The obturator oblique and iliac oblique/outlet views predict most accurately the adequate position of an anterior column acetabular screw.

OBJECTIVE: Percutaneous fixation of the acetabulum is a treatment option for select acetabular fractures. Intra-operative fluoroscopy is required, and despite various described imaging strategies, it is debatable as to which combination of fluoroscopic views provides the most accurate and reliable assessment of screw position. MATERIALS AND METHODS: Using five synthetic pelvic models, an experimental setup was created in which the anterior acetabular columns were instrumented with screws in five distinct trajectories. Five fluoroscopic images were obtained of each model (Pelvic Inlet, Obturator Oblique, Iliac Oblique, Obturator Oblique/Outlet, and Iliac Oblique/Outlet). The images were presented to 32 pelvic and acetabular orthopaedic surgeons, who were asked to draw two conclusions regarding screw position: (1) whether the screw was intra-articular and (2) whether the screw was intraosseous in its distal course through the bony corridor. RESULTS: In the assessment of screw position relative to the hip joint, accuracy of surgeon's response ranged from 52% (iliac oblique/outlet) to 88% (obturator oblique), with surgeon confidence in the interpretation ranging from 60% (pelvic inlet) to 93% (obturator oblique) (P < 0.0001). In the assessment of intraosseous position of the screw, accuracy of surgeon's response ranged from 40% (obturator oblique/outlet) to 79% (iliac oblique/outlet), with surgeon confidence in the interpretation ranging from 66% (iliac oblique) to 88% (pelvic inlet) (P < 0.0001). CONCLUSIONS: The obturator oblique and obturator oblique/outlet views afforded the most accurate and reliable assessment of penetration into the hip joint, and intraosseous position of the screw was most accurately assessed with pelvic inlet and iliac oblique/outlet views. EVIDENCE: Clinical Question.

Fc receptor-like 3 (-169T>C) polymorphism increases the risk of tendinopathy in volleyball athletes: a case control study.

BACKGROUND: Tendinopathy pathogenesis is associated with inflammation. Regulatory T (Treg) cells contribute to early tissue repair through an anti-inflammatory action, with the forkhead box P3 (FOXP3) transcription factor being essential for Treg function, and the FC-receptor-like 3 (FCRL3) possibly negatively regulating Treg function. FCRL3 -169T>C and FOXP3 -2383C>T polymorphisms are located near elements that regulate respective genes expression, thus it was deemed relevant to evaluate these polymorphisms as risk factors for tendinopathy development in athletes. METHODS: This case-control study included 271 volleyball athletes (146 tendinopathy cases and 125 controls) recruited from the Brazilian Volleyball Federation. Genotyping analyses were performed using TaqMan assays, and the association of the polymorphisms with tendinopathy evaluated by multivariate logistic regression. RESULTS: Tendinopathy frequency was 63% patellar, 22% rotator cuff and 15% Achilles tendons respectively. Tendinopathy was more common in men (OR = 2.87; 95% CI = 1.67-4.93). Higher age (OR = 8.75; 95% CI = 4.33-17.69) and more years of volleyball practice (OR = 8.38; 95% CI = 3.56-19.73) were risk factors for tendinopathy. The FCRL3 -169T>C frequency was significantly different between cases and controls. After adjustment for potential confounding factors, the FCRL3 -169C polymorphism was associated with increased tendinopathy risk (OR = 1.44; 95% CI = 1.02-2.04), either considering athletes playing with tendon pain (OR = 1.98; 95% CI = 1.30-3.01) or unable to train due to pain (OR = 1.89; 95% CI = 1.01-3.53). The combined variant genotypes, FCRL3 -169TC or -169CC and FOXP3 -2383CT or -2383TT, were associated with an increased risk of tendinopathy among athletes with tendon pain (OR = 2.24; 95% CI: 1.14-4.40 and OR = 2.60; 95% CI: 1.11-6.10). The combined analysis of FCRL3 -169T>C and FOXP3 -2383C>T suggests a gene-gene interaction in the susceptibility to tendinopathy. CONCLUSIONS: FCRL3 -169C allele may increase the risk of developing tendinopathy, and together with knowledge of potential risk factors (age, gender and years playing) could be used to personalize elite athletes' training or treatment in combination with other approaches, with the aim of minimizing pathology development risk.

