Christina Steiger

Purpose: Supracondylar fractures of the distal humerus are among the most common pediatric fractures. For unstable fractures, reduction with pin fixation and postoperative immobilization is standard, but the optimal duration of pin fixation and splinting remains uncertain. This study evaluated whether pin and splint removal approximately 3 weeks after surgery was associated with secondary fracture displacement in children treated for displaced supracondylar humeral fractures. Methods: We retrospectively reviewed pediatric patients surgically treated for displaced supracondylar humeral fractures at our institution between January 2015 and December 2024. Both closed and open reduction cases were eligible. Collected data included demographics, Rigault-Lagrange fracture stage, fixation construct, duration of pin and splint immobilization, radiographic displacement before and after removal, and postoperative complications. Results: A total of 211 patients were included (mean age 6.5 ± 2.3 years). According to the Rigault-Lagrange classification, 87 fractures were stage 2, 54 were stage 3, and 70 were stage 4. Pins and splints were removed after a mean of 23.6 ± 4.0 days. Secondary radiological displacement was observed in 11 patients, corresponding to 13 displacement events: 10 occurred before pin removal and 3 after removal. Three patients showed a change in Baumann’s angle greater than 12° after removal, and no patient lost intersection of the anterior humeral line with the capitellar ossification center after removal. One patient required early revision before pin removal, and no patient required delayed corrective osteotomy. Conclusion: In this retrospective cohort, pin and splint removal approximately 3 weeks after surgical fixation of pediatric supracondylar humeral fractures was associated with a low rate of subsequent secondary displacement, irrespective of fracture stage. Most displacement events occurred before pin removal, and no patient required delayed corrective osteotomy. Early removal may limit exposure to complications associated with prolonged pin fixation and immobilization, although this potential benefit requires confirmation in comparative studies. Level of evidence: III (retrospective cohort study).

Synovial fluid leucocyte count has long been regarded as a cornerstone in the diagnosis of paediatric septic arthritis, with a threshold of 50,000 cells/mm³ widely adopted in clinical practice. This narrative review critically appraised the available evidence regarding its diagnostic utility and interpretation in paediatric septic arthritis. To enhance the transparency and representativeness of the narrative synthesis, rather than to achieve the exhaustive and reproducible study retrieval required for a systematic review, relevant studies were identified through a structured literature search. Fourteen paediatric studies evaluating synovial fluid leucocyte count in the diagnostic assessment of septic arthritis were identified. Whilst several studies reported markedly elevated leucocyte counts in children with septic arthritis, others demonstrated microbiologically confirmed infections below the traditional cut-off, with substantial overlap observed with alternative diagnoses, particularly Lyme arthritis and juvenile idiopathic arthritis. Pathogen characteristics, host inflammatory responses, and prior antibiotic exposure were identified as important factors influencing synovial fluid findings. Current evidence suggests that synovial leucocyte count is best regarded as a marker of intra-articular inflammation rather than a definitive diagnostic test for septic arthritis. Its value lies in contributing to an integrated diagnostic assessment incorporating clinical presentation, imaging findings, microbiological investigations, and emerging molecular diagnostic techniques.

Background/Objectives: Slipped capital femoral epiphysis (SCFE) is frequently diagnosed after substantial delay, which may be associated with greater deformity and more complex treatment. We aim to describe diagnostic delay in a Swiss tertiary-care cohort and examine its associations with radiographic severity and surgical treatment. Methods: We retrospectively reviewed patients younger than 16 years treated for SCFE between 2000 and 2024. Patient-level demographic characteristics were distinguished from hip-level clinical, radiographic, and treatment variables, and hip-level regression models used patient-clustered robust standard errors. Results: The cohort comprised 63 patients and 71 affected hips, including 8 patients with bilateral SCFE. Diagnostic delay was 0–3 weeks for 8 hips (11%), 3–12 weeks for 34 (48%), and >12 weeks for 29 (41%). Mean Southwick angle was 35.7° (SD 19.6) and was greater in the >12-week group. In an exploratory multivariable clustered logistic model adjusted for Southwick angle, age, and surgery year, each additional week of diagnostic delay was associated with higher odds of osteotomy (OR 1.11, 95% CI 1.05–1.17; p < 0.001). The exploratory ROC AUC was 0.903 (patient-cluster bootstrap 95% CI 0.808–0.969). Conclusions: Substantial diagnostic delay was observed in this Swiss tertiary-care cohort and was associated with radiographic severity and surgical treatment. These associations remain observational and should not be interpreted causally.

