance in the consensus statements in this article, to ensure care in all medical settings is consistent and safe. Cite this article: Bone Joint J 2023;105-B(7):815–820

Aims. The purpose of this study was to determine the weightbearing practice of operatively managed fragility fractures in the setting of publically funded health services in the UK and Ireland. Methods. The Fragility Fracture Postoperative Mobilisation (FFPOM) multicentre audit included all patients aged 60 years and older undergoing surgery for a fragility fracture of the lower limb between 1 January 2019 and 30 June 2019, and 1 February 2021 and 14 March 2021. Fractures arising from high-energy transfer trauma, patients with multiple injuries, and those associated with metastatic deposits or infection were excluded. We analyzed this patient cohort to determine adherence to the British Orthopaedic Association Standard, “all surgery in the frail patient should be performed to allow full weight-bearing for activities required for daily living”. Results. A total of 19,557 patients (mean age 82 years (SD 9), 16,241 having a hip fracture) were included. Overall, 16,614 patients (85.0%) were instructed to perform weightbearing where required for daily living immediately postoperatively (15,543 (95.7%) hip fracture and 1,071 (32.3%) non-hip fracture patients). The median length of stay was 12.2 days (interquartile range (IQR) 7.9 to 20.0) (12.6 days (IQR 8.2 to 20.4) for hip fracture and 10.3 days (IQR 5.5 to 18.7) for non-hip fracture patients). Conclusion. Non-hip fracture patients experienced more postoperative weightbearing restrictions, although they had a shorter hospital stay. Patients sustaining fractures of the shaft and distal femur had a longer median length of stay than demographically similar patients who received hip fracture surgery. We have shown a significant disparity in weightbearing restrictions placed on patients with fragility fractures, despite the publication of a national guideline. Surgeons intentionally restrict postoperative weightbearing in the majority of non-hip fractures, yet are content with unrestricted weightbearing following operations for hip fractures. Cite this article: Bone Joint J 2022;104-B(8):972–979

Aim. Failed consolidation (nonunion) after foot and ankle arthrodesis is a major complication, which can lead to additional revision arthrodesis with increased risk of morbidity. Multiple factors can contribute to developing a nonunion, including a low-grade infection. The aim of this study was to investigate the rate of unsuspected low-grade infection in revision arthrodesis for nonunions after foot and ankle arthrodesis. We also analyzed the outcome of unsuspected low-grade infections. Method. We conducted a retrospective study in The Sint Maartenskliniek, The Netherlands. All patients who underwent revision arthrodesis for assumed aseptic nonunion after foot and ankle arthrodesis between January 2020 and July 2021 were included. Patients were excluded if <5 tissue samples were obtained during revision arthrodesis or if they were treated for infection after the index arthrodesis. For the included patients, at least 5 tissue samples for culture were taken during the revision arthrodesis. The causative microorganisms, antibiotic susceptibility and treatment were assessed. An unsuspected infection was defined as ≥2 positive cultures with phenotypical identical microorganisms. Success was defined as union on imaging during clinical follow-up, without signs of persistent infection after finishing the antibiotic treatment. Results. In total 91 revision arthrodesis due to nonunion were performed. The mean duration between index and revision arthrodesis was 571 days. In 14 patients, an unexpected infection was diagnosed. The most frequent causative bacteria identified were Cutibacterium acnes (n=10) and Staphylococcus spps. (n=5). One infection was caused by a Gram-negative bacilli (Acinetobacter spps.). Two infections were polymicrobial. Of the 14 infections, 12 were treated with antibiotics for 12 weeks, 1 for 6 weeks and 1 was not treated. After one-year follow-up, the success rate was 86% and in one patient re-surgery was performed for a non-infectious reason. Conclusions. In 18% of the revisions for nonunion after foot and ankle arthrodesis, an unexpected low- grade infection was the cause of the nonunion. Nonunion occurring after foot and ankle arthrodesis is a severe complication, leading to additional revision arthrodesis. Low-grade infection should be considered as possible explanation of the nonunion, despite the lack of local inflammatory signs. As 18% of the nonunions were unexpectedly caused by low-grade infection, we strongly recommend obtaining at least 5 tissue samples for culture during revision arthrodesis. The outcome of unexpected infection as cause of nonunion is good, when treated with targeted antibiotics for 12 weeks

