Effects of jump training on the repair of bone injuries / Efeitos do treinamento de salto no reparo de lesões ósseas / Efectos del entrenamiento de salto en la reparación de lesiones óseas

ABSTRACT Introduction: Long jump is a technically complex sport. Its technique encompasses running, jumping, and landing. It has high speed, fast pace, and high-intensity characteristics. Objective: Study the effect of long jump training on bone repair and rehabilitation of human fatigue injury in the lower limbs of young athletes. Methods: A scientific literature search, experimental comparison, mathematical statistics, and other research methods were used to analyze the causes and mechanisms of sports injuries in distance jumpers. An eccentric contraction training was formulated and tried out in practice. Results: After 12 weeks of eccentric contraction training, the FMS scores of jumpers in jumping improved, existing problems were recovered, and eccentric contraction training reduced the probability of sports injuries in jumpers. Conclusion: Eccentric contraction training improves the performance of young athletes in the long jump, greatly increases stability, and reduces the likelihood of future sports injuries. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: O salto em distância é um esporte tecnicamente complexo. Sua técnica engloba corrida, saltos e aterrissagem. Tem as características de alta velocidade, ritmo rápido e alta intensidade. Objetivo: Estudar o efeito do treinamento de salto à distância no reparo ósseo e na reabilitação da lesão por fadiga humana nos membros inferiores de jovens atletas. Métodos: Foi utilizada uma consulta de literatura científica, comparação experimental, estatística matemática e outros métodos de pesquisa para analisar as causas e mecanismos das lesões esportivas em saltadores à distância. Um treinamento excêntrico de contração foi formulado e experimentado na prática. Resultados: Após 12 semanas de treinamento de contração excêntrica, a pontuação FMS dos saltadores em salto melhorou, os problemas existentes foram recuperados e o treinamento de contração excêntrica reduziu a probabilidade de lesões esportivas nos saltadores. Conclusão: O treinamento de contração excêntrica melhora o desempenho dos jovens atletas no salto em distância, aumenta muito a estabilidