Efectos de la microvibración y estrógeno en la remodelación ósea: revisión sistemática / Effects of micro-vibration and estrogen on bone: a systematic review

Introducción: la pérdida de hueso es un suceso que afecta a la totalidad del esqueleto. Así, las alteraciones musculoesqueléticas afectan a millones de personas en todo el mundo y están entre las causas más comunes de dolor crónico. Objetivo: conocer los efectos de la microvibración y estrógeno en el remodelado óseo. Material y métodos: se realizó una revisión sistemática, se buscó en siete bases de datos, se incluyeron estudios clínicos controlados realizados con ratas o ratones en el periodo de publicación del 2004 al 2022. La calidad de la evidencia sintetizada se evaluó con la escala de Jadad. Resultados: se identificaron quince artículos como estudios primarios. La microvibración reportó cambios in vivo/in vitro totalmente dependientes del estímulo que conlleva incremento de la cortical externa. A su vez, con la administración de estrógeno se reportaron efectos, específicamente, en el hueso trabecular y en el periostio, así como colágeno inmaduro que indican un recambio óseo. Conclusión: tanto la microvibración como la administración de estrógeno coadyuvan a la remodelación del tejido óseo y son aprovechables como tratamiento en el momento que exista un problema de pérdida ósea (AU)

Introduction: Bone loss is an event that affects the entire skeleton. Thus, musculoskeletal disorders affect millions of people worldwide and are among the most common causes of chronic pain. Objective: to know the effects of micro-vibration and estrogen on bone remodelling. Material and methods: a systematic review was carried out; seven databases were searched; Controlled clinical studies conducted with rats or mice in the publication period from 2004 to 2022 were included. The quality of the synthesized evidence was assessed using the Jadad scale. Results: fifteen articles were identified as primary studies. Micro vibration reported in vivo/in vitro changes dependent on the stimulus that entails an increase in the outer cortex. In turn, with the administration of estrogen, effects were reported, specifically in the trabecular bone and in the periosteum, as well as immature collagen that indicates bone turnover. Conclusion: both micro-vibration and the administration of estrogen contribute to the remodelling of bone tissue and are usable as a treatment for bone loss (AU)

Research progress on anterior alveolar bone changes after orthodontic treatment involving extractions / 口腔疾病防治

@#It has been traditionally believed that a 1:1 cortical bone remodeling/tooth movement ratio has been preserved during orthodontic treatment for tooth movement, with the alveolar bone on the tension side growing and the alveolar bone on the pressure side resorbing to maintain the balance of the alveolar bone. However, recent studies have shown that alveolar bone loss has been found in patients who have undergone orthodontic treatment, suggesting that the alveolar bone does not change as the teeth change over time. Whether the morphology of the alveolar bone will change when the anterior teeth are moved has been the clinical focus. The changes of anterior alveolar bone in patients who have undergone tooth extraction after orthodontic treatment were summerized by literature review in this paper. The results of the review showed that the alveolar bone at the lingual/palatal root-cervical site of the anterior root is more prone to bone loss after extensive movement of the anterior teeth. With the development of imaging technology, CBCT is now more commonly used for analysis instead of two-dimensional images for measurement, as its results are more accurate. However, there are few multifactorial studies in which CBCT has been used to assess the morphological changes in the alveolar bone. The focus of future research is to compare the long-term changes in the anterior alveolar bone of patients of different ages based on three-dimensional imaging, and to study the correlation between different skeletal features, tooth movement patterns and alveolar bone remodeling.

Feasible low bone density condition for assessing bioactivity in ex-in vivo and in vivo studies

Abstract Objective To choose a critical animal model for assessments of bone repair with implant installation by comparing senile rats (SENIL) to young ovariectomized rats (OXV). Methodology For the ex-in vivo study, the femurs were precursors for bone marrow mesenchymal stem cells. Cellular responses were performed, including cell viability, gene expression of osteoblastic markers, bone sialoprotein immunolocalization, alkaline phosphatase activity, and mineralized matrix formation. For the in vivo study, the animals received implants in the region of the bilateral tibial metaphysis for histometric, microtomography, reverse torque, and confocal microscopy. Results Cell viability showed that the SENIL group had lower growth than OVX. Gene expression showed more critical responses for the SENIL group (p<0.05). The alkaline phosphatase activity obtained a lower expression in the SENIL group, as for the mineralization nodules (p<0.05). The in vivo histological parameters and biomechanical analysis showed lower data for the SENIL group. The confocal microscopy indicated the presence of a fragile bone in the SENIL group. The microtomography was similar between the groups. The histometry of the SENIL group showed the lowest values (p<0.05). Conclusion In experimental studies with assessments of bone repair using implant installation, the senile model promotes the most critical bone condition, allowing a better investigation of the properties of biomaterials and topographic changes.

Mid-term follow-up of reconstruction with liquid nitrogen-inactivated autologous bone graft in patients with diaphyseal malignant tumours / 中华骨科杂志

Objective:To explore the mid-term efficacy of liquid nitrogen-inactivated autologous tumor segment bone replantation for repairing bone defects after resection of malignant tumors in the long bone shaft.Methods:A retrospective analysis was performed on the clinical data of 16 patients treated with liquid nitrogen-inactivated autologous bone graft at Beijing Jishuitan Hospital from July 2015 to June 2017 to repair defects caused by malignant tumour resection of the diaphysis. There were 10 males and 6 females with a mean age of 23.4±11.6 years (range, 8-44 years), including 8 classic osteosarcoma, 2 high-grade surface osteosarcoma, 4 Ewing's sarcoma, 1 periosteal osteosarcoma, and 1 undifferentiated pleomorphic sarcoma. Tumors were located in the humerus in 2 cases, in the femur in 8 cases and in the tibia in 6 cases. The mean length of tumor was 12.4±4.8 cm (range, 5.5-26 cm). Postoperative imaging examination was performed every 6 months, and the healing status of the transplanted bone-host bone was evaluated based on the imaging assessment method of the International Society of Limb Salvage (ISOLS) imaging assessment after allogeneic bone transplantation, and the complications were assessed using the Henderson classification. The five-year survival rate for patients and grafted bone was calculated using the Kaplan-Meier survival curve.Results:The median follow-up was 64 (60.3, 69.8) months. At the end of follow-up, 13 patients were tumour free and 3 patients died of multiple metastases at 19, 20 and 33 months after surgery. There were 32 osteotomy ends in 16 patients, of which 30 healed, including 11 metaphyseal osteotomy ends, and the healing time was 9 (6, 12) months after replantation of the tumour segment with liquid nitrogen-inactivated autologous bone; 19 osteotomy ends in the diaphysis took 13 (9, 21) months to heal, with a statistically significant difference in healing time between different sites ( Z=-2.25, P=0.025). Sixteen patients had six complications, including two cases of non-union at the diaphyseal site, one case of failure of internal fixation due to non-union, three cases of recurrence, and no soft tissue complications or infections. One patient with failed internal fixation was treated with a vascularized tip iliac bone graft that healed 6 months after surgery. Another patient died of multiple metastases with 1 unhealed diaphysis left. Three cases of recurrence were all located in the extracranial soft tissue of the autologous tumor segment inactivated by liquid nitrogen. Among them, one case underwent reoperation and local radiotherapy, and there was still no tumor survival after 65 months of surgery, and two cases died due to multiple metastases. The five-year survival rate of patients was 81% as calculated using the Kaplan-Meier survival curve, and the graft survival rate was 100%. There was no amputation and the limb salvage rate was 100%. Conclusion:The use of liquid nitrogen-inactivated autologous tumor segment bone replantation for reconstruction of bone defects after resection of malignant tumors in the shaft has advantages of higher healing rate, shorter healing time at the metaphyseal end compared to the osteotomy end, fewer complications, and higher survival rate of the replanted bone.

Treatment of infected nonunion after internal fixation of subtrochanteric fracture with a reconstruction stent of external fixation / 中华创伤骨科杂志

Objective:To evaluate the treatment of infected nonunion after internal fixation of subtrochanteric fracture with a reconstruction stent of external fixation.Methods:A retrospective study was conducted to analyze the data of 5 male patients with infected nonunion after internal fixation of subtrochanteric fracture who had been treated and completely followed up at The Great Wall Orthopaedics and Hand Surgery Hospital from January 2017 to October 2022. The patients were (30.0±13.5) years old. Seinsheimer fracture types: ⅢA (1 case), ⅢB (1 case), Ⅳ (2 cases), and Ⅴ (1 case); original internal fixation: intramedullary system (4 cases) and plate fixation (1 case); the Cierny-Mader anatomical classification: type Ⅳ (diffuse type) for all. After complete debridement at stage one, 2 or 3 hydroxyapatite (HA) coated screws were placed at both fracture ends from the lateral side of the femur for unilateral reconstruction external fixation. Next, a hybrid external fixation scaffold was added with a 1/3 ring at the sagittal position and 1 or 2 HA screws in 4 cases while unilateral reconstruction external fixation was constructed at both sides by inserting 2 HA screws into both fracture ends from the anterior femur at the sagittal position in 1 case. Antibiotic bone cement was used to fill bone defects of (3.8±1.8) cm. At 6 to 8 weeks after debridement when infection did not recur, antibiotic bone cement was removed before autogenous iliac bone grafting was performed in 3 patients and osteotomy bone transport in 2 patients. Infection control, bone union time, time for removal of external fixation stent, complications, Sanders hip function score and Paley bone outcome score were recorded.Results:The 5 patients were followed up for (23.4±8.1) months after surgery. Infection at the fracture ends was controlled after 1 time of debridement in 3 patients and after 2 times of debridement in 2 patients. The loosening HA screws were replaced twice due to infection at the proximal nail tract, and autologous bone grafting was performed at the opposite fracture ends in 1 case; no complications occurred in the other 4 cases. Bony union was achieved at the extended segment and fracture ends in all patients. The time for imaging union after bone reconstruction was (10.2±3.4) months. The time for wearing a stent of external fixation was (18.0±4.5) months. There was no recurrent infection or lingering infection. According to the Sanders hip function score at the last follow-up, 4 cases were excellent and 1 case was good; according to the Paley bone outcome score, the curative effect was excellent in all.Conclusion:Application of a reconstruction stent of external fixation combined with antibiotic bone cement can control infection at the first stage and conduct bone reconstruction at the second stage to successfully treat the infected nonunion and preserve the hip function after internal fixation of subtrochanteric fracture.