Aim. Acute post-surgical infection is one of the most serious complications after instrumented thoracolumbar fusion with an incidence of 0.7%-12%. Acute infection can lead to an increase in morbidity, mortality, and economic costs for the healthcare system. The main objective of our study was to determine the variables associated with a higher risk of acute infection after thoracolumbar instrumentation in our center. Methods. We conducted an observational case-control study including instrumented fusions of the thoracolumbar spine performed between 2015 and 2021 at our institution. We included patients with thoracolumbar fusions after a fracture or for the treatment of degenerative pathology. We analyzed demographic variables related to the surgical procedure, the causative microorganism of infection, the outcome of infection treatment, and complications. We performed a descriptive analysis of all variables and a univariate comparison of cases and controls. The dichotomous variables were compared using the Fisher test, while the quantitative variables were compared using the Student's T-test. A p-value of <0.05 is taken into account to consider the statistical significance. SPSS v25 Windows program was used for statistical analyses. Results. 455 patients were included, 53% were male with a mean age of 60 years. 35% of patients had a BMI (Body Mass Index) >30, 21.1% were classified as ASA (American Society of Anesthesiologists) >3, 15.8% were diabetic, and 2.6% were under chronic corticosteroid treatment. In 34.1% of the fusions, the procedure lasted more than 3 hours. We identified 26 post-surgical acute infections (5.7%). Patients with an infection had a higher prevalence of diabetes (14.7% vs 34.6% p=0.012), chronic corticosteroid treatment (2.1% vs 11.5% p=0.026), and a higher percentage of surgeries with duration > 3 hours (32.4% vs. 61.1%, p=0.019). A trend towards significance was also observed in patients classified as ASA >3 (20.3% vs. 34.6%, p=0.088), and BMI >30 (33.8% vs. 53.8%, p=0.054). No significant differences were observed in the rest of the variables studied. The most frequent causative microorganism was S.epidermidis (38%), followed by S.aureus (34%) and polymicrobial infections (34%). Conclusions. There is a significant increase in infection in diabetic patients, patients with chronic corticosteroid treatment, and in surgeries lasting > 3 hours

Aims. Periprosthetic joint infection (PJI) occurs in approximately 1% to 2% of total knee arthroplasties (TKA) presenting multiple challenges, such as difficulty in diagnosis, technical complexity, and financial costs. Two-stage exchange is the gold standard for treating PJI but emerging evidence suggests 'two-in-one' single-stage revision as an alternative, delivering comparable outcomes, reduced morbidity, and cost-effectiveness. This study investigates five-year results of modified single-stage revision for treatment of PJI following TKA with bone loss. Methods. Patients were identified from prospective data on all TKA patients with PJI following the primary procedure. Inclusion criteria were: revision for PJI with bone loss requiring reconstruction, and a minimum five years’ follow-up. Patients were followed up for recurrent infection and assessment of function. Tools used to assess function were Oxford Knee Score (OKS) and American Knee Society Score (AKSS). Results. A total of 24 patients were included with a mean age of 72.7 years (SD 7.6), mean BMI of 33.3 kg/m. 2. (SD 5.7), and median ASA grade of 2 (interquartile range 2 to 4). Mean time from primary to revision was 3.0 years (10 months to 8.3 years). At revision, six patients had discharging sinus and three patients had negative cultures from tissue samples or aspirates. Two patients developed recurrence of infection: one was treated successfully with antibiotic suppression and one underwent debridement, antibiotics, and implant retention. Mean AKSS scores at two years showed significant improvement from baseline (27.1 (SD 10.2 ) vs 80.3 (SD 14.8); p < 0.001). There was no significant change in mean AKSS scores between two and five years (80.3 (SD 14.8 ) vs 74.1 (SD 19.8); p = 0.109). Five-year OKS scores were not significantly different compared to two-year scores (36.17 (SD 3.7) vs 33.0 (SD 8.5); p = 0.081). Conclusion. ‘Two-in-one’ single-stage revision is effective for treating PJI following TKA with bone loss, providing patients with sustained improvements in outcomes and infection clearance up to five years post-procedure. Cite this article: Bone Jt Open 2022;3(2):107–113

