Infection: musculoskeletal

Subsequent Complications of Pediatric Patients With Osteomyelitis and Accompanying Subperiosteal Abscess

BACKGROUND

Subperiosteal abscesses (SAs) are a complication of osteomyelitis that requires surgical intervention. This study aimed to characterize the occurrence of subsequent complications in pediatric patients with osteomyelitis and accompanying SA.

METHODS

Fourteen pediatric patients with SAs were included. We recorded clinical information, including age at diagnosis, interval (days) between the onset of symptoms and diagnosis, location of SAs (long/flat bone), pathogens [methicillin-resistant Staphylococcus aureus (MRSA)/non-MRSA], treatment period (days) and any subsequent complications. Patients were classified based on SAs with or without complications. Mann-Whitney U and Fisher exact tests were used for statistical analyses, and data are expressed as median and interquartile range.

RESULTS

Six patients (42.9%) had subsequent complications. There were significant differences in location of SAs between these two groups (long/flat bone, with versus without complication = 6/0 versus 3/5; P = 0.031). No significant differences were observed between the groups in terms of age [with versus without complication = 13.8 (9.7-24.5) versus 556.3 (5.0-107.8) months; P = 0.491], the interval (days) between symptoms onset and diagnosis [with versus without complications = 5 (1-10) versus 5 (3-6.5) days; P = 0.950], pathogenesis (MRSA/non-MRSA, with versus without complication = 4/2 versus 2/6; P = 0.277) and treatment period [with versus without complication = 50.5 (31-57) versus 29 (24.5-41.5) days; P = 0.108].

CONCLUSIONS

Pediatric patients with SAs in the long bones have a higher likelihood of experiencing subsequent complications than those with SAs in flat bones. Physicians should carefully manage this vulnerable patient group.

The correlation between serum calcium levels and prognosis in patients with severe acute osteomyelitis

Objective

To explore the relationship between serum calcium levels and the prognosis of severe acute osteomyelitis, and to assess the effectiveness of calcium levels in prognostic evaluation.

Methods

Relevant patient records of individuals diagnosed with severe acute osteomyelitis were obtained for this retrospective study from the Medical Information Mart for Intensive Care (MIMIC-IV). The study aimed to assess the impact of different indicators on prognosis by utilizing COX regression analysis. To enhance prognostic prediction for critically ill patients, a nomogram was developed. The discriminatory capacity of the nomogram was evaluated using the Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve, in addition to the calibration curve.

Result

The study analyzed a total of 1,133 cases of severe acute osteomyelitis, divided into the survivor group (1,025 cases) and the non-survivor group (108 cases). Significant differences were observed between the two groups in terms of age, hypertension, sepsis, renal injury, and various laboratory indicators, including WBC, PLT, Ca2+, CRP, hemoglobin, albumin, and creatinine (P<0.05). However, no significant differences were found in race, gender, marital status, detection of wound microbiota, blood sugar, lactate, and ALP levels. A multivariate COX proportional hazards model was constructed using age, hypertension, sepsis, Ca2+, creatinine, albumin, and hemoglobin as variables. The results revealed that hypertension and sepsis had a significant impact on survival time (HR=0.514, 95% CI 0.339-0.779, P=0.002; HR=1.696, 95% CI 1.056-2.723, P=0.029). Age, hemoglobin, Ca2+, albumin, and creatinine also showed significant effects on survival time (P<0.05). However, no statistically significant impact on survival time was observed for the other variables (P>0.05). To predict the survival time, a nomogram was developed using the aforementioned indicators and achieved an AUC of 0.841. The accuracy of the nomogram was further confirmed by the ROC curve and calibration curve.

Conclusion

According to the findings, this study establishes that a reduction in serum calcium levels serves as a distinct and standalone predictor of mortality among individuals diagnosed with severe acute osteomyelitis during their stay in the Intensive Care Unit (ICU) within a span of two years.

Neoplastic and Non-neoplastic Bone Lesions of the Knee

Numerous anatomical variants are described around the knee, many of which look like bony lesions, so it is important to know them to avoid unnecessary complementary tests and inadequate management. Likewise, several alterations in relation to normal development can also simulate bone lesions.However, numerous pathologic processes frequently affect the knee, including traumatic, inflammatory, infectious, and tumor pathology. Many of these entities show typical radiologic features that facilitate their diagnosis. In other cases, a correct differential diagnosis is necessary for proper clinical management.Despite the availability of increasingly advanced imaging techniques, plain radiography is still the technique of choice in the initial study of many of these pathologies. This article reviews the radiologic characteristics of tumor and nontumor lesions that may appear around the knee to make a correct diagnosis and avoid unnecessary complementary radiologic examinations and inadequate clinical management.

[Imaging Findings in Pediatric Musculoskeletal Infection and Inflammation]

Infections and inflammatory conditions of immature musculoskeletal systems in pediatric patients also affect the adjacent muscles, connective tissues, and joints. Rapid diagnosis leading to appropriate treatment can significantly impact the occurrence of complications and mortality rates due to these conditions. When a radiologist becomes familiar with the imaging findings of pediatric musculoskeletal infections and inflammatory diseases, rapid differential diagnoses and more timely and appropirate treatment could be possible. In this paper, we introduce the imaging findings of infectious and inflammatory diseases affecting the immature musculoskeletal system, such as osteomyelitis, pyogenic arthritis, juvenile idiopathic arthritis, and hemophilic arthritis, based on the anatomical and pathophysiological characteristics of the immature musculoskeletal system in children.