Long-term consequences of osteoporosis therapy with denosumab

ABSTRACT Denosumab (DMAb) is a human monoclonal antibody used as an antiresorptive drug in the treatment of osteoporosis. Approval at a dosage of 60 mg every 6 months was based on the results of the randomized, placebo-controlled trial (FREEDOM). The design of this 3-year study included an extension for up to 10 years. Those who were randomized to DMAb continued on drug, while those who were randomized to placebo transitioned to DMAb. The 10-year experience with DMAb provides data on efficacy of drug in terms of reduced fractures and continued increases in bone mineral density (BMD). The 10-year experience with denosumab also provides information about rare complications associated with the use of DMAb, such as osteonecrosis of the jaw (ONJ), and atypical femoral fractures (AFF). This experience provided new insights into the reversibility of effects upon discontinuation without follow-on therapy with another agent. This review focuses upon prolonged treatment with DMAb, with regard to beneficial effects on fracture reduction and safety. Additionally, its use in patients with impaired renal function, compare its results with those of bisphosphonates (BPs), the occurrence/frequency of complications, in addition to the use of different tools, from imaging techniques to histological findings, to evaluate its effects on bone tissue.

Genetic, Cellular and Molecular Aspects involved in Apical Periodontitis

Abstract The development, establishment and repair of apical periodontitis (AP) is dependent of several factors, which include host susceptibility, microbial infection, immune response, quality of root canal treatment and organism's ability to repair. The understanding of genetic contributions to the risk of developing AP and presenting persistent AP has been extensively explored in modern Endodontics. Thus, this article aims to provide a review of the literature regarding the biochemical mediators involved in immune response signaling, osteoclastogenesis and bone neoformation, as the genetic components involved in the development and repair of AP. A narrative review of the literature was performed through a PUBMED/MEDLINE search and a hand search of the major AP textbooks. The knowledge regarding the cells, receptors and molecules involved in the host's immune-inflammatory response during the progression of AP added to the knowledge of bone biology allows the identification of factors inherent to the host that can interfere both in the progression and in the repair of these lesions. The main outcomes of studies evaluated in the review that investigated the correlation between genetic polymorphisms and AP in the last five years, demonstrate that genetic factors of the individual are involved in the success of root canal treatment. The discussion of this review gives subsides that may help to glimpse the development of new therapies based on the identification of therapeutic targets and the development of materials and techniques aimed at acting at the molecular level for clinical, radiographic and histological success of root canal treatment.

Resumo O desenvolvimento, estabelecimento e reparo da periodontite apical (PA) depende de vários fatores, que incluem a susceptibilidade do hospedeiro, infecção microbiana, resposta imune, bem como a qualidade do tratamento do canal radicular e a capacidade de reparo do organismo. A compreensão das contribuições genéticas para o risco de desenvolver a PA e apresentar PA persistente tem sido extensivamente explorada na Endodontia moderna. Assim, este manuscrito pretende fornecer uma revisão da literatura em relação aos mediadores bioquímicos envolvidos na sinalização da resposta imune, osteoclastogênese e neoformação óssea, bem como os componentes genéticos envolvidos no desenvolvimento e reparo da PA. Uma revisão narrativa da literatura foi realizada através de uma pesquisa nas bases PUBMED/MEDLINE e uma pesquisa manual nos principais livros sobre a PA. O conhecimento sobre as células, receptores e moléculas envolvidas na resposta imuno-inflamatória do hospedeiro durante a progressão da PA somado ao conhecimento da biologia óssea, especialmente o papel dos osteoblastos, osteócitos e osteoclastos no turnover ósseo, permite a identificação de fatores inerentes ao hospedeiro que podem interferir tanto na progressão como no reparo destas lesões. Os principais resultados dos estudos avaliados na revisão que investigaram a correlação entre polimorfismos genéticos e PA, nos últimos cinco anos, demonstram que os fatores genéticos do indivíduo estão envolvidos no sucesso do tratamento do canal radicular. A discussão desta revisão fornece subsídios que podem ajudar a vislumbrar o desenvolvimento de novas terapias baseadas na identificação de alvos terapêuticos e no desenvolvimento de materiais e técnicas destinadas a atuar a nível molecular para o sucesso clínico, radiográfico e histológico do tratamento endodôntico.

Electromechanical Effects of Bone Remodeling Based on Edge Smoothed Finite Element Method / 医用生物力学

Objective Aiming at solving the problem of poor accuracy for numerical solution of traditional finite element method (FEM) in numerical analysis on piezoelectric effects of bone remodelling, a model with an edge-based smoothed FEM (ES-FEM) was proposed. Methods The bone model was discretized by triangular elements, and the smoothing domain was constructed based on edges of the existing mesh element. Based on gradient smoothing technique, the smoothed strain gradient and the smoothed electric field gradient were obtained, and the discrete equations of the system were constructed under the framework of smoothed Galerkin weakform. Results The changes of bone mineral density (BMD) and the distributions of electric potential under piezoelectric effects in the process of bone remodelling were reflected by using the above model. Compared with FEM, ES-FEM could improve the accuracy of simulation result for bone remodelling to a certain extent. Conclusions The proposed ES-FEM can simulate the process of bone remodelling more accurately. The accurate prediction for piezoelectric effect of bone reconstruction by this method provides an effective theoretical basis for clinical research of bone diseases.