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. Methods. This was a prospective pilot study, including 24 patients divided into three groups, with eight patients each undergoing revision of their hip arthroplasty due to aseptic reasons, and low- and high-grade PJI, respectively. The number of intraoperative samples and the incidence of positive cultures were recorded for each patient. Additionally, venous blood samples and periarticular tissue samples were collected from each patient to determine miRNA expressions between the groups. MiRNA screening was performed by small RNA-sequencing using the miRNA next generation sequencing (NGS) discovery (miND) pipeline. Results. Overall, several miRNAs in plasma and tissue were identified to be progressively deregulated according to ongoing PJI. When comparing the plasma samples, patients with a high-grade infection showed significantly higher expression levels for hsa-miR-21-3p, hsa-miR-1290, and hsa-miR-4488, and lower expression levels for hsa-miR-130a-3p and hsa-miR-451a compared to the aseptic group. Furthermore, the high-grade group showed a significantly higher regulated expression level of hsa-miR-1260a and lower expression levels for hsa-miR-26a-5p, hsa-miR-26b-5p, hsa-miR-148b-5p, hsa-miR-301a-3p, hsa-miR-451a, and hsa-miR-454-3p compared to the low-grade group. No significant differences were found between the low-grade and aseptic groups. When comparing the tissue samples, the high-grade group showed significantly higher expression levels for 23 different miRNAs and lower expression levels for hsa-miR-2110 and hsa-miR-3200-3p compared to the aseptic group. No significant differences were found in miRNA expression between the high- and low-grade groups, as well as between the low-grade and aseptic groups. Conclusion. With this prospective pilot study, we were able to identify a circulating miRNA signature correlating with high-grade PJI compared to aseptic patients undergoing hip arthroplasty revision. Our data contribute to establishing miRNA signatures as potential novel diagnostic and prognostic biomarkers for PJI. Cite this article: Bone Jt Open 2024;5(6):479–488

Aims. The aim of this study was to examine whether socioeconomic status (SES) is associated with a higher risk of infections following total hip arthroplasty (THA) at 30 and 90 days. Methods. We obtained individual-based information on SES markers (cohabitation, education, income, and savings) on 103,901 THA patients from Danish health registries between 1 January 1995 and 31 December 2017. The primary outcome measure was any hospital-treated infection (i.e. all infections). The secondary outcomes were further specified to specific hospital-treated infections (pneumonia, urinary tract infection, and periprosthetic joint infection). The primary timepoint was within 90 days. In addition, the outcomes were further evaluated within 30 days. We calculated the cumulative incidence, and used the pseudo-observation method and generalized linear regression to estimate adjusted risk ratios (RRs) with 95% confidence intervals (CIs) for each marker. Results. The cumulative incidence of any infection at 90 days was highest in patients who lived alone (1.5% (95% CI 1.3 to 1.6)) versus cohabitant (0.7% (95% CI 0.7 to 0.8)), had the lowest educational achievement (1.1% (95% CI 1.0 to 1.2)) versus highest (0.7% (95% CI 0.5 to 0.8)), had the lowest income (1.6% (95% CI 1.5 to 1.70)) versus highest (0.4% (95% CI 0.3 to 0.5)), or had lowest savings (1.3% (95% CI 1.2 to 1.4)) versus highest (0.7% (95% CI 0.6 to 0.8)). Within 90 days, the RRs for any infection were 1.3 (95% CI 1.2 to 1.4) for patients living alone versus cohabiting, 1.2 (95% CI 1.0 to 1.3) for low education achievement versus high, 1.7 (95% CI 1.4 to 2.1) for low income versus high income, and 1.5 (95% CI 1.4 to 1.8) for low savings versus high savings. The same trends were also seen for any infections within the first 30 days. Conclusion. Our study provides evidence that socioeconomic inequality adversely influences the risk of infection after THA, thus contributing to healthcare disparities and inequalities. We found that living alone, low educational achievement, low income, or low savings were associated with higher risks of infections within the first 30 and 90 days after THA. Therefore, the development of targeted intervention strategies with the aim of increasing awareness of patients identified as being at greatest risk is needed to mitigate the impact of SES on the risk of infections following THA. Cite this article: Bone Joint J 2022;104-B(2):221–226

