Validating an Algorithm to Predict Adjacent Musculoskeletal Infections in Pediatric Patients With Septic Arthritis

Clinical characteristics of and risk factors for poor outcomes in children with bacterial culture-negative septic arthritis of the hip

BACKGROUND

Septic arthritis of the hip is a serious infection in children. However, blood and joint fluid cultures are often negative, which makes the diagnosis and treatment challenging. We analyzed the clinical features of children with septic arthritis of the hip with negative bacterial cultures and identified the risk factors for poor outcomes.

METHODS

The clinical data of children with septic arthritis of the hip with negative bacterial cultures who were treated at our hospital from January 2010 to December 2020 were retrospectively analyzed. The clinical characteristics and outcomes of the culture-negative cohort were compared with those of children with positive bacterial cultures treated during the same period. Culture-negative patients were divided into a group with good outcomes and a group with poor outcomes. The differences between the two groups were compared.

RESULTS

Thirty-nine children with culture-negative septic arthritis of the hip were compared with 37 children with culture-positive sepsis. Compared with the culture-positive group, the culture-negative group had a significantly younger mean age and a significantly lower mean serum C-reactive protein concentration. Logistic regression analysis of culture-negative patients with good versus poor outcomes revealed that the independent risk factors for poor outcomes were an increased serum C-reactive protein concentration and prolonged time from onset to surgery. The cut-off values for predicting a poor outcome in the culture-negative group were a time from onset to surgery of greater than 21 days and a C-reactive protein concentration of greater than 23 mg/L.

CONCLUSIONS

Culture-negative septic arthritis of the hip has similar clinical features to culture-positive septic arthritis of the hip and can result in sequelae of varying severity. Therefore, active anti-infective and hip drainage therapy should be performed when children present with clinical symptoms, inflammatory marker concentrations, and imaging findings that are clinically diagnostic for septic arthritis of the hip.

LEVEL OF EVIDENCE

Level II, retrospective study.

Analysis of poor prognostic factors for septic arthritis of the hip in children: a case series of 76 patients

The clinical characteristics, treatment and outcomes of children with septic arthritis of the hip in our hospital were analyzed to identify the risk factors for a poor prognosis. The clinical data of 76 children with septic arthritis of the hip who were treated at our hospital from January 2010 to December 2020 were retrospectively analyzed. According to the most recent follow-up data, the patients were classified as good prognosis or poor prognosis. The differences between the two groups were analyzed. From January 2010 to December 2020, a total of 76 children with septic arthritis of the hip were admitted to our hospital, comprising 52 (68.4%) with a good prognosis and 24 (31.6%) with a poor prognosis. The risk of a poor prognosis was significantly higher in the group with time from onset to surgery >22 days than in the group with time from onset to surgery <11 days. The risk of poor prognosis in the group with C-reactive protein (CRP) > 100 mg/L was significantly higher than that in the group with CRP < 20 mg/L. Time from onset to surgery >14 days and CRP > 93 mg/L were the cutoff values for a poor prognosis. Significant elevation of CRP and prolonged time from onset to surgery in children with septic arthritis of the hip are risk factors for a poor prognosis. Early diagnosis and effective treatment are very important because delays in these factors can lead to a poor prognosis. Level of Evidence: Level II, retrospective study.

Optimizing Advanced Imaging of the Pediatric Patient in the Emergency Department: Technical Report

Advanced diagnostic imaging modalities, including ultrasonography, computed tomography, and magnetic resonance imaging, are key components in the evaluation and management of pediatric patients presenting to the emergency department. Advances in imaging technology have led to the availability of faster and more accurate tools to improve patient care. Notwithstanding these advances, it is important for physicians, physician assistants, and nurse practitioners to understand the risks and limitations associated with advanced imaging in children and to limit imaging studies that are considered low value, when possible. This technical report provides a summary of imaging strategies for specific conditions where advanced imaging is commonly considered in the emergency department. As an accompaniment to the policy statement, this document provides resources and strategies to optimize advanced imaging, including clinical decision support mechanisms, teleradiology, shared decision-making, and rationale for deferred imaging for patients who will be transferred for definitive care.

