Imaging of osteomyelitis: current concepts

Prevalence of radiographic findings in chronic osteomyelitis

BACKGROUND

Simple radiography in conjunction with pertinent medical history and a comprehensive physical examination is typically adequate for diagnosing chronic osteomyelitis (CO). However, radiographic manifestations of CO lack specificity; therefore, the concordance among specialists in this regard has not been systematically assessed. This study aimed to compare and evaluate the proficiency of orthopedic surgeons and radiologists in identifying radiographic indicators present in simple radiographs for diagnosing CO.

METHODS

This cross-sectional study was a correlational investigation utilizing plain radiographs obtained from a cohort of 60 patients diagnosed with CO. Comprehensive assessments of the demographic and clinical characteristics, comorbidities, and microbiological parameters were conducted. Additional variables included the anatomical location of the CO, existence of fistulas, disease duration, and presence of pseudoarthrosis. This study meticulously documented the presence or absence of six specific findings: bone destruction, which incorporates erosion and radiolucencies around implants; bone sclerosis; cortical thinning concomitant with erosion; cortical thickening; sequestrum formation; and soft-tissue swelling.

RESULTS

Most patients were men (75%), with a mean age of 45.1 years. Hematogenous etiology of CO represented 23%. Bone sclerosis (71.3%) and cortical thickening (67.7%) were the most common radiographic findings, followed by soft-tissue swelling (51.3%), sequestration (47.3%), bone destruction (33.3%), and cortical erosion (30.3%). The mean agreement was 74.2%, showing a marked disagreement rate of 25.8% among all radiographic findings. The presence or absence of soft tissue edema, a prominent radiographic finding that was more important than the other findings, showed the greatest disagreement.

CONCLUSIONS

Radiographic findings in CO were universally observed in all patients, demonstrating a high degree of concordance among specialists, with the exception of soft tissue swelling.

Interfacial and Defect Polarization Enhanced Microwave Noninvasive Therapy for Staphylococcus aureus-Infected Chronic Osteomyelitis

Chronic osteomyelitis (COM), is a long-term, constant, and intractable disease mostly induced by infection from the invasion of Staphylococcus aureus (S. aureus) into bone cells. Here, we describe a highly effective microwave (MW) therapeutic strategy for S. aureus-induced COM based on the in situ growth of interfacial oxygen vacancy-rich molybdenum disulfide (MoS2)/titanium carbide (Ti3C2Tx) MXene with oxygen-deficient titanium dioxide (TiO2-x) on Ti3C2Tx (labeled as HU-MoS2/Ti3C2Tx) by producing reactive oxygen species (ROS) and heat. HU-MoS2/Ti3C2Tx produced heat and ROS, which could effectively treat S. aureus-induced COM under MW irradiation. The underlying mechanism determined by density functional theory (DFT) and MW vector network analysis was that HU-MoS2/Ti3C2Tx formed a high-energy local electric field under MW irradiation, consequently generating more high-energy free electrons to pass and move across the interface at a high speed and accelerate by the heterointerface, which enhanced the charge accumulation on both sides of the interface. Moreover, these charges were captured by the oxygen species adsorbed at the HU-MoS2/Ti3C2Tx interface to produce ROS. MoS2 facilitated multiple reflections and scattering of electromagnetic waves as well as enhanced impedance matching. Ti3C2Tx enhanced the conduction loss of electromagnetic waves, while functional groups induced dipole polarization to enhance attenuation of MW.

Primary sternal osteomyelitis: A case report

INTRODUCTION

Primary sternal osteomyelitis is a rare condition that is frequently caused by Staphylococcus aureus. It is often confused with other cardiac and pulmonary conditions. Early antimicrobial treatment and surgical debridement is the cornerstone of treatment.

CASE PRESENTATION

A 51-year-old male adult came to the emergency room (ER) with a 2-week history of chest pain, fever, and malaise. His past medical history was unremarkable. Examination revealed a tender anterior chest wall swelling. White Blood Cells (WBCs) (21.6 × 104)/mm3) and C-reactive protein (CRP) (294.10 mg/L) were elevated. Pus from the swelling and blood samples were sent for culture and sensitivity. Electrocardiogram (ECG) was normal and a computed tomography (CT) scan of the chest showed a large dense anterior chest wall abscess extending deep in the chest and to both axillae which caused bony erosion of the sternum. Incision and drainage of the abscess were performed, followed by surgical debridement of the wound. Cultures along the course showed both Staphylococcus aureus and Enterococcus. The patient improved gradually and 2 months after his initial presentation, he became free of symptoms, and CT has shown complete resolution.

DISCUSSION

Osteomyelitis usually happens after an external bacterium seeds the bone where it begins to grow and thrive, leading to the destruction and pus accumulation under the periosteum. For the treatment, identifying the causative agent is critical in giving intravenous (IV) antibiotic. Thereafter, incision and drainage of an abscess can be performed, similar to what was done with the patient mentioned. Radiography, specifically a CT scan, is crucial as it clearly reveals bony margins and can differentiate between a sequestrum and an involucrum. It also identifies cortical erosion, intraosseous gases and periosteal reactions.