Numerical Simulation of Bone Remodeling under Low Loading Coupled with Electrical Stimulation / 医用生物力学

Objective To study the bone disuse behavior with electric field under low load stimulation frequency. Methods A disuse model was proposed to describe the effects of mechanical and electrical stimulation on bone remodeling through the activation frequency. By establishing the finite element model of proximal femur and using the finite element method, the process of bone remodeling under low load stimulation frequency coupled with electrical stimulation was simulated, and the loss of bone density was analyzed. Results The density was significantly decreased by decreasing the frequency of daily load stimulation frequency. The electrical stimulation could resist density loss caused by the low load stimulation frequency to a certain degree, and its main influence areas were distributed in the femoral head and femoral neck. The duration of electrical stimulation significantly affected density loss of the cortical bone and cancellous bone. Conclusions The model can simulate the process of disuse caused by the decrease of daily load stimulation frequency. Meanwhile, the effect of electric field is taken into account to show the resistance to bone density loss.

Arthrodesis reconstruction of distal tibia by 3D-printed porous prosthesis after malignant tumor resection / 中华骨科杂志

Objective:To evaluate the safety and short-term clinical postoperative functional outcomes of a novel 3D-printed porous prosthesis of the distal tibia for the bone defect after tumorectomy.Methods:From December 2017 to December 2019, a total of eight patients diagnosed with malignant bone tumor of the distal tibia were enrolled in this study. All cases received standard preoperative chemotherapy, after which osteosarcoma resection was performed and ankle arthrodesis was reconstructed using a 3D-printed prosthesis developed by our medical center. The contact surface between the distal part of the prosthesis and the talus is a 3D-printed porous surface, which is conducive to ankle fusion. The length of the prosthesis is adjusted by the conical mounting part of the modular prosthesis. The proximal part of the prosthesis can be fixed either biologically or with bone cement. At postoperative follow-up, the function of the fused ankle was assessed by radiographs and the monthly Musculoskeletal Tumor Society (MSTS) score.Results:Of the 8 patients, 5 were male and 3 were female, aged 8-29 years (mean 16.1±7.4 years), including 7 osteoblastic osteosarcomas and 1 telangiectatic osteosarcoma. Among the procedures, the mean length of osteotomy was 16 cm (11-20 cm). The method of fixation of the proximal part of the prosthesis included one case with 3D-printing of trabecular metal bone, one case with autogenous fibular graft, and six cases with bone cement. All patients were followed up for 7-39 months (mean 15.6±10.5 months). The distal prosthesis and talus were completely fused in all cases. The mean fusion duration was 4.3±0.7 months. The mean MSTS score was 84.2%±3.0% (mean 80%-90%). No tumor recurrence, wound complications, or prosthesis loosening were observed during the follow-up period.Conclusion:The novel 3D-printed distal tibial prosthesis is a safe and effective technique for reconstruction of a massive bone defect after tumorectomy of a malignant bone tumor, with high fusion rate, few complications, and satisfactory postoperative function.

Research progress on ubiquitin-specific proteases in regulation of bone remodeling / 口腔疾病防治

@#Maintaining bone homeostasis relies on the balance between bone remodeling involving bone resorption by osteoclasts and bone formation by osteoblasts under physiological conditions. An increasing number of studies have shown that the ubiquitin-proteasome system plays an important role in bone remodeling. The ubiquitination process is reversible through the action of deubiquitinase (DUB), and ubiquitin-specific proteases (USPs) are the largest of the DUB families. This article summarizes the mechanisms by which USPs regulate bone homeostasis, including USP4 and USP7, by affecting bone formation through signaling pathways such as Wnt/β-catenin and cylindromatosis (CYLD) and regulating bone resorption through signaling pathways such as nuclear factor-kappa B (NF-κB). In addition to affecting bone resorption and bone formation during bone reconstruction, the effect of USPs on bone is also reflected in the osteogenic differentiation of human periodontal membrane stem cells and implant bone binding. Future research should determine whether USPs have a greater regulatory effect on bone reconstruction and the specific mechanism of their regulatory effect to provide more approaches for the treatment of bone diseases.

Experimental study on the regulation of subchondral bone plate osteoprotegerin/receptor activator of nuclear factor kappa-B ligand system by berberine to retard the development of osteoarthritis in rabbits / 中国骨伤

