The Heterogeneity of Pediatric Knee Infections: A Retrospective Analysis

CRP Predicts the Need to Escalate Care After Initial Debridement for Musculoskeletal Infection

BACKGROUND

Musculoskeletal infections (MSKIs) are a major cause of morbidity in the pediatric population and account for nearly 1 in every 10 consultations with a pediatric orthopaedic provider at a tertiary care center. To prevent or deescalate the risk of adverse medical and musculoskeletal outcomes, timely medical intervention in the form of antibiotics and potential surgical debridement is required. While there have been numerous studies indicating the value of laboratory testing during the initial workup of a child with MSKI, few studies to date have examined the utility of longitudinal assessment of laboratory measures in the acute setting to monitor the efficacy of antibiotic therapy and/or surgical intervention. The purpose of this investigation was to retrospectively determine whether measuring changes in the inflammatory response could indicate the need for escalated care. Specifically, this study examined the hypothesis that serial measurements of C-reactive protein (CRP), immediately preoperatively and 2 days after surgical debridement, could predict the need for medical (change in antibiotics) or surgical (additional debridement) escalation.

METHODS

Retrospective review of pediatric patients undergoing operative debridement for the treatment of MSKI between September 2009 and December 2015 from whom laboratory data (CRP) was obtained preoperatively and at postoperative day (POD) 2. Patient demographics, the need for escalated care, and patient outcomes were evaluated.

RESULTS

Across 135 pediatric patients, preoperative CRP values >90 mg/L and a positive change in CRP at POD2 effectively predicted the need for escalation of care after initial surgical debridement (Area under the Receiver Operator Curve: 0.883). For each 10-unit increase in preoperative CRP or postoperative change in CRP, there was a 21% or 22% increased risk of needing escalated care, respectively. Stratification by preoperative CRP >90 mg/L and change in CRP postoperatively likewise correlated with increased rates of disseminated disease, percent tissue culture positivity, length of stay, and rate of adverse outcomes.

CONCLUSIONS

This study demonstrates the utility of serial CRP to assess the need for escalated care in patients being treated for MSKI. As serial CRP measurements become standard of practice in the acute setting, future prospective studies are needed to optimize the timing of CRP reassessment during inpatient hospitalization to prognosticate patient outcomes, weighing both improvements of patient care and clinical burden.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

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.

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.

Clinical presentations of Kingella kingae musculoskeletal infections in South Australian children

AIM

This study aimed to alert clinicians to the spectrum of presentations of Kingella kingae musculoskeletal infections.

METHODS

Between August 2010 and March 2018, 55 children presented with positive K. kingae polymerase chain reaction on joint fluid, bone or deep soft tissue collections involving the limbs and subsequently underwent retrospective medical record, radiological and laboratory review. Demographics and clinical information are presented.

RESULTS

Median age at presentation was 15.9 months (range 4.3 months-10.7 years) and 64% were male. Septic arthritis was the most common diagnosis (95%), median duration of symptoms was 4 days, 65% had a preceding infection (e.g. upper respiratory or gastrointestinal) and 22% re-presented to emergency departments after prior discharge. The lower limb was involved in 84%, with the knee being most affected (55%). If the lower limb was involved, 82% of previously weight-bearing children had a limp or were unable to weight bear. On presentation, median temperature was 36.7°C and inflammatory markers were mildly elevated. No blood cultures grew K. kingae. Five synovial fluid cultures were positive for K. kingae. Plain radiography showed effusion, soft tissue swelling or a lesion in 53% of patients. All 41 ultrasounds showed effusion, soft tissue swelling or synovial thickening. One patient with delayed diagnosis later presented with avascular necrosis of the femoral head.

CONCLUSION

Kingella kingae is difficult to diagnose due to non-specific symptoms, absence of fevers and often unremarkable blood tests. Despite generally having good long-term outcomes, our case of avascular necrosis suggests accurate diagnosis and treatment are important.

Diagnostic approach and arthroscopic treatment of septic arthritis of the knee, in an infant

A 9-month-old baby presented with sudden inability to stand and unable to move his leg. Clinical examination showed edema and knee effusion. Blood tests and MRI confirmed septic knee arthritis without bone involvement. He was treated with arthroscopic lavage. He had a complete recovery and normal growth.