Optimizing Advanced Imaging of the Pediatric Patient in the Emergency Department: Technical Report

Advanced diagnostic imaging modalities, including ultrasonography, computed tomography, and magnetic resonance imaging (MRI), are key components in the evaluation and management of pediatric patients presenting to the emergency department. Advances in imaging technology have led to the availability of faster and more accurate tools to improve patient care. Notwithstanding these advances, it is important for physicians, physician assistants, and nurse practitioners to understand the risks and limitations associated with advanced imaging in children and to limit imaging studies that are considered low value, when possible. This technical report provides a summary of imaging strategies for specific conditions where advanced imaging is commonly considered in the emergency department. As an accompaniment to the policy statement, this document provides resources and strategies to optimize advanced imaging, including clinical decision support mechanisms, teleradiology, shared decision-making, and rationale for deferred imaging for patients who will be transferred for definitive care.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Role of Magnetic Resonance Imaging in Concomitant Periarticular Infections in Septic Arthritis of Large Joints in Children: A Systematic Review

Background

Septic arthritis associated with adjacent infections, presents a diagnostic challenge as the clinical presentation is similar to that of isolated septic arthritis, additional diagnostic tools are needed to detect these infections. The purpose of this study was to examine the effectiveness of magnetic resonance imaging (MRI) for diagnosis of concomitant infection in children with septic arthritis of large joints and its effect on patient outcome and treatment.

Materials and Methods

Electronic literature research of PubMed, Cochrane and Scopus, was conducted in January 2022 using a combination of MeSH, search terms and keywords. The data extracted included the study details, demographic data, the proportion of patients having a concomitant periarticular infection, clinical presentation, blood parameters and culture findings and outcomes.

Results

This review included seven studies with 499 patients. The mean age was 7.08 ± 2.38 years in the study. There was a male predominance, with 174 being males (62.36%). The most common joint involved was the hip joint (44.47%). 42.48% had concomitant periarticular infections detected by MRI. Osteomyelitis was the most common infection seen in 209 patients (41.84%). The mean duration of antibiotics given and hospital stay was significantly more in periarticular infections (P > 0.05). 32.5% of the patients with septic arthritis underwent a second surgical procedure whereas 61.11% of patients with periarticular infections underwent second procedure in this review (P > 0.05).

Conclusions

The use of MRI to diagnose these complicated infections appears to be beneficial. Multi-centric randomised control trials are needed to investigate the efficacy of MRI and its impact on patient care and outcome.

What's New in Pediatric Septic Arthritis? A Review of Pertinent Clinical Questions

BACKGROUND

The evaluation and treatment of children with septic arthritis (SA) is challenging and requires an organized approach to address the spectrum of pathogens which appear to aggregate in age-specific groups. Although evidence-based guidelines have recently been published for the evaluation and treatment of children with acute hematogenous osteomyelitis, there is a relative dearth of literature devoted exclusively to SA.

METHODS

Recently published guidance for the evaluation and treatment of children with SA was reviewed and evaluated with respect to pertinent clinical questions to summarize what is new in this area of practice for pediatric orthopaedic surgeons.

RESULTS

Evidence suggests that there is a profound difference between children with primary SA and those who have contiguous osteomyelitis. This disruption of the commonly accepted paradigm of a continuum of osteoarticular infections has important implications in the evaluation and treatment of children with primary SA. Clinical prediction algorithms have been established to help determine the applicability of magnetic resonance imaging during the evaluation of children suspected to have SA. Antibiotic duration for SA has been recently studied with some evidence in favor of short-course parenteral followed by short-course oral therapy may be successful if the pathogen is not methicillin-resistant Staphylococcus aureus .

CONCLUSION

Recent studies of children with SA have provided better guidance for evaluation and treatment to improve diagnostic accuracy, processes of evaluation, and clinical outcomes.

LEVEL OF EVIDENCE

Level 4.

[Septic arthritis and transient synovitis of the hip]

CLINICAL/METHODICAL ISSUE

Differentiating between septic arthritis and transient synovitis can be challenging but is very important as a late diagnosis of septic arthritis can lead to sepsis and joint damage. For correct diagnosis and prediction of complications, the right combination of physical examination, laboratory and radiological studies is needed.

STANDARD RADIOLOGICAL METHODS

Hip ultrasound is easy to learn and has a high sensitivity for joint effusion. Faster diagnosis and therapy are possible due to increasing use of ultrasound. Magnetic resonance imaging (MRI) is primarily used to rule out co-infections (osteomyelitis, pyomyositis) and differential diagnoses. X‑ray is typically nonremarkable in septic arthritis.

PRACTICAL RECOMMENDATIONS

Routine use of ultrasound in nontraumatic pediatric hip pain. Generous use of MRI in case of elevated inflammatory markers or inconclusive clinical findings. Using only few sequences may be appropriate to avoid sedation, primarily fluid sensitive sequences (fat-saturated T2, TIRM, STIR), in case of positive findings, accompanied by T1-weighted images.

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.

Relevant factors in the diagnosis of concomitant osteomyelitis in pediatric hip septic arthritis. A series of 41 cases treated by hip arthroscopy

INTRODUCTION

Septic arthritis of the hip can appear isolated or concomitant with pelvic osteomyelitis. Delay in the diagnosis of a concomitant osteomyelitis increases the number of required surgeries and of possible complications.

PURPOSE

This study aims to establish relevant factors in the diagnosis of concomitant osteomyelitis in cases with septic arthritis of the hip among paediatric patients.

METHODS

The data were collected between 2005 and 2020. 41 pediatric patients with suspicion of septic arthritis of the hip joint, treated arthroscopically, were included. The following diagnostic test parameters were collected: ultrasound, MRI, X-Rays, blood samples, temperature, and incapacity to bear weight. The data were analysed with the sensitive analysis method using descriptive statistic.

RESULTS

41 patients were analyzed, with an average age of 6.04 y (7 months to 14 years), of which ten patients (24.39%) presented concomitant osteomyelitis. 6 out of ten patients needed secondary surgery. Regarding age, concomitant osteomyelitis was most common in the age group 4-14 years old. Average number of days of clinical symptoms before admission was 6.2 days. 36/41 cases showed CRP values higher than 2 mg/dl. 9/10 cases with concomitant osteomyelitis showed a CRP > 2 mg/dl, with an average value of 8.9 mg/dl. 22/41 patients underwent an MRI, of which nine cases presented a concomitant osteomyelitis. The probability of a child to have septic arthritis of the hip with adjacent osteomyelitis was analysed through a score based on four factors: impossibility to bear weight and/or hip pain in children in the non-walking age category, CRP > 2 mg/dl, age older than > 4 y, symptoms longer than 4 days.

CONCLUSIONS

Children at the age of walking, with incapacity to bear weight, presenting symptoms longer than 4 days and a CRP > 2 mg/dl, should receive an MRI before surgery to exclude adjacent osteomyelitis.

LEVEL OF EVIDENCE

IV.

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.

Magnetic resonance imaging in the evaluation of suspected hip sepsis in children

BACKGROUND

Rapid and accurate diagnosis of musculoskeletal infection in children is critical to enable appropriate, targeted surgical interventions. Distinguishing between septic arthritis, myositis, and osteomyelitis around the hip can be difficult using clinical criteria and ultrasound scan alone.

MATERIALS AND METHODS

We performed a retrospective 5-year observational review of selective magnetic resonance imaging scanning for hip sepsis in a pediatric tertiary referral center. Included were children with atraumatic hip pain with symptom duration <2 weeks, minimum of two positive modified Kocher's criteria, and a hip effusion on ultrasound. All cases were followed up to discharge. We evaluated hip ultrasound and magnetic resonance imaging findings, operative procedures, microbiology results, duration of treatment, outcomes, and complications.

RESULTS

Fifty-one patients, 55% male, with a mean age 6.4 (0-16) years were included. Thirty-nine underwent magnetic resonance imaging scan for suspected septic arthritis of the hip; 24 prior to surgical washout (pre-emptive), and 15 afterwards (postoperative). In the pre-emptive group, 1/24 had septic arthritis, 7/24 had osteomyelitis, 6/24 had myositis, 5/24 had osteomyelitis and myositis, and 5/24 had no evidence of infective pathology. In the postoperative group, 3/15 had myositis, 3/15 had osteomyelitis, 3/15 had re-accumulation of the hip effusion requiring repeat washout, 3/15 had myositis and osteomyelitis, and 1/15 had septic arthritis of a contiguous joint.