OBJECTIVE@#To investigate the effect of intra-articular berberine injection on the structural remodeling of subchondral bone plate and osteoprotegerin/receptor activator of nuclear factor kappa-B ligand(OPG/RANKL) system expression in rabbits with osteoarthritis(OA).@*METHODS@#Forty 12-month-old male rabbits with an average of(2.73±0.18) kg of body weight, underwent left anterior cruciate ligament transection(ACLT), and were divided into berberine group and placebo groups after operation, 20 rabbits in each group. The berberine group received intra-articular injection of 100 μmol/L berberine 0.3 ml every week for 6 weeks. In placebo group, the same dose of 0.9% sodium chloride injection was injected into the left knee joint cavity every week for 6 weeks. Another 20 12-month-old male rabbits, weighing (2.68±0.18) kg, underwent sham operation on the left knee joint without intra-articular injection intervention (sham operation group). On the last day of the sixth week after operation, three groups of animals were sacrificed to obtain knee joint specimens. The femoral medial condyle samples were obtained for histological evaluation of cartilage and subchondral bone, Mankin scoring system was used to evaluate articular cartilage structure. Image-Pro Plus(IPP) software was used to evaluate subchondral bone plate bone volume(BV), bone volume/total volume(BV/TV), trabecular circumference(TC), mean trabecular thickness (Tb.Th). Real-time quantitative reverse transcription polymerization Enzyme chain reaction(reverse transcription-polymerase chain reaction, RT-PCR) was used to detect the mRNA expression levels of OPG and RANKL in subchondral bone tissue at 6 weeks after operation.@*RESULTS@#The cartilage structure evaluation showed that the surface of cartilage tissue in the sham operation group was smooth and flat, and the safranin coloration was full in the full thickness of the cartilage;the cartilage tissue in the berberine group showed uneven surface layer, and the staining of safranin O was mildly decreased;the surface layer fibrosis was seen in placebo group, Safranin O faded significantly. The Mankin score in the berberine group was lower than that in placebo group(P<0.01), but higher than that in sham operation group(P<0.01). The structural evaluation of subchondral bone plate showed that the trabecular bone in sham-operated group was densely arranged;after berberine intervention, the trabeculae were closely arranged;the subchondral bone trabeculae in placebo group were relatively sparse, and the distance between trabeculae was wider. Subchondral bone plate IPP software evaluation showed that BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), BV, BV/TV, TC, Tb.Th in berberine group were higher than those in placebo group(P<0.01), while lower than the sham operation group (P<0.01). PCR test results showed that the expression of OPG mRNA in the berberine group was significantly higher than that in placebo group(P<0.01), and OPG mRNA in the berberine group was lower than that in sham operation group (P<0.01). There was no significant difference in mRNA expression of RANKL among three groups(P>0.05);the ratio of OPG/RANKL in berberine group was higher than that in placebo group(P<0.01), but lower than that in sham operation group(P<0.01).@*CONCLUSION@#Intra-articular injection of berberine can effectively inhibit the resorption of subchondral bone in the early stage of OA and delay the development of the disease. The specific mechanism may be that berberine maintains the balance of OPG/RANKL system by up-regulating the expression of OPG gene in subchondral bone.

Progress in the research of medial column reconstruction of proximal humerus fractures in the elderly / 中国骨伤

The proximal medial column of the humerus is a continuous cortical region in the inner and lower part of the humerus head, which has attracted more and more attention in clinical and scientific research since it was proposed. It has been shown to increase the stability of internal fixation, maintain the height of the humeral head to prevent varus, and reduce the risk of screw penetration. Biomechanical studies have also shown that the medial column has an outstanding performance in increasing the stiffness, torsion resistance, and shear resistance of the locking plate. Although it has many benefits, there is no unified definition of its concept and specific region, and the existing classification does not include the medial column, therefore more researches are required to provide supporting information. The methods of medial column reconstruction mainly include locking plate combined with talus screw, locking plate combined with bone grafting, internal and external double plate combined support, locking plate combined with bone cement, and humeral cage. These methods have their own characteristics, however they will increase the cost of surgery and bring new complications. How to determine the best way of reconstruction is one of the focuses of future research. In this review, the concept of the proximal medial humerus column, the role of maintaining internal fixation, the role of biomechanics and the reconstruction methods are reviewed.

Advances in immunoporosis / 中华内分泌代谢杂志

Osteoporosis is a common metabolic bone disease, which is involved in disrupted normal bone remodeling process and bone resorption exceeding bone formation. Osteoblasts and osteoclasts play critical roles in maintaining bone homeostasis. In recent years, more and more studies have found that immune cells are involved in the regulation of osteoblast and osteoclast activity via releasing various chemokines and cytokines, and the concept of immunoporosis has been proposed accordingly. This article summarizes the current state of knowledge on the immune system in the pathophysiology of osteoporosis, so as to study and prevent osteoporosis from the perspective of immunology.

Effects of Gait Level on Bone Remodeling around Hip Prosthesis after Hip Replacement / 医用生物力学

Objective To investigate changes in gait level of patients after hip replacement, the variation trend of bone mineral density (BMD) around the prothesis was studied, so as to reveal the influence pattern of gait level at postoperative initial and long-term stages on bone reomodeling. Methods Based on adaptive bone remodeling theory, the finite element model of femer-prosthesis was developed. The BMD distribution was calculated using the initial and long-term gait level after hip replacement as the remodeling parameters. Gruen method was applied to quantify the BMD changes. Results At the postoperative initial stage, obvious variations existed in constant gait group and changing gait group. The maximum difference occurred in low gait group, resulting in the decrease of BMD by 41% in greater trochanter region. The improvement of gait level would promote the enhancement of BMD in proximal and middle region of the prosthesis, resulting in the increase of BMD by 47%. Long-term gait recovery would promote BMD recovery in middle and end region of prosthesis, with BMD increase by 2%-9%. Conclusions The research findings provide guidance for rehabilitation process of patients after hip replacement.

Effects of Total Hip Arthroplasty on Proximal Femoral Bone Remodeling / 医用生物力学

Objective To analyze the influence of total hip arthroplasty (THA) on the process of proximal femoral bone remodeling by using the Wolff bone remodeling theory. Methods According to control equation of bone remodeling, the program of bone remodeling was written in Python language. Preoperative femur model and postoperative femur and prosthesis finite element models were established respectively in ABAQUS software. The process of bone reconstruction before and after THA operation was compared to analyze the effect of prosthesis implantation on mechanical properties of the femur in the middle and long term after THA operation. Results The stress in proximal femur continued to decrease after prosthesis implantation, and the stress site was transferred from the femoral head to the prosthesis, resulting in an obvious stress shielding phenomenon. Bone loss in the stress shielding area was serious. The femoral shaft cortical bone became thinner and the stress shielding was relieved. The medial side at the bottom of the prosthesis was compressed, and the stress was significantly higher than that of the lateral side, where the bone was unevenly distributed. Conclusions After THA operation, obvious stress shielding occured at proximal medial side of the femur, leading to bone loss and prosthesis loosening. The difference in stress levels on both sides at the bottom of the prosthesis resulted in an uneven bone distribution, causing the discordance between the prosthesis and the femur, as well as postoperative pain in the middle part of the thigh.

Comparison of bone parameters by body region in university athletes: systematic review / Comparación de parámetros óseos por región corporal en atletas universitarios: revisión sistemática / Comparação dos parâmetros ósseos por região corporal em atletas universitários: revisão sistemática

ABSTRACT Introduction: Bone mineral density (BMD) and bone mineral content (BMC) vary depending on the type of sport practiced and the body region, and their measurement can be an effective way to predict health risks throughout an athlete's life. Objective: To describe the methodological aspects (measurement of bone parameters, body regions, precision errors and covariates) and to compare BMD and BMC by body region (total body, upper limbs, lower limbs and trunk) among university athletes practicing different sports. Methods: A search was performed on the databases PubMed, Web of Science, Scopus, ScienceDirect, EBSCOhost, SportDiscus, LILACS and SciELO. Studies were selected that: (1) compared BMD and BMC of athletes practicing at least two different sports (2) used dual-energy X-ray absorptiometry (DXA) to assess bone parameters (3) focused on university athletes. The extracted data were: place of study, participant selection, participants' sex, sport practiced, type of study, bone parameters, DXA model, software used, scan and body regions, precision error, precision protocol, covariates and comparison of bone parameters between different sports by body region. Results: The main results were: 1) BMD is the most investigated bone parameter; 2) total body, lumbar spine and proximal femur (mainly femoral neck) are the most studied body regions; 3) although not recommended, the coefficient of variation is the main indicator of precision error; 4) total body mass and height are the most commonly used covariates; 5) swimmers and runners have lower BMD and BMC values; and 6) it is speculated that basketball players and gymnasts have greater osteogenic potential. Conclusions: Swimmers and runners should include weight-bearing exercises in their training routines. In addition to body mass and height, other covariates are important. The results of this review can help guide intervention strategies focused on preventing diseases and health problems during and after the athletic career. Level of evidence II; Systematic Review.

RESUMEN Introducción: La densidad mineral ósea (DMO) y el contenido mineral óseo (CMO) varían en función del deporte practicado y de la región corporal, y su medición puede ser una forma efectiva de predecir los riesgos para la salud a lo largo de la vida de un atleta. Objetivo: Describir los aspectos metodológicos (medición de parámetros óseos, regiones corporales, errores de precisión y covariables) y comparar la DMO y el CMO por región corporal (cuerpo total, miembros superiores, miembros inferiores y tronco) en atletas universitarios de diferentes deportes. Métodos: La búsqueda se realizó en las bases de datos PubMed, Web of Science, Scopus, ScienceDirect, EBSCOhost, SportDiscus, LILACS y SciELO. Se seleccionaron estudios que: (1) compararon la DMO y el CMO de atletas que practicaban al menos dos deportes; (2) utilizaron la absorciometría de rayos X de doble energía (DXA) para evaluar los parámetros óseos y (3) se centraron en atletas universitarios. Los datos extraídos fueron: ubicación del estudio, selección de los participantes, sexo de los participantes, deporte practicado, tipo de estudio, parámetros óseos, modelo de DXA, software utilizado, escaneo y regiones corporales, error de precisión, protocolo de precisión, covariables y comparación de parámetros óseos entre deportes por región corporal. Resultados: Los principales resultados fueron: 1) DMO como el parámetro óseo más investigado; 2) cuerpo total, columna lumbar y parte proximal del fémur (principalmente cuello femoral) como las regiones corporales más estudiadas; 3) aunque no se recomienda, el coeficiente de variación fue el principal indicador de error de precisión; 4) la masa corporal total y la altura fueron las covariables más utilizadas; 5) los nadadores y corredores presentan valores más bajos de DMO y CMO; 6) se especula un mayor potencial osteogénico en jugadores del baloncesto y gimnastas. Conclusiones: Los nadadores y corredores deben incluir ejercicios con pesas en su rutina de entrenamiento. Además de la masa corporal y la altura, otras covariables son importantes. Los resultados de esta revisión pueden guiar las estrategias de intervención centradas en la prevención de enfermedades y problemas de salud durante y después de la carrera deportiva. Nivel de evidencia II, Revisión Sistemática.