Approaches to preserve human osteochondral allografts.

Osteochondral defects may progress to osteoarthritis. Many attempts have been developed to overcome this issue, including osteochondral autografts and allografts. The goal of this study was to develop a new protocol for storage of human osteochondral allografts. Osteochondral plugs were randomly allocated in the following groups: control, immediate freezing up to -70 °C, cooling at 4 °C, and storage at 37 °C. Samples from the cooling at 4 °C and storage at 37 °C groups were stored in tubes containing medium plus human albumin and analyzed after 1, 3, and 14 days. The frozen groups' samples were cryopreserved for 1 year in cryotubes containing medium only (FM), medium plus human albumin (FA), and medium plus human albumin and glucose (FG) and were then analyzed. Analysis involved histological study with hematoxylin-eosin and Safranin O and a modified Live/Dead assay. In samples stored both at 37 and 4 °C, analysis showed statistically significant higher cellular mortality at 14 days compared to 1 and 3 days, but mortality in the 4 °C group was lower. In the freezing protocols, the FA group showed less cellular mortality than the FM and FG groups. Cooling at 4 °C offers better preservation capacity than storage at 37 °C, but both offer the capacity for preservation for 14 days. Adding human albumin to the storage medium is useful in reducing cellular mortality in samples frozen for 1 year.

New strategy to control cell migration and metastasis regulated by CCN2/CTGF.

Connective tissue growth factor (CTGF)/CCN family member 2 (CCN2) is a CCN family member of matricellular signaling modulators. It has been shown that CCN2/CTGF mediates cell adhesion, aggregation and migration in a large variety of cell types, including vascular endothelial cells, fibroblasts, epithelial cells, aortic smooth muscle and also pluripotent stem cells. Others matricellular proteins are capable of interacting with CCN2/CTGF to mediate its function. Cell migration is a key feature for tumor cell invasion and metastasis. CCN2/CTGF seems to be a prognostic marker for cancer. In addition, here we intend to discuss recent discoveries and a new strategy to develop therapies against CCN2/CTGF, in order to treat cancer metastasis.

Evidence of genetic variations associated with rotator cuff disease.

BACKGROUND: Rotator cuff disease (RCD) is a complex process influenced by a multitude of factors, and a number of gene pathways are altered in rotator cuff tears. Polymorphisms in these genes can lead to an extended tendon degeneration process, which explains why subsets of patients are more susceptible to RCD. MATERIALS AND METHODS: Twenty-three single-nucleotide polymorphisms within 6 genes involved in repair and degenerative processes (DEFB1, DENND2C, ESRRB, FGF3, FGF10, and FGFR1) were investigated in 410 patients, 203 with a diagnosis of RCD and 207 presenting with absence of RCD. Exclusion criteria were patients older than 60 years and younger than 45 years with a history of trauma, rheumatoid arthritis, autoimmune syndrome, pregnancy, and use of corticosteroids. Genomic DNA was obtained from saliva samples. Genetic markers were genotyped with TaqMan real-time polymerase chain reaction. The χ(2) test compared genotypes and haplotype differences between groups. Multivariate logistic regression analyzed the significance of many covariates and the incidence of RCD. RESULTS: Statistical analysis revealed female sex (P = .001; odds ratio, 2.07 [1.30-3.30]) and being white (P = .002; odds ratio, 1.88 [1.21-2.90]) to be risk factors for RCD development. A significant association of haplotypes CCTTCCAG in ESRRB (P = .05), CGACG in FGF3 (P = .01), CC in DEFB1 (P = .03), and FGFR1 rs13317 (P = .02) with RCD could be observed. Also, association between FGF10 rs11750845 (P = .03) and rs1011814 (P = .01) was observed after adjustment by ethnic group and sex. CONCLUSIONS: Our work clearly supports the role of DEFB1, ESRRB, FGF3, FGF10, and FGFR1 genes in RCD. Identification of these variants can clarify causal pathways and provide a clue for therapeutic targets.