CONCLUSION

Sternal osteomyelitis can have a nonspecific clinical presentation. Laboratory investigations and radiological findings are crucial for a prompt diagnosis. To prevent the progression of the disease and complications, early intervention is vital to ensure a good prognosis.

Localization of osteomyelitis lesions for operative eradication of chronic osteomyelitis of the lower extremities by bone SPECT/CT: a feasibility study

PURPOSE

This study was performed to investigate the feasibility of bone single-photon emission tomography/computed tomography (SPECT/CT) for pre-operative planning of chronic osteomyelitis (COM) of the lower extremities by localization of osteomyelitis lesions.

METHODS

From January 2016 to January 2020, we surgically treated ten adult patients with Cierny-Mader type III COM in the tibia or femur for a mean duration of 24.4 months (range 7.0-70.0 months). We conducted pre-operative planning by bone SPECT/CT and localization of osteomyelitis lesions. The treatment consisted of intra-operative eradication of the infective focus and antibiotic administration. The clinical and radiological outcomes were retrospectively analyzed after a minimum of one year of follow-up.

RESULTS

The patients were surgically treated by thorough debridement, dead space management, and appropriate antibiotics without bone transport or an external fixator. The location of the hot uptake region on bone SPECT/CT coincided with that of the osteomyelitis lesion, which was confirmed intra-operatively in all patients. At an average of 16.5 ± 4.3 months (range, 13.0-25.0 months), clinical eradication of osteomyelitis was achieved in nine of the ten patients. One patient required amputation due to recurrence of osteomyelitis. A successful clinical outcome was achieved in eight patients; one suffered persistent ankle pain due to a destructive change in the ankle joint despite eradication of the infection.

CONCLUSION

Bone SPECT/CT is a feasible method for the localization and eradication of osteomyelitis lesions in COM of the lower extremities and has favourable clinical outcomes. It can also be applied in cases of distorted bony structures caused by previous trauma or surgery, or in the presence of implants.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Update on MRI findings of osteomyelitis of long bones in the adult population

OBJECTIVES

To evaluate the usefulness of new and established MRI signs of osteomyelitis in long bones in adults.

METHODS

All patient records over a 9-year period with clinical or MRI suspicion for osteomyelitis were retrospectively reviewed, using strict criteria for proof of infection. Two musculoskeletal radiologists independently reviewed the MRIs of proven osteomyelitis.

RESULTS

Out of 45 MRIs of confirmed osteomyelitis, 2 MRIs (4%) did not show confluent low-signal intensity on T1-weighted images, but all showed confluent high-signal intensity on T2-weighted images. Central hypoenhancing regions of marrow without abscess formation were found in 15-18/35 (43-51%) cases where gadolinium was given. We often found multiple foci of marrow replacement in the same bone. The areas of marrow involvement often had an irregular contour. Penumbra sign, marrow fat globules, and sequestra were uncommon.

CONCLUSION

Multiple foci of bone marrow signal abnormalities, an irregular contour of marrow abnormality, and central marrow hypoenhancement without abscess are common signs of osteomyelitis of long bones in adults. Confluent low T1-signal intensity is not always present.

Complications of Lesser Toe Surgery: How To Avoid Them before Surgery and How To Assess and Treat Them When They Have Occurred

Complications following lesser toe surgery are challenging to manage. The keys to treatment of any of these conditions are, first, to try to avoid them through identification of patient- and surgeon-related variables that contribute to their development and, second, following the occurance of a complication, to understand what can and cannot be corrected with surgical and nonsurgical management. This review provides a comprehensive assessment of current literature, demonstrates best practices and approaches to lesser toe complications, and provides an illustration of clinical examples.

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.

Bone and Joint Infections: The Role of Imaging in Tailoring Diagnosis to Improve Patients' Care

Imaging is needed for the diagnosis of bone and joint infections, determining the severity and extent of disease, planning biopsy, and monitoring the response to treatment. Some radiological features are pathognomonic of bone and joint infections for each modality used. However, imaging diagnosis of these infections is challenging because of several overlaps with non-infectious etiologies. Interventional radiology is generally needed to verify the diagnosis and to identify the microorganism involved in the infectious process through imaging-guided biopsy. This narrative review aims to summarize the radiological features of the commonest orthopedic infections, the indications and the limits of different modalities in the diagnostic strategy as well as to outline recent findings that may facilitate diagnosis.

Pediatric Musculoskeletal Infections: Imaging Guidelines and Recommendations

Pediatric musculoskeletal infections often pose a diagnostic challenge due to their frequently vague and nonspecific clinical presentation. Imaging evaluation is a crucial component to diagnostic workup of these entities. Changed epidemiology of these infections over the past 2 decades has resulted in increases in both disease incidence and severity in the pediatric population. Prompt and accurate diagnosis is essential in order to reduce the risk of morbid sequelae, and to optimize patient management. In this article, the unique pathophysiology of musculoskeletal infections and characteristic imaging findings in children compared with adults are reviewed.