CONCLUSION

Pre-emptive magnetic resonance imaging scanning avoided unnecessary hip washout in 23 cases and enabled targeted drainage of an alternative focus in four of those. Magnetic resonance imaging scanning after hip washout indicated that four cases required further surgery to drain a different focus of infection.

The Use of Biomarkers in the Early Diagnosis of Septic Arthritis and Osteomyelitis-A Pilot Study

BACKGROUND

The diagnosis of septic arthritis (SA) and osteomyelitis (OM) has remained challenging in the pediatric population, often accompanied by delays and requiring invasive interventions. The purpose of this pilot study is to identify a novel panel of biomarkers and cytokines that can accurately differentiate SA and OM at initial presentation using serum alone.

METHODS

Twenty patients below 18 years old whose working diagnosis included SA (n=10) and OM (n=10) were identified. Serum was collected at initial evaluation. Each sample underwent seven ELISA [C1-C2, COMP, CS-846, hyaluronan, procalcitonin, PIIANP, C-terminal telopeptide of type II collagen (CTX-II)] and 65-plex cytokine panels. Principal component and Lasso regression analysis were performed to identify a limited set of predictive biomarkers.

RESULTS

Mean age was 4.7 and 9.5 years in SA and OM patients, respectively (P=0.029). 50% of SA patients presented within 24 hours of symptom onset, compared with 0% of OM patients (P=0.033). 30% of SA patients were discharged home with an incorrect diagnosis and re-presented to the emergency department days later. At time of presentation: temperature ≥38.5°C was present in 10% of SA and 40% of OM patients (P=0.12), mean erythrocyte sedimentation rate (mm/h) was 51.6 in SA and 44.9 in OM patients (P=0.63), mean C-reactive protein (mg/dL) was 55.8 in SA and 71.8 in OM patients (P=0.53), and mean white blood cells (K/mm3) was 12.5 in SA and 10.4 in OM patients (P=0.34). 90% of SA patients presented with ≤2 of the Kocher criteria. 100% of SA and 40% of OM patients underwent surgery. 70% of SA cultures were culture negative, 10% MSSA, 10% Kingella, and 10% Strep pyogenes. 40% of OM cultures were culture negative, 50% MSSA, and 10% MRSA. Four biomarkers [CTx-II, transforming growth factor alpha (TGF-α), monocyte chemoattractant protein 1 (MCP-1), B cell-attracting chemokine 1] were identified that were able to classify and differentiate 18 of the 20 SA and OM cases correctly, with 90% sensitivity and 80% specificity.

CONCLUSIONS

This pilot study identifies a panel of biomarkers that can differentiate between SA and OM at initial presentation using serum alone.

LEVEL OF EVIDENCE

Level II-diagnostic study.

ACR Appropriateness Criteria® Osteomyelitis or Septic Arthritis-Child (Excluding Axial Skeleton)

Imaging plays an integral role in the evaluation of suspected musculoskeletal infections in children, not only in the accurate identification of infection such as osteomyelitis or septic arthritis, but also in guiding management. Various diagnostic modalities serve different purposes in the assessment of suspected pediatric musculoskeletal infections. The purpose of this document is to provide imaging guidance in the most frequently encountered clinical scenarios in which osteomyelitis and/or septic arthritis are suspected, outside of the axial skeleton. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion.

Predictive Algorithms in the Diagnosis and Management of Pediatric Hip and Periarticular Infection

➤ Although the criteria of Kocher et al. were an important advancement in our ability to diagnose septic arthritis of the hip early, the changing microbial landscape and availability of advanced imaging have rendered it insufficient for contemporary clinical use.➤ Routine use of magnetic resonance imaging and recognition of disseminated disease have prompted the development of algorithms to predict concurrent osteoarticular infection in cases of septic arthritis and osteomyelitis that were previously assumed to be "isolated."➤ Recent research has attempted to stratify childhood bone and joint infection (BJI) by severity to guide treatment planning. This is valuable, as patients with multifocal disease, more virulent pathogens, and immunocompromise can have longer hospital stays and require multiple surgeries.➤ The increasing prevalence of clinical prediction algorithms in childhood BJI is not completely matched by quality in methodology. Clinicians need to be wary of adopting predictive algorithms prior to robust external validation.

