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Introduction Self-reported penicillin allergies in patients undergoing total joint arthroplasty often results in the use of second-line prophylactic antibiotics. A higher risk of prosthetic joint infection (PJI) is associated with suboptimal antibiotics vs first generation cephalosporins, which have historically been grouped with other beta-lactam antibiotics such as penicillin for potential allergic reactions. This study evaluates the economic burden of self-reported penicillin allergies in total joint arthroplasty (TJA). Methods Data from studies reporting true incidence of IgE-mediated penicillin allergies, infection-free survivorship of TJA, and cost of PJI attributed to use of second-line antibiotics were obtained. Projected cost of preoperative penicillin allergy testing and potentially avoidable PJI associated with second-line antibiotic usage were calculated. This was compared with projected cost of PJI in the current state to estimate cost savings. Results Implementation of preoperative penicillin allergy testing leads to a potential savings of nearly $37 million to payors in the first year based on 1-year survivorship. This savings increases to $411.6 million over a 10-year span and $1.18 billion over a 20-year span. Conclusion Preoperative penicillin allergy testing or risk stratification via thorough history should be implemented as standard of care for patients with self-reported penicillin allergies before TJA and would result in decreased cost of PJI.

Background Prior studies have demonstrated that depression is an independent risk factor for developing a prosthetic joint infection (PJI) after total joint arthroplasty (TJA). To our knowledge, there is no literature examining whether PJI or aseptic failure increases the risk of developing a new mental health diagnosis. Methods PearlDiver Patient Database (Colorado Springs, CO) was used to identify 80,826 patients who underwent TJA without a pre-existing diagnosis of depression, anxiety, a stress and/or adjustment disorder, and/or current use of a selective serotonin reuptake inhibitor within the year prior to surgery. The odds of developing a new mental health issue or being prescribed a selective serotonin reuptake inhibitor within 1 year of an uncomplicated TJA was compared to those who developed PJI or mechanical failure within 90 days after TJA as well as to those who subsequently underwent revision surgery within 30 days of either complication using Fisher’s exact test and Baptista-Pike. Results A total of 6474 (8%) patients were diagnosed with a new mental health issue after TJA. PJI or mechanical failure led to significantly higher odds of new diagnoses with an odds ratio of 1.67 (95% confidence interval = 1.26, 2.22) and 1.57 (1.24, 2.00), respectively. Undergoing revision surgery for PJI or mechanical failure increased the odds of developing a new mental health diagnosis to 2.10 (1.29, 3.42) and 2.24 (1.36, 3.72), respectively. There was no significant difference comparing those who developed PJI vs those who sustained mechanical complications. Conclusion Patients who sustain complications after TJA are at increased odds of receiving a new mental health diagnosis, an effect further amplified if revision surgery is required.

Background and purpose - Proton-pump inhibitors (PPI) have previously been associated with an increased risk of infections such as community-acquired pneumonia, gastrointestinal infections and central nervous system infection. Therefore, we evaluated a possible association between proton-pump inhibitor use and prosthetic joint infection (PJI) in patients with total hip arthroplasty (THA), because they can be stopped perioperatively or switched to a less harmful alternative. Patients and methods - A cohort of 5,512 primary THAs provided the base for a case-cohort design; cases were identified as patients with early-onset PJI. A weighted Cox proportional hazard regression model was used for the study design and to adjust for potential confounders. Results - There were 75 patients diagnosed with PJI of whom 32 (43%) used PPIs perioperatively compared with 75 PPI users (25%) in the control group of 302 patients. The risk of PJI was 2.4 times higher (95% CI 1.4-4.0) for patients using PPI. This effect remained after correction for possible confounders. Interpretation - The use of PPIs was associated with an increased risk of developing PJI after THA. Hence, the use of a PPI appears to be a modifiable risk factor for PJI.

Prosthetic joint infections (PJIs) can be challenging to eradicate and have high morbidity and mortality. Current microbiology culture methods can be associated with a high false-negative rate of up to 50%. Early and accurate diagnosis is crucial for effective treatment, and negative results have been linked to a greater rate of reoperation.There has been increasing investigation of the use of next-generation sequencing (NGS) technology such as metagenomic shotgun sequencing to help identify causative organisms and decrease the uncertainty around culture-negative infections. The clinical importance of the organisms detected and their management, however, requires further study. The polymerase chain reaction (PCR) has shown promise, but in recent years multiple studies have reported similar or lower sensitivity for bacteria detection in PJIs when compared to traditional culture. Furthermore, issues such as high cost and complexity of sample preparation and data analysis are to be addressed before it can move further toward routine clinical practice.Metagenomic NGS has shown results that inspire cautious optimism - both in culture-positive and culture-negative cases of joint infection. Refinement of technique could revolutionize the way PJIs are diagnosed, managed, and drastically improve outcomes from this currently devastating complication.

Background A multidisciplinary team responsible for the management plan of prosthetic joint infections (PJI) was founded in January 2008. The aim of this study was to investigate whether a decrease in the number of surgeries and length of stay (LOS) was seen in the management of PJI with the aid of the multidisciplinary team. Methods This retrospective cohort study consisted of a total of 154 postoperative PJIs from three time periods: 21 PJIs from 2005 to 2007 (Group 1), 65 PJIs from 2011 to 2013 (Group 2), and 68 PJIs from 2015 to 2016 (Group 3). Successful outcome was classified as the retention of the original implant or revised implant and no infection-related death. Results The median number of operations decreased from 2.0 operations (Group 1) to 1.0 operation (Group 3) (p = .023), and the median LOS was shortened from 49.0 days (Group 1) to 17.0 days (Group 3) (p = .000). The number of PJIs treated with two-stage exchange decreased from 52.4% (11/21, Group 1) to 16.2% (11/68, Group 3) (p = .004). Simultaneously, debridement, antibiotics, and implant retention (DAIR) as primary surgical treatment increased from 42.9% (9/21, Group 1) to 89.7% (61/68, Group 3) (p = .000). The successful outcome of DAIR improved from 55.6% (5/9, Group 1) to 85.2% (52/61, Group 3) (p = .077). Conclusions Treatment of PJI in a specialized centre with the aid of a multidisciplinary team lead to fewer surgeries and reduced LOS. Successful outcome of DAIR improved over time.

Background Two-stage revision remains the standard of care for prosthetic joint infection after total hip arthroplasty. However, there are substantial complications associated with articulating antibiotic hip spacers. Handmade and molded spacers have been shown to have higher rates of spacer fracture than antibiotic-coated prostheses (ACPs). The aim of this study is to review outcomes with an implant that is often categorized as an ACP spacer, the Zimmer-Biomet StageOne Select Femoral Spacer (ZBSO). Methods A retrospective review was performed of 63 patients who underwent placement of a ZBSO. Patients were compared based on whether or not an extended trochanteric osteotomy (ETO) was performed using Fisher’s exact and t-tests. Results Five patients were excluded due to lack of follow-up or death shortly after stage 1 surgery, leaving 58 patients. Spacer fracture was noted in 5 of 58 patients (8.6%). Sixteen patients underwent ETO and 25.0% suffered a spacer fracture compared to 2.3% without ETO (odds ratio 13.7, P = .0248). There was no association between patient demographics or ETO length and spacer fracture. Two patients had periprosthetic fractures (3.4%) and 4 had dislocations (6.9%). Forty-nine patients (84.4%) went on to second-stage revision; of those 26.5% failed to clear the infection and required an average of 2.2 additional surgeries. Conclusion The ZBSO spacer has overall complication rates similar to previously reported spacer series. Although the ZBSO looks like an ACP spacer, in the setting of ETO, it behaves like a molded or handmade spacer with a high rate of spacer fracture (25%) due to the small diameter of the core. This implant should be used with caution in combination with an ETO.