Imaging of Joint and Soft Tissue Involvement in Systemic Lupus Erythematosus

PURPOSE OF REVIEW

To highlight the potential uses and applications of imaging in the assessment of the most common and relevant musculoskeletal (MSK) manifestations in systemic lupus erythematosus (SLE).

RECENT FINDINGS

Ultrasound (US) and magnetic resonance imaging (MRI) are accurate and sensitive in the assessment of inflammation and structural damage at the joint and soft tissue structures in patients with SLE. The US is particularly helpful for the detection of joint and/or tendon inflammation in patients with arthralgia but without clinical synovitis, and for the early identification of bone erosions. MRI plays a key role in the early diagnosis of osteonecrosis and in the assessment of muscle involvement (i.e., myositis and myopathy). Conventional radiography (CR) remains the traditional gold standard for the evaluation of structural damage in patients with joint involvement, and for the study of bone pathology. The diagnostic value of CR is affected by the poor sensitivity in demonstrating early structural changes at joint and soft tissue level. Computed tomography allows a detailed evaluation of bone damage. However, the inability to distinguish different soft tissues and the need for ionizing radiation limit its use to selected clinical circumstances. Nuclear imaging techniques are valuable resources in patients with suspected bone infection (i.e., osteomyelitis), especially when MRI is contraindicated. Finally, dual energy X-ray absorptiometry represents the imaging mainstay for the assessment and monitoring of bone status in patients with or at-risk of osteoporosis. Imaging provides relevant and valuable information in the assessment of MSK involvement in SLE.

[Diagnostic Imaging for Infections of the Hand]

Clinical signs of an infection of the hand can be subtle initially or in a chronic state. But even in a progressive stadium it might be difficult to define an involvement of soft tissue, joint or bone. This review article addresses the diagnostic options of radiologic imaging. Radiographs of the affected region are the basic diagnostics. Sonographics provides information about an abscess or effusion versus diffuse edema and phlegmon. Both are in most situations promptly available. In chronic cases and unclear findings, MRI is of value. With bone involvement and an implant related osteomyelitis suspected, CT is the most valid method.

Radiologic Mimics of Osteomyelitis and Septic Arthritis: A Pictorial Essay

Various imaging techniques may be employed in the investigation of suspected bone and joint infections. These include ultrasound, radiography, functional imaging such as positron emission tomography (PET) and nuclear scintigraphy, and cross-sectional imaging, including computed tomography (CT) and magnetic resonance imaging (MRI). The cross-sectional modalities represent the imaging workhorse in routine practice. The role of imaging also extends to include assessment of the anatomical extent of infection, potentially associated complications, and treatment response. The imaging appearances of bone and joint infections are heterogeneous and depend on the duration of infection, an individual patient's immune status, and virulence of culprit organisms. To add to the complexity of radiodiagnosis, one of the pitfalls of imaging musculoskeletal infection is the presence of other conditions that can share overlapping imaging features. This includes osteoarthritis, vasculopathy, inflammatory, and even neoplastic processes. Different pathologies may also coexist, for example, diabetic neuropathy and osteomyelitis. This pictorial review aims to highlight potential mimics of osteomyelitis and septic arthritis that are regularly encountered, with emphasis on specific imaging features that may aid the radiologist and clinician in distinguishing an infective from a noninfective aetiology.

MRI nomenclature for musculoskeletal infection

The Society of Skeletal Radiology (SSR) Practice Guidelines and Technical Standards Committee identified musculoskeletal infection as a White Paper topic, and selected a Committee, tasked with developing a consensus on nomenclature for MRI of musculoskeletal infection outside the spine. The objective of the White Paper was to critically assess the literature and propose standardized terminology for imaging findings of infection on MRI, in order to improve both communication with clinical colleagues and patient care.A definition was proposed for each term; debate followed, and the committee reached consensus. Potential controversies were raised, with formulated recommendations. The committee arrived at consensus definitions for cellulitis, soft tissue abscess, and necrotizing infection, while discouraging the nonspecific term phlegmon. For bone infection, the term osteitis is not useful; the panel recommends using terms that describe the likelihood of osteomyelitis in cases where definitive signal changes are lacking. The work was presented virtually to SSR members, who had the opportunity for review and modification prior to submission for publication.

Diagnosing Osteomyelitis: A Histology Guide for Pathologists

Histopathologic examination of bone specimens coupled with bone culture is considered the gold standard for the diagnosis of osteomyelitis (OM). Despite this, studies have demonstrated interpathologist agreement in the diagnosis of OM as low as 30%, largely stemming from a lack of specific definitions and diagnostic criteria. Review of the literature has provided insight into the lifecycle of OM, illustrating the histologic progression of OM phases from acute to chronic, and provides support for defining subcategories of OM. Using an algorithmic histopathologic tool consisting of 15 criteria, each with an associated score, we defined 5 categories of OM: (1) acute OM, (2) acute and chronic OM, (3) chronic OM, (4) chronic active OM, and (5) chronic inactive OM. We reviewed 462 microscopic slides from 263 patients with suspected OM, and for each slide, we determined an algorithm-derived diagnosis, which was then used to calculate a total histopathologic load score (Jupiter score). Algorithm-derived diagnoses recapitulated original clinical diagnoses and diagnosed cases as OM that had not been originally diagnoses. These novel cases were more likely to have subsequent clinical complications. Finally, pathologic load scores were assessed for association with the category of OM.