Predicting adjacent infections in pediatric septic arthritis: Do predictive criteria extrapolate across geographic regions?: Predicting Periarticular Infection in the Southeast

Purpose

This study aims to assess previously determined predictive criteria for presence of adjacent infection in septic arthritis within a Southeastern United States (US) pediatric population.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value of the Rosenfeld criteria were: 91.7%, 22.7%, 39.3%, and 83.3%, respectively. The patients with periarticular infection were more likely to have positive blood cultures than those with isolated septic arthritis. There was no difference in likelihood of secondary surgical intervention.

Conclusions

Previously defined criteria to predict adjacent infection in pediatric septic arthritis did not demonstrate external validity in a Southeastern US pediatric population.

Children with Primary Septic Arthritis Have a Markedly Lower Risk of Adverse Outcomes Than Those with Contiguous Osteomyelitis

BACKGROUND

It is widely believed that septic arthritis poses a risk of joint destruction and long-term adverse outcomes for children if not treated emergently. In the present study, children who had primary confirmed septic arthritis were compared with those who had septic arthritis and adjacent osteomyelitis to evaluate differences that affect the relative risk of adverse outcomes.

METHODS

Children who underwent multidisciplinary treatment for septic arthritis with or without contiguous osteomyelitis between 2009 and 2019 were retrospectively studied. Clinical, laboratory, treatment, and outcome data were compared between cohorts of children with primary confirmed septic arthritis and children with septic arthritis and contiguous osteomyelitis.

RESULTS

One hundred and thirty-four children had primary confirmed septic arthritis, and 105 children had septic arthritis with contiguous osteomyelitis. Children with osteomyelitis were older (median, 7.4 versus 2.4 years), had higher initial C-reactive protein (median, 15.7 versus 6.4 mg/dL), and had a higher rate of thrombocytopenia (21.0% versus 1.5%). They also had a higher rate of bacteremia (69.5% versus 20.2%) for a longer duration (median, 2.0 versus 1.0 days). Detected pathogens in children with osteomyelitis as compared with those with primary septic arthritis were more likely to be Staphylococcus aureus (77.1% versus 32.1%) and less likely to be Kingella kingae (2.9% versus 32.1%). Children with contiguous osteomyelitis had longer hospitalizations (median, 8.0 versus 4.0 days), a higher rate of intensive care (21.0% versus 1.5%), a higher readmission rate (17.1% versus 5.2%), and a higher complication rate (38.1% versus 0.7%).

CONCLUSIONS

Primary septic arthritis in children is dissimilar to septic arthritis associated with osteomyelitis. The present study demonstrates that long-term adverse outcomes in children with septic arthritis are likely due to the contiguous osteomyelitis. Children with primary septic arthritis are sufficiently distinguishable from those who have contiguous osteomyelitis to guide decisions for magnetic resonance imaging acquisition, duration of antibiotic therapy, and length of outpatient follow-up in order to recognize and address adverse outcomes.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

External Validation of an Algorithm to Predict Adjacent Musculoskeletal Infection in Pediatric Patients With Septic Arthritis

BACKGROUND

Septic arthritis (SA) remains a potentially morbid disease in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive tool for recognizing associated osteomyelitis and intramuscular abscess, but is a limited resource. The aim of this study is to externally validate a previously developed algorithm (Rosenfeld and colleagues) to predict adjacent infection in pediatric patients diagnosed with SA.

METHODS

We identified 120 children under 16 with presumed SA presenting to a tertiary referral center between 2008 and 2018. Patients without confirmed SA, those with insufficient data, and patients who did not receive perioperative MRI were excluded, leaving 53 patients. The previous algorithm suggests that patient age (above 4 y), C-reactive protein (>8.9 mg/L), platelet count (<310×10cells/µL), duration of symptoms (>3 d), and absolute neutrophil count (>7.2×10cells/µL) are risk factors for adjacent infection, with 3 or more variables signifying a "positive" result. Comparing against the gold standard of MRI, the accuracy of the algorithm was validated in terms of sensitivity, specificity, likelihood ratio (LR), and positive and negative predictive value. Discrimination and calibration of this algorithm have been assessed using receiver operating curve analysis and calibration plots.