Current updates in MSK infection imaging: A narrative review

This article presents a comprehensive overview of the diagnostic utility of existing imaging techniques including radiography, computed tomography, ultrasonography, magnetic resonance imaging (MRI), and radionuclide imaging in the context of the most common orthopaedic or musculoskeletal infections. It also includes illustrative images showcasing significant findings in various musculoskeletal infections including osteomyelitis, cellulitis, septic arthritis, necrotising infections and peri-prosthetic joint infections and their associated complications.

Bacterial osteomyelitis in pediatric patients: a comprehensive review

Bacterial osteomyelitis, an inflammatory response in the bone caused by microorganisms, typically affects the metaphysis in the skeletally immature. Bacterial osteomyelitis possesses a significant diagnostic challenge in pediatric patients due to its nonspecific clinical presentation. Because the metaphysis is the primary focus of infection in skeletally immature patients, understanding the normal physiologic, maturation process of bones throughout childhood allows to understand the pathophysiology of osteomyelitis. Timely and accurate diagnosis is crucial to initiate appropriate treatment, and prevent long-term sequelae and efforts must be made to isolate the causative organism. The potential causative organism changes according to the age of the patient and underlying medical conditions. Staphylococcus Aureus is the most common isolated bacteria in pediatric pyogenic osteomyelitis whereas Kingella Kingae is the most common causative agent in children aged 6 months to 4 years. Imaging plays a pivotal role in the diagnosis, characterization, evaluation of complications, and follow up of bacterial osteomyelitis. Imaging also plays a pivotal role in the evaluation of potential neoplastic and non-neoplastic mimickers of osteomyelitis. In children, MRI is currently the gold standard imaging modality when suspecting bacterial osteomyelitis, whereas surgical intervention may be required in order to isolate the microorganism, treat complications, and exclude mimickers.

Imaging of MSK infections in the ER

Musculoskeletal infections in the ER are not an uncommon presentation. The clinical context is critical in determining the suspicion for infection and degree of tissue involvement which can involve all layers from the skin to bones. The location, extent, and severity of clinically suspected infection directly relate to the type of imaging performed. Uncomplicated cellulitis typically does not require any imaging. Localized and superficial infections can mostly be evaluated with ultrasound. If there is a diffuse site (an entire extremity) or suspected deeper involvement (muscle/deep fascia), then CT is accurate in diagnosing, widely available, and performed quickly. With potential osseous involvement, MRI is the gold standard for diagnosing acute osteomyelitis; however, it has the drawbacks of longer scan times, artifacts including patient motion, and limited availability.

Imaging of the post-operative hallux valgus: what do radiologists need to know?

Hallux valgus surgery concerns many patients and various techniques are performed. The assessment of the first toe deformity correction is mainly visual and imaging is required to analyze the intermetatarsal angle and depict complications. However, it is often difficult for the radiologist to distinguish normal and pathological conditions, especially in case of osteotomies which may show various aspects of bone mineralization and healing. In this review, the most relevant imaging features of the post-operative hallux valgus are summarized.

Predictive Value of Radiographic and Magnetic Resonance Imaging Characteristics on Patient Outcomes in Confirmed Acute Osteomyelitis of the Extremities

OBJECTIVE

The aim of this study was to determine whether imaging characteristics on plain radiography, magnetic resonance imaging (MRI), and diffusion-weighted imaging are predictive of patient outcomes in cases of confirmed osteomyelitis (OM).

MATERIALS AND METHODS

In this cross-sectional study, 3 experienced musculoskeletal radiologists evaluated pathologically proven cases of acute extremity OM and recorded imaging characteristics on plain radiographs, MRI, and diffusion-weighted imaging. These characteristics were then compared with the patient outcomes after a 3-year follow-up using length of stay, amputation-free survival, readmission-free survival, and overall survival using multivariate Cox regression analysis. Hazard ratio and corresponding 95% confidence intervals are reported. False discovery rate-adjusted P values were reported.

RESULTS

For the 75 consecutive cases of OM in this study, multivariate Cox regression analysis adjusting for sex, race, age, body mass index, erythrocyte sedimentation rate, C-reactive protein, and white blood cell count showed no correlation among any of the recorded characteristics on imaging and patient outcomes. Despite the high sensitivity and specificity of MRI for diagnosing OM, there was no correlation between MRI characteristics and patient outcomes. Furthermore, patients with coexistent abscess of the soft tissue or bone with OM had comparable outcomes using the previously mentioned metrics of length of stay, amputation-free survival, readmission-free survival, and overall survival.

CONCLUSION

Neither radiography nor MRI features predict patient outcomes in extremity OM.

Micro-CT analysis of osteomyelitis of rabbit tibial for model establishment and biomaterials application in tissue engineering

Osteomyelitis is one of the most difficult diseases to treat in orthopedics field. The construction of animal models of osteomyelitis is now more mature but still lacks a deeper criterion other than "successful infection". In this work, rabbit tibial osteomyelitis model with S. aureus infection was established. Whole tibia, cortical bone around bone window, and tibial condyle were characterized in considerable detail using micro-CT and other means at 2/4/6 weeks, respectively. The results show that in addition to the obvious inflammatory response and bone destruction, osteomyelitis caused some other effects on compact and cancellous bone, and in particular, changes in bone mineral density after infection were of interest. Although the modeling groups all exhibited osteolysis and bone loss, their overall bone mineral density averages and those of the control groups were mostly in the range of 870 mg/cm³ to 920 mg/cm³, without statistical difference. The results suggest that overall bone mineral density is determined by both bone destruction conditions and the amount of dead bone deposition. This work provides a reference basis for the selection of time points for the subsequent animal models establishment and some valuable reference indicators of the application of biomaterials in tissue engineering.

