Francisella tularensis Bone and Joint Infections: United States, 2004-2023.

Tularemia is caused by the highly infectious bacterium Francisella tularensis, which is recognized as a Tier 1 bioterrorism agent. Tularemia has a range of recognized clinical manifestations, but fewer than 20 bone or joint infections from 6 countries have been reported in the literature to date. This series includes 13 cases of F. tularensis septic arthritis or osteomyelitis in the United States during 2004-2023 and describes exposures, clinical presentation, diagnosis, and outcomes for this rare but severe form of tularemia. Clinicians should consider F. tularensis in patients with compatible exposures or a history of joint replacement or immunosuppression.

Civilian Ballistic Arthrotomies: Infection Rates and Operative Versus Nonoperative Management.

OBJECTIVES: The purpose of this study was to determine whether a significant difference existed in the rate of infection after ballistic traumatic arthrotomy managed operatively compared with those managed without surgery. DESIGN: Retrospective cohort study. SETTING: Academic Level I Trauma Center. PATIENT SELECTION CRITERIA: Patients with ballistic traumatic arthrotomies of the shoulder, elbow, wrist, hip, knee, or ankle who received operative or nonoperative management. OUTCOME MEASURES AND COMPARISONS: The rates of infection and septic arthritis in those who received operative or nonoperative management. RESULTS: One hundred ninety-five patients were studied. Eighty patients were treated nonoperatively (Non-Op group), 16 patients were treated with formal irrigation and debridement in the operating room (I&D group), and 99 patients were treated with formal I&D and open reduction and internal fixation (ORIF) (I&D + ORIF group). Patients in all 3 groups received local wound care and systemic antibiotics. No patients in the Non-Op or I&D group developed an infection. Six patients in the I&D + ORIF group developed extra-articular postoperative infections requiring additional interventions. CONCLUSIONS: The infection rate in the I&D + ORIF group was consistent with the infection rates reported in orthopaedic literature after fixation alone. In addition, none of the infections were cases of septic arthritis. This suggests that traumatic arthrotomy does not increase the risk for infection beyond what is expected after fixation alone. Importantly, the Non-Op group represented a series of 80 patients who were treated nonoperatively without developing an infection, indicating that I&D may not be necessary to prevent infection after ballistic arthrotomy. The results suggest that septic arthritis after civilian ballistic arthrotomy is a rare complication regardless of the choice of treatment. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Mycobacterium avium complex prosthetic joint infection: A systematic review of the literature and pooled analysis.

BACKGROUND: Mycobacterium avium complex (MAC) prosthetic joint infection (PJI) has been rarely reported. METHODS: This study aimed to investigate the epidemiology and outcomes of MAC PJI. A systematic review of the literature regarding the MAC infection following total joint arthroplasty including hip and knee joint was performed. Multiple databases were searched for published English-written articles up to May 2023. Studies that reported cases of PJI by MAC were reviewed. RESULTS: A total of 17 patients were identified and analyzed from 11 published studies. All patients presented with joint symptom of pain or swelling prior to the diagnosis and MAC was confirmed by culture. The most of the patients (16/17 patients, 94.1%) were noted to have underlying medical condition(s) that might have affected immunity. Treatment consisted of anti-MAC medication therapy only in two patients and anti-MAC medication therapy plus surgery in 15 patients. Among the patients who underwent surgery, 14 patients (82.3%) had removal of the prosthesis including seven patients who had two-stage surgery to have reimplantation of the prosthesis. No relapse of MAC infection was reported despite of one case of relapse of infection caused by different pyogenic bacteria. The rate of overall mortality was 29.4%, however, identified attributable mortality due to MAC infection was low (5.9%). CONCLUSION: PJI by MAC is a rare disease. However, MAC needs to be considered in the differential diagnosis in immunocompromised patients presenting with symptoms of PJI. Two-stage exchange arthroplasty may result in successful treatment outcomes without higher risks of relapse of infection if undertaken in association with appropriate active anti-MAC antibiotic therapy.

An update on recent progress of the epidemiology, etiology, diagnosis, and treatment of acute septic arthritis: a review.