Hui-Ming Peng,1 Zong-Ke Zhou,2 Fei Wang,3 Shi-Gui Yan,4 Peng Xu,5 Xi-Fu Shang,6 Jia Zheng,7 Qing-Sheng Zhu,8 Li Cao,9 Xi-Sheng Weng1 1Department of Orthopedics, Peking Union Medical College Hospital, CAMS & PUMC, Beijing, 100730, People’s Republic of China; 2Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan Province, People’s Republic of China; 3Department of Orthopedic Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, 050051, Hebei Province, People’s Republic of China; 4Department of Orthopedic Surgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang Province, People’s Republic of China; 5Department of Adult Joint Reconstruction, Xi’ an Honghui Hospital, Xi’ An, 710054, Shaanxi Province, People’s Republic of China; 6Department of Orthopedic Surgery, First Affiliated Hospital of University of Science and Technology of China, Hefei, 230001, Anhui Province, People’s Republic of China; 7Department of Orthopedic Surgery, Henan Provincial People’s Hospital, Zhengzhou, 450003, Henan Province, People’s Republic of China; 8Department of Orthopedic Surgery, Xijing Hospital of Air Force Medical University, Xi’ An, 710032, Shanxi Province, People’s Republic of China; 9Department of Orthopedic Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830054, Xinjiang, People’s Republic of ChinaCorrespondence: Xi-Sheng WengDepartment of Orthopedics, Peking Union Medical College Hospital, CAMS & PUMC, No. 1 Shuaifuyuan, Wangfujing, Dongcheng District, Beijing, 100730, People’s Republic of ChinaTel/Fax +86-10-69152710Email drweng_wxs1377@163.comBackground and Aim: Periprosthetic joint infection (PJI) is one of the most devastating complications after total joint arthroplasty (TJA). However, the antibiotic resistance of infecting pathogens can significantly vary in different parts of the country. In the current study, we analyzed the demographic and microbiological profiles of knee and hip PJI over three years and compared the microbiological differences between them.Methods: A multicenter retrospective study of PJI patients in 34 referral medical centers in mainland China from January 2015 to November 2017 was performed.Results: A total of 925 PJI patients were recruited, 452 were identified as knee PJIs, and 473 were hip PJIs. The most common causative pathogens were Staphylococcus aureus (26.5%) and coagulase-negative staphylococci (14.3%). Methicillin-resistant staphylococci were involved in 25.6% (237/925) of all PJI cases. Mycobacterium and fungus only accounted for 6.5% (61) of all cases. Enteric gram-negative bacilli, anaerobes, and polymicrobial pathogens were more common in hip joint prostheses than in knee PJI (P = 0.014; P = 0.006; P = 0.002, respectively).Conclusion: While the majority of causative pathogens in PJI cases are staphylococcal species, the prevalence of atypical organisms and resistant pathogens should also be given attention and warrant the need for empiric antibiotic treatment.Keywords: arthroplasty, hips, knees, microorganism, prosthetic joint infection

Background Prosthetic joint infection (PJI) is a significant cause of morbidity and mortality following knee replacement surgery. The diagnosis can be challenging and is based on a combination of clinical suspicion, radiographic findings and also biochemical/ microbiological investigations. Our Aim was to review the role of aspiration and biopsy in the diagnosis of PJI in Total Knee Arthroplasty (TKA). Method/results Aspirated synovial fluid should be analysed by direct culture, via blood culture bottles, EDTA bottles for cell count and ‘point of care’ testing such as leucocyte esterase or alpha defensin. Synovial WCC and PMN cell percentage are important steps in diagnosis of both acute and chronic PJI. A minimum of 5 deep samples using a 5 clean instrument technique should be obtained and sent for tissue culture done either blind or arthroscopic. Formal fluoroscopic guided interface biopsy has also been described with excellent results. In a recent series of 86 TKRs preoperative arthroscopic biopsy group had a sensitivity of 100%, specificity of 94.7%, positive predictive value of 87.4% and a negative predictive value of 100%. Conclusion In the presence of clinical suspicion with raised biomarkers, it is recommended that aspiration +/- biopsy with synovial fluid testing is performed. Direct culture and cell count are recommended. ‘Point of care tests’ such as Leucocyte Esterase testing should be considered. Duration of culture, including pathogen and host factors, should be discussed with a local microbiology/ID department in the context of a formal multi-disciplinary team.

Instability remains one of the most frequent complications requiring revision surgery after primary total hip arthroplasty (THA). Elevated liners are often utilized to reduce the risk of dislocation; however, the literature is inconclusive, with no systematic reviews summarizing the data. Thus, this systematic review aimed to establish a consensus for the efficacy of elevated liners in primary THA by determining rates of overall revision and revision specifically for recurrent dislocation. This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eligible randomized-controlled trials and observational studies reporting on the use of elevated liners in primary total hip arthroplasty were identified through May 2020. A random effects model meta-analysis was conducted, and the I2 statistic was used to assess for heterogeneity. Eight studies met inclusion criteria, and overall, 26,507 patients undergoing primary THA with use of an elevated liner were included. In aggregate, the most common cause of revision was recurrent hip dislocation (1.3%, N = 82/6,267) followed by joint infection (1.2%, N = 45/3,772) and acetabular loosening (0.3%, N = 10/3,772). Notably, elevated liners were associated with a lower risk of revision for recurrent dislocation compared to neutral liners (HR: 0.74; 95% CI: 0.55–1.00; p = 0.048). This review found that after primary THA with the use of elevated liners, hip dislocation and prosthetic joint infection continued to be the most frequent reasons for revision surgery. However, elevated liners had a lower risk of revision for recurrent dislocation compared to neutral liners.

Background: The 2010 American Academy of Orthopaedic Surgeons Clinical Practice Guidelines report insufficient evidence to address the diagnostic efficacy of magnetic resonance imaging (MRI) for periprosthetic joint infection (PJI). Questions/Purposes: The purpose of this study was to determine the utility of MRI with multiacquisition variable-resonance image combination (MAVRIC) metal artifact suppression techniques in diagnosing PJI in the setting of total hip arthroplasty (THA). Methods: Multiacquisition variable-resonance image combination MRIs obtained of THAs between November 2012 and November 2016 were queried. Radiology reports were classified as positive (suspicious for infection), negative (no features of infection), or inconclusive (infection cannot be excluded or correlation with aspiration suggested if clinically concerned). Chart review identified cases of deep PJI according to the modified Musculoskeletal Infection Society criteria. Results: Of 2156 MRIs of THAs included, MRI was concerning for infection in 1.8% (n = 39), inconclusive in 1.2% (n = 26), and negative in 97.0% (n = 2091). Deep PJI was identified in 53 (2.5%) patients, 30 of whom (56.6%) had conclusively positive finding on MRI (false-negative rate: 43.4%, sensitivity: 56.6%). Of 2103 aseptic THAs, only 9 (0.4%) MRIs were read as suspicious for infection (false-positive rate: 0.4%; specificity: 99.6%). Conclusion: Magnetic resonance imaging with MAVRIC is a highly specific test for PJI with a low false-positive rate. This indicates that when clinicians are provided with an MRI that unexpectedly suggests infection, a formal evaluation for infection is indicated. In patients with otherwise equivocal diagnostic findings, MRI may help confirm, but not refute, a diagnosis of PJI. Prospective study with more experienced image reviewers may further support the use of MRI in PJI.