Imaging Review of Normal and Abnormal Skeletal Maturation

The growing skeleton undergoes well-described and predictable normal developmental changes, which may be misinterpreted a as pathologic condition at imaging. Primary and secondary ossification centers (SOCs), which form the diaphysis and the epiphysis of long bones, respectively, are formed by endochondral and intramembranous ossification processes. During skeletal maturation, the SOCs may appear irregular and fragmented, which should not be confused with fractures, osteochondritis dissecans, and osteochondrosis. These normal irregularities are generally symmetric with a smooth, round, and sclerotic appearance, which are aspects that help in the differentiation. The metaphysis, epiphysis, and growth plates or physes are common sites of injuries and normal variants in the pediatric skeleton. The metaphysis contains the newly formed bone from endochondral ossification and is highly vascularized. It is predisposed to easy spread of infections and bone tumors. The physis is the weakest structure of the immature skeleton. Injuries to this location may disrupt endochondral ossification and lead to growth disturbances. Pathologic conditions of the epiphyses may extend into the articular surface and lead to articular damage. At MRI, small and localized foci of bone marrow changes within the epiphysis and metaphysis are also a common finding. These can be related to residual red marrow (especially in the metaphysis of long bones and hindfoot), focal periphyseal edema (associated with the process of physeal closure), and ultimately to a normal ossification process. The authors review the imaging appearance of normal skeletal maturation and discuss common maturation disorders on the basis of developmental stage and location. ^©RSNA, 2022.

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.

Chronic Osteomyelitis of Long Bones: Imaging Pearls and Pitfalls in Pediatrics

Chronic bacterial osteomyelitis is characterized by progressive inflammatory bone destruction and apposition of new bone most often caused by pyogenic bacteria. Clinical findings are nonspecific, and serum inflammatory markers can be normal. Prompt diagnosis and treatment are essential. Left untreated, chronic infection can lead to high morbidity and mortality. Imaging's major role is to suggest the correct diagnosis, exclude other diagnoses that can mimic osteomyelitis, document extent of disease, and guide interventions such as image-guided biopsy or surgical debridement. Several conditions can mimic chronic osteomyelitis clinically and radiographically. The main differential diagnoses include an oncologic process, chronic nonbacterial or chronic recurrent multifocal osteomyelitis, bone infarct in sickle cell disease, osteoid osteoma, and stress reaction/fracture. The oncologic process to consider includes metastatic neuroblastoma and Langerhans cell histiocytosis in a child younger than five years or leukemia, Ewing sarcoma, and osteosarcoma in the older age group. However, these lesions can typically be excluded based on radiographs and magnetic resonance imaging findings. Therefore, radiologist familiarity with imaging findings and mimickers is essential. In this article, we briefly review the epidemiologic, clinical, and histopathologic features of chronic bacterial osteomyelitis and emphasize imaging pearls and pitfalls, with discussion of the most common differential diagnoses.

Magnetic resonance imaging texture analysis in the quantitative evaluation of acute osteomyelitis of the mandibular bone

OBJECTIVES

Accurate assessment of radiological images can help in early diagnosis and therapy of suppurative osteomyelitis (OM). The purpose of this study was to apply texture analysis to MRI as a means of quantitatively evaluating acute OM of the mandible.

METHODS

We analyzed the data from 38 patients who complained of pain and underwent MRI between April 2017 and March 2019. From the MRIs of these patients, with (n = 19) and without OM (n = 19), 279 radiomics features were extracted using short tau inversion recovery, data of the regions of interest and analyzed with MaZda v. 3.3. 10 features, including one histogram feature (90th percentile), eight gray-level co-occurrence matrix features (Sum Averg), and one gray-level run-length matrix feature (Horzl_RLNonUni), were selected using Fisher coefficient and compared between the acute OM and non-OM groups. The two groups were compared using Mann-Whitney U test with p value set at 0.05.

RESULTS

All 10 radiomics features showed significant differences between the acute OM and non-OM groups (p < 0.05).

CONCLUSIONS

MRI texture analysis has potential application in radiomics diagnosis of acute OM of the mandible.

PET/MRI in paediatric disease

Nuclear medicine and molecular imaging have a small but growing role in the management of paediatric and neonatal diseases. During the past decade, combined PET/MRI has emerged as a clinically important hybrid imaging modality in paediatric medicine due to diagnostic advantages and reduced radiation exposure compared to alternative techniques. The applications for nuclear medicine, radiopharmaceuticals and combined PET/MRI in paediatric diagnosis is broadly similar to adults, however there are some key differences. There are a variety of clinical applications for PET/MRI imaging in children including, but not limited to, oncology, neurology, cardiovascular, infection and chronic inflammatory diseases, and in renal-urological disorders. In this article, we review the applications of PET/MRI in paediatric and neonatal imaging, its current role, advantages and disadvantages over other hybrid imaging techniques such as PET/CT, and its future applications. Overall, PET/MRI is a powerful imaging technology in diagnostic medicine and paediatric diseases. Higher soft tissue contrasts and lower radiation dose of the MRI makes it the superior technology compared to other conventional techniques such as PET/CT or scintigraphy. However, this relatively new hybrid imaging has also some limitations. MRI based attenuation correction remains a challenge and although methodologies have improved significantly in the last decades, most remain under development.