Aims. This study aimed to evaluate the clinical application of the PJI-TNM classification for periprosthetic joint infection (PJI) by determining intraobserver and interobserver reliability. To facilitate its use in clinical practice, an educational app was subsequently developed and evaluated. Methods. A total of ten orthopaedic surgeons classified 20 cases of PJI based on the PJI-TNM classification. Subsequently, the classification was re-evaluated using the PJI-TNM app. Classification accuracy was calculated separately for each subcategory (reinfection, tissue and implant condition, non-human cells, and morbidity of the patient). Fleiss’ kappa and Cohen’s kappa were calculated for interobserver and intraobserver reliability, respectively. Results. Overall, interobserver and intraobserver agreements were substantial across the 20 classified cases. Analyses for the variable ‘reinfection’ revealed an almost perfect interobserver and intraobserver agreement with a classification accuracy of 94.8%. The category 'tissue and implant conditions' showed moderate interobserver and substantial intraobserver reliability, while the classification accuracy was 70.8%. For 'non-human cells,' accuracy was 81.0% and interobserver agreement was moderate with an almost perfect intraobserver reliability. The classification accuracy of the variable 'morbidity of the patient' reached 73.5% with a moderate interobserver agreement, whereas the intraobserver agreement was substantial. The application of the app yielded comparable results across all subgroups. Conclusion. The PJI-TNM classification system captures the heterogeneity of PJI and can be applied with substantial inter- and intraobserver reliability. The PJI-TNM educational app aims to facilitate application in clinical practice. A major limitation was the correct assessment of the implant situation. To eliminate this, a re-evaluation according to intraoperative findings is strongly recommended. Cite this article: Bone Joint Res 2024;13(1):19–27

Aims. This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection. Methods. This is a retrospective population-based cohort study using prospectively collected patient-level data between 1 January 2013 and 1 March 2020. The diagnosis of deep SSI was defined as per the Centers for Disease Control/National Healthcare Safety Network criteria. The Mann-Kendall Trend test was used to detect monotonic trends in annual rates of early-onset deep SSI over time. Multiple logistic regression was used to analyze the effect of different patient, surgical, and healthcare setting factors on the risk of developing a deep SSI within 90 days from surgery for patients with complete data. We also report 90-day mortality. Results. A total of 39,038 patients underwent primary TKA for osteoarthritis during the study period. Of these, 275 patients developed a deep SSI within 90 days of surgery, representing a cumulative incidence of 0.7%. The annual infection rate did not significantly decrease over the seven-year study period (p = 0.162). Overall, 13,885 (35.5%) cases were excluded from the risk analysis due to missing data. Risk factors associated with early-onset deep SSI included male sex, American Society of Anesthesiologists grade ≥ 3, blood transfusion, acute length of stay, and surgeon volume < 30 TKAs/year. Early-onset deep SSI was not associated with increased 90-day mortality. Conclusion. This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis using robust Infection Prevention and Control surveillance data, and identifies several potentially modifiable risk factors. Cite this article: Bone Joint J 2023;105-B(9):971–976