Detection of extremity chronic traumatic osteomyelitis by machine learning based on computed-tomography images: A retrospective study

Despite the availability of a series of tests, detection of chronic traumatic osteomyelitis is still exhausting in clinical practice. We hypothesized that machine learning based on computed-tomography (CT) images would provide better diagnostic performance for extremity traumatic chronic osteomyelitis than the serological biomarker alone. A retrospective study was carried out to collect medical data from patients with extremity traumatic osteomyelitis according to the criteria of musculoskeletal infection society. In each patient, serum levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and D-dimer were measured and CT scan of the extremity was conducted 7 days after admission preoperatively. A deep residual network (ResNet) machine learning model was established for recognition of bone lesion on the CT image. A total of 28,718 CT images from 163 adult patients were included. Then, we randomly extracted 80% of all CT images from each patient for training, 10% for validation, and 10% for testing. Our results showed that machine learning (83.4%) outperformed CRP (53.2%), ESR (68.8%), and D-dimer (68.1%) separately in accuracy. Meanwhile, machine learning (88.0%) demonstrated highest sensitivity when compared with CRP (50.6%), ESR (73.0%), and D-dimer (51.7%). Considering the specificity, machine learning (77.0%) is better than CRP (59.4%) and ESR (62.2%), but not D-dimer (83.8%). Our findings indicated that machine learning based on CT images is an effective and promising avenue for detection of chronic traumatic osteomyelitis in the extremity.

An infective cause for the limping child

A 7-year-old girl presented with left hip pain and a limp, in the absence of any other systemic features, having recently been treated for a urinary tract infection. Examination revealed limited active hip movements on the left, with a tendency to weight bear on the contralateral side. Biochemical investigations were significant for raised inflammatory markers, and subsequent MRI imaging revealed osteomyelitis of the left pubis and ischium with an associated large soft tissue collection. Treatment was bimodal with surgical drainage and long-term antibiotics. The patient consequently recovered, without significant effect on either growth or mobility.

Primary infectious costochondritis due to Prevotella nigrescens in an immunocompetent patient: clinical and imaging findings

Infection of costal cartilage is a rare observation. We report the case of a 43-year-old male patient without relevant history who presented with a progressive painful swelling of the left chest wall since 4 months. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated an abscess within the left ninth costal cartilage with surrounding reactive changes. A CT-guided biopsy was performed and the culture of the sample revealed the presence of Prevotella nigrescens. Musculoskeletal infections by Prevotella are rarely described in the literature, Prevotella oralis and Prevotella bivia being the most frequently observed pathogens. These infections usually originate from a hematogenous spread after thoracic surgery or dental procedure. In our patient, conservative treatment was chosen. A clinical improvement was noted after 1-month antibiotherapy, confirmed by short-term and 6-month imaging follow-up showing the complete disappearance of all previously observed abnormalities.

Bacterial osteomyelitis in veterinary orthopaedics: Pathophysiology, clinical presentation and advances in treatment across multiple species

Bacterial osteomyelitis in veterinary patients can be challenging to diagnose and treat, given limited therapeutic options and reported success rates. Osteomyelitis is frequently associated with surgical implant devices, including those required to optimise stability and healing of fractures. However, management of osteomyelitis sometimes necessitates the removal of these surgical implant devices in order to eradicate infection or limit implant-related osteolysis. The goal of this article is to provide a general and species-specific review of bacterial osteomyelitis in a selection of domestic veterinary species, including cats, dogs, horses, cattle and camelids, with a focus on classification, clinical presentation, aetiologic agents, and common therapeutic interventions reported in the literature. New treatment options emerging from research and human medicine will be also discussed, as they also apply to current or future care of veterinary patients with osteomyelitis.

Hybrid FDG-PET/MR imaging of chronic osteomyelitis: a prospective case series

Background

Magnetic resonance imaging (MRI) and 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography paired with computed tomography (PET/CT) are two commonly used imaging modalities in the complicated diagnostic workup of osteomyelitis. Diagnosis using these modalities relies on, respectively, anatomical (MRI) and metabolic (PET) signs. With hybrid PET/MRI being recently available, our goal is to qualitatively compare hybrid FDG PET/MRI to FDG PET/CT in the diagnosis and operative planning of chronic osteomyelitis.

Methods

Five patients with suspected chronic osteomyelitis in an extremity underwent an ¹⁸F-FDG single-injection/dual-imaging protocol with hybrid PET/CT and hybrid PET/MR. Images and clinical features were evaluated using a standardized assessment method. Standardized uptake value (SUV) measurements were performed on all images. Concordant and discordant findings between PET/MRI and PET/CT were analysed.