High-grade Pleomorphic Sarcoma Associated with Metallosis in a Patient with Total Hip Arthroplasty.

Although the relationship between hip arthroplasty and the development of sarcoma was first described in the literature about forty years ago, this association is extremely rare. In the present case report, we describe the association between orthopedic implants and soft tissue sarcoma in a 79-year-old man who underwent primary total hip arthroplasty (THA) for coxarthrosis 24 years ago. In the present case report, we describe the clinical evolution and the radiographic and histopathological findings of the lesion. In the intraoperative period of the second revision surgery, loosening of the acetabular and femoral components in association with extensive areas of necrosis and metallosis was evidenced. We performed debridement of the hip and right thigh region and removed the implants. Due to the extent of the lesion and to necrosis, it was not possible to perform a new joint reconstruction. The histopathological diagnosis of high-grade undifferentiated pleomorphic sarcoma associated with extensive areas of metallosis was confirmed in tissue adjacent to the implant. The patient developed pulmonary metastases and died 6 months after the diagnosis. Despite the rarity of this association, sarcomas should be considered in the differential diagnosis of aseptic loosening, especially in the presence of metallosis in the peri-implant tissue. To our knowledge, the 24-year latency period between primary THA and the establishment of a sarcoma diagnosis is one of the longest reported to date.

Open Fracture of the Femoral Neck in an Adult: Case Report and Surgical Solution.

Intracapsular proximal femoral fracture is a frequent injury in elderly patients, often associated with low-energy trauma and reduced bone mass. In young patient, it is uncommon, usually caused by high-energy trauma and accompanied by damage to the adjacent soft tissues. However, reports of open intracapsular proximal femoral fracture due to indirect trauma are rare in the orthopedic literature. In the present article, we describe a case of this injury in a 35-year-old man involved in a car accident. The proximal femur was exposed at the gluteal region due to a mechanism similar to dislocation of the posterior hip. We describe the initial treatment and subsequent management until achieving a definitive solution using total hip arthroplasty and muscle transfer to reconstruct the abductor mechanism of the hip. At 10 months of follow-up, the patient presented good functional outcome, with gradual recovery of the abductive strength and a Harris Hip Score of 91 points. In addition, a radiographic study showed that the cemented total prosthesis was well-positioned. This therapeutic strategy (total hip arthroplasty with muscle transfer to reconstruct the abductor musculature) was successful to treat an intracapsular proximal femoral fracture with bone exposure.

Characterization of the Masquelet Induced Membrane Technique in a Murine Segmental Bone Defect Model.

Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208µm) than at four (186.9 ± 70.21µm, p = 0.0002) and two weeks (252.2 ± 55.1µm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.

Fine structure and molecular content of human chondrocytes encapsulated in alginate beads.

Preservation of the chondrocytic phenotype in vitro requires a 3D (three-dimensional) culture model. Diverse biomaterials have been tested as scaffolds for culture of animal chondrocytes; however, to date, none is considered a gold standard in regenerative medicine. Here, we studied the fine structure and the GAGs (glycosaminoglycans) content of human chondrocytes encapsulated in alginate beads by using electron microscopy and radioactive sulfate [35S] incorporation, respectively. Cells were obtained from human cartilage, encapsulated in alginate beads and cultured for 28 days. [35S]Na2SO4 was added to the culture media and later isolated for quantification of the sulfated GAGs found in three compartments: IC (intracellular), IB (intra-bead) and EB (extra-bead). Round cells were seen isolated or forming small groups throughout the alginate. Human chondrocytes presented the features of active cells such as euchromatic nuclei, abundant RER (rough endoplasmic reticulum) and many transport vesicles. We observed an extracellular matrix rich in collagen fibres and electrondense material adjacent to the cells. Most of the GAGs produced (74%) were found in the culture medium (EB), indicating that alginate has a limited capacity to retain the GAGs. CS (chondroitin sulfate), the major component of aggrecan, was the most prominent GAG produced by the encapsulated cells. Human chondrocytes cultured in alginate can sustain their phenotype, confirming the potential application of this biomaterial for cartilage engineering.

Identification of periodontal pathogens in healthy periimplant sites.

