Usefulness of MRI findings in differentiating between septic arthritis and transient synovitis of hip joint in children: A systematic review and meta-analysis

Imaging evaluation of hip capsule disorders: a comprehensive review

The hip capsule and capsular ligaments play crucial roles in providing hip stability and mobility. Their role in hip pathologies is being increasingly recognized, underscoring the need for thorough imaging evaluation, which is better performed through MRI-arthrography. Various diseases affect the hip capsule directly or indirectly. Improper mechanical loading, as seen in conditions such as femoroacetabular impingement or chondrolabral pathology, can induce capsule thickening, whereas thinning and laxity of the capsule are characteristics of microinstability. Inflammatory conditions, including adhesive capsulitis of the hip, crystal deposition disease, polymyalgia rheumatica, and infections, also lead to capsular changes. Traumatic events, particularly posterior hip dislocations, cause capsule ligament disruption and may lead to hip macroinstability. Friction syndromes can lead to capsular edema due to impingement of the adjacent capsule. Hip arthroscopy can result in various postoperative findings ranging from fibrotic adhesions to focal or extensive capsule discontinuation. Although the significance of hip capsule thickness and morphology in the pathogenesis of hip diseases remains unclear, radiologists must recognize capsule alterations on imaging evaluation. These insights can aid clinicians in accurately diagnosing and effectively managing patients with hip conditions.

Native Joint Septic Arthritis

Native joint septic arthritis (NJSA) is a severe and rapidly progressing joint infection, predominantly bacterial but also potentially fungal or viral, characterized by synovial membrane inflammation and joint damage, necessitating urgent and multidisciplinary management to prevent permanent joint damage and systemic sepsis. Common in large joints like knees, hips, shoulders, and elbows, NJSA's incidence is elevated in individuals with conditions like rheumatoid arthritis, diabetes, immunosuppression, joint replacement history, or intravenous drug use. This review provides a comprehensive overview of NJSA, encompassing its diagnosis, treatment, antibiotic therapy duration, and surgical interventions, as well as the comparison between arthroscopic and open debridement approaches. Additionally, it explores the unique challenges of managing NJSA in patients who have undergone graft anterior cruciate ligament (ACL) reconstruction. The epidemiology, risk factors, pathogenesis, microbiology, clinical manifestations, diagnosis, differential diagnosis, antibiotic treatment, surgical intervention, prevention, and prophylaxis of NJSA are discussed, highlighting the need for prompt diagnosis, aggressive treatment, and ongoing research to enhance patient outcomes.

Application of AI-assisted MRI for the identification of surgical target areas in pediatric hip and periarticular infections

OBJECTIVE

To develop an AI-assisted MRI model to identify surgical target areas in pediatric hip and periarticular infections.

METHODS

A retrospective study was conducted on the pediatric patients with hip and periarticular infections who underwent Magnetic Resonance Imaging(MRI)examinations from January 2010 to January 2023 in three hospitals in China. A total of 7970 axial Short Tau Inversion Recovery (STIR) images were selected, and the corresponding regions of osteomyelitis (label 1) and abscess (label 2) were labeled using the Labelme software. The images were randomly divided into training group, validation group, and test group at a ratio of 7:2:1. A Mask R-CNN model was constructed and optimized, and the performance of identifying label 1 and label 2 was evaluated using receiver operating characteristic (ROC) curves. Calculation of the average time it took for the model and specialists to process an image in the test group. Comparison of the accuracy of the model in the interpretation of MRI images with four orthopaedic surgeons, with statistical significance set at P < 0.05.

RESULTS

A total of 275 patients were enrolled, comprising 197 males and 78 females, with an average age of 7.10 ± 3.59 years, ranging from 0.00 to 14.00 years. The area under curve (AUC), accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 1 were 0.810, 0.976, 0.995, 0.969, 0.922, and 0.957, respectively. The AUC, accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 2 were 0.890, 0.957, 0.969, 0.915, 0.976, and 0.972, respectively. The model demonstrated a significant speed advantage, taking only 0.2 s to process an image compared to average 10 s required by the specialists. The model identified osteomyelitis with an accuracy of 0.976 and abscess with an accuracy of 0.957, both statistically better than the four orthopaedic surgeons, P < 0.05.

CONCLUSION

The Mask R-CNN model is reliable for identifying surgical target areas in pediatric hip and periarticular infections, offering a more convenient and rapid option. It can assist unexperienced physicians in pre-treatment assessments, reducing the risk of missed and misdiagnosis.

Septic arthritis in the pediatric hip joint: a systematic review of diagnosis, management, and outcomes

Septic arthritis of the pediatric hip joint (SAH) is a rare but serious orthopedic emergency requiring immediate diagnosis and management. Delayed recognition can lead to severe complications, emphasizing the need for timely intervention. This systematic review aims to provide a comprehensive analysis of SAH in the pediatric population, focusing on its diagnosis, management, and outcomes. The review included 11 studies involving 391 patients with SAH, aged between three months and 12 years. Staphylococcus aureus was identified as the most common causative pathogen, with increasing cases of methicillin-resistant strains. Diagnosis is challenging due to nonspecific clinical presentations, necessitating validated criteria and a multidisciplinary approach. Ultrasound emerged as a valuable tool for early detection, and MRI was used in challenging cases. Treatment options include hip aspiration, arthrotomy, and arthroscopy, often combined with appropriate antibiotic therapy. Success rates were comparable among different surgical procedures. Early intervention is vital for optimal outcomes. However, the review highlights the need for standardized protocols and further prospective studies to address limitations and improve understanding and management of SAH in the pediatric hip joint.

[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.