Results

The consensus diagnoses based on PET/MRI and PET/CT images were identical for all five patients. One discrepancy between PET/MRI and PET/CT was found in the assessment of the features in one patient. PET signal intensities and target-to-background ratios were on average highest for PET/MRI. On PET/MRI, the location of infection based on FDG uptake could clearly be correlated with certain soft tissue structures (oedema, fluid collection, or muscle), which is paramount for surgical planning.

Conclusions

In the presented cases, FDG PET/MRI led to the same diagnosis and provided at least the same diagnostic information as PET/CT. PET/MRI was able to provide additional soft-tissue information for the physician planning treatment. Because of this, we suggest that PET/MRI could be used for osteomyelitis diagnosis and treatment planning.

Subacute Osteomyelitis of the Pediatric Talus: A First Report of Brodie's Abscess from Morganella morganii

Brodie's abscess is a subacute form of osteomyelitis which generally occurs in the metaphysis of the femur and tibia in the pediatric population. Pathogens are most commonly Gram-positive bacteria, notably Staphylococcus and Streptococcus. In this article, we describe a young pediatric patient presenting with subacute ankle pain with a subsequent diagnosis of Brodie's abscess of the talus secondary to Morganella morganii. We review the presentation, diagnosis, and treatment of this unique patient. To our knowledge, this is the first report of Morganella morganii as a cause of Brodie's abscess.

An untapped potential for imaging of peripheral osteomyelitis in paediatrics using [18F]FDG PET/CT -the inference from a juvenile porcine model

PURPOSE

To examine parameters affecting the detection of osteomyelitis (OM) by [18F]FDG PET/CT and to reduce tracer activity in a pig model.

BACKGROUND

[18F]FDG PET/CT is recommended for the diagnosis of OM in the axial skeleton of adults. In children, OM has a tendency to become chronic or recurrent, especially in low-income countries. Early diagnosis and initiation of therapy are therefore essential. We have previously demonstrated that [18F]FDG PET/CT is promising in juvenile Staphylococcus aureus (S. aureus) OM of peripheral bones in a pig model, not failing even small lesions. When using imaging in children, radiation exposure should be balanced against fast diagnostics in the individual case.

METHODS

Twenty juvenile pigs were inoculated with S. aureus. One week after inoculation, the pigs were [18F]FDG PET/CT scanned. PET list-mode acquired data of a subgroup were retrospectively processed in order to simulate and examine the image quality obtainable with an injected activity of 132 MBq, 44 MBq, 13.2 MBq, and 4.4 MBq, respectively.

RESULTS

All lesions were detected by [18F]FDG PET and CT. Some lesions were very small (0.01 cm3), and others were larger (4.18 cm3). SUVmax was higher when sequesters (p = 0.023) and fistulas were formed (p < 0.0001). The simulated data demonstrated that it was possible to reduce the activity to 4.4 MBq without compromising image quality in pigs.

CONCLUSIONS

[18F]FDG PET/CT localized even small OM lesions in peripheral bones. It was possible to reduce the injected activity considerably without compromising image quality, impacting the applicability of PET/CT in peripheral OM in children.

Implementing Precision Medicine and Artificial Intelligence in Plastic Surgery: Concepts and Future Prospects

Precision medicine, or the individualization of evidence-based medicine, is forthcoming. As surgeons, we must be prepared for the integration of patient and system factors. Plastic surgeons regard themselves as innovators and early adopters. As such, we need our adaptability now more than ever to implement digital advancements and precision medicine into our practices. The integration of artificial intelligence (AI) technology and the capture of big data techniques should foster the next great leaps in medicine and surgery, allowing us to capture the detailed minutiae of precision medicine. The algorithmic process of artificial neural networks will guide large-scale analysis of data, including features such as pattern recognition and rapid quantification, to organize and distribute data to surgeons seamlessly. This vast digital collection of information, commonly termed “big data,” is only one potential application of AI. By incorporating big data, the cognitive abilities of a surgeon can be complemented by the computer to improve patient-centered care. Furthermore, the use of AI will provide individual patients with increased access to the broadening world of precision medicine. Therefore, plastic surgeons must learn how to use AI within the contexts of our practices to keep up with an evolving field in medicine. Although rudimentary in its practice, we present a glimpse of the potential applications of AI in plastic surgery to incorporate the practice of precision medicine into the care that we deliver.

Radiographic Musculoskeletal Findings Indicating Opioid Misuse: An Overview for Orthopedic Surgeons

BACKGROUND

Given the high prevalence of musculoskeletal conditions in the USA, it is important for orthopedic surgeons to promptly identify patients who may be at risk for opioid misuse.

QUESTIONS/PURPOSES

The aim of this literature review was to elucidate various musculoskeletal pathologies and complications, as seen on imaging, that may indicate opioid misuse or opioid use disorder.

METHODS

A literature search was conducted using the PubMed, Scopus, and Cochrane Library databases for articles related to imaging findings associated with chronic opioid use or misuse in orthopedic patients. Two independent reviewers conducted the search utilizing pertinent Boolean operations.

RESULTS

We reviewed 36 full-text articles and categorized the radiographic evidence of opioid misuse as follows: soft-tissue radiologic findings, cellulitis, necrotizing fasciitis, abscess formation, retained needles, discitis, myopathy and rhabdomyolysis, osteomyelitis, septic arthritis, and septic thrombophlebitis.