Acute septic arthritis is on the rise among all patients. Acute septic arthritis must be extensively assessed, identified, and treated to prevent fatal consequences. Antimicrobial therapy administered intravenously has long been considered the gold standard for treating acute osteoarticular infections. According to clinical research, parenteral antibiotics for a few days, followed by oral antibiotics, are safe and effective for treating infections without complications. This article focuses on bringing physicians up-to-date on the most recent findings and discussions about the epidemiology, etiology, diagnosis, and treatment of acute septic arthritis. In recent years, the emergence of antibiotic-resistant, particularly aggressive bacterial species has highlighted the need for more research to enhance treatment approaches and develop innovative diagnosis methods and drugs that might combat better in all patients. This article aims to furnish radiologists, orthopaedic surgeons, and other medical practitioners with contemporary insights on the subject matter and foster collaborative efforts to improve patient outcomes. This review represents the initial comprehensive update encompassing patients across all age groups.

Clinical Spectrum and Microbial Etiology of Bone and Joint Infections in Children: A Retrospective Analysis from South India.

Acute infections of bone and joints are medical emergencies. Early diagnosis and treatment are essential for limb salvage and prevention of deformities. Data from developing countries are essential to develop region-specific treatment guidelines including choice of empiric antibiotics. We reviewed electronic medical records of children (≤ 12 years old) admitted to the pediatrics or orthopedics department of a tertiary care hospital in South India from 2013 to 2017 with a diagnosis of septic arthritis and/or osteomyelitis. Clinical, microbiological, and follow-up data were collected and analyzed. The median (interquartile range, IQR) age of the children (N = 207) was 48 (7.5-105) months. Acute infections were more common in infants, whereas chronic cases were common in children > 5 years of age. Staphylococcus aureus (71%) was the most common organism identified. Gram-negative organisms were more frequently isolated in infants compared with older children. Blood and/or wound culture positivity was 78% (N = 161) overall and 78% (N = 31) in chronic cases. The median (IQR) duration of antibiotics was 7 (5-8) weeks. Sequelae and readmissions occurred in 47% (N = 81) of the 172 patients followed for a year. Culture positivity rates especially of wound were high even after receiving antibiotics.

Rates of Septic Arthritis After ACL Reconstruction: A Single-Center Analysis Highlighting Quadriceps Tendon Grafts.

BACKGROUND: Although the infection rates for bone-patellar tendon-bone autograft (BTB), hamstring tendon autograft (HT), and allograft have been reported previously, there are limited data available for a large cohort of individuals undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) using quadriceps tendon autograft (QT). PURPOSE: The aims of this study are (1) to compare rates of septic arthritis after primary and revision ACLR with QT, BTB, HT, and allograft and (2) to evaluate the association between an infection after ACLR and potential risk factors in a large single-system analysis. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All ACLR cases performed by 10 high-volume sports medicine fellowship-trained ACL surgeons between January 2000 and January 2022 were retrospectively analyzed. Minimum follow-up was 90 days after ACLR, and all multiligament reconstructions were excluded. Demographic information, surgical variables, infection characteristics, and rate of ACL graft retention were collected for all included patients. Independent samples t test, chi-square test, or Fisher exact tests with adjusted Benjamini-Hochberg post hoc procedure were used for group comparisons. RESULTS: In total, 6652 patients were included in this study. The most commonly used graft was allograft (n = 2491; 37.4%), followed by HT (n = 1743; 26.2%), BTB (n = 1478; 22.2%), and QT (n = 940; 14.1%). The overall postoperative rate of septic arthritis was 0.34% (n = 23). Septic arthritis rates based on graft type were 0.74% (n = 13) for HT, 0.24% (n = 6) for allograft, 0.20% (n = 3) for BTB, and 0.10% (n = 1) for QT. While a statistically significant difference with regard to graft type (P = .01) was observed, no significant relationships were found between postoperative septic arthritis and age, sex, revision ACLR, ACLR surgical technique, and accompanying intra-articular procedures for all septic arthritis patients (P > .05). The average time from the onset of the symptoms of infection to surgical irrigation and debridement (I&D) was 2 days (minimum, 0; maximum, 6). ACL grafts were retained during I&D procedures in all patients with postoperative septic arthritis. CONCLUSION: The postoperative rate of septic arthritis was 0.1% after use of the QT autograft. While graft choice may affect rates of septic arthritis after ACLR, patient characteristics, ACLR technique, revision ACLR, and accompanying intra-articular procedures during ACLR were not associated with postoperative septic arthritis with the numbers available for analysis.

The Risk of Acute Infection Following Intra-Articular Corticosteroid Injection During Total Knee Manipulation Under Anesthesia.

BACKGROUND: Manipulation under anesthesia (MUA) is an established option for improving motion in patients presenting with early stiffness following total knee arthroplasty (TKA). Intra-articular corticosteroid injections (IACI) are sometimes administered adjunctively, yet literature examining their efficacy and safety remains limited. STUDY DESIGN: Retrospective, Level IV. METHODS: A total of 209 patients (TKA = 230) were retrospectively examined to determine the incidence of prosthetic joint infections within 3 months following manipulation with IACI. Approximately 4.9% of initial patients had inadequate follow-up where the presence of infection could not be determined. Range of motion was assessed in patients who had follow-up at or beyond one year (n = 158) and was recorded over multiple time points. RESULTS: No infections (0 of 230) were identified within 90 days of receiving IACI during TKA MUA. Before receiving TKA (preindex), patients averaged 111° of total arc of motion and 113° of flexion. Following index procedures, just prior to manipulation (pre-MUA), patients averaged 83° and 86° of total arc and flexion motion, respectively. At final follow-up, patients averaged 110° of total arc of motion and 111° of flexion. At six weeks following manipulation, patients had gained a mean of 25° and 24° of their total arc and flexion motion found at 1 year. This motion was preserved through a 12-month follow-up period. CONCLUSION: Administering IACI during TKA MUA does not harbor an elevated risk for acute prosthetic joint infections. Additionally, its use is associated with substantial increases in short-term range of motion at six weeks following manipulation, which remain preserved through long-term follow-up.

[Septic arthritis]. / Die septische Arthritis.

Septic arthritis Abstract. A painful, red, and swollen joint may have different causes. Septic arthritis is one of the most serious conditions and should be diagnosed and treated right away. In the native joint, an infection can damage the cartilage within the first 24 hours with impacts on joint function including lingering joint problems leading to possible future joint destruction. An interdisciplinary approach is essential for achieving optimal results. Most infections are caused by bacteria from the patient's own microbiome. In general, the incidence of native joint infections is growing, whether it is due to more appropriate diagnostics, or an actual increase cannot be determined at this point. In case of an acute infection, the patients usually describe a relatively short and acute period of pain, redness, and swelling of the affected joint. For diagnostic purposes the common blood serum laboratory work-up serves as a basis, complemented by puncture of the affected joint. Cell count and cell differentiation in the synovial liquid, microbiological and histopathological workup serve as gold standard in detecting septic arthritis. Septic arthritis lacks a distinctive presentation and other inflammatory conditions, like CPPD and gout must be considered. Prior to antibiotic therapy, joint lavage is the most important method to reduce bacterial load, leading to an improved outcome. Prognosis is determined by a swift diagnosis and initiation of therapy. The patient's comorbidities are significant, especially immunocompromising factors such as rheumatoid arthritis, diabetes or immunomodulating therapy. In case of a second focus of infection, chronic kidney disease or older age, patients are at greater risk for an inferior outcome.

Increasing Incidence of Sternoclavicular Joint Infections in Intravenous Drug Users.

Sternoclavicular joint septic arthritis is rarely seen in the general population. The majority of cases are seen in intravenous drug users. Given the lack of reported cases in the literature, there is no standardized treatment algorithm for this disease. Described treatment methods range from medical management to wide local debridement. The incidence of sternoclavicular joint septic arthritis will likely continue to increase with rising usage of intravenous drugs in the United States. Within the past year, our institution treated four cases.

Descriptive Epidemiology of Upper Extremity Septic Arthritis in Children-Review of a Retrospective Multicenter Database.

BACKGROUND: There is limited information on the presentation and management of upper extremity septic arthritis (UESA) in children. Our purpose was to report on the characteristics and short-term treatment outcomes of pediatric UESA from a multicenter database. METHODS: Patients with UESA were identified from a multicenter retrospective musculoskeletal infection database. Demographics, laboratory tests, culture results, number of surgeries, and complications were collected. RESULTS: Of 684 patients with septic arthritis (SA), 68 (10%) patients had UESA. Septic arthritis was most common in the elbow (53%), followed by the shoulder (41%) and wrist (4%). The median age at admission was 1.7 years [interquartile range(IQR, 0.8-8.0 y)] and 66% of the cohort was male. Blood cultures were collected in 65 (96%) patients with 23 (34%) positive results. Joint aspirate and/or tissue cultures were obtained in 66 (97%) patients with 49 (72%) positive results. Methicillin-sensitive Staphylococcus aureus (MSSA) was the most common causative organism overall, but Streptococcus was the most common pathogen in the shoulder. Sixty-six (97%) patients underwent irrigation and debridement, with 5 (7%) patients requiring 2 surgeries and 1 patient (1%) requiring 3 surgeries. The median length of stay was 4.9 days (IQR, 4.0-6.3 d). Thirty-one (46%) children had adjacent musculoskeletal infections and/or persistent bacteremia. No patients experienced venous thromboembolism, and 4 patients with associated osteomyelitis experienced a musculoskeletal complication (3 avascular necrosis, 1 pathologic fracture). One child had re-admission and 3 children with associated osteomyelitis had a recurrence of UESA. Comparison between elbow and shoulder locations showed that children with septic arthritis of the shoulder were younger (4.6 vs. 1.0 y, P =0.001), and there was a difference in minimum platelet count (280 vs. 358 ×10 9 cells/L, P =0.02). CONCLUSIONS: UESA comprises 10% of cases of septic arthritis in children. The elbow is the most common location. Shoulder septic arthritis affects younger children. MSSA is the most common causative organism in UESA, but Streptococcus is common in shoulder septic arthritis. Irrigation and debridement result in excellent short-term outcomes with a low complication rate. Re-admissions and repeat surgical interventions are rare. LEVEL OF EVIDENCE: Level IV, prognostic.

Intra-articular Hip Injections Prior to Total Hip Arthroplasty: Infection and Cost-Related Associations.

Intra-articular injections prior to total hip arthroplasty (THA) have been associated with postoperative infections. The purpose of this study was to determine whether a temporal relationship exists between hip injections prior to THA and infection. Specifically, we asked (1) Do patients who receive hip injections within 3 months of THA have a higher incidence of prosthetic joint infections (PJIs) or surgical site infections (SSIs)? and (2) Do these patients incur higher 90-day costs? Patients with hip injections prior to THA were identified using a national database from 2010 to 2019. Three laterality-specific groups (injection 0 to 3 months, 3 to 6 months, and 6 to 12 months prior to THA)were compared with a matched cohort without prior injection (n=277,841). Primary outcomes included PJIs, SSIs, and costs. Patients who had injections within 3 months of THA had a higher incidence of PJIs at 90 days (5.1% vs 1.6%, P<.01) and 1 year (6.8% vs 2.1%, P<.01), when compared with the matched cohort. They also had a higher incidence of SSIs at 90 days (2.8% vs 1.2%, P<.01) and 1 year (3.7% vs 1.7%, P<.01). Mean costs were 13.7% higher in this injection cohort. Patients who had injections between 3 and 6 months prior to THA had higher incidence and odds of postoperative PJIs at 90 days (2.6% vs 1.6%, P<.04), whereas those with injections beyond 6 months had no differences in PJIs (P≥.46). Patients who receive hip injections within 3 months of undergoing primary THA are at increased risk for postoperative PJIs, SSIs, and higher costs. This study reaffirms guidelines for when to perform THAs in these populations. [Orthopedics. 2023;46(1):19-26.].

Seasonal Variation of Pediatric Septic Arthritis in the United States: A PHIS Database Study.

BACKGROUND: The presence of seasonal patterns in pediatric septic arthritis cases is a common orthopaedic teaching. Seasonal variation has been seen in centers outside of the United States and with other inflammatory and infectious joint-related conditions within the country, but it is unknown if a seasonal pattern exists among different regions of the United States. The purpose of this study was to examine the seasonal variation of septic arthritis within specific regions across the United States. METHODS: The Pediatric Health Information System database was queried for all patients 19 years or younger who were treated for septic arthritis. Data from 34 pediatric hospitals in the Pediatric Health Information System initiative were included. Centers were organized by geographical region, and season of presentation was determined using equinoxes/solstices. χ 2 tests were performed to detect seasonal differences in septic arthritis for the entire cohort and separated by geographical region. Proportion differences along with 95% CIs were provided. RESULTS: Between 2016 and 2019, there were 5764 cases of septic arthritis. Median age at diagnosis was 6.2 years (range: 0 to 19.0 y). Each season contributed 24% to 25% of the total septic arthritis cases, and there were no significant differences detected between the 4 seasons ( P =0.66). There was no seasonal variation seen in the Midwest, South, or West ( P =0.71, 0.98, 0.36, respectively). However, there was seasonal variation in the Northeast ( P =0.05), with fall and summer having a higher percentage of cases (28%) than the winter (21%). CONCLUSIONS: This study showed no clear seasonal variation in septic arthritis in children across the United States using a national database of pediatric hospital centers. However, there is regional seasonal variation in the Northeast, which may relate to climate differences. With no clear seasonal variation across the United States, continued diligence is needed in diagnosing septic arthritis throughout the year. LEVEL OF EVIDENCE: Prognostic II.

Prior Septic Arthritis Within One Year of Knee Arthroplasty is Associated With a High Risk for Infection.

BACKGROUND: A prior history of a septic knee may predispose patients to a periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). We performed multivariate analyses of known risk factors that portend a periprosthetic infection for patients who have a history of septic arthritis (SA). The focus of the study was an assessment of the incidence of TKA PJIs at various time intervals after the onset of a septic knee (0 to 3 months, 3 to 6 months, 6 to 9 months, and 9 months to 1-year). METHODS: We queried a national database to identify patients who underwent a primary TKA between 2010 and 2021 (n = 1.9 million). Patients who had a prior septic knee ipsilateral to the primary TKA were characterized (n = 4,251) and were put into four specific cohorts based on the interval between the SA diagnosis and TKA: less than 3 months; 3 to 6 months; 6 to 9 months; and 9 to 12 months. A cohort of patients who did not have history of septic knee were used for comparison (n = 5,000). The incidence of PJIs from 90 days to 1 year was identified and compared using multivariate analyses. RESULTS: All time cohorts were more likely to require revisions due to PJI, as compared to the comparison group. Significant differences were demonstrated among all time cohorts who had prior SA compared to patients who did not have a history of SA (odds ratio [OR] range, 90.0 to 113.0, P < .001). CONCLUSION: This study has shown an increased PJI risk in the first year after SA (P < .05). The surgeon should be aware of the increased PJI risk after SA within the first year after TKA.

Surveillance of osteoarticular infections caused by Staphylococcus aureus in a paediatric hospital in Mexico City.

Staphylococcus aureus is the main aetiologic agent of osteoarticular infections (OAIs) in paediatric patients. The aim of this prospective unicenter study was to describe the phenotypic and genotypic characteristics of S. aureus isolates obtained from OAIs in paediatric patients admitted to tertiary care hospital. Through a surveillance program called OsteoCode, a multidisciplinary team was created and we identified 27 patients with OAIs caused by S. aureus from 2019 to 2021. The susceptibility profile, virulence factors, biofilm formation, pulsed-field gel electrophoresis (PFGE), clonal complex (CC) and sequence type (ST) were determined. In addition, the clinical characteristics and evolution of the patients presented six months after the diagnosis of OAIs were described. Ninety-two percent of the isolates were methicillin-sensitive S. aureus (MSSA). In methicillin-resistant S. aureus (MRSA), SCCmec-II and SCCmec-V were detected. The pvl gene was only observed in MSSA (18.5%) and was associated with highest fever (p=0.015), multiple localization (p=0.017), and soft tissue sites of infection beyond the bone (pyomyositis, pulmonary abscess) (p=0.017). Biofilm formation was detected in 55.6% of isolates. The most common CC were CC5 and CC30 which represent the most common linages for bone and joint infections worldwide. The isolates were distributed in different STs, and ST672 was predominant. MRSA were associated with a longer duration of intravenous treatment and a prolonged hospital stay (p=0.023). Recurrent infection occurred in five children and orthopaedic complications in 33.3% of patients. This is the first study that reflects the epidemiology of S. aureus in OAIs in paediatric patients in Mexico; a clear predominance of MSSA distributed in different STs was observed. Our findings highlight that a multidisciplinary team is required for the diagnosis and treatment of OAIs.

Mortality of septic knee arthritis in Korea: risk factors analysis of a large national database.

This study aimed to analyze the risk factors for mortality of septic knee arthritis in Korea through a large nationwide data research. The National Health Insurance Service-Health Screening database was used to analyze 89,120 hospitalizations for septic knee arthritis between 2005 and 2018. In-hospital, thirty-day, and ninety-day mortality, and their association with patient's demographic factors, various comorbidities (i.e., cerebrovascular disease, congestive heart failure, and myocardial infarction) and Charlson Comorbidity Index (CCI) were assessed. Secondary outcomes of complications (osteomyelitis, knee arthroplasty, recurrence) were analyzed. The number of hospitalization with septic knee arthritis increased from 1847 cases in 2005 to 8749 cases in 2018. There was no significant difference in mortality after diagnosis of septic knee arthritis between years. The risk of mortality in patients who hospitalized with septic knee arthritis increased in comorbidities like Congestive heart failure, dementia, myocardial infarction, chronic kidney disease. Hazard ratio (HR) decreased in patients who have comorbidities such as rheumatoid arthritis, liver disease, rheumatologic disease. HR for mortality in septic knee arthritis increased in patients with CCI more than 1. The risk factors for mortality in all periods were male sex, old age, high CCI, comorbidities such as congestive heart failure, dementia, myocardial infarction, chronic kidney disease. Efforts to reduce mortality should be concentrate more on patients with these risk factors.

Clinical profiles of post-infectious arthritis and transient synovitis of the hip in children.

BACKGROUND: Acute inflammatory arthritides can present as a result of immune reaction following infections. Post-infectious arthritis and transient synovitis of the hip in children are included in this disease entity. The aim of this study was to describe the clinical profiles of post-infectious arthritis and transient synovitis of the hip in Thai children. METHODS: A retrospective review was performed at a tertiary care hospital in Bangkok, Thailand from January 2005 to July 2017. RESULTS: Eighty-six patients (56 boys and 30 girls) were included in this study. Mean age was 8.4 ± 4.8 years. Reactive arthritis was diagnosed in two patients (2.3%) following Salmonella spp. and Chlamydia trachomatis infections. Post-streptococcal reactive arthritis was present in 10 patients (11.6%). Transient synovitis of the hip was found in 30 patients (34.9%). Forty-four patients (51.2%) were clinically diagnosed with post-infectious arthritis. Mono/oligoarthritis was the most common clinical profile (84.9%). The distribution of lower-extremity involvement was as follows: hip, 47.6%; knee, 46.5%; and ankle joints, 30.2%. The documented preceding illness consisted mostly of upper respiratory tract symptoms (30.2%). Non-steroidal anti-inflammatory drugs were prescribed for 70 patients (81.4%). CONCLUSION: Mono/oligoarthritis of the lower extremity was the main clinical profile. Preceding viral illness was documented in one-third of children. Reactive arthritis was rarely seen.

Simplified antibiotic treatment for paediatric osteoarticular infections achieved good outcomes.

AIM: Early diagnosis of osteoarticular infections (OAI) in children and effective treatment prevents complications. The objective of this study was to evaluate effectiveness and safety of shortened intravenous antibiotic treatment of OAI. Incidence, diagnostics and pathogens of paediatric OAI were assessed. METHODS: This retrospective study included all paediatric OAI admissions to The Children's Hospital Iceland in 2006-2020. The treatment was evaluated by dividing the study cohort into two groups. The simplified treatment group received intravenous antibiotics for less than 7 days. The longer intravenous group received intravenous antibiotics for a minimum of 7 days. RESULTS: In total, 205 cases of OAI were included: 106 osteomyelitis, 83 septic arthritis and 16 with both. Age standardised incidence was 17 per 100,000 children and decreased over the study period (p = 0.004). A pathogen was identified in 37% (75/205) of cases of which 65% (49/75) were Staphylococcus aureus and 12% (9/75) Kingella kingae. Simplified treatment was not associated with increased risk of complications. CONCLUSION: This study supports claims that simplified treatment for OAI is safe and effective. Further simplification of treatment might be viable. For uncertain reasons the incidence of OAI was decreasing in Iceland, predominantly in young children.

An analysis of Neisseria meningitidis strains causing meningococcal septic arthritis in England and Wales: 2010-2020.