RESULTS

The sensitivity and specificity of criteria from Rosenfeld algorithm were 73% and 44%, respectively. Receiver operating curve showed poor discrimination [area under the curve=0.54, confidence interval (CI): 0.26-0.83]. The positive predictive value was 55.9% and the negative predictive value was 63.1% with LR +1.23 (CI: 0.87-1.98) and LR -0.61 (CI 0.28-1.30). Only 53% of patients with 4 or more criteria had an adjacent infection on MRI. Examining our cohort, children with a positive MRI finding had higher mean C-reactive protein (77 vs. 122 mg/L, P=0.04) and were more likely to have waited >72 hours days between symptom onset and hospital presentation (P=0.03).

CONCLUSION

Although treatment algorithms are an attractive tool to guide clinicians and resource allocation, they need to take into account the local population characteristics before routine implementation.

LEVEL OF EVIDENCE

Level IV-retrospective cohort study.

Current Concepts in Pediatric Septic Arthritis

Septic arthritis continues to present challenges regarding the clinical diagnosis, workup, and definitive management. Urgent management is essential, so treating surgeons must efficiently work through differential diagnoses, identify concomitant infections, and do a timely irrigation and débridement. The incidence of methicillin-resistant Staphylococcus aureus is increasing, typically resulting in a more rapid progression of symptoms with more severe clinical presentation. The diagnostic utility of MRI has resulted in improved detection of concomitant septic arthritis and osteomyelitis, although MRI must not substantially delay definitive management. Early diagnosis followed by urgent irrigation and débridement and antibiotic therapy are essential for satisfactory long-term outcomes. Antibiotics should not be administered until blood cultures and arthrocentesis fluid are obtained, except in rare cases of a septic or toxic patient. Once cultures are obtained, empiric antibiotic therapy should commence and provide coverage for the most likely pathogens, given the patient's age. Laboratory markers, especially C-reactive protein, should be followed until normalization and correlate with resolution of clinical symptoms. Definitive antibiotic selection should be shared with a pediatric infectious disease specialist, who can help guide the duration of treatment.

Existing and emerging methods of diagnosis and monitoring of pediatric musculoskeletal infection

Methods of diagnosing and monitoring pediatric musculoskeletal infections are rapidly evolving. Key serologic tests are typically used in screening patients with suspected infections, and remain an integral part of the initial work-up. Synovial studies from arthrocentesis in possible septic arthritis, and source-specific cultures have been the foundation of our treatment algorithm. Given the prevalence of soft tissue abscesses and osteoarticular infections, advanced imaging is an advantageous tool. More affordable use and expanded access to MRI has made it a valuable adjunct to clinical picture and existing tests in order to comprehensively visualize the extent of musculoskeletal infections in children. Ongoing validation for criteria to help determine the patients that stand to benefit the most from MRI, even when surgical intervention may be delayed, remains of significant clinical interest. Given the rates of culture-negative infections, and the need for timely diagnosis, new diagnostic techniques are always being considered. The search for more accurate biomarkers, and technology such as Whole genome sequencing (WGS) and next-generation sequencing (NGS) that can rapidly identify pathogens of all types of phyla based on a small sample of DNA, has promising clinical implications. While once novel and prohibitively expensive, these tests are now being applied in university and tertiary care centers in certain scenarios. Applying these techniques to pediatric musculoskeletal will require a large change in lab workflow and training. However, the benefits of acquiring diagnostic information along with will make them a superior tool in our arsenal of diagnostic tests.

Ten-year retrospective review of paediatric septic arthritis in a New Zealand centre

BACKGROUND

Paediatric septic arthritis, although a rare diagnosis in the developed world, remains a significant challenge in the New Zealand population. In recent years, there has been effort to characterize the nature of paediatric bone and joint infection for New Zealand due to rising incidence of osteomyelitis and staphylococcal sepsis [1, 2]. We have sought to identify trends in presentation, diagnosis and management of paediatric septic arthritis, with added focus on ethnicity and access to healthcare.