Acute Pyogenic Osteomyelitis of the Pubic Bone in a Patient with Systemic Lupus Erythematosus Mimicking Fracture of the Pubic Bone and Periprosthetic Joint Infection of the Hip

Introduction

Pubic bone osteomyelitis is atypical, and the diagnosis is often overlooked. It may present as osteitis pubis, fracture, or noninfectious inflammation of the pubic symphysis. Case Report. We report a case of a 65-year-old lady who has systemic lupus erythematosus with acute pyogenic osteomyelitis of the pubic bone who presented initially with a suspicious healing pubic rami fracture and periprosthetic infection of the hip joint.

Conclusion

Acute osteomyelitis of the pubic bone has often an infrequent and delayed presentation. Clinical awareness, early diagnosis, and appropriate treatment including surgical debridement and long-term antibiotics can prevent ongoing morbidities such as chronic osteomyelitis, pain, and deformities of pelvic bone and joints.

Staphylococcus aureus clones causing osteomyelitis: a literature review (2000-2020)

OBJECTIVES

Staphylococcus aureus is the most common causative organism of osteomyelitis (OM). Nevertheless, the molecular epidemiology of S. aureus causing OM remains ill-defined. This study aimed to address the global epidemiology of S. aureus clones from OM patients.

METHODS

Literature databases were searched for studies reporting the molecular typing of S. aureus involved in OM published between 1 January 2000 and 29 July 2020. Data from 32 articles that fulfilled the inclusion criteria were analysed for year of publication, country of patients, methicillin susceptibility and genotypic characteristics of S. aureus isolates.

RESULTS

Pandemic clones CC5, CC8, CC22, CC30 and CC45 were the most common in OM. The distribution of clones differed greatly among studies owing to the local epidemiology of S. aureus and the MSSA heterogeneity. PVL-positive MRSA clones belonging to ST80/CC80 and ST8/CC8/USA300 were the most common among paediatric patients in Europe and the USA; greater variability was observed in the adult population. In Europe, MRSA belonged to PVL-negative CC5, CC8 and CC22 indicating a nosocomial origin of infections; in Asia PVL-positive ST59/CC59 MRSA was the most frequent. PVL-positive clones were often detected in haematogenous OM in children and adults. Although MSSA were polyclonal, PVL-negative ST398/CC398 MSSA was the most prevalent clone in diabetic foot OM.

CONCLUSION

All major S. aureus clones circulating both in hospital and community settings appear to be capable of causing OM. Future studies reporting molecular typing and genomic data will provide more insights into the epidemiology and pathobiology of S. aureus clones causing OM.

A Rare Presentation of Brodie Abscess in the Clavicle

A 12-year-old otherwise healthy boy presented with acute shoulder pain and remote history of trauma. Despite an unimpressive clinical examination, laboratory workup, and initial radiographic evaluation, the patient was ultimately diagnosed with a Brodie abscess of the distal clavicle. Complete resolution was achieved with débridement and tailored antibiotic therapy. These abscesses are rare, often presenting surreptitiously with nonspecific symptoms and without systemic signs of infection. Therefore, maintaining a broad differential and high clinical suspicion is crucial to mitigate the increased morbidity that can result from a delayed diagnosis.

Osseous Pathology on Wrist Magnetic Resonance Imaging

Advanced imaging of the osseous structures of the wrist by magnetic resonance imaging (MRI) yields powerful information regarding marrow composition and overall bone structure. Various forms of pathology, both benign and malignant, have unique marrow signal abnormalities that can be easily detected by MRI given its high sensitivity to radiographically occult processes. In particular, osseous pathology can be seen in the setting of traumatic, degenerative, congenital, infectious, and neoplastic conditions. The acuity or chronicity of these conditions can often be determined by imaging to aid in appropriate therapy. A thorough understanding of the breadth of pathology and corresponding MRI appearances can allow the interpreting radiologist to formulate a concise and accurate assessment of an examination.

Radiological evaluation of postoperative osteomyelitis in long bones: Which is the best tool?

Currently, definitive diagnosis of osteomyelitis involves a combination of clinical signs, symptoms, laboratory tests, imaging modalities and cultures from blood, joint or body fluid. Imaging plays a critical role in the osteomyelitis diagnosis. Each of these tests incurs an additional cost to the patient or healthcare system and their use varies according to the preference of the healthcare professional and the healthcare setup. Imaging plays a critical role in the diagnosis and management of postoperative long bone osteomyelitis, with the aim of reducing long-term complications such as non-union, amputation and pathological fractures. In this review, we discuss the key findings on different radiological modalities and correlate them with disease pathophysiology. Currently, magnetic resonance imaging is the best available imaging modality due to its sensitivity in detecting early signs of long bone osteomyelitis and high soft tissue resolution. Other modalities such as radio-nuclear medicine, computed tomography and ultrasound have been proved to be useful in different clinical scenarios as described in this narrative review.

[Pediatric bone marrow alterations]

The age-dependent development of the bone marrow follows a constant pattern and has an impact on the localization and morphology of various bone marrow processes. Physiological, reactive and benign bone marrow alterations must be differentiated from inflammatory or malignant infiltrations. In many cases, a specific age distribution pattern and typical morphological characteristics in magnetic resonance imaging (MRI) enable a diagnostic classification. The only adequate imaging modality that can provide information about the bone marrow composition is MRI.

Acute hematogenous osteomyelitis in pediatric patients: epidemiology and risk factors of a poor outcome

Objective

Methods

Results

Conclusions

Acute hematogenous pelvic osteomyelitis: appropriate timing for magnetic resonance imaging

BACKGROUND

The precise time of appearance of bone marrow edema in acute hematogenous pelvic osteomyelitis (AHPO) is unknown. The purpose of the present research is to clarify the time of appearance of bone marrow edema on magnetic resonance imaging (MRI) in AHPO. Our hypothesis was that onset is slower than in long-bone osteomyelitis.