Aims Periprosthetic joint infections (PJIs) are among the most devastating complications after joint arthroplasty. There is limited evidence on the efficacy of different antiseptic solutions on reducing biofilm burden. The purpose of the present study was to test the efficacy of different antiseptic solutions against clinically relevant microorganisms in biofilm. Methods We conducted an in vitro study examining the efficacy of several antiseptic solutions against clinically relevant microorganisms. We tested antiseptic irrigants against nascent (four-hour) and mature (three-day) single-species biofilm created in vitro using a drip-flow reactor model. Results With regard to irrigant efficacy against biofilms, Povidone-iodine treatment resulted in greater reductions in nascent MRSA biofilms (logarithmic reduction (LR) = 3.12; p < 0.001) compared to other solutions. Bactisure treatment had the greatest reduction of mature Pseudomonas aeruginosa biofilms (LR = 1.94; p = 0.032) and a larger reduction than Vashe or Irrisept for mature Staphylococcus epidermidis biofilms (LR = 2.12; p = 0.025). Pooled data for all biofilms tested resulted in Bactisure and Povidone-iodine with significantly greater reductions compared to Vashe, Prontosan, and Irrisept solutions (p < 0.001). Conclusion Treatment failure in PJI is often due to failure to clear the biofilm; antiseptics are often used as an adjunct to biofilm clearance. We tested irrigants against clinically relevant microorganisms in biofilm in vitro and showed significant differences in efficacy among the different solutions. Further clinical outcome data is necessary to determine whether these solutions can impact PJI outcome in vivo. Cite this article: Bone Joint J 2021;103-B(5):908–915.

Background Extensor mechanism disruption (EMD) combined with periprosthetic joint infection (PJI) after total knee arthroplasty are life-changing complications. The literature suggests many eventually receive above-knee amputation and lose ambulatory function. An alternative is modular knee fusion (KF), but little is known about its outcomes and biomechanical function. We report early term results on a case series of patients. Methods A retrospective review was conducted of patients who underwent 2-stage reconstruction with modular KF for combined EMD and PJI. Patient-reported outcomes at 1 year after arthrodesis and complications of surgery were recorded. Biomechanical analysis was conducted on 6 patients >1 year after surgery to measure gait speed and balance. Results Fifteen patients received a modular KF. At the most recent follow-up visit (average 25.7 months), 12 patients had their modular KFs in place and were ambulatory while 2 had died. Six patients used a walker; 4, a cane; and 2, unassisted. Gait analysis of 6 of these patients showed variation in patterns and speed. Balance was better than historical controls treated with above-knee amputation. Average Knee Injury and Osteoarthritis Outcome Score Junior was 76 ± 11. Conclusion Modular KF for EMD and PJI can result in successful outcomes in terms of preventing additional operations and maintaining ambulation. While speed is variable, physical testing shows this method for limb salvage may allow patients to ambulate with a gait aid although further studies are needed to evaluate midterm and long-term results.

Fungal periprosthetic joint infections are an uncommon but potentially devastating complication of arthroplasty surgery. The concurrent presence of a coexistent bacterial pathogen—a so called “super-infection”—adds further complexity. With delays to definitive diagnosis and a large number of procedures before cure, the associated physical and psychological morbidity is considerable. Beyond this, the economic and resource burden can be substantial. This case report presents the successful rapid treatment of an atypical bacterial and fungal periprosthetic super-infection with two-stage revision surgery augmented with a commercially available dissolving calcium sulfate bead system permitting targeted local antifungal elution. While not the panacea for treatment, these beads provide another potentially useful tool in the atypical pathogen eradication armamentarium. Much research is still indicated to define the optimal care pathway for fungal periprosthetic super-infections.

It remains unclear whether rheumatoid arthritis might be a cause of false positive of the histology for the diagnosis of prosthetic joint infection. Our aim was to evaluate the usefulness of the histology for the diagnosis of infection during hip and knee prosthesis revision in patients with rheumatoid arthritis. All patients with the diagnosis of rheumatoid arthritis (RA) undergoing hip or knee revision surgery (total or partial) were retrospectively reviewed. Positive histology was considered when ≥ 5 neutrophils per high-power field (400×) were found in at least five separate microscopic fields. Patients who presented ≥ 2 positive cultures for the same microorganism or the presence of fistula were considered as “true positives”. Thirty-two hip (n = 12) and knee (n = 20) revision procedures were performed. Sensitivity, specificity, positive and negative predictive value of the histology were 50%, 78.6%, 25% and 91.7%, respectively. Six out of the eight patients presenting with positive histology had negative cultures (75.0% of false positives). Our results suggest that, in the context of RA, negative histological results have a very high negative predictive value. RA poses false positive histology results for the diagnosis of infection during hip and knee revision when conventional cultures are used for diagnosis of infection.

Background Prosthetic joint infection (PJI) is a morbid complication following total joint arthroplasty (TJA). PJI diagnosis and treatment has changed over time, and patient co-management with a high-volume musculoskeletal infectious disease (MSK ID) specialist has been implemented at our institution in the last decade. Methods We retrospectively evaluated all consecutive TJA patients treated for PJI between 1995 and 2018 by a single high-volume revision TJA surgeon. Microbial identities, antibiotic resistance, prior PJI, and MSK ID consultation were investigated. Results In total, 261 PJI patients (median age 66 years, interquartile range 57-75) were treated. One-year and 5-year reinfection rates were 15.8% (95% confidence interval [CI] 11.6-20.7) and 22.1% (95% CI 17.0-27.7), respectively. Microbial identities and antibiotic resistances did not change significantly over time. Despite seeing more prior PJI patients (53.3% vs 37.6%, P = .012), MSK ID-managed patients had similar infection rates as non-MSK ID-managed patients (hazard ratio [HR] 1.02, 95% CI 0.6-1.75, P = .93). Prior PJI was associated with higher reinfection risk (HR 2.39, 95% CI 1.39-4.12, P = .002) overall and in patients without MSK ID consultation, specifically (HR 2.78, 95% CI 1.37-5.65, P = .005). This risk was somewhat lower and did not reach significance in prior PJI patients with MSK ID consultation (HR 1.97, 95% CI 0.87-4.48, P = .106). Conclusion We noted minimal differences in microbial/antibiotic resistances for PJI over 20 years in a single institution, suggesting current standards of PJI treatment remain encouragingly valid in most cases. MSK ID involvement was not associated with lower reinfection risk overall; however, in patients with prior PJI, the risk of reinfection appeared to be somewhat lower with MSK ID involvement. Level of Evidence Level IV–Case Series.

In view of the demographic changes and projected increase of arthroplasty procedures worldwide, the number of prosthetic joint infection cases will naturally grow. Therefore, in order to counteract this trend more rigid rules and a stricter implementation of effective preventive strategies is of highest importance. In the absence of a "miracle weapon" priorities should lie in evidence-based measures including preoperative optimization of patients at higher infection risks, the fulfilment of strict hygiene rules in the operating theatre and an effective antibiotic prophylaxis regimen. Instead of a "one size fits all" philosophy, it has been proposed to adjust the antibiotic prophylaxis protocol to major infection risks taking into account important patient- and procedure-related risk factors. A stronger focus on the local application mode via use of high dose dual antibiotic-loaded bone cement in such risk situations may have its advantages and is easy to apply in the theatre. The more potent antimicrobial growth inhibition in vitro and the strong reduction of the prosthetic joint infection rate in risk for infection patients with aid of dual antibiotic-loaded bone cement in clinical studies align with this hypothesis.