PURPOSE: : The aim of this study was to evaluate the presence of periodontopathogens in subgingival periimplant sites in partially edentulous patients using polymerase chain reaction procedures, with regard to areas with clinical and radiographic signs of health and areas presenting periimplant disease. MATERIALS AND METHODS: : Thirty nonsmoking, partially edentulous patients, aged 30 to 76 years, were included in this study and divided in 3 groups according their clinical and radiographic characteristics. Group A (n = 10) presented periimplant health, group B (n = 10) presented periimplant mucositis, and group C (n = 10) were patients with periimplantitis. Periimplant tissues were clinically examined as regards the color of mucosae, presence of bacterial plaque, depth and bleeding on probing, and local suppuration. History of periodontal disease was also considered. Radiographic analysis evaluated the presence of bone loss around the implant. Samples of periimplant crevicular fluid were collected to analyze the presence of periodontal pathogens, Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), and Treponema denticola (Td). RESULTS: : The results showed that the history of periodontal disease is associated with periimplant disease. The bacteria Aa, Pg, Pi, Td, and Tf were present in periimplant sites clinically and radiographically characterized, as healthy periimplant tissues, mucositis, and periimplantitis. CONCLUSIONS: : We concluded that Aa, Pg, Pi, Td, and Tf are present in healthy and diseased conditions. Therefore, these periodontal pathogens are not strictly related to periimplant disease sites.

Predictive Factors for Blood Transfusion after Total Knee Arthroplasty.

Objectives The present paper aims to (1) verify the incidence and volume of blood transfusion among patients undergoing unilateral cemented total knee arthroplasty (TKA) in a single Brazilian reference center; (2) identify pre and perioperative variables to determine subjects with higher risk (i.e., predictive factors) for blood transfusion within 48 hours following surgery; (3) estimate the risk of blood transfusion during the first 48 hours after the procedure. Methods The initial sample consisted of all patients undergoing TKA from August 2010 to August 2013. After applying the exclusion criteria, 234 patients aged 30 to 83 years old and diagnosed with primary or secondary osteoarthritis due to rheumatoid arthritis remained in the study. Results Preoperative hemoglobin levels ≤ 12.3 g/dL and ischemia time ≥ 87 minutes were independent predictors for post-TKA blood transfusion, with a relative risk of 2.48 and 1.78, respectively. Approximately half of the TKA patients (51.3%) presenting these two variables required a blood transfusion. Conclusion The incidence of post-TKA blood transfusion was 33.7%. On average, each transfused patient received 480 mL of packed red blood cells. Preoperative hemoglobin levels ≤ 12.3 g/dL ( p < 0.001) and ischemia time ≥ 87 minutes ( p < 0.047) were independent predictors for blood transfusion in TKA using a pneumatic cuff, with a relative risk of 2.48 and 1.78, respectively. Age, gender, diagnosis, or body mass index were not considered independent predictors for the need for blood transfusion up to 48 hours after the procedure.

Epidemiology of Dupuytren disease and Patients Undergoing Selective Fasciectomy.

Objective To describe the epidemiological and clinical profile of patients with Dupuytren disease treated by selective fasciectomy and the factors associated with the severity of the disease. Methods Retrospective descriptive observational study involving 247 patients with Dupuytren disease, from 2013 to 2019. Multivariate logistic regression was performed for data analysis. Results Most patients were male (83.8%), self-declared white (65.2%), alcoholics (59.6%) and 49% were smokers, with a mean age of 66 ± 9 years old, with 77.2% presenting symptoms of the disease after the age of 51 years old. Approximately 51.9, 29.6 and 17.3%, respectively, had arterial hypertension, diabetes mellitus and dyslipidemia comorbidities. Bilateral involvement of the hands was observed in 73.3% of the patients. The rate of intra- and post-selective fasciectomy complications was of 0.6 and 24.3%, respectively, with 5.2% of the patients needing reintervention after 1 year of follow-up. After multivariate analysis, males were associated with bilateral involvement of the hands (odds ratio [OR] = 2.10; 95% confidence interval [CI]: 1.03-4.31) and with a greater number of affected rays (OR = 3.41; 95% CI: 1.66-7.03). Dyslipidemia was associated with reintervention (OR = 5.7; 95% CI = 1.03-31.4) and bilaterality with a higher number of complications (35.7 versus 19.7%). Conclusion A low rate of reintervention and operative complications was observed in patients with Dupuytren disease treated by selective fasciectomy. Male gender was associated with severe disease (bilaterality and more than two affected rays), and dyslipidemia with reintervention.