METHODS

We selected 12 patients (mean, 11.8 years) with MRI findings and clinical diagnosis of AHPO. The signal ratios of bone marrow (BM) and gluteus maximus muscle (M, BM/M ratio) in fat-suppressed T2- and T1-weighted images (T2WI, T1WI) were calculated to evaluate changes in bone-marrow signals. The correlation between BM/M ratios and days from onset was evaluated statistically and compared with lower extremity osteomyelitis.

RESULTS

Bone marrow/M ratio of T2WI increased over time after the onset of the primary symptom in all patients and showed a statistically positive correlation (r = 0.36). In seven patients in whom an MRI scan was conducted twice, all showed higher values for the second MRI, and changes were more pronounced over time. The mean BM/M ratio of T2WI was 4.1 when 7 days or less had elapsed from the primary symptom, and 6.4 when more than 7 days had elapsed. The BM/M ratios in the sacroiliac joint group were lower than in the non-sacroiliac joint group.

CONCLUSIONS

Unlike long-bone osteomyelitis, it took 1 week before findings for AHPO became fully evident. A definitive diagnosis can be made in patients with suspected sacroiliitis by performing a further MRI scan at 7 days or later.

Use of Magnetic Resonance Imaging for Orthopedic Trauma and Infection in the Emergency Department

Conditions affecting the musculoskeletal system constitute a significant portion of medical emergencies in the United States, with traumatic injury and infection being two of the most common etiologies. Although physical examination and plain radiographs are often sufficient to guide diagnosis and treatment, there are myriad traumatic and infectious pathologies that are commonly missed or simply not detectable on plain radiographs. Advanced imaging is subsequently warranted for additional workup.Magnetic resonance imaging (MRI) has become an increasingly used imaging modality for musculoskeletal complaints in the emergency department due to its superior visualization of soft tissues, focal edematous changes, and occult osseous insults often not visible on plain radiographs. Although multiple studies have evaluated its utility in the workup of emergency musculoskeletal complaints, there remains a dearth of literature examining the use of MRI for certain occult diagnoses.Radiologists, emergency clinicians, and orthopedic surgeons must be knowledgeable of the indications for MRI in the emergency setting, as delayed diagnosis may contribute to increased morbidity and possibly mortality. This review summarizes the use of MRI in diagnoses relating to trauma or infection among patients presenting to the emergency department with a musculoskeletal complaint.

Revisiting the important role of magnetic resonance imaging (MRI) in long bone acute osteomyelitis: A case report of methicillin resistant Staphylococcus aureus acute tibial osteomyelitis with conventional radiography, computed tomography, and MRI

The tibia is an atypical site of osteomyelitis (OM) in adults, and patients with this infection experience a significant degree of morbidity as well as the need for prolonged aggressive antibiotic therapy. The early diagnosis of OM remains challenging, and often relies on imaging modalities which are of variable sensitivity. We present a case of a 49-year-old male with a methicillin resistant Staphylococcus aureus (MRSa) left tibial OM, contiguous left knee septic arthritis, and concurrent bacteraemia. Eight days after the onset of pain in the left knee and lower limb, conventional radiography and computed tomography (CT) imaging had only subtleties of a soft tissue collection and a knee effusion. A MRI demonstrated significant involvement of his tibial bone with a collection, from which surgical specimens confirmed MRSa. This case demonstrates the difficulty of diagnosing early acute OM with conventional radiography and CT imaging, even after a week of symptoms in the affected limb. Given the poor sensitivity of conventional radiography and CT in the diagnosis of early acute OM, this case report illustrates how MRI is the imaging modality of choice in this setting.

Characteristics and outcomes of osteomyelitis in children with sickle cell disease: A 10-year single-center experience

BACKGROUND

Patients with sickle cell disease (SCD) are at increased risk for osteomyelitis (OM). Diagnosis of OM in SCD is challenging as the clinical presentation is similar to a vasoocclusive crisis (VOC) with no diagnostic gold standard. We report characteristics and outcomes of OM in SCD patients treated at our center over 10-year period.

DESIGN/METHOD

We conducted a retrospective analysis of patients with SCD who were treated for OM at our center over a 10-year period (2006-2016). Cases were identified utilizing radiology data mining software. Radiology reports and medical charts of potential OM cases were reviewed.

RESULTS

Twenty-eight children with SCD were treated for OM at our institution. Patients treated for OM were largely similar to patients treated for a VOC. However, patients treated for OM had significantly higher C-reactive protein (10 mg/dL vs 5.58 mg/dL, P = 0.03) and erythrocyte sedimentation rate (60 mm/h vs 47 mm/h, P = 0.02). Magnetic resonance imaging (MRI) findings were consistent with OM in 18 (64%) patients and indeterminate in the remaining. Based on clinical, laboratory, and radiological findings, the diagnosis of OM was considered confirmed in 3 patients, probable in 6 patients, and presumed in 19 patients. Nontyphoidal Salmonella was isolated from cultures in 9 (32%) patients, while no organism was identified in 19 (67%) patients. All patients were treated with antibiotics. Six patients (21%) required surgical interventions.

CONCLUSIONS

OM continues to pose diagnostic challenges. Most patients are treated for OM without definitive confirmation. Nontyphoidal Salmonella was the only organism identified in our cohort.