Background Prosthetic joint infection (PJI) is one of the most frequent and devastating causes of short-term revision total knee arthroplasty (TKA). In vitro evidence suggests ceramic surfaces demonstrate resistance to biofilm, but the clinical effect of bearing surface modifications on the risk of PJI remains unclear. This premier registry-based study examines the influence of ceramic bearing surface coatings on the outcome in cemented primary TKA. Methods In total, 117,660 cemented primary TKAs in patients with primary osteoarthritis recorded in the German arthroplasty registry since 2012 were followed up for a maximum of 3 years. The primary endpoint was risk of revision for PJI on ceramic coated and uncoated cobalt-chromium-molybdenum femoral components. Propensity score matching for age, gender, obesity, diabetes mellitus, depression and Elixhauser comorbidity index, and substratification on common design twins with and without coating was performed. Results In total, 4637 TKAs (85.1% female) with a ceramic-coated femoral component were identified, 42 had been revised for PJI and 122 for other reasons at 3 years. No survival advantage due to the risk of revision for PJI could be determined for ceramic-coated components. Revision for all other reasons demonstrated a significant higher rate for TKAs with ceramic-coated components. However, the results of this were confounded by a strong prevalence (20.7% vs 0.3%) of metal sensitivity in the ceramic-coated group. Conclusion No evidence of reduced risk for PJI due to ceramic-coated implants in cemented primary TKA was found. Further analysis for revision reasons other than PJI is required.

Background Prosthetic joint infection (PJI) of total hip (THA) or total knee arthroplasty (TKA) after dental procedures is uncommon, and antibiotic prophylaxis remains controversial. For high-risk patients, the American Academy of Orthopedic Surgeons recommends amoxicillin prophylaxis. However, no systematic review of the literature of PJIs associated with dental procedures explores if amoxicillin is suitable for the reported organisms. Methods A librarian-assisted search of the major databases (PubMed, Medline, Embase, Scopus) identified 954 articles. Only case reports, case series, and reviews with patient level data were included. After exclusions, 79 articles were fully reviewed. Results Forty-four PJIs after dental procedures were identified, 22 in primary THA, 20 in primary TKA, one in revision THA, and one in a hip resurfacing procedure. Antibiotic prophylaxis was documented for 5 patients. The dental procedure was invasive in 35 (79.5%). Comorbidities were present in 17 patients (38.7%). The organisms reported were Streptococcus spp. in 44%, other aerobic gram-positives in 27%, anaerobic gram-positives in 18%, and gram-negative organisms in 11%. An estimated 46% of organisms may be resistant to amoxicillin. The outcomes of treatment were reported for 35 patients (79.5%). Twenty-seven patients (61.4%) had no clinical signs of PJI at the final follow-up visit. Conclusions Lower extremity PJI associated with dental procedures is often caused by organisms unlikely to be prevented with amoxicillin. Additional studies are warranted to determine the choice and efficacy of antibiotic prophylaxis to prevent dental-associated PJI in the highest risk patients. Insufficient data exist to recommend the optimal treatment for patients with PJI in THA and TKA associated with dental procedures.

Despite different criteria to diagnose a prosthetic joint infection (PJI), aetiological diagnosis of the causing microorganism remains essential to guide treatment. Molecular-biology-based PJI diagnosis is progressing (faster, higher specificity) in different techniques, from the experimental laboratory into clinical use. Multiplex polymerase chain reaction techniques (custom-made or commercial) provide satisfactory results in clinical series of cases, with specificity close to 100% and sensitivity over 70–80%. Next-generation metagenomics may increase sensitivity while maintaining high specificity. Molecular biology techniques may represent, in the next five years, a significant transformation of the currently available microbiological diagnosis in PJI. Cite this article: EFORT Open Rev 2021;6:93-100. DOI: 10.1302/2058-5241.6.200118

Aims This study aimed to compare the effect of antibiotic-loaded bone cement (ALBC) versus plain bone cement (PBC) on revision rates for periprosthetic joint infection (PJI) and all-cause revisions following primary elective total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods MEDLINE, Embase, Web of Science, and Cochrane databases were systematically searched for studies comparing ALBC versus PBC, reporting on revision rates for PJI or all-cause revision following primary elective THA or TKA. A random-effects meta-analysis was performed. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID CRD42018107691). Results Nine studies and one registry report were identified, enabling the inclusion of 371,977 THA and 671,246 TKA. Pooled analysis for THA demonstrated ALBC was protective against revision for PJI compared with PBC (relative risk (RR) 0.66, 95% confidence interval (CI) 0.56 to 0.77; p < 0.001), however, no differences were seen for all-cause revision rate (RR 0.62, 95% CI 0.35 to 1.09; p = 0.100). For TKA, there were no significant differences in revision rates for PJI or all causes between ALBC and PBC (RR 0.92, 95% CI 0.59 to 1.45; p = 0.730, and RR 0.73, 95% CI 0.53 to 1.02; p = 0.060, respectively). Conclusion ALBC demonstrated a protective effect against revision for PJI compared with PBC in THA with no difference in all-cause revisions. No differences in revision rates for PJI and all-cause revision between ALBC and PBC for TKA were observed. Cite this article: Bone Joint J 2021;103-B(1):7–15.

Background The burden of knee replacement prosthetic joint infection (KR PJI) is increasing. KR PJI is difficult to treat, outcomes can be poor and it is financially expensive and limited evidence is available to guide treatment decisions. Aim To provide guidelines for surgeons and units treating KR PJI. Methods Guideline formation by consensus process undertaken by BASK's Revision Knee Working Group, supported by outputs from UK-PJI meetings. Results Improved outcomes should be achieved through provision of care by revision centres in a network model. Treatment of KR PJI should only be undertaken at specialist units with the required infrastructure and a regular infection MDT. This document outlines practice guidelines for units providing a KR PJI service and sets out: • The necessary infrastructure required to provide a high-quality KR PJI service • The MDT composition — who and when • The KR PJI care pathway • Medical and surgical treatment strategies • The indications for referral to tertiary units (Major Revision Centres) • Outcome metrics and auditable standards Conclusions KR PJI patients treated within the NHS should be provided the best care possible. This report sets out guidance and support for surgeons and units to achieve this.

We present the first reported case of prosthetic joint infection caused by Trueperella pyogenes. This animal pathogen rarely causes human infection. Our patient was successfully treated with single-stage exchange and 12 weeks of rifampicin and moxifloxacin.

We report a case series of 5 patients who underwent revision total hip arthroplasty (THA) using a polypropylene mesh for capsular reconstruction for chronic THA instability. The average follow-up is 16.6 months (range, 9-20 months). There were no postoperative dislocations in our series. Three patients had previous infections with two-stage revisions before final revision surgery and were infection free at their most recent follow-up. One patient developed a prosthetic joint infection 2 months postoperatively. The use of a polypropylene mesh appears to be another tool that surgeons can use when dealing with the difficult dilemma on how to treat the patient with chronic THA instability and severe abductor and capsular tissue loss.