CONCLUSION

Knowledge of the radiologic findings of opioid misuse will assist orthopedic surgeons in making timely diagnoses that may alter therapeutic regimens for their patients.

Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography

The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.

Musculoskeletal Infections in the Emergency Department

Bone and joint infections are potentially limb-threatening or even life-threatening diseases. Emergency physicians must consider infection when evaluating musculoskeletal complaints, as misdiagnosis can have significant consequences. Patients with bone and joint infections can have heterogeneous presentations with nonspecific signs and symptoms. Staphylococcus aureus is the most commonly implicated microorganism. Although diagnosis may be suggested by physical examination, laboratory testing, and imaging, tissue sampling for Gram stain and microbiologic culture is preferable, as pathogen identification and susceptibility testing help optimize long-term antibiotic therapy. A combination of medical and surgical interventions is often necessary to effectively manage these challenging infections.

FDG-PET/CT for differentiating between aseptic and septic delayed union in the lower extremity

BACKGROUND

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) has proven to have a high diagnostic accuracy for the detection of bone infections. In patients with delayed union it may be clinically important to differentiate between aseptic and septic delayed union. The aim of this study was to evaluate the efficacy and to assess the optimal diagnostic accuracy of FDG-PET/CT in differentiating between aseptic and septic delayed union in the lower extremity.

METHODS

This is a retrospective study of consecutive patients who underwent FDG-PET/CT scanning for suspicion of septic delayed union of the lower extremity. Diagnosis of aseptic delayed union or septic delayed union was made based on surgical deep cultures following PET/CT scanning and information on clinical follow-up. FDG-uptake values were measured at the fractured site by use of the maximum standardized uptake value (SUV_max). Sensitivity, specificity and diagnostic accuracy of FDG-PET/CT were calculated at various SUV_max cut-off points.

RESULTS

A total of 30 patients were included; 13 patients with aseptic delayed unions and 17 patients with septic delayed unions. Mean SUV_max in aseptic delayed union patients was 3.23 (SD ± 1.21). Mean SUV_max in septic delayed union patients was 4.77 (SD ± 1.87). A cut-off SUV_max set at 4.0 showed sensitivity, specificity and diagnostic accuracy of FDG-PET/CT were 65, 77 and 70% to differentiate between aseptic and septic delayed union, respectively.

CONCLUSION

Using a semi-quantitative measure (SUV_max) for interpretation of FDG-PET/CT imaging seems to be a promising tool for the discrimination between aseptic and septic delayed union.

Diagnosing Infection in a Neonate Using Whole-Body Screening Magnetic Resonance Imaging

The location of invasive infections is difficult to detect in infants, in part due to their inability to localize signs and symptoms. However, identifying the location often significantly alters clinical management by extending the duration of antibiotic therapy or revealing a source requiring surgical intervention. Compared with commonly used first-line imaging techniques such as radiographs and ultrasounds, MRI has higher sensitivity for identifying invasive infections and allows for simultaneous evaluation of multiple foci. We present 2 cases in which whole-body screening MRI was used in neonates to identify invasive sources of infection, including one in which traditional modalities failed to detect multiple clinically significant sources. We posit that whole-body screening MRI merits consideration as a potential first-line imaging method when investigating invasive infections in infants.

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.

Definitive Diagnosis of Children Presenting to A Pediatric Emergency Department With Fever and Extremity Pain

BACKGROUND

Children who present to the emergency department (ED) with complaint of fever and new-onset joint or extremity pain can be a diagnostic dilemma for many emergency and consulting physicians.

OBJECTIVES

The purpose of our study was to identify the etiologies of pediatric fever and extremity pain presenting to a tertiary care pediatric ED and to define factors that were associated with advanced imaging, admission, and surgical intervention.

METHODS

The electronic medical records of children presenting to our institution's pediatric ED with fever and extremity pain were retrospectively reviewed. Data collected included demographic characteristics, laboratory studies, diagnostic imaging, need for admission, and surgical procedures.

RESULTS

The initial ED diagnosis was consistent with the definitive diagnosis 42% of the time. Children with the inability to bear weight on the affected limb were more likely to have a bacterial infection, such as osteomyelitis, septic arthritis, or intramuscular abscess (p = 0.016). An erythrocyte sedimentation rate >36 mm/hour and C-reactive protein levels >60 mg/L were found in children with osteomyelitis or septic arthritis (p = 0.043 and <0.001, respectively). Magnetic resonance imaging was ordered in 63% of children with multiple visits compared to 34% of children with a single visit (p = 0.05).

CONCLUSIONS

In addition to a thorough history and physical examination, a complete set of laboratory studies and diagnostic imaging is necessary to reach an accurate diagnosis. The inability to bear weight, elevated C-reactive protein levels, and an elevated erythrocyte sedimentation rate are associated with bacterial infection. Magnetic resonance imaging is a useful imaging modality in determining an accurate diagnosis.