PTH1-34 improves devitalized allogenic bone graft healing in a murine femoral critical size defect.

The treatment of large segmental defects of long bones resulting from trauma, infection, or bone tumor resections is a major challenge for orthopedic surgeons. The reconstruction of bone defects with acellular allografts can be used as an osteoconductive approach. However, devitalized allografts are associated with high rates of clinical failure as a result of poor intrinsic osteoinduction properties and a lack of further remodeling. Nevertheless, evidence suggests that due to its anabolic properties, teriparatide (PTH1-34) could be effective as an adjuvant therapy for massive allograft healing. Therefore, our goal was to investigate in a murine critical-sized defect model whether the intermittent administration of PTH1-34 improves the incorporation and revitalization of acellular structural bone allografts. Thus, a 2.5-mm critical-sized defect was established in the right femur of C57BL/6 mice, followed by the reconstruction with a devitalized cortical structural allograft. A titanium micro locking plate was applied to the anterior femoral surface and secured in place with self-tapping locking screws. Subsequently, daily doses of PTH1-34 (30, and 40 µg/kg) or saline were administered to the mice for 14 days after surgery. The mice were maintained without PTH1-34 therapy for an additional 7 days before being euthanized at 3 weeks post-surgery. Bone graft consolidation was assessed on radiographic images and by histomorphometric analysis. Additionally, to determine the frequency of osteoprogenitor cells in the bone marrow and their in vitro osteogenic capacity, stromal cells were isolated from the bone marrow of animals treated with 30 or 40 µg/kg/day of PTH1-34 following the same protocol used for the experimental animals. Our results suggest that intermittent PTH1-34 treatment at 30 µg/kg/day after femoral allograft reconstruction surgery accelerated the healing process as evidenced by new bone formation induced on endosteal and periosteal surfaces, enhanced revitalization of allogeneic graft, and increased frequency and osteogenic capacity of bone marrow stromal cells (BMSC). These findings should encourage further studies aimed at investigating the potential therapeutic use of intermittent PTH1-34, specifically with regards to the optimal dosing regimen in clinically challenging orthopedic scenarios.

Impact of the Strategies Adopted to Face the COVID-19 Pandemic in a Brazilian Reference Institute for High Complexity Surgery in Orthopedics and Traumatology.

COVID-19 pandemics required substantial reorganization and adaptation of healthcare services all over the world. This study aims to analyze the effect of operational strategies implemented in Brazil to manage the extra strain placed on healthcare services by the COVID-19 pandemic of 2020. In particular, this investigation examines the strategy to convert an institute specialized in elective orthopedic procedures of high complexity into a trauma unit for all musculoskeletal trauma patients of an entire federative unit. A retrospective study was conducted comparing hospital variables at the peak period of the pandemic (from March 16, 2020 to June 30, 2020) with the same period in 2019 as a comparative baseline. The variables analyzed included number of professionals away from work, surgeries performed, outpatient care, transfers, length of stay, number of patients diagnosed with COVID-19 and patient mortality. During the COVID-19 peak period, there was a 48.5% reduction in surgical productivity and 72.4% reduction in outpatient care compared with the same period in 2019. The number of transfers increased substantially (124.5%), while 94 confirmed cases and 77 suspected cases of COVID-19 were reported. The mortality rate increased by 245%. The present study highlighted the effect of COVID-19 on a tertiary orthopedic hospital. Despite the dramatic changes in hospital operations, due to the implementation of protocols to manage the pandemic, the results demonstrated the feasibility and efficiency of such protocols in prioritizing quality and safety for patients and the healthcare workforce.

Ridge bone maintenance in human after extraction.