RESUMO Introdução: A densidade mineral óssea (DMO) e o conteúdo mineral ósseo (CMO) variam dependendo do esporte praticado e região corporal, e sua medição pode ser uma forma eficaz de prever riscos para a saúde ao longo da vida de um atleta. Objetivo: Descrever os aspectos metodológicos (mensuração dos parâmetros ósseos, regiões corporais, erros de precisão e covariáveis) e comparar a DMO e o CMO por região corporal (corpo total, membros superiores, membros inferiores e tronco) em atletas universitários de diferentes modalidades esportivas. Métodos: A busca foi realizada nos bancos de dados PubMed, Web of Science, Scopus, ScienceDirect, EBSCOhost, SportDiscus, LILACS e SciELO. Foram selecionados estudos que: (1) compararam a DMO e o CMO de atletas que praticam pelo menos dois esportes; (2) usaram absorciometria de raios X de dupla energia (DXA) para avaliar os parâmetros ósseos e (3) com foco em atletas universitários. Os dados extraídos foram local do estudo, seleção dos participantes, sexo dos participantes, esporte praticado, tipo de estudo, parâmetros ósseos, modelo DXA, software utilizado, varredura e regiões corporais, erro de precisão, protocolo de precisão, covariáveis e comparação de parâmetros ósseos entre esportes por região do corpo. Resultados: Os principais resultados foram: 1) DMO como parâmetro ósseo mais investigado; 2) corpo total, coluna lombar e parte proximal do fêmur (principalmente colo do fêmur) como as regiões corporais mais estudadas; 3) embora não seja recomendado, o coeficiente de variação foi o principal indicador de erro de precisão; 4) massa corporal total e estatura como covariáveis mais usadas; 5) nadadores e corredores têm valores mais baixos de DMO e CMO e 6) especula-se que jogadores de basquete e ginastas têm maior potencial osteogênico. Conclusões: Nadadores e corredores devem incluir exercícios de sustentação de peso na rotina de treinamento. Além da massa corporal e da estatura, outras covariáveis são importantes. Os resultados desta revisão podem ajudar a orientar estratégias de intervenção focadas na prevenção de doenças e problemas de saúde durante e depois da carreira esportiva. Nível de evidência II, Revisão sistemática.

Immediate autogenous extracted tooth as a grafting material for fresh socket preservation: a systematic review / Diente autógeno de extracción inmediata como material de injerto para la conservación de alvéolos frescos: una revisión sistemática

Objectives: To evaluate the use of extracted autogenous teeth for socket preservation after tooth extraction. Material and Methods: Cochrane, Scopus, and PubMed databases search was conducted to identify human clinical studies reporting the clinical, radiographic and/or histological outcomes of socket preservation techniques with autogenous extracted tooth Only studies published in English language in the last 10 years were included in the study. Results: In total, 82 articles were identified. Five articles were included in the review. They included 58 teeth that were prepared as a graft for socket preservation. The grafts derived from autogenous teeth were presented in three forms: particles, blocks and powder. The mean bone loss ranged from 0.28 mm to 0.41mm in height and 0.15 mm in width. Conclusion: Immediate autogenous extracted tooth as a grafting material for fresh socket preservation is promising for future daily clinical practice. More clinical comparative studies are needed.

Objetivo: Evaluar el uso de dientes extraídos autógenos para la preservación del alveolo tras la extracción dental.Material y Métodos: Se realizó una búsqueda en las bases de datos Cochrane, Scopus y PubMed para identificar estudios clínicos en humanos que informaban los resultados clínicos, radiográficos y / o histológicos de las técnicas de preservación de alveolos con dientes extraídos autógenos. Solo se incluyeron estudios publicados en inglés en los últimos 10 años. Resultados: En total se identificaron 82 artículos. Se incluyeron cinco artículos en la revisión. Incluyeron 58 dientes que se prepararon como injerto para la preservación del alveolo. Los injertos derivados de dientes autógenos se presentaron en tres formas: partículas, bloques y polvo. La pérdida ósea media osciló entre 0,28 mm y 0,41 mm de altura y 0,15 mm de ancho. Conclusión: El diente autógeno extraído de forma inmediata utilizado como material de injerto para la conservación del alveolo fresco es prometedor para la práctica clínica diaria futura. Se necesitan más estudios clínicos comparativos.

Cambios Dimensionales en Técnicas de Preservación Alveolar Bartee y Bio-Col con Xenoinjerto Inteross®

RESUMEN: La preservación de las dimensiones y contorno del reborde alveolar posterior a una extracción es de suma importancia para evitar problemas subsecuentes para la colocación de un implante dental. El objetivo de este estudio fue comparar los cambios dimensionales mediante el análisis en tomografía computarizada de haz cónico (CBCT) en sitios pre y post preservados con técnica Bartee y Bio-Col con xenoinjerto a los 6 meses de cicatrización. En un paciente de 62 años, se realizaron 6 preservaciones alveolares en órganos dentarios uniradiculares, con diagnóstico periodontal sin esperanza, grupo A la técnica de preservación alveolar Bartee (n= 3) y grupo B la técnica de preservación alveolar Bio-Col (n= 3). Se utilizó xenoinjerto (InterOss ® Anorganic Cancellous Bone Graft Granules 0,25- 1mm Sigma graft) en ambos grupos. En el grupo A se colocó injerto óseo en la totalidad del alveolo asistido por una membrana no reabsorbible de politetrafluoroetile no denso (Cytoplast ™ Regentex TXT-200 singles, Osteogenics Biomedical Inc, Lubbock, Texas). En el grupo B se colocó el injerto óseo en 3⁄4 del alveolo y el último 1⁄4 del alveolo fue ocupado por apósito de colágeno reabsorbible (CollaPlug ® Zimmer biomet). Se registraron mediciones obtenidas mediante CBCT inicial previa a la realización de preservaciones alveolares y se tomó una segunda CBCT a los 6 meses de cicatrización obteniendo la medición en sentido vertical y horizontal, coincidiendo en el plano de corte. Se observó mediante el análisis dimensional en grupo A y Grupo B obteniendo en sentido vertical un 13,58 % y 20,76 % de reabsorción y en sentido horizontal 13,45 % y 15,72 % respectivamente a los 6 meses de cicatrización, utilizando xenoinjerto por lo que no existe diferencia estadísticamente significativa en cuanto a los cambios dimensionales entre ambas técnicas p>0,05. La preservación alveolar proporciona una estabilidad dimensional contrarrestando el proceso de reabsorción fisiológica, siendo una opción predecible.