The management of prosthetic joint infection (PJI) requires discussion between experts working towards the aims and expectations of the patient. Each discipline typically does not offer a single-minded approach, but instead collectively weighs up the strengths and weaknesses of different management options. At a basic level, the infection specialist provides antimicrobial solutions based on laboratory results. During multi-disciplinary team (MDT) discussions however, they can offer additional insights into how the microbiology could influence the surgical decisions, respond to the surgical debate by designing a rational approach to antimicrobials and contribute to an option-appraisal that can be presented to the patient. In this short opinion piece, we describe some of the thoughts we have during MDT discussions to ultimately recommend an optimised treatment plan for the individual patient: is there infection? what is the pathogen? where did it come from? (and where else has it gone), and what is the best treatment strategy?

Background Higher rates of prosthetic joint infections (PJIs) are related to patient risk factors and/or to special surgical procedures such as revision total knee arthroplasty (rTKA). Among the measures discussed to better protect those patients from the higher infection risks use of dual antibiotic-loaded bone cement has emerged as a further prophylactic option. Methods This retrospective study included 246 patients undergoing strictly aseptic revision knee arthroplasty at our institution in the time period 2015-2018. Based on the type of bone cement used for the cementation of the revision prosthesis, 2 groups were defined. In total, 143 patients received the low-dose single antibiotic-loaded bone cement (SALBC) PALACOS R+G and 103 patients received the high-dose dual antibiotic-loaded bone cement (DALBC) COPAL G+C. The number of PJI cases in each group over a follow-up time of minimum 1 year was compared and the extra costs for the DALBC use calculated against the economic savings per each avoided PJI case on basis of 3 different assumptions (treatment costs and amount of cement use). Results Use of DALBC in aseptic rTKA was associated with a significant reduction in PJI cases (relative risk = 57%, PJI rate in the SALBC group 4.1% vs 0% in the DALBC group, P = 0.035). The calculated total savings per patient was $1367. Depending on the economic assumptions the range of savings was between $1413 (less favorable calculation model) and $3661 (most favorable calculation model). Conclusion The use of DALBC in rTKA has been found to be more effective in preventing PJI and proved cost-efficient in all our cost-calculation models.

Diagnostic thresholds used to standardize the definition for prosthetic joint infection (PJI) have largely focused on total joint arthroplasty (TJA). Established PJI thresholds exist for serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in TJA; however, they do not exist for revision hip hemiarthroplasty (rHHA). The purpose of this study was to establish thresholds for (1) ESR and (2) CRP to diagnose PJI in rHHA. Data were collected on a prospective cohort of 69 rHHA patients undergoing orthopaedic surgery between 1/2017 and 2/2019 in a single health care system. Procedures were categorized as septic or aseptic revisions using Musculoskeletal Infection Society (MSIS) criteria (2013). There were 44 ESRs (n = 28 aseptic, n = 16 septic) and 46 CRPs (n = 29 aseptic, n = 17 septic) available for analysis. Two tailed t-tests were performed to compare the mean ESR and CRP in aseptic and septic cases. Receiver operator characteristic (ROC) curves were generated to obtain diagnostic cutoff thresholds using the Youden's Index (J) for ESR and CRP. The mean ESR was 50.3 ± 30.6 mm/h versus 15.4 ± 17.7 mm/h (p

KEY POINTS An 82-year-old woman was transferred to our hospital from another centre after sustaining a fall, which had been preceded by several days of right hip pain. She had undergone a right total hip arthroplasty (uncemented with femoral head of cobalt–chromium alloy) for osteoarthritis

Introduction: This study aims to investigate whether patients undergoing two-stage revision total hip arthroplasty (THA) for prosthetic joint infection (PJI) and one-stage revision THA for aseptic reasons have similar clinical outcomes and patient satisfaction during their post-operative follow-up. We hypothesise that the two-stage revision THA for PJI is associated with poorer outcomes as compared to aseptic revision THA. Materials and Methods: We reviewed prospectively collected data in our tertiary hospital arthroplasty registry and identified patients who underwent revision THA between 2001 and 2014, with a minimum of two years follow-up. The study group (two-stage revision THA for PJI) consists of 23 patients and the control group (one-stage revision THA for aseptic reasons) consists of 231 patients. Patient demographics, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Oxford Hip Score (OHS), Short Form-36 (SF-36) scores and patient reported satisfaction were evaluated. Student’s t-test was used to compare continuous variables between the two groups. Statistical significance was defined as p

Neisseria meningitidis is a rare cause of prosthetic joint infection (PJI), with only three cases previously reported. Here we report three further cases, all of which were successfully treated with implant retention and short-course antibiotics (

Aims This study aimed to explore whether serum combined with synovial interleukin-6 (IL-6) measurement can improve the accuracy of prosthetic joint infection (PJI) diagnosis, and to establish the cut-off values of IL-6 in serum and synovial fluid in detecting chronic PJI. Methods Patients scheduled to have a revision surgery for indications of chronic infection of knee and hip arthroplasties or aseptic loosening of an implant were prospectively screened before being enrolled into this study. The Musculoskeletal Infection Society (MSIS) definition of PJI was used for the classification of cases as aseptic or infected. Serum CRP, ESR, IL-6, and percentage of polymorphonuclear neutrophils (PMN%) and IL-6 in synovial fluid were analyzed. Statistical tests were performed to compare these biomarkers in the two groups, and receiver operating characteristic (ROC) curves and area under the curve (AUC) were analyzed for each biomarker. Results A total of 93 patients were enrolled. There was no difference in demographic data between both groups. Synovial fluid IL-6, with a threshold of 1,855.36 pg/ml, demonstrated a mean sensitivity of 94.59% (95% confidence interval (CI) 81.8% to 99.3%) and a mean specificity of 92.86% (95% CI 82.7 to 98.0) for detecting chronic PJI. Then 6.7 pg/ml was determined to be the optimal threshold value of serum IL-6 for the diagnosis of chronic PJI, with a mean sensitivity of 97.30% (95% CI 85.8% to 99.9%) and a mean specificity of 76.79% (95% CI 63.6% to 87.0%). The combination of synovial IL-6 and serum IL-6 led to improved accuracy of 96.77% in diagnosing chronic PJI. Conclusion The present study identified that a combination of IL-6 in serum and synovial IL-6 has the potential for further improvement of the diagnosis of PJI. Cite this article: Bone Joint Res 2020;9(9):587–592.

Management of large acetabular bone defects is challenging. The Masquelet technique has successfully reconstructed segmental defects in long bones arising from trauma, tumors, or infection but not been described for large acetabular defects. We present 3 cases of large acetabular bone defects arising from chronic prosthetic joint infection, treated via a novel induced membrane bone grafting technique, drawn from the Masquelet technique. All cases showed satisfactory clinical and radiological outcomes at midterm follow-up. This technique holds promise and can be an alternative means when treating large acetabular bone defects.

Cutibacterium acnes is a lipophilic, anaerobic, gram-positive bacillus that mainly colonizes the pilosebaceous glands of human skin. It has been implicated as the leading cause of prosthetic joint infection (PJI) after shoulder arthroplasty. However, PJI caused by C acnes rarely manifests as overt clinical, laboratory, or imaging features. In fact, more than 40% of shoulders undergoing revision arthroplasty are likely to be culture positive. However, rates of infection following a positive culture can be as low as 5%. The purpose of this review was to put forth alternative explanations for this discordance between positive cultures and infection. We describe C acnes roles as a commensal, bystander, and/or contaminant organism; the role of cultures in diagnosis and other methods that may be more accurate; its existence in a shoulder microbiome; and the variable virulence of C acnes. C acnes is an important cause of shoulder PJI in some patients. However, there is a large body of literature that suggests other functions that need to be considered. Further research is needed to define the role of C acnes that is logically explained by all of the literature and not only some.