Bone Pathology for Hematopathologists

Bone pathology can be challenging because the skeleton is a living tissue prone to developing a diverse array of inflammatory, metabolic, genetic, reactive, circulatory, and neoplastic abnormalities. Several areas of bone pathology are particularly difficult or problematic for hematopathologists given the close resemblance of some hematologic entities to primary/metastatic bone lesions; examples include plasmacytic disorders versus osteoblastic tumors and lymphoma/leukemia versus round cell tumors of bone. This article provides a conceptual and practical overview of selective bone disorders commonly encountered in the differential diagnosis of hematologic diseases.

Osteomyelitis of a sacral neurocentral synchondrosis: a case report of another metaphyseal equivalent

Pelvic osteomyelitis may occur in a metaphyseal equivalent, defined as a portion of flat or irregular bone that is adjacent to cartilage. The pelvic bone is known to have several metaphyseal equivalents and of these, the sacroiliac joint is the most frequent site of involvement. However, a sacral neurocentral synchondrosis has not been recognized as a metaphyseal equivalent, and there have been no previous reports describing this as the site of origin of sacral osteomyelitis. We here report two cases of sacral osteomyelitis originating in a neurocentral synchondrosis, another metaphyseal equivalent. We, as pediatric radiologists, should recognize a sacral neurocentral synchondrosis as another metaphyseal equivalent, especially in infants and younger patients.

Acute hot foot: Charcot neuroarthropathy or osteomyelitis? Untangling a diagnostic web

A 55-year-old man with poorly controlled type 1 diabetes with microvascular and macrovascular complications presented with a 1-week history of painful erythematous swelling on the dorsum of the left foot with two areas of foot ulceration. Inflammatory markers were raised. MRI of the left foot revealed a soft tissue swelling on the dorsum of the left foot, marrow oedema and destruction of several small joints of the foot, indicating osteomyelitis and Charcot neuroarthropathy (CN). The soft tissue swelling on the dorsum of the left foot was debrided; per-operatively bone destruction of base of the fifth metatarsal was found. The patient received intravenous antibiotics for 6 weeks. The clinical features of CN including erythema, oedema and elevated temperature of the left foot settled with off-loading the foot in an air cast walker after 6 months. Our case highlights the need to recognise CN in an acutely inflamed foot of diabetic patients with neuropathy, even when other conditions like soft tissue infection and osteomyelitis can explain the clinical features.

Extended field of view magnetic resonance imaging for suspected osteomyelitis in very young children: is it useful?

BACKGROUND

Osteomyelitis is a challenging diagnosis for clinicians, particularly in very young children. At our institution, the magnetic resonance imaging (MRI) protocol in suspected osteomyelitis for children 5 years of age or younger includes a large field of imaging regardless of the clinical site of concern.

OBJECTIVE

To determine if extended field of view (FOV) MRI contributes important information in young children with suspected osteomyelitis.

MATERIALS AND METHODS

A retrospective study was performed including children 5 years of age or younger with suspected osteomyelitis from January 2011 to September 2015. All children underwent coronal fluid-sensitive MRI from neck to feet. Focused imaging was performed as necessary on abnormal sites depicted on survey imaging. Two radiologists reviewed the imaging findings, which were compared to the clinical outcome.

RESULTS

We studied 51 children with a mean age of 2.2 years (range: 21 days-5.5 years); 53% were boys. Osteomyelitis was depicted by MRI in 20 subjects (39.2%). Survey coronal fluid-sensitive imaging was accomplished by adding a single fluid-sensitive series in 1 child, 2 series in 31 children, 3 series in 16 children and 4 series in 3 children. Survey imaging added a median total time of 6:51 min to the examination (range: 2.29-20.54 min). Extended FOV imaging added important information in 11/51 subjects (21.6%), in 6 cases (11.8%) of infection and in 5 cases (9.8%) by suggesting alternative diagnoses.

CONCLUSION

The addition of extended FOV MRI in young children with suspected osteomyelitis added important clinical information in 21.6% of patients while only adding a median of 6:51 min to the examination. It is our experience that in children ≤5 years of age with suspected osteomyelitis, extended FOV imaging adds important information and may result in changes in management.

Detection of pediatric musculoskeletal pathology using the fluid-sensitive sequence

BACKGROUND

Musculoskeletal complaints are common among children, and magnetic resonance (MR) is increasingly used to supplement the clinical assessment. The validation of a short triage protocol could reduce the number of unnecessary contrast-enhanced MR studies that sometimes also require the need for sedation.

OBJECTIVE

To compare the diagnostic accuracy between fluid-sensitive sequence and contrast-enhanced MR study in the detection of musculoskeletal pathology in the pelvis and the appendicular skeleton in children older than 2 years.

MATERIALS AND METHODS

We performed a retrospective review between Feb. 1, 2016, and Oct. 31, 2016, and identified 99 studies from 96 patients (48 boys and 48 girls; mean age ± standard deviation, 11.1±4.6 years) without syndromic deformity, recent trauma, a history of infectious or inflammatory arthropathy, prior instrumentation or incomplete records. Two radiologists reviewed each study twice, at least 1 month apart, first using only the fluid-sensitive sequences (triage study) and later using the contrast-enhanced study. Readers rated the presence or absence of pathology independently and generated final impressions in consensus. We used Cohen's kappa (κ) and percentage agreement to compare agreement between readers and between studies, respectively.

RESULTS

Inter-reader agreement was overall higher for the contrast-enhanced studies (κ range = 0.91-1) than for the triage studies (κ range = 0.49-1). Percentage agreement between studies was high for the detection of pathology (97-100%) and for the impressions (93%). Clinical diagnoses were stress reaction or overuse in 31%, infection in 21%, space-occupying process in 17%, normal in 15%, inflammatory in 14%, and both inflammatory and overuse in 1%. The full study increased diagnostic confidence in five studies and accuracy in two but did not alter management.