Identifying the causative pathogen of paediatric osteoarticular infections (OAIs) is essential for guiding management. Kingella kingae infections are generally milder than pyogenic infections, which may have more severe and lasting consequences. Because standard inflammatory markers have limited discriminatory value, we assessed whether complete blood count-derived immune–inflammatory biomarkers (IIBs) could provide a simple, low-cost diagnostic aid. We retrospectively reviewed children younger than 5 years admitted to a tertiary hospital with confirmed OAIs. K. kingae cases were included from 2007 to 2025 and pyogenic cases from 1997 to 2025. Admission clinical data, conventional inflammatory markers, and six IIBs—NLR, MLR, PLR, SII, SIRI, and PIV—were analysed. The cohort included 118 K. kingae and 39 pyogenic OAIs. Pyogenic infections were associated with higher admission temperature and CRP levels and lower lymphocyte counts. All six IIBs were significantly increased in pyogenic infections and showed excellent univariable discrimination, with AUCs of 0.92–0.94. In a common complete-case cohort, the clinical model incorporating age, admission temperature, and CRP achieved an optimism-corrected AUC of 0.848. Adding lymphocyte count or an individual IIB increased corrected AUCs to 0.951–0.962; apparent AUCs were significantly higher than that of the clinical model after Holm adjustment. The abnormal-IIB-count model achieved the highest corrected AUC of 0.970; apparent sensitivity and specificity at the Youden-optimal threshold were 97.3% and 90.3%, respectively, but it did not significantly outperform the model with lymphocyte count alone. Routine CBC-derived IIBs may improve early differentiation between K. kingae and pyogenic OAIs, although external validation is required before clinical implementation.

Joint aspiration remains the gold standard and an urgent step in the diagnosis of paediatric septic arthritis (SA). Unlike in acute haematogenous osteomyelitis, it has both diagnostic and therapeutic value. No previous review has specifically addressed when bacteriological sampling is essential and when it may reasonably be omitted. The bacteriological profile in children is highly age-dependent: Kingella kingae predominates before 4 years of age, whereas Staphylococcus aureus—including Panton–Valentine leukocidin (PVL)-producing and methicillin-resistant (MRSA) strains—predominates thereafter. We critically review the evidence through nine clinical questions and propose a conceptual risk-stratified framework in which the sampling approach is tailored to age and clinical context. In children younger than 4 years with a positive oropharyngeal K. kingae PCR and a mild clinical presentation—defined as CRP < 20 mg/L, absence of fever, and preserved weight-bearing—non-invasive confirmation may be sufficient. This proposal is explicitly hypothesis-generating: it is derived from observational data, it has not been validated prospectively, and it is not endorsed by current PIDS/IDSA or ESPID guidance. A positive oropharyngeal PCR alone is never sufficient, given the 10–12% asymptomatic carriage rate and the limited reliability of the Kocher–Caird criteria in this age group; the decision requires a cluster of concordant findings together with mandatory clinical and laboratory reassessment at 48–72 h and a low threshold for escalation to arthrocentesis. In children older than 4 years, arthrocentesis under general anaesthesia remains the standard approach, with pathogen identification and antimicrobial susceptibility testing as the primary microbiological determinants of therapy and toxin profiling as an adjunctive investigation in selected cases.

Kingella kingae is now recognised as the leading cause of osteoarticular infections (OAIs) in young children. Because these infections typically produce mild symptoms and a weak inflammatory response, early diagnosis remains challenging. Complete blood count-derived immune-inflammatory biomarkers (IIBs) have recently gained interest as accessible, low-cost indicators of systemic inflammation, with potential diagnostic value in several fields, including oncology, rheumatology, cardiology, and infectious diseases. This study therefore aimed to assess whether IIBs could support the screening of K. kingae OAIs. We retrospectively reviewed the medical records of 209 children admitted to our hospital between 2007 and 2025 with confirmed or highly suspected K. kingae OAIs. Complete blood counts were analysed for each patient, including leukocyte subtypes such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils. We then calculated biomarkers (NLR, MLR, PLR, SII, SIRI, and PIV) and interpreted them using age-adjusted reference values. As expected, most children were younger than 48 months, and septic arthritis was the predominant clinical presentation. Classical acute-phase reactants (WBC, CRP, and ESR) were frequently normal or only mildly elevated. Likewise, most IIBs remained within or near reference ranges; the platelet-to-lymphocyte ratio was the most commonly abnormal marker, exceeding the threshold in only 59.3% of patients. These results indicate that, like conventional inflammatory markers, CBC-derived IIBs have limited standalone screening utility for K. kingae OAIs. Further studies are needed to determine whether systemic IIBs can help distinguish OAIs caused by K. kingae from those caused by pyogenic bacteria.