Objectives Pathogen identification is crucial for the diagnosis and management of periprosthetic joint infection (PJI). Although culturing methods are the foundation of pathogen detection in PJI, false-negative results often occur. Oxford nanopore sequencing (ONS) is a promising alternative for detecting pathogens and providing information on their antimicrobial resistance (AMR) profiles, without culturing. Methods To evaluate the capability of metagenomic ONS (mONS) in detecting pathogens from PJI samples, both metagenomic next-generation sequencing (mNGS) and mONS were performed in 15 osteoarticular samples from nine consecutive PJI patients according to the modified Musculoskeletal Infection Society (MSIS) criteria. The sequencing data generated from both platforms were then analyzed for pathogen identification and AMR detection using an in-house-developed bioinformatics pipeline. Results Our results showed that mONS could be applied to detect the causative pathogen and characterize its AMR features in fresh PJI samples. By real-time sequencing and analysis, pathogen identification and AMR detection from the initiation of sequencing were accelerated. Conclusion We showed proof of concept that mONS can function as a rapid, accurate tool in PJI diagnostic microbiology. Despite efforts to reduce host DNA, the high proportion of host DNA was still a limitation of this method that prevented full genome analysis.

Aims This study aimed to evaluate calprotectin in synovial fluid for diagnosing chronic prosthetic joint infection (PJI) . Methods A total of 63 patients who were suspected of PJI were enrolled. The synovial fluid calprotectin was tested by an enzyme-linked immunosorbent assay (ELISA). Laboratory test data, such as ESR, CRP, synovial fluid white blood cells (SF-WBCs), and synovial fluid polymorphonuclear cells (SF-PMNs), were documented. Chi-squared tests were used to compare the sensitivity and specificity of calprotectin and laboratory tests. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was calculated to determine diagnostic efficacy. Results The median calprotectin level was 776 μg/ml (interquartile range (IQR) 536.5 to 1132) in the PJI group and 54.5 μg/ml (IQR, 38.75 to 78.25) in the aseptic failure (AF) group (p < 0.05). Using a threshold of 173 ug/ml, the sensitivity was 95.2%, with a 97.6% specificity, and the AUC was 0.993. The sensitivity of calprotectin of the antibiotic-treated PJI group was 100% versus 90.9% of the non-antibiotic-treated PJI group. Although 47.6% (ten cases) of the patients in the PJI group received antibiotics before aspiration, the diagnostic efficacy of calprotectin was not affected. The sensitivity and specificity of ESR, CRP, SF-WBCs, and SF-PMNs ranged from 76.2% to 90.5% and 64.3% to 85.7%, respectively. Conclusion Calprotectin in synovial fluid has great diagnostic efficacy for PJI diagnosisand outperformed ESR, CRP, SF-WBCs, and SF-PMNs. Cite this article: Bone Joint Res 2020;9(8):450–456.

Aims To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI). Methods A retrospective cohort study was performed involving 36 chronic PJI patients treated with different types of articulating antibiotic-loaded cement spacers between January 2014 and December 2017. The incidence of complications and the therapeutic effects of different types of antibiotic-loaded articulating cement spacers were compared. Results A total of 36 patients with chronic hip PJI were included. Of these, 13 patients were treated with spacers with Kirschner wires as an endoskeleton (group I), ten patients were treated with spacers with a cemented femoral prosthesis as an endoskeleton (group II), and 13 patients were treated with cemented femoral prostheses combined with polyethylene sockets as a spacer (group III). All patients were followed for 12 to 60 months, with a mean follow-up period of 26.44 months (SEM 14.09). Infection was controlled in 34 patients (94.44%), and there were no significant differences in the eradication rate among the three groups (p = 0.705), but the risk of complications related to the spacer in group III was significantly lower than that in groups I and II (p = 0.006). Conclusion Articulating antibiotic-loaded cement spacers is effective in the treatment of chronic hip PJI, but we must pay attention to the occurrence of spacer fracture and dislocation, which can lead to poor joint function. The risk of spacer-related mechanical complications is low, and better joint function can be achieved when using cemented femoral prostheses combined with polyethylene sockets as spacers. Cite this article: Bone Joint Res 2020;9(8):484–492.

Aims The aim of this study was to evaluate the performance of metagenomic next-generation sequencing (mNGS) in detecting pathogens from synovial fluid of prosthetic joint infection (PJI) patients. Methods A group of 75 patients who underwent revision knee or hip arthroplasties were enrolled prospectively. Ten patients with primary arthroplasties were included as negative controls. Synovial fluid was collected for mNGS analysis. Optimal thresholds were determined to distinguish pathogens from background microbes. Synovial fluid, tissue, and sonicate fluid were obtained for culture. Results A total of 49 PJI and 21 noninfection patients were finally included. Of the 39 culture-positive PJI cases, mNGS results were positive in 37 patients (94.9%), and were consistent with culture results at the genus level in 32 patients (86.5%) and at the species level in 27 patients (73.0%). Metagenomic next-generation sequencing additionally identified 15 pathogens from five culture-positive and all ten culture-negative PJI cases, and even one pathogen from one noninfection patient, while yielding no positive findings in any primary arthroplasty. However, seven pathogens identified by culture were missed by mNGS. The sensitivity of mNGS for diagnosing PJI was 95.9%, which was significantly higher than that of comprehensive culture (79.6%; p = 0.014). The specificity is similar between mNGS and comprehensive culture (95.2% and 95.2%, respectively; p = 1.0). Conclusion Metagenomic next-generation sequencing can effectively identify pathogens from synovial fluid of PJI patients, and demonstrates high accuracy in diagnosing PJI. Cite this article: Bone Joint Res 2020;9(7):440–449.

Objectives The purpose of this study was to explore the role of mNGS in the diagnosis of PJI by detecting the presence of bacteria in periprosthetic tissues. Methods Patients who were suspected of PJI and underwent surgery in our center were enrolled. Microbial culture and mNGS were performed on periprosthetic tissues collected intraoperatively. Patient age, body mass index (BMI), laboratory tests, microbial culture and mNGS results were recorded. The diagnostic performance of microbial culture and mNGS in the diagnosis of PJI was compared. Results A total of 44 patients were included. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of periprosthetic tissue microbial culture in the diagnosis of PJI were 72.72%, 77.27%, 76.19%, 73.91% and 75%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of periprosthetic tissue mNGS in the diagnosis of PJI were 95.45%, 90.91%, 91.3%, 95.24% and 93.18%, respectively. The sensitivity and specificity of mNGS in the diagnosis of PJI were superior to those of microbial culture. Conclusion Periprosthetic tissue can be used as an alternative to synovial fluid and sonication fluid, as mNGS can improve the diagnosis of PJI. mNGS of the periprosthetic tissues showed higher sensitivity than microbial culture.