CONCLUSION

The fluid-sensitive sequence had a near-perfect percentage of agreement with the contrast-enhanced study in the detection of musculoskeletal pathology and could possibly be used to screen children who need a contrast-enhanced MR study.

Sternoclavicular Joint Infection Presenting as Nonspecific Chest Pain

BACKGROUND

Sternoclavicular joint infection (SJI), to include septic arthritis (SA), is a rare cause of chest pain and is often found in patients with significant risk factors and sources for SA. Most acute care laboratory results lack significant sensitivity to rule out SA. Radiographic findings in common acute care imaging often does not reveal findings of SA and osteomyelitis in the acute phase of the infection.

CASE REPORT

We present a patient without significant risk factors for SA, who initially presented with 3 days of pain to the left chest, left neck and shoulder. He had fever and was treated with a short course of antibiotics for possible pneumonia. His symptoms recurred along with fever 36 days after the initial onset of symptoms and was then diagnosed radiographically with left-sided SJI. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case reinforces the need to maintain a broad differential diagnosis in the evaluation for chest pain and pursue advanced imaging, such as magnetic resonance imaging, when the pretest probability of SJI is high, especially in the acute phase of the infection.

Radionuclide Imaging of Infection and Inflammation in Children: a Review

With the exception of radiolabeled monoclonal antibodies, antibody fragments and radiolabeled peptides which have seen little application in the pediatric population, the nuclear medicine imaging procedures used in the evaluation of infection and inflammation are the same for both adults and children. These procedures include (1) either a two- or a three-phase bone scan using technetium-99m methylene diphosphonate; (2) Gallium 67-citrate; (3) in vitro radiolabeled white blood cell imaging (using ¹¹¹Indium-oxine or ^99mTechnetium hexamethyl-propylene-amine-oxime-labeled white blood cells); and (4) hybrid imaging with ¹⁸F-FDG. But children are not just small adults. Not only are the disease processes encountered in children different from those in adults, but there are developmental variants that can mimic, but should not be confused with, pathology. This article discusses some of the differences between adults and children with osteomyelitis, illustrates several of the common developmental variants that can mimic disease, and, finally, focuses on the increasing use of ¹⁸F-FDG PET/CT in the diagnosis and response monitoring of children with infectious and inflammatory processes. The value of and need for pediatric specific imaging protocols are reviewed.

Posttraumatic Reconstruction of the Foot and Ankle in the Face of Active Infection

Posttraumatic infection of the foot and ankle is a challenging issue for orthopedic surgeons. Making the diagnosis often requires combining laboratory and radiologic testing, patient examination, and history. Patient comorbidities should be identified and optimized whenever possible. Treatment must combine effective antibiotic therapy with thorough debridement of the infected zone. Reconstruction often requires a 2-staged approach using antibiotic spacers and temporary external fixation, with the goal of obtaining a functional, pain-free limb that is free of infection.

Radiologic Approach to Musculoskeletal Infections

Imaging is often used to establish a diagnosis of musculoskeletal infections and evaluate the full extent and severity of disease. Imaging should always start with radiographs, which provide an important anatomic overview. MRI is the test of choice in most musculoskeletal infections because of its superior soft tissue contrast resolution and high sensitivity for pathologic edema. However, MRI is not always possible. Alternative imaging modalities including ultrasound scan, computed tomography, and radionuclide imaging may be used. This article reviews the individual imaging modalities and discusses how specific musculoskeletal infections should be approached from an imaging perspective.

Multifocal bone and bone marrow lesions in children - MRI findings

Polyostotic bone and bone marrow lesions in children may be due to various disorders. Radiographically, lytic lesions may become apparent after loss of more than 50% of the bone mineral content. Scintigraphy requires osteoblastic activity and is not specific. MRI may significantly contribute to the correct diagnosis and management. Accurate interpretation of MRI examinations requires understanding of the normal conversion pattern of bone marrow in childhood and of the appearances of red marrow rests and hyperplasia. Differential diagnosis is wide: Malignancies include metastases, multifocal primary sarcomas and hematological diseases. Benign entities include benign tumors and tumor-like lesions, histiocytosis, infectious and inflammatory diseases, multiple stress fractures/reactions and bone infarcts/ischemia.

MRI of acute osteomyelitis in long bones of children: Pathophysiology study

INTRODUCTION

The classic pathophysiology of acute osteomyelitis in children described by Trueta has a metaphyseal infection as the starting point. This hypothesis was recently brought into question by Labbé's study, which suggested a periosteal origin. Thus, we wanted to study this disease's pathophysiology through early MRI examinations and to look for prognostic factors based on abnormal findings.

MATERIAL AND METHODS

This was a prospective, multicentre study that included cases of long bone osteomyelitis in children who underwent an MRI examination within 7days of the start of symptoms and within 24hours of the initiation of antibiotic therapy. We also collected clinical, laboratory and treatment-related data.

RESULTS

Twenty patients were included, including one with a bifocal condition. The lower limb was involved in most cases (19/21). Staphylococcus aureus was found most frequently. Metaphyseal involvement was present in all cases. No isolated periosteal involvement was found in any of the cases. No prognostic factors were identified based on the various abnormal findings on MRI.

CONCLUSION

Our study supports the metaphyseal origin of acute osteomyelitis in children.

LEVEL OF EVIDENCE

II.