METHODS

A ten year retrospective review of all cases < 16 years with presumed septic arthritis presenting to a tertiary referral centre between 2008 and 2018 was performed.

RESULTS

A total of 103 cases met inclusion criteria. Mean age was 5.9 years (SD +/- 4.17) with a male predominance (64%). Traditional laboratory culture method isolated an organism in 66% of cases: Staphylococcus aureus was the most common pathogen identified (61%). Incidence varied greatly by ethnicity 1:16,000 for NZ European children; 1:8760 for Pacifica and 1:4300 for Māori. Mean distance travelled by patients to reach the nearest emergency department was 38.3 km, ranging from 2 to 188 km. Assessment using NZ deprivation scores showed the Māori paediatric population were likely to reside in areas of worse socioeconomic deprivation (p = 0.0005). The majority (66%) of cases were treated surgically with a low recurrence rate (2.9%). Delayed presentation was associated with worse outcomes and more likely in patients residing > 20 km away from the nearest emergency department.

CONCLUSION

The incidence of paediatric septic arthritis in New Zealand is concerningly high within Māori and Pacific populations. Future health interventions should consider environmental, socioeconomic, and microbiological trends in the burden of disease.

Point-of-care hip ultrasound leads to expedited results in emergency department patients with suspected septic arthritis

BACKGROUND

The evaluation of septic hip arthritis often incorporates the utilization of hip ultrasonography to determine the presence of a hip joint effusion, as well as to guide arthrocentesis. Point-of-care (POC) hip ultrasound has previously been demonstrated to be accurate when performed by the emergency physician. Time to diagnosis and subsequent intervention in septic arthritis (SA) is critical to favorable outcomes.

METHODS

Retrospective single-center study of all emergency department (ED) patients who had a POC or radiology hip ultrasound or arthrocentesis as part of their ED evaluation for SA in a 3-year period. We investigated the difference in time to obtain hip ultrasonography results and the time to arthrocentesis between radiology and emergency physician-performed studies in cases of suspected septic hip arthritis.

RESULTS

Seventy-four patients met inclusion criteria. The median time to hip ultrasound completion was 68 (interquartile range [IQR], 38.8-132) minutes in the emergency physician-performed ultrasound group versus 208.5 (IQR, 163.8-301.3) minutes for the radiology group (P < 0.001). A total of 17 patients had a hip arthrocentesis performed. Time to arthrocentesis was 211 (IQR 141.3-321.5) minutes in the emergency physician-performed arthrocentesis group and 602 (IQR 500-692) minutes in the radiology arthrocentesis (P < 0.001).

CONCLUSION

There was a statistically shorter time to ultrasound result and arthrocentesis when POC hip ultrasound was utilized by the emergency physician. Given that unfavorable outcomes in SA are associated with delay in treatment, further study is warranted to determine if emergency physician-performed hip ultrasound and arthrocentesis could lead to improved patient-centered clinical end points.

Pediatric Septic Arthritis: An Update

Septic arthritis in children is a surgical emergency, and prompt diagnosis and treatment are mandatory. If diagnosed quickly and treated correctly, the outcomes can be good. With delay in diagnosis and without proper treatment, outcomes often are quite devastating, with growth disturbance and joint destruction.

Septic arthritis of the pediatric hip: update on diagnosis and treatment

PURPOSE OF REVIEW

To review the clinical diagnosis, management and natural history of septic arthritis of the hip (SAH) in the pediatric patient, and to highlight new information that may improve the management of these patients.

RECENT FINDINGS

The basics of management of possible pediatric SAH have remained largely unchanged for generations. New questions have been raised regarding the role and timing of advanced imaging (MRI) in the evaluation of patients with possible SAH. Published criteria have been derived to guide the need for MRI studies in these patients. Validation of these guidelines continues. Recent reviews have highlighted the possibility of Lyme disease as a potential cause of monoarticular pediatric hip pain. The role of PCR technology in the diagnosis and management of SAH remains unclear at this time.

SUMMARY

The child with a limp remains a common and urgent clinical concern. There may be expanded roles for MRI and PCR to better diagnose and treat the involved joint itself, as well as any associated nonarticular area of infection. Lyme disease should remain on the list of possible differential diagnoses in this population, particularly in geographic areas where the disease vector is known to be endemic.