Osteoarticular infections (OAIs) present a significant diagnostic and therapeutic challenge to paediatric clinical practice. When evaluating suspected paediatric OAIs, the principal pathogens commonly considered are Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Kingella kingae. However, advances in molecular diagnostic techniques, particularly polymerase chain reaction assays and next-generation sequencing, have considerably improved the detection of less commonly identified pathogens responsible for OAIs. Consequently, familiarity with fastidious, emerging, exposure-related and uncommon bacterial pathogens is essential to ensure accurate diagnoses and appropriate therapeutic interventions. This review summarises bacterial pathogens responsible for OAIs in immunocompetent children that are fastidious, emerging, exposure-related or otherwise less commonly encountered. We describe their microbiological characteristics, clinical phenotypes, diagnostic pitfalls and organism-specific diagnostic strategies.

Osteoarticular infections (OAIs) present a significant diagnostic and therapeutic challenge to paediatric clinical practice. When evaluating suspected paediatric OAIs, the principal pathogens commonly considered are Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Kingella kingae . Osteoarticular infections (OAIs) present a significant diagnostic and therapeutic challenge to paediatric clinical practice. When evaluating suspected paediatric OAIs, the principal pathogens commonly considered are Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Kingella kingae. Consequently, comprehensive knowledge about these emerging, atypical bacterial pathogens is essential to ensure accurate diagnoses and appropriate therapeutic interventions. This review summarises uncommon, fastidious, and emerging bacterial pathogens responsible for OAIs in immunocompetent children . We describe their microbiological characteristics and clinical phenotypes and examine potential diagnostic pitfalls and organism-specific diagnostic strategies.

Background/Objectives: Wrist fractures are common paediatric injuries, yet some remain radiographically occult. The Pronator Quadratus Sign (PQS), defined by displacement or alteration of the fat stripe overlying the pronator quadratus muscle (PQm), remains a debated radiologic diagnostic marker. This study evaluated whether PQS can serve as a diagnostic adjunct for wrist fractures and whether specific PQS morphological types are associated with different fracture patterns. Methods: This retrospective study included paediatric patients presenting with wrist trauma. Radiographs were categorized into three groups: no fracture, torus fracture, and other non-displaced distal radius fractures. PQS morphology was classified using a six-tier system. Quantitative assessment included measurement of the anterior distance from the distal radius to the external border of the pronator quadratus muscle (X) and radial width (R), expressed as the X/R ratio to standardize comparisons. Results: A total of 247 patients were included. The X/R ratio differed significantly among groups (p < 0.001), with higher values observed in patients with fractures. ROC analysis demonstrated good discrimination performance between no fracture and non-displaced distal radius fractures (AUC = 0.80), but limited performance for torus fractures (AUC = 0.62). Although PQS morphology alone was not a reliable indicator of fracture presence, the distribution of PQS types—representing distinct patterns of pronator quadratus fat stripe appearance and displacement—differed significantly across fracture groups (p < 0.001). Conclusions: Quantitative PQS assessment using the X/R ratio is associated with improved discrimination for non-displaced distal radius fractures, while PQS morphology alone shows limited diagnostic utility. Further prospective studies incorporating magnetic resonance imaging are warranted to clarify its role in occult fracture detection.

Background: This observational study systematically used magnetic resonance imaging (MRI) to determine the prevalence of concomitant osteomyelitis and its influence on clinical outcomes in cases of pediatric septic arthritis (SA) of the hip. Methods: We retrospectively analyzed the demographic, clinical, microbiological, and radiographic data of 58 children treated for SA of the hip who underwent systematic MRI between 2000 and 2025. Patients were categorized into 2 groups: isolated septic arthritis and septic arthritis with concomitant osteomyelitis. The clinical and laboratory parameters, causative pathogens, and treatments were compared between the groups. Results: Concomitant osteomyelitis was identified with MRI in 43% (25) of the 58 patients, while radiographs detected it in only 16%. Demographic, clinical, and inflammatory parameters were statistically similar between the groups. Kingella kingae was the most commonly identified pathogen (37.9%), and Staphylococcus aureus and Streptococcus spp. were more frequently associated with repeat surgery. No significant differences in complication rates, treatment duration, or outcomes were found between the groups. Conclusions: The systematic use of MRI revealed concomitant osteomyelitis in >40% of cases of pediatric SA. However, the presence of osteomyelitis was not associated with worse outcomes, suggesting that factors related to the microorganism profile or virulence must contribute substantially to disease severity. Nonetheless, MRI should be considered early in any diagnostic work-up of pediatric SA of the hip. Level of Evidence: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.