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

Prosthetic joint infection is a rare but serious complication of total shoulder replacement. After infection control, shoulder reconstruction is also required to repair the shoulder defect. The shoulder is a complex structure consisting of mechanical soft tissue and the joint, making reconstruction challenging. A 78-year-old female patient was diagnosed of wound necrosis and exposed prosthesis due to prosthetic joint infection after reverse total shoulder replacement. The infection was controlled with appropriate antibiotic treatment, and the necrotic tissue was removed by radical debridement. To reduce the size of the massive shoulder defect and minimize exposure of the prosthesis, negativepressure wound therapy (NPWT) was administered for 8 weeks and shoulder reconstruction was performed using a pedicled latissimus dorsi (LD) flap and split-thickness skin graft. The patient recovered without any complications, and no reinfection of the surgical site or other complications were observed during follow-up visits. This report demonstrates that antibiotic treatment, radical debridement of necrotic tissue, NPWT, and shoulder reconstruction using a pedicled LD flap can be an effective method of treatment for prosthetic joint infection with exposed prosthesis, tissue necrosis, and massive shoulder defect.

Актуальность . глубокая инфекция после эндопротезирования коленного сустава требует радикальной хирургической обработки очага инфекции, удаления компонентов эндопротеза и установки антимикробного спейсера. При невозможности выполнения операции ревизионного эндопротезирования коленного сустава для восстановления опороспособной функции нижней конечности «золотым стандартом» считается выполнение операции артродезирования коленного сустава. Цель исследования — провести сравнительный анализ выполнения артродеза коленного сустава с использованием внешней и внутренней фиксации. Материал и методы . Проведен анализ 60 случаев лечения пациентов, которым был выполнен артродез коленного сустава. Пациенты были разделены на две группы по 30 пациентов в каждой. В первой группе артродез коленного сустава выполнялся с использованием интрамедуллярного блокируемого стержня, во второй группе использовался аппарат внешней фиксации. При анализе мы сравнивали между группами объем интраоперационной и дренажной кровопотери, длительность стационарного лечения, сроки наступления анкилоза и осложнения. Качество жизни пациентов оценивали с использованием опросника SF-36 до операции, на сроках 3, 6 и 12 мес. после оперативного лечения. Результаты . Сравнение двух методик выполнения артродеза коленного сустава показало, что кровопотеря при интрамедуллярной фиксации в сравнении с чрескостной в 2,0 раза больше, длительность стационарного лечения в 1,4 раза меньше, общее количество осложнений в 4,4 раза меньше. Однако осложнений, повлиявших на результат лечения, в этой группе было в 1,5 раза больше. Различия в среднем времени формирования анкилоза статистически не значимы ( p

Prosthetic joint infections (PJIs) are typically caused by Staphylococcus aureus and coagulase-negative Staphylococci species. Corynebacterium species are microorganisms of the human skin and mucous membranes that are often considered contaminants when grown in culture. In the past, Corynebacterium species were often classified as diphtheroids based on growing as gram-positive rods in aerobic environments, but with advances in technology, the identification of Corynebacterium species has improved. Corynebacterium can cause infection, but there are few case reports of orthopaedic infection. We present 3 cases of total hip arthroplasty and 3 cases of total knee arthroplasty PJI caused by Corynebacterium species. We found a high failure rate of surgical treatment of Corynebacterium PJI, defined as reoperation for infection. This information adds to the limited literature on these organisms in total joint arthroplasty PJI.

Aims Preoperative diagnosis is important for revision surgery after prosthetic joint infection (PJI). The purpose of our study was to determine whether reverse transcription-quantitative polymerase chain reaction (RT-qPCR), which is used to detect bacterial ribosomal RNA (rRNA) preoperatively, can reveal PJI in low volumes of aspirated fluid. Methods We acquired joint fluid samples (JFSs) by preoperative aspiration from patients who were suspected of having a PJI and failed arthroplasty; patients with preoperative JFS volumes less than 5 ml were enrolled. RNA-based polymerase chain reaction (PCR) and bacterial culture were performed, and diagnostic efficiency was compared between the two methods.According to established Musculoskeletal Infection Society (MSIS) criteria, 21 of the 33 included patients were diagnosed with PJI. Results RNA-based PCR exhibited 57.1% sensitivity, 91.7% specificity, 69.7% accuracy, 92.3% positive predictive value, and 55.0% negative predictive value. The corresponding values for culture were 28.6%, 83.3%, 48.5%, 75.0%, and 40.0%, respectively. A significantly higher sensitivity was thus obtained with the PCR method versus the culture method. Conclusion In situations in which only a small JFS volume can be acquired, RNA-based PCR analysis increases the utility of preoperative puncture for patients who require revision surgery due to suspected PJI. Cite this article: Bone Joint Res. 2020;9(5):219–224.

Aims Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. Methods Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting. Results Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment. Conclusion Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI. Cite this article: Bone Joint Res. 2020;9(5):211–218.

Aims This pilot study tested the performance of a rapid assay for diagnosing prosthetic joint infection (PJI), which measures synovial fluid calprotectin from total hip and knee revision patients. Methods A convenience series of 69 synovial fluid samples from revision patients at the Norfolk and Norwich University Hospital were collected intraoperatively (52 hips, 17 knees) and frozen. Synovial fluid calprotectin was measured retrospectively using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone AS) and compared to International Consensus Meeting (ICM) 2018 criteria and clinical case review (ICM-CR) gold standards. Results According to ICM, 24 patients were defined as PJI positive and the remaining 45 were negative. The overall accuracy of the lateral flow test compared to ICM was 75.36% (52/69, 95% CI 63.51% to 84.95%), sensitivity and specificity were 75.00% (18/24, 95% CI 53.29% to 90.23%) and 75.56% (34/45, 95% CI 60.46% to 87.12%), respectively, positive predictive value (PPV) was 62.07% (18/29, 95% CI 48.23% to 74.19%) and negative predictive value (NPV) was 85.00% (34/40, 95% CI 73.54% to 92.04%), and area under the receiver operating characteristic (ROC) curve (AUC) was 0.78 (95% CI 0.66 to 0.87). Patient data from discordant cases were reviewed by the clinical team to develop the ICM-CR gold standard. The lateral flow test performance improved significantly when compared to ICM-CR, with accuracy increasing to 82.61% (57/69, 95% CI 71.59% to 90.68%), sensitivity increasing to 94.74% (18/19, 95% CI 73.97% to 99.87%), NPV increasing to 97.50% (39/40, 95% CI 85.20% to 99.62%), and AUC increasing to 0.91 (95% CI 0.81 to 0.96). Test performance was better in knees (100.00% accurate (17/17, 95% CI 80.49% to 100.00%)) compared to hips (76.92% accurate (40/52, 95% CI 63.16% to 87.47%)). Conclusion This study demonstrates that the calprotectin lateral flow assay could be an effective diagnostic test for PJI, however additional prospective studies testing fresh samples are required. Cite this article: Bone Joint Res. 2020;9(5):202–210.

Aims In patients with a “dry” aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. Methods Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared. Results A total of 78 patients had data available for analysis; 17 underwent revision THA and 61 underwent revision TKA. A total of 16 patients met modified Musculoskeletal Infection Society (MSIS) criteria for PJI. Pre- and post-lavage %PMNs were similar in septic patients (87% vs 85%) and aseptic patients (35% vs 39%). Pre- and post-lavage synovial fluid WBC count were far more disparate in septic (53,553 vs 8,275 WBCs) and aseptic (1,103 vs 268 WBCs) cohorts. At a cutoff of 80% PMN, the post-lavage aspirate had a sensitivity of 75% and specificity of 95%. At a cutoff of 3,000 WBCs, the post-lavage aspirate had a sensitivity of 63% and specificity of 98%. As the post-lavage synovial WBC count increased, the difference between pre- and post-lavage %PMN decreased (mean difference of 5% PMN in WBC < 3,000 vs mean difference 2% PMN in WBC > 3,000, p = 0.013). Of ten positive pre-lavage fluid cultures, only six remained positive post-lavage. Conclusion While saline lavage aspiration significantly lowered the synovial WBC count, the %PMN remained similar, particularly at WBC counts of > 3,000. These findings suggest that in patients with a dry-tap, the %PMN of a saline lavage aspiration has reasonable sensitivity (75%) for the detection of PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):138–144.