ABSTRACT: Preserving the dimensions and contour of the alveolar ridge after the dental extraction, it´s of utmost importance to avoidsubsequent problems for the placement of a dental implant. The objective of this study was compare the dimensional changes through the analysis in Cone-beam computed tomography (CBCT), in pre and post sites preserved with the Bartee and Bio-Col technique with xenograft at 6 months of healing. In a 62-year-old patient, 6 alveolar preservations were performed in uniradicular dental organs, with a hopeless periodontal diagnosis, group A the Bartee alveolar ridge preservation technique (n = 3) and group B the Bio-Col alveolar ridge preservation technique (n = 3). Xenograft (InterOss ® Anorganic Cancellous Bone Graft Granules 0.25-1mm Sigma graft) was used in both groups. In the group A a bone graft was placed in the entire socket, assisted by a dense non-absorbable polytetrafluoroethylene membrane (Cytoplast ™ Regentex TXT-200 singles, Osteogenics Biomedical Inc, Lubbock, Texas). In the group B the bone graft was placed in 3⁄4 of the socket and the last 1⁄4 of the socket was occupied by an absorbable collagen dressing (CollaPlug ® Zimmer biomet). Measurements obtained by initial CBCT before recording alveolar ridge preservations were recorded, and the second CBCT was taken 6 months after healing obtaining the measurement vertically and horizontally, coinciding in the section plane. It was observed through dimensional analysis in group A and Group B, obtaining 13.58% and 20.76% of reabsorption vertically and 13.45% and 15.72% respectively at 6 months of healing, using xenograft, so there is no statistical difference significant in terms of dimensional changes between both techniques p> 0.05. Alveolar ridge preservation provides dimensional stability by counteracting the physiological resorption process, being a predictable option.

Hexavalent chromium exposure alters bone remodeling in the developing tooth alveolus and delays tooth eruption / La exposición a cromo hexavalente altera la remodelación ósea del alvéolo dental en desarrollo y retarda la erupción dentaria

ABSTRACT Although it has been demonstrated that exposure of lactating rats to CrVI delays tooth eruption, the effects of CrVI exposure on bone remodeling in the developing alveolus during tooth eruption remain unknown. Our purpose was to analyze the effect of CrVI in the alveolus of the first lower molar of rats. Thirty-two suckling Wistar rats were divided into two groups. The experimental group received 12.5 mg/kg body weight/day of potassium dichromate dissolved in saline solution by oral gavage as of day 4 of the experiment; the control group received an equal dose of saline solution. Each group was divided into two sub-sets and euthanized at the ages of 9 and 15 days, respectively. Histochemical and histomorphometric studies of the bone surfaces of the developing tooth alveolus were performed. The percentage of bone formation surfaces was lower in experimental animals than in age-matched controls. The percentage of bone resorption surfaces was significantly lower in 9-day-old experimental rats than in controls and significantly higher in 15-day-old experimental rats than in controls. Exposure to CrVI during lactation alters the sequence of bone resorption and formation in the walls of the developing alveolus, both of which are necessary for tooth eruption, thus causing a delay.

RESUMEN Si bien ya ha sido demostrado que la exposición a CrVI de ratas lactantes retrasa la erupción dentaria, aún se desconocen los efectos de la exposición a CrVI que se producen sobre la modelación y remodelación de las paredes del alvéolo en formación que ocurren en los diferentes estadios de la erupción dentaria. Por tal motivo, el propósito de este trabajo fue estudiar el efecto del CrVI sobre la formación y la reabsorción óseas del alvéolo del primer molar inferior en desarrollo en ratas, a los 9 y a los 15 días de edad, que corresponden a los estadios intraóseo y de penetración mucosa de la erupción dentaria, respectivamente. El grupo experimental recibió una dosis diaria de 12,5 mg/kg de peso corporal de dicromato de potasio disuelto en solución salina por sonda bucal a partir del 4° día; mientras que el grupo control, un volumen equivalente de solución salina. Cada grupo fue dividido en 2 subgrupos de acuerdo al tiempo experimental en el que se llevó a cabo la eutanasia: 9 y 15 días de edad. Se llevaron a cabo estudios histoquímicos e histomorfométricos de las superficies óseas de los alveólos dentarios en formación. Los datos fueron analizados estadísticamente utilizando la prueba t de Student; estableciéndose un valor de p<0,05 como estadísticamente significativo. El porcentaje de superficies en formación fue menor en los animales experimentales de 9 y de 15 días de edad que en los respectivos controles. El porcentaje de superficies en reabsorción en los animales experimentales de 9 días de edad fue significativamente menor y en los animales de 15 días de edad fue significativamente mayor con respecto a sus controles. La exposición al cromo hexavalente durante la lactancia altera la secuencia de la reabsorción y la formación ósea de las paredes del alvéolo en desarrollo necesarias para que la pieza dentaria erupcione, causando su retraso. Los hallazgos obtenidos muestran la importancia del control de sustancias tóxicas en el agua potable, ya que sus efectos pueden alterar la remodelación ósea y por ende, el crecimiento y el desarrollo de los individuos que fueron expuestos durante la infancia temprana.