Population mobility, well-mixed clustering and disease spread: a look at COVID-19 Spread in the United States and preventive policy insights.

The epidemiology of pandemics is classically viewed using geographical and political borders; however, these artificial divisions can result in a misunderstanding of the current epidemiological state within a given region. To improve upon current methods, we propose a clustering algorithm which is capable of recasting regions into well-mixed clusters such that they have a high level of interconnection while minimizing the external flow of the population towards other clusters. Moreover, we analyze and identify so-called core clusters, clusters that retain their features over time (temporally stable) and independent of the presence or absence of policy measures. In order to demonstrate the capabilities of this algorithm, we use USA county-level cellular mobility data to divide the country into such clusters. Herein, we show a more granular spread of SARS-CoV-2 throughout the first weeks of the pandemic. Moreover, we are able to identify areas (groups of counties) that were experiencing above average levels of transmission within a state, as well as pan-state areas (clusters overlapping more than one state) with very similar disease spread. Therefore, our method enables policymakers to make more informed decisions on the use of public health interventions within their jurisdiction, as well as guide collaboration with surrounding regions to benefit the general population in controlling the spread of communicable diseases.

Review of calcium-sulphate-based ceramics and synthetic bone substitutes used for antibiotic delivery in PJI and osteomyelitis treatment.

Infection in orthopaedic and trauma surgery remains a destructive complication with particularly challenging diagnosis and treatment due to bacterial antibiotic resistance and biofilm formation.Along with surgical debridement and systemic antibiotics, an important type of adjuvant therapy is local antibiotic delivery, with the purpose of eliminating bacterial colonization and biofilm development.Calcium sulphate, as a synthetic absorbable biomaterial used for local antibiotic delivery, has experienced an increasing popularity during the last decade, with multiple promoted advantages such as predictable antibiotic elution kinetics, complete and quick biodegradation, good biocompatibility, and limited associated complications.A series of commercially available antibiotic-delivery systems based on calcium sulphate are under investigation and in clinical use, with different presentations, compositions, and application techniques.The current article presents the main available calcium-sulphate-based products and the existing data about the clinical and preclinical research results, stemming from their implementation as local antibiotic carriers for surgical site and implant-associated infections treatment and prevention. Cite this article: EFORT Open Rev 2021;6:297-304. DOI: 10.1302/2058-5241.6.200083.

Failure Analysis of Retrieved Osteosynthesis Implants.

Failure of osteosynthesis implants is an intricate matter with challenging management that calls for efficient investigation and prevention. Using implant retrieval analysis combined with standard radiological examination, we evaluated the main causes for osteosynthesis implant breakdown and the relations among them for a series of cases. Twenty-one patients diagnosed with implant failure were assessed for this work. For metallurgical analysis, microscopy techniques such as scanning electron microscopy (SEM), stereomicroscopy, and optical microscopy were employed. The results showed that material structural deficiencies (nine patients) and faulty surgical techniques (eight patients) were the main causes for failure. An important number of patients presented with material structural deficiencies superimposed on an imperfect osteosynthesis technique (six patients). Consequently, the importance of failure retrieval analysis should not be overlooked, and in combination with other investigational techniques, must provide information for both implant manufacturing and design improvement, as well as osteosynthesis technique optimization.

Proximal humerus chondrosarcoma in a young male patient.

Proximal humerus chondrosarcoma is a rare localization of the common primary malignant cartilaginous tumor. Management is based on oncological surgical excision because of the inherent resistance to chemotherapy and radiation therapy. The most important prognostic factors with great impact on treatment strategy are histological grading and localization of the tumor. Proximal humerus chondrosarcoma carries a slightly better prognosis, especially for the low and moderate grade tumors. We present the case of a young patient with proximal humerus chondrosarcoma surgically managed in our Department, with the purpose of underlining the challenges posed by this localization for oncological excision and reconstruction but also the importance of histological grading for the treatment algorithm.

Current review of surgical management options for extremity bone sarcomas.

Modern surgical management of extremity bone sarcomas is governed by limb-sparing surgery combined with adjuvant and neoadjuvant chemotherapy.All the resection and reconstruction techniques have to achieve oncologic excision margins, with survival rates and functional results superior to amputation.The main reconstruction techniques of bone defects resulted after resection are: modular endoprosthetic reconstruction; bone graft reconstruction; bone transport; resection arthrodesis; and rotationplasty.Oncologic resection and modular endoprosthetic reconstruction are the generally approved surgical options adopted for the majority of cases in major specialized bone sarcoma centres.Good basic principles, efficient multidisciplinary approach and sustained research in the field can provide a better future for the challenge posed by extremity bone sarcoma treatment. Cite this article: EFORT Open Rev 2019;4:174-182. DOI: 10.1302/2058-5241.4.180048.

Chondrosarcoma of the pelvis - case report.

Chondrosarcoma (CHS) is the third most common primary bone tumor after myeloma and osteosarcoma. Histologically, it is made of pure hyaline cartilage differentiation. The tumor itself may have myxoid modification and calcification. It occurs especially after 50 years, with an equal gender distribution. Most CHS are solitary, the etiology is still unclear and most of them are discovered accidentally. Early diagnosis is crucial for a good prognosis. In this paper, we would like to present a case of a female patient with an accidentally discovered CHS of the iliopubic and ischiopubic ramus of the pelvis. The purpose of this report is to highlight the importance of multidisciplinary management of tumor pathology, especially when the site of the tumor is surgically hardly accessible and to underline possible common genetic aspects of benign and malignant tumors.