OBJECTIVES: To analyze clinical meningococcal strains associated with meningococcal septic arthritis cases in England and Wales, and to identify associations between patient age, the synovial joint affected and strain characteristics. METHODS: IMD cases confirmed by the Meningococcal Reference Unit (UK Health Security Agency) between January 2010 and December 2020 were included in the analysis. Septic arthritis cases were defined as those featuring detection and/or isolation of N. meningitidis from an articular site. Capsular grouping was performed by serology on clinical isolates and/or real-time PCR on clinical samples. RESULTS: We identified 162 cases of meningococcal septic arthritis, representing 2% of all invasive meningococcal disease cases during the study period. The knee and the hip were the most commonly affected joints, with the former significantly more frequent in adults and the latter seen more commonly in children and adolescents. Group B strains were between 2 and 6 times less likely to cause septic arthritis in relation to groups W, C and Y strains. CONCLUSIONS: Meningococcal septic arthritis remains a rare manifestation of invasive meningococcal disease. Strain and age associations identified in this study remain unexplained. Future analyzes including clinical case information may help to explain these findings.

Epidemiology and outcome of septic arthritis in childhood: a 16-year experience and review of literature.

INTRODUCTION: Septic arthritis (SA) is a devastating infection with a high rate of sequelae. The aim of this retrospective study was to determine the epidemiology, clinically significant sequelae and risk factors for developing these sequelae in children admitted to our hospital with SA. METHODS: Patients with bacteriologically and/or radiologically confirmed SA from January 1999 to December 2014 were identified from discharge and laboratory records. Data was collected through a retrospective review of the case notes. RESULTS: A total of 75 patients (62.7% male) met the inclusion criteria. The median age at presentation was six years (range two weeks to 15 years), and six patients were neonates. Microbiologic aetiology was determined in 40 (53.3%) patients, with Staphylococcus aureus being the most common organism. 68.0% of the patients underwent arthrotomy, and the average hospital stay was 15.3 days. Sequelae of SA were observed in nine patients on follow-up. Univariate and multivariate statistical analyses showed that young age, pyogenic bacterial isolation and concomitant osteomyelitis were significant risk factors for developing sequelae. CONCLUSION: Our study demonstrated that young age, pyogenic bacterial isolation and concomitant osteomyelitis are associated with a high risk of sequelae. Timely microbiologic diagnosis by novel polymerase chain reaction methods and the use of magnetic resonance imaging in high-risk children to identify adjacent infection could possibly prevent lifelong disabling sequelae in SA.

A Clinical Prediction Rule for Bacterial Musculoskeletal Infections in Children with Monoarthritis in Lyme Endemic Regions.

STUDY OBJECTIVE: Children with a bacterial musculoskeletal infection (MSKI) require prompt identification and treatment. In Lyme disease endemic areas, children with an MSKI can present similarly to those with Lyme arthritis. Our goal was to derive a clinical prediction rule to accurately identify children at a low risk for an MSKI. METHODS: We enrolled children with monoarthritis presenting to 1 of 6 Pedi Lyme Net centers and performed a procalcitonin (PCT) and a first-tier Lyme C6 enzyme immunoassay (EIA) test. Our primary outcome was an MSKI (septic arthritis, osteomyelitis, or pyomyositis). Using recursive partitioning with k-fold cross validation, we derived a clinical prediction rule to identify children at a low risk of an MSKI. We calculated the accuracy of our novel rule in a derivation cohort. RESULTS: Of the 735 children in the derivation cohort with an available research biosample, 39 (5%) had an MSKI (18 had septic arthritis, 20 had osteomyelitis, and 1 had pyomyositis), 260 (37%) had Lyme arthritis, and 436 (53%) had other inflammatory arthritis. Children with a PCT level of more than or equal to 0.50 ng/mL and those with a C-reactive protein (CRP) level of more than or equal to 0.6 mg/dL with a negative Lyme C6 EIA were classified as not low risk for an MSKI. Of the 451 (61%) children categorized as low risk, none had an MSKI (sensitivity 100%, 95% confidence interval 91.0% to 100%; specificity 74.2%, 95% confidence interval 70.5% to 77.6%). CONCLUSION: A novel clinical decision rule that includes PCT, CRP, and a first-tier Lyme EIA was highly sensitive for MSKIs. Although broader external validation is required, the application of this rule may safely reduce invasive testing, procedures, and treatment for low risk children.