Aims Two-stage exchange arthroplasty is the most common definitive treatment for prosthetic joint infection (PJI) in the USA. Complications that occur during treatment are often not considered. The purpose of this study was to analyze complications in patients undergoing two-stage exchange for infected total knee arthroplasty (TKA) and determine when they occur. Methods We analyzed all patients that underwent two-stage exchange arthroplasty for treatment of PJI of the knee from January 2010 to December 2018 at a single institution. We categorized complications as medical versus surgical. The intervals for complications were divided into: interstage; early post-reimplantation (three months); and late post-reimplantation (three months to minimum one year). Minimum follow-up was one year. In total, 134 patients underwent a first stage of a two-stage exchange. There were 69 males and 65 females with an mean age at first stage surgery of 67 years (37 to 89). Success was based on the new Musculoskeletal Infection Society (MSIS) definition of success reporting. Results Overall, 70 (52%) patients experienced a complication during the planned two-stage treatment, 36 patients (27%) experienced a medical complication and 47 (41%) patients experienced a surgical complication. There was an 18% mortality rate (24/134) at a mean of 3.7 years (0.09 to 8.3). During the inter-stage period, 28% (37/134) of patients experienced a total of 50 complications at a median of 47 days (interquartile range (IQR) 18 to 139). Of these 50 complications, 22 were medical and 28 required surgery. During this inter-stage period, four patients died (3%) and an additional five patients (4%) failed to progress to the second stage. While 93% of patients (125/134) were reimplanted, only 56% (77/134) of the patients were successfully treated without antibiotic suppression (36%, 28/77) or with antibiotic suppression (19%, 15/77) at one year. Conclusion Reported rates of success of two stage exchanges for PJI have not traditionally considered complications in the definition of success. In our series, significant numbers of patients experienced complications, more often after reimplantation, highlighting the morbidity of this method of treatment. Cite this article: Bone Joint J 2020;102-B(6 Supple A):145–150.

Background Prosthetic joint infection (PJI) is a challenging complication after total knee arthroplasty (TKA). Above-knee amputation (AKA) is a salvage procedure that may be performed after revision TKAs fail to eradicate PJI. Few studies have investigated patient-reported outcomes. This study investigates patient-reported functional outcomes and overall satisfaction in a cohort of patients who underwent AKA for PJI. Methods We performed a retrospective study of all patients who underwent AKA for PJI from 2002 to 2015 at a tertiary academic institution in the rural northeastern United States, along with prospective phone interviews. Functional outcomes and overall satisfaction were adapted from the Above-The-Knee Amputation Functional Ability Questionnaire. Additional variables included age, sex, American Society of Anesthesiologists (ASA) Score, and mortality. Results Forty-four patients were included in the study. Eighteen patients died prior to study initiation, with a mean time of 948 days (2.6 years) between AKA and death. The 5-year mortality rate was 50%. Among the 14 patients who completed the survey, 12 (86%) were fit for prosthesis following AKA. Of these, 10 (71%) required the use of an assistive device and one (seven percent) reported being functionally independent with their prosthesis. Five (36%) required further surgery after their AKA. Twelve (86%) stated that they were satisfied with their AKA and 5 (42%) would have done it sooner if offered. Conclusions Patients who underwent AKA for PJI reported a low level of independence and ability to ambulate with a high mortality rate. However, most were satisfied with their AKA and would choose it again.

Purpose The aims of our study were to (1) evaluate the concordance of both methods for detecting prosthetic joint infection (PJI) pathogens in joint fluid and to (2) clarify whether broad-range polymerase chain reaction (BR-PCR) can be used as a verification method for metagenomic next-generation sequencing (mNGS) for PJI diagnosis. Methods In total, 63 patients underwent total joint arthroplasty, with 45 PJI and 18 aseptic failure patients included. Joint fluids were sampled after antibiotics were withheld for more than 2 weeks, and then, culture, BR-PCR and mNGS were performed for all samples. Results The joint fluid BR-PCR sensitivity was 82.2%, which was not significantly different from that of mNGS (95.6%) or culture (77.8%). The specificities of the 3 methods were all 94.4%. BR-PCR failed to identify the pathogens in 1 polymicrobial infection patient and 4 fungal infection patients. Conclusion mNGS was more sensitive than BR-PCR for detecting PJI pathogens in joint fluid. BR-PCR is insufficient for use as an mNGS verification method.

Introduction: We aim to evaluate the use of silver (PorAg®) coated compared to uncoated prosthesis in two-stage revision for prosthetic joint infection (PJI) of distal femur and proximal tibia megaprosthesis in oncological patients. Materials and methods: In total, 68 patients were retrospectively evaluated. Median age was 30years (range 14–83). In total, 29 patients were re-implanted with PorAg® prosthesis and 39 with uncoated prosthesis (Megasystem C®, Waldemar Link GmbH & Co. KG, Hamburg, Germany). All patients had PJI confirmed according to Musculoskeletal Infection Society (MSIS) criteria. In 10 cases, no microorganism was identified at the time of first-stage revision, but all had a sinus communicating with the prosthesis. Successful eradication of the infection was defined by the absence of clinical/serologic evidence of infection at 6months after the second stage or at latest follow-up. Infection was again defined according to the MSIS criteria. Results: At 3-year follow-up, estimated reinfection rate in the silver group was slightly lower than in uncoated EPR (10.3% vs. 17.5%, p = 0.104). Among reinfected patients, only one out of three patients (33%) in the silver group required an amputation compared to 80% in the nonsilver group (p = 0.047). Conclusions: Our results show the efficacy of PorAg® coating in the two-stage revision of knee EPR. PorAg®-coated EPR may have possible advantages over this traditional strategy, in particular when applied to patients with a higher risk of reinfection.

Background: To determine the prevalence of prosthetic joint infections (PJIs) after elective clean hand surgery in order to determine whether prophylactic antibiotics are warranted in patients who have previously undergone total joint arthroplasty (TJA). Methods: All patients undergoing elective clean hand surgery between 2012 and 2018 were retrospectively cross-referenced with patients who had previously undergone a TJA at the same urban academic medical center. Inclusion criteria were any patients who underwent clean hand surgery during the study period who were an adult between the ages of 30 and 90, had a previous TJA, and did not have a previous history of a PJI. All charts were reviewed to collect data on patient demographics, co-morbidities, the type of TJA and hand surgery performed, whether prophylactic antibiotics were used prior to the hand surgery, and whether a PJI occurred within 3 months of the hand surgery. Results: Total of 331 patients (181 females and 150 males) were identified over the 6-year period that met inclusion criteria. In total, 13% of the patients received prophylactic antibiotics prior to their hand surgery and 87% had not. Only 1 case of a PJI occurred within 3 months of a hand surgery. No relationship was identified between the PJI and the hand surgery, nor the need for preoperative antibiotic prophylaxis. Conclusions: Incidence of PJI after clean hand surgery is very low. We do not recommend the routine use of antibiotic prophylaxis in patients undergoing clean elective hand surgery with a history of prior TJA in order to prophylax against a PJI.