Despite the routine use of systemic antibiotic prophylaxis, postoperative infection following fracture surgery remains a persistent issue with substantial morbidity. The use of additional local antibiotic prophylaxis may have a protective effect and some orthopaedic surgeons have adopted their use in recent years, despite limited evidence of its beneficial effect. The purpose of this systematic review and meta-analysis was to evaluate the current literature regarding the effect of prophylactic local antibiotics on the rate of infection in fracture surgery in both open and closed fractures. A comprehensive search of Medline, EMBASE, and PubMed was performed. Cohort studies were eligible if they investigated the effect on infection rate of additional local antibiotic prophylaxis compared with systemic prophylaxis alone following fracture surgery. The data were pooled in a meta-analysis. In total, four randomized controlled trials and 11 retrospective cohort studies with a total of 6161 fractures from various anatomical locations were eligible for inclusion. The majority of the included studies were Level 3 evidence and had a moderate risk of bias. When all fractures were pooled, the risk of infection was significantly reduced when local antibiotics were applied compared with the control group receiving systemic prophylaxis only (OR = 0.39; 95%CI: 0.26 to 0.53, P < 0.001). In particular, there was a significant reduction in deep infections (OR = 0.59; 95%CI: 0.38 to 0.91, P = 0.017). The beneficial effect of local antibiotics for preventing total infection was seen in both open fractures (OR = 0.35; 95%CI: 0.23 to 0.53, P < 0.001) and closed fractures (OR = 0.58; 95%CI: 0.35 to 0.95, P = 0.029) when analyzed separately. This meta-analysis suggests a significant risk reduction for postoperative infection following fracture surgery when local antibiotics were added to standard systemic prophylaxis, with a protective effect present in both open and closed fractures

Abstract. Aims. The primary aim of this study was to evaluate the outcomes of fungal knee periprosthetic joint infection following knee arthroplasty. The secondary aim was to evaluate risk factors for acquiring a fungal PJI. Patients and Methods. This was a retrospective analysis of patients presenting with a confirmed fungal PJI of the knee in two tertiary centres. There were a total of 45 cases. Isolated fungal infections along with mixed bacterial and fungal infections were included. Mean follow up was 40 months (range 3–118). Results. The mean age at presentation was 69 years (range 46 to 87) and mean BMI was 31 kg/m2 (range 20 to 44). The median number of procedures that patients had on the affected limb from the index primary arthroplasty procedure was 6 (range 2–17). The median procedure number at which a fungal infection was identified was 5 (range 2–10). A history of prolonged antibiotic therapy (above 6 months total) was present in 37 patients (88%). During the study period 22 patients were infection free, 14 treated with lifelong suppression, 7 had above knee amputations and 6 had died. Overall infection cure rate was 49%. Conclusions. Patients with fungal PJI are generally poor hosts with multiple co-morbidities, long term exposure to antibiotics and high rates of open wounds and sinuses. The poor outcome associated with fungal PJI relative to bacterial PJI should be shared with patients in order to manage the expectations of this complex cohort

Aims. The aim of this study was to analyze the prevalence of culture-negative periprosthetic joint infections (PJIs) when adequate methods of culture are used, and to evaluate the outcome in patients who were treated with antibiotics for a culture-negative PJI compared with those in whom antibiotics were withheld. Methods. A multicentre observational study was undertaken: 1,553 acute and 1,556 chronic PJIs, diagnosed between 2013 and 2018, were retrospectively analyzed. Culture-negative PJIs were diagnosed according to the Muskuloskeletal Infection Society (MSIS), International Consensus Meeting (ICM), and European Bone and Joint Society (EBJIS) definitions. The primary outcome was recurrent infection, and the secondary outcome was removal of the prosthetic components for any indication, both during a follow-up period of two years. Results. None of the acute PJIs and 70 of the chronic PJIs (4.7%) were culture-negative; a total of 36 culture-negative PJIs (51%) were treated with antibiotics, particularly those with histological signs of infection. After two years of follow-up, no recurrent infections occurred in patients in whom antibiotics were withheld. The requirement for removal of the components for any indication during follow-up was not significantly different in those who received antibiotics compared with those in whom antibiotics were withheld (7.1% vs 2.9%; p = 0.431). Conclusion. When adequate methods of culture are used, the incidence of culture-negative PJIs is low. In patients with culture-negative PJI, antibiotic treatment can probably be withheld if there are no histological signs of infection. In all other patients, diagnostic efforts should be made to identify the causative microorganism by means of serology or molecular techniques. Cite this article: Bone Joint J 2022;104-B(1):183–188

Aims. Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (. 99m. Tc-UBI. 29-41. -Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. Methods. 99m. Tc-UBI. 29-41. -Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be complemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were identified using imaging, which included 500 to 2,000 viable bacteria. Conclusion. The hybrid tracer . 99m. Tc-UBI. 29-41. -Cy5 allowed effective bacterial staining. Qualitative real-time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Cite this article: Bone Joint Res 2023;12(1):72–79