PURPOSE: The aim of this study was to evaluate, clinically and histologically, the tissues formed in human alveolar sockets filled with bovine morphogenetic protein/bovine organic matrix (BOM) and absorbable membrane (AM) immediately after extraction. MATERIALS: Forty-six human alveolar sockets, exhibiting buccal bone defects were selected for this study. Group 1 received no biomaterial to serve as control. Sockets from group 2 were filled with bovine bone morphogenetic protein (bBMP) associated with bOM. The association of bBMP/bOM/AM filled the alveolar defects from group 3. AM was placed over the defects from group 4. Clinical evaluation analyzed ridge width before biomaterial filling and 4 months after filling. Fifteen specimens were collected from groups 2, 3, and 4 for histologic analyses. RESULTS: Clinical results showed no significant augmentation on the control group (-0.16 +/- 0.28 mm). All test sites, groups 2, 3, and 4, showed relevant ridge width augmentation (3.0 +/- 0.5 mm, 2.4 +/- 0.3 mm, and 2.9 +/- 0.6 mm, respectively) and no resorption. Histologically, all experimental alveolar sockets showed active bone formation with osteoid, osteoblasts, and cell differentiation. CONCLUSION: On the basis of this study, we concluded that bBMP/bOM with or without AM could preserve the ridge showing viable bone formation for future implant placement.

Evaluation of the Radiographic Parameters of Sagittal and Spinopelvic Alignment in Patients with Osteoarthritis submitted to Total Hip Arthroplasty.

Objective To evaluate radiographic parameters of sagittal and spinopelvic alignment in patients with hip osteoarthritis (OA) undergoing primary total hip arthroplasty (THA) to define the primary surgical approach in individuals with concomitant spinal and hip joint disease. Methods Longitudinal, prospective, comparative study with 27 patients undergoing THA and 43 subjects without OA. Results An association between hip and spine degenerative disease in patients with OA was noted. After THA, radiographic parameters of pelvic tilt angle, sagittal vertical axis (EVS) and seventh cervical vertebra/sacrofemoral distance (C7/DSF) ratio were similar to values from volunteers without joint disease. Global coronal alignment (ACG), sagittal alignment, spinopelvic T1 and T9 tilts (IT1EP and IT9EP), sacral tilt (IS), pelvic version (VP), pelvic type and lumbopelvic complex (CLP) did not change after THA. Conclusion Among the sagittal and spinopelvic alignment parameters evaluated, the pelvic tilt angle, the EVS, and the C7/DSF ratio were corrected after THA and can guide the surgeon in the decision-making process for patients with concomitant spinal and hip joint disease. Spinal deformity may compensate for hip changes.

An association between successful engraftment of osteosarcoma patient-derived xenografts and clinicopathological findings.

Although osteosarcoma is a rare disease, with a global incidence rate estimated at 5.0/million/year, it is the most frequent primary bone sarcoma in children and adolescents. In translational research, the patient-derived xenograft (PDX) model is considered an authentic in vivo model for several types of cancer, as tumorgrafts faithfully retain the biological characteristics of the primary tumors. Our goal was to investigate the association between PDX formation and clinical findings of osteosarcoma patients and the ability of the model to preserve in immunocompromized mice the characteristics of the parental tumor. A fresh sample of the patient tumor obtained from a representative biopsy or from surgical resection was implanted into nude mice. When tumor outgrowths reached ~1,500mm³, fresh PDX fragments were re-transplanted into new hosts. Engraftment in mice was obtained after a latency period of 19-225 days (median 92 days) in 40.54% of the implanted samples. We confirmed the histopathological fidelity between the patient tumor and their respective established PDXs, including the expression of biomarkers. PDX take rate was higher in surgical resection samples, in post-chemotherapy surgical samples and in samples from patients with metastatic disease at presentation. In conclusion, we have shown that the osteosarcoma PDX model reliably recapitulates the morphological aspects of the human disease after serial passage in mice. The observation that more aggressive forms of osteosarcoma, including those with metastatic disease at presentation, have a higher efficiency to generate PDXs provides a promising scenario to address several unanswered issues in clinical oncology.

Cyclosporine A, but not tacrolimus, is associated with impaired proliferation and differentiation of human osteoblast-like cells in vitro.