The imaging of osteomyelitis

Osteomyelitis is an important cause of morbidity and mortality in children and adults. Imaging plays a crucial role in establishing a timely diagnosis and guiding early management, with the aim of reducing long-term complications. Recognition of the imaging features of osteomyelitis requires a good understanding of its pathogenesis. In this review, the key imaging findings in osteomyelitis are correlated with the underlying pathological processes. There is a particular emphasis on magnetic resonance imaging (MRI), which is the best available imaging modality owing to its high sensitivity for detecting early osteomyelitis, excellent anatomical detail and superior soft tissue resolution. However, other modalities such as nuclear medicine and computed tomography (CT) are also useful in many clinical contexts, and will also be described in this review.

Staphylococcus aureus-Associated Musculoskeletal Infections

Musculoskeletal infections caused by Staphylococcus aureus are among the most difficult-to-treat infections. S. aureus osteomyelitis is associated with a tremendous disease burden through potential for long-term relapses and functional deficits. Although considerable advances have been achieved in diagnosis and treatment of osteomyelitis, the management remains challenging and impact on quality of life is still enormous. S. aureus acute arthritis is relatively seldom in general population, but the incidence is considerably higher in patients with predisposing conditions, particularly those with rheumatoid arthritis. Rapidly destructive course with high mortality and disability rates makes urgent diagnosis and treatment of acute arthritis essential. S. aureus pyomyositis is a common disease in tropical countries, but it is very seldom in temperate regions. Nevertheless, the cases have been increasingly reported also in non-tropical countries, and the physicians should be able to timely recognize this uncommon condition and initiate appropriate treatment. The optimal management of S. aureus-associated musculoskeletal infections requires a strong interdisciplinary collaboration between all involved specialists.

Utility of unenhanced fat-suppressed T1-weighted MRI in children with sickle cell disease -- can it differentiate bone infarcts from acute osteomyelitis?

BACKGROUND

Children with sickle cell disease (SCD) are at risk of bone infarcts and acute osteomyelitis. The clinical differentiation between a bone infarct and acute osteomyelitis is a diagnostic challenge. Unenhanced T1-W fat-saturated MR images have been proposed as a potential tool to differentiate bone infarcts from osteomyelitis.

OBJECTIVE

To evaluate the reliability of unenhanced T1-W fat-saturated MRI for differentiation between bone infarcts and acute osteomyelitis in children with SCD.

MATERIALS AND METHODS

We retrospectively reviewed the records of 31 children (20 boys, 11 girls; mean age 10.6 years, range 1.1-17.9 years) with SCD and acute bone pain who underwent MR imaging including unenhanced T1-W fat-saturated images from 2005 to 2010. Complete clinical charts were reviewed by a pediatric hematologist with training in infectious diseases to determine a clinical standard to define the presence or absence of osteomyelitis. A pediatric radiologist reviewed all MR imaging and was blinded to clinical information. Based on the signal intensity in T1-W fat-saturated images, the children were further classified as positive for osteomyelitis (low bone marrow signal intensity) or positive for bone infarct (high bone marrow signal intensity).

RESULTS

Based on the clinical standard, 5 children were classified as positive for osteomyelitis and 26 children as positive for bone infarct (negative for osteomyelitis). The bone marrow signal intensity on T1-W fat-saturated imaging was not significant for the differentiation between bone infarct and osteomyelitis (P = 0.56). None of the additional evaluated imaging parameters on unenhanced MRI proved reliable in differentiating these diagnoses.

CONCLUSION

The bone marrow signal intensity on unenhanced T1-W fat-saturated MR images is not a reliable criterion to differentiate bone infarcts from osteomyelitis in children.

Distinguishing Osteomyelitis From Ewing Sarcoma on Radiography and MRI

OBJECTIVE

The purpose of this study was to determine whether clinical and imaging features can distinguish osteomyelitis from Ewing sarcoma (EWS) and to assess the accuracy of percutaneous biopsy versus open biopsy in the diagnosis of these diseases.

MATERIALS AND METHODS

Three radiologists reviewed the radiographs and MRI examinations of 32 subjects with osteomyelitis and 31 subjects with EWS to determine the presence of 36 imaging parameters. Information on demographic characteristics, history, physical examination findings, laboratory findings, biopsy type, and biopsy results were recorded. Individual imaging and clinical parameters and combinations of these parameters were tested for correlation with findings from histologic analysis. The diagnostic accuracy of biopsy was also determined.

RESULTS

On radiography, the presence of joint or metaphyseal involvement, a wide transition zone, a Codman triangle, a periosteal reaction, or a soft-tissue mass, when tested individually, was more likely to be noted in subjects with EWS (p ≤ 0.05) than in subjects with osteomyelitis. On MRI, permeative cortical involvement and soft-tissue mass were more likely in subjects with EWS (p ≤ 0.02), whereas a serpiginous tract was more likely to be seen in subjects with osteomyelitis (p = 0.04). African Americans were more likely to have osteomyelitis than EWS (p = 0). According to the results of multiple regression analysis, only ethnicity and soft-tissue mass remained statistically significant (p ≤ 0.01). The findings from 100% of open biopsies (18/18) and 58% of percutaneous biopsies (7/12) resulted in the diagnosis of osteomyelitis, whereas the findings from 88% of open biopsies (22/25) and 50% of percutaneous biopsies (3/6) resulted in a diagnosis of EWS.

CONCLUSION

Several imaging features are significantly associated with either EWS or osteomyelitis, but many features are associated with both diseases. Other than ethnicity, no clinical feature improved diagnostic accuracy. Compared with percutaneous biopsy, open biopsy provides a higher diagnostic yield but may be inconclusive, especially for cases of EWS. Our findings underscore the need for better methods of diagnosing these disease processes.