Primary Sternal Osteomyelitis caused by Staphylococcus aureus in an Immunocompetent Adult

Primary sternal osteomyelitis (PSO) is a rare condition that may develop without any contiguous focus of infection. Due to the rarity of the disease, early diagnosis and appropriate treatment are often delayed. Herein, we describe a patient with PSO caused by Staphylococcus aureus that presented with chest pain and fever. The patient had no predisposing factors for sternal osteomyelitis. The chest pain was thought to be non-cardiogenic, as electrocardiography and cardiac enzyme did not reveal ischemic changes when he visited the emergency room. After blood culture revealed the presence of S. aureus, every effort was made to identify the primary focus of infection. Bone scan and magnetic resonance imaging revealed osteomyelitis with soft tissue inflammation around the sternum. After 8 weeks of antibiotics treatment, the patient recovered without any complications.

Pediatric Tibial Osteomyelitis

BACKGROUND

Osteomyelitis shows a strong predilection for the tibia in the pediatric population and is a significant source of complications. The purpose of this article is to retrospectively review a large series of pediatric patients with tibial osteomyelitis. We compare our experience with that in the literature to determine any factors that may aid diagnosis and/or improve treatment outcomes.

METHODS

A 10-year retrospective review was performed of clinical records of all cases of pediatric tibial osteomyelitis managed at the 2 children's orthopaedic departments in the Auckland region. The Osteomyelitis Database was used to identify all cases between 1997 and 2007, at Starship Children's Hospital, and 1998 and 2008 at Middlemore's Kids First Hospital.

RESULTS

One hundred ninety-one patients fulfilled the inclusion criteria, and had a review of clinical notes and relevant investigations. The average duration of symptoms before presentation to hospital was 5.7 days. Less than 40% of patients had a recent episode of trauma. Almost 60% of patients could not bear weight on admission. Over 40% of patients had a temperature above 38°C. Erythrocyte sedimentation rate was elevated in 78% and the C-reactive protein was elevated in 90% of patients. In total, 42% of blood cultures and almost 75% of tissue cultures were positive, with Staphylococcus aureus being the most commonly cultured organism. X-rays, bone scans, and magnetic resonance imaging were all used to aid the diagnosis. About 43% of patients had surgery. Treatment length was an average of 2 weeks 6 days of intravenous antibiotics followed by 3 weeks 2 days of oral treatment. Six postsurgical complications and 46 readmissions were noted: 25 for relapse, with the remainder due to social and antibiotic-associated complications.

CONCLUSIONS

Although generally diagnosed on presentation, pediatric tibial osteomyelitis can require more sophisticated investigations and prolonged management. Treatment with intravenous and oral antibiotics and surgical debridement where indicated can lead to a good clinical outcome, although complications are often noted.

LEVEL OF EVIDENCE

Level IV-Prognostic study.

Levofloxacin loaded mesoporous silica microspheres/nano-hydroxyapatite/polyurethane composite scaffold for the treatment of chronic osteomyelitis with bone defects

Chronic osteomyelitis is a prolonged persistent disease accompanied by bone destruction and sequestrum formation, it is very difficult to treat. Antibiotic loaded polymethyl methacrylate (PMMA) has been used in clinical. However, when PMMA was implanted in the body, the deficiencies is that it is non-biodegradable and a second operation is needed. Here, we synthesize a novel levofloxacin loaded mesoporous silica microspheres/nano-hydroxyapatite/polyurethane composite scaffolds, and evaluated the therapeutic effect in treating chronic osteomyelitis with bone defects in rabbit model compared with bulk PMMA. X-ray, Micro CT, gross pathology as well as immunohistochemical staining were performed at predesignated time points (1, 3, 6 and 12 weeks). Our results demonstrated that the efficiency of mesoporous silica microspheres/nano-hydroxyapatite/polyurethane composite scaffolds loaded with 5 mg levofloxacin was much better at treating bone defects than the other groups. This novel synthetic scaffold may provide a solution for the treatment of chronic osteomyelitis.

A Rare Case of Clavicle Osteomyelitis in a Child and Literature Review

Acute clavicle osteomyelitis in children is rare representing <3% of osteomyelitis cases. We treated a 12-year-old boy who presented with acute pain in the right clavicle and high fever for 4 days. MRI showed abnormal signal in the right clavicle with periosteal reaction. Staphylococcus aureus isolated from blood was susceptible to methicillin, clindamycin, and macrolides. Clindamycin was given intravenously for 3 wks and orally for another 3 wks with no recurrence. We reviewed clavicle osteomyelitis cases in children searching PubMed English literature. From a total of 89 studies retrieved, only 6 fulfilled the criteria and were analyzed. Sixteen patients (56% female) were included with a median age of 9 yrs (range 2 wks–16 yrs). Osteomyelitis was hematogenous in most cases, with S. aureus being the most frequent cause, isolated from either blood or tissue. Symptoms included fever, swelling, and localized bone tenderness. Antimicrobial therapy lasted for 4–12 weeks (median 7.5). Three patients required drainage or curettage. Recurrence occurred in 1/16 cases (6.2%) and persistence of symptoms occurred to 2/16 cases (12.5%) reported before 90s with unknown antimicrobial susceptibility of the pathogen. Acute clavicle osteomyelitis mainly affects older children and has generally good prognosis. Staphylococcus aureus is most commonly implicated and surgery may be needed.

Amebic osteomyelitis in an immunocompromised patient

Acanthamoeba spp. are pathogenic protozoa that are uncommonly encountered. They tend to infect immunocompromised patients, most often causing cutaneous lesions and in some instances granulomatous amebic encephalitis, as well as rare instances of dissemination to other organs. We present a case of amebic osteomyelitis of the fibula in a patient with rejection of a transplanted kidney who was chronically immune-suppressed.

Oral Ambulatory Treatment of Acute Osteomyelitis in Children: A Case-Control Study

The treatment of acute hematogenous osteomyelitis has evolved in recent years to a shorter parenteral treatment with an early switch to the oral route. Current publications recommend a 2- to 4-day parenteral treatment before the oral switch. We retrospectively analyzed a series of 45 children aged 1 to 11 years and treated in our department for acute osteomyelitis without severity criterion. Nineteen of 45 patients were treated by an exclusive ambulatory oral treatment by amoxicillin and clavulanic acid. Twenty six of 45 patients had a 2- to 4-day parenteral treatment before the oral switch. The minimum follow-up was 6 months. The primary endpoint was a clinical, radiographic, and biologic healing, 6 months after the beginning of the treatment. The secondary endpoints evaluated were the length of hospitalization, the total duration of treatment, and the type of antibiotic used. On the primary endpoint, we did not find any significant difference between the 2 treatments (P = 0.38). On the duration of treatment, we found a significant difference (P = 0.049) in favor of oral treatment. The ambulatory oral treatment by amoxicillin and clavulanic acid seems to be a valid alternative to the classical parenteral then oral sequence in the treatment of acute hematogenous osteomyelitis in children without severity criterion.

Ultrasound-Guided Diagnosis of Femoral Osteomyelitis and Abscess

Skin and soft tissue infections are common disease presentations to the pediatric emergency department, and rapid and accurate identification of potentially serious skin and soft tissue infections is critical. In cases of atraumatic musculoskeletal pain with systemic complaints, a bacterial etiology must be ruled out. Point-of-care ultrasonography is increasingly common in the pediatric emergency department and assists in rapid and accurate identification of a variety of disease processes. We present a case of a 14-year-old adolescent boy with atraumatic right knee pain to illustrate the benefits of point-of-care ultrasonography in the timely diagnosis of musculoskeletal and soft tissue pathology. Moreover, we describe the use of ultrasound in procedural guidance of deep-space fluid aspiration, with an eventual diagnosis of femoral osteomyelitis. Ultrasonographic techniques and the emergent work-up and management of osteomyelitis are reviewed.

Methicillin-resistant Staphylococcus aureus mandibular osteomyelitis in an extremely low birth weight preterm infant

Methicillin-resistant Staphylococcus aureus (MRSA) is an established nosocomial pathogen with frequent multidrug resistance. The immaturity of the immune system along with intravascular lines and empirical antibiotic treatments place hospitalized preterm infants at major risk of MRSA infection.

We report a case of MRSA mandibular osteomyelitis complicating a persistent S. aureus bacteremia in a 23-week preterm infant. From the first weeks of life, the infant showed recurrent C-reactive protein (CRP) elevation, associated with S. aureus bacteremia. Antibiotic courses, including vancomycin and linezolid, were performed with transitory normalization of blood parameters. On day 74, the infant suddenly deteriorated and showed a significant increase of both CRP and procalcitonin. Empiric vancomycin and piperacillin-tazobactam treatment was started; nevertheless, she developed a progressive hard swelling of neck and mandible. Radiological evaluation revealed a mandibular osteomyelitis complicated by an abscess, whose culture grew MRSA. Vancomycin was thus changed to teicoplanin and complete clinical and radiological healing was gradually achieved.

In the presence of major risk factors, persistent bacteremia and nonspecific symptoms, a localized focus of infection should be suspected. Microbiological diagnosis should always be attempted and antibiotic treatment should be guided by both susceptibility results and clinical response.

Role of ultrasonography in the detection of a subperiosteal abscess secondary to mastoiditis in pediatric patients

The aim of the study described here was to evaluate experience in the diagnosis of a subperiosteal abscess secondary to mastoiditis by means of ultrasound. Ten consecutive cases in which an ultrasound examination of the retro-auricular region was performed for suspected mastoiditis were identified. In nine cases, we found a poorly demarcated, inhomogeneous, irregular, poorly perfused lesion abutting the outer table of the cranial vault, with elevation of the outer periosteum and a clearly delineated defect of the cortical layer. In one case, there was additional invasion of the insertion of the sternocleidomastoid muscle on the mastoid process of the temporal bone, raising the suspicion of Bezold mastoiditis. Ultrasound may help in selecting patients for further imaging and might spare computer tomography, especially in sensitive patient groups such as children and pregnant women, if a defect of the outer cortex of the temporal bone can be excluded with certainty.