BACKGROUND: The prevention of graft rejection after liver transplant with cyclosporine A (CyA) and tacrolimus has been associated to decreased bone mineral density. The aim of this study was to investigate the in vitro effects of increasing concentrations of CyA and tacrolimus on human osteoblasts. MATERIAL/METHODS: Human osteoblast-like cells obtained by the outgrowth of cells from bone chips were exposed to tacrolimus (10-1000 ng/mL) or CyA (1000-50,000 ng/mL). Alkaline phosphatase (ALP) activity was determined on days 2, 4, 6, and 8, and cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell counting on days 2, 4, 6, and 8. Cell death was investigated by flow cytometry with propidium iodine, and apoptosis was assessed by flow cytometry with fluorescently conjugated annexin V. RESULTS: No effects of tacrolimus were detected with respect to ALP activity or cell proliferation. In CyA-treated cultures, concentrations greater than 10 000 ng/mL were associated with decreased ALP activity after 8 days (P<0.05). In addition, a dose-dependent reduction in cell proliferation was detected after 6 days (P<0.05). This decreased cell proliferation was associated with increased apoptosis in response to 50 000 ng/mL CyA. CONCLUSIONS: Our results showed that CyA reduced, in a time- and concentration-dependent manner, the number of metabolically active cells via a decrease in proliferation and an increase in cell death, and induced impairment of osteoblast differentiation. These negative effects of CyA on human osteoblast-like cells might contribute to the bone loss reported in vivo.

Factors Influencing the Outcome of Osteosynthesis in the Fracture of the Femoral Neck in Young Adult Patients.

Objectives To evaluate the factors that influence the outcome of osteosynthesis after closed reduction of the fracture of the femoral neck in young adult patients. Methods A retrospective study was conducted, reviewing the data of patients operated in a large orthopedic hospital from 2003 to 2011; a total of 81 patients met the inclusion criteria. The time interval between the fracture and the surgery, the initial fracture deviation, the quality of the reduction, and the placement of the implant were evaluated. Results The present study observed a strong relationship between the quality of the reduction and therapeutic success. The degree of the initial deviation and the time elapsed between the initial trauma and the osteosynthesis did not influence the surgical outcome regarding bone consolidation. The correct positioning of the implants was associated with a satisfactory evolution in the postoperative period. Conclusion The quality of the reduction and the positioning of the implants are factors that influence the results of osteosynthesis in fractures of the femoral neck in young adult patients.

Bone morphogenetic protein-2 promotes osteosarcoma growth by promoting epithelial-mesenchymal transition (EMT) through the Wnt/ß-catenin signaling pathway.

The correlation between BMP-2 and osteosarcoma growth has gained increased interest in the recent years, however, there is still no consensus. In this study, we tested the effects of BMP-2 on osteosarcoma cells through both in vitro and in vivo experiments. The effect of BMP-2 on the proliferation, migration and invasion of osteosarcoma cells was tested in vitro. Subcutaneous and intratibial tumor models were used for the in vivo experiments in nude mice. The effects of BMP-2 on EMT of osteosarcoma cells and the Wnt/ß-catenin signaling pathway were also tested using a variety of biochemical methods. In vitro tests did not show a significant effect of BMP-2 on tumor cell proliferation. However, BMP-2 increased the mobility of tumor cells and the invasion assay demonstrated that BMP-2 promoted invasion of osteosarcoma cells in vitro. In vivo animal study showed that BMP-2 dramatically enhanced tumor growth. We also found that BMP-2 induced EMT of osteosarcoma cells. The expression levels of Axin2 and Dkk-1 were both down regulated by BMP-2 treatment, while ß-catenin, c-myc and Cyclin-D1 were all upregulated. The expression of Wnt3α and p-GSK-3ß were also significantly upregulated indicating that the Wnt/ß-catenin signaling pathway was activated during the EMT of osteosarcoma driven by BMP-2. From this study, we can conclude that BMP-2 significantly promotes growth of osteosarcoma cells (143B, MG63), and enhances mobility and invasiveness of tumor cells as demonstrated in vitro. The underlying mechanism might be that BMP-2 promotes EMT of osteosarcoma through the Wnt/ß-catenin signaling pathway. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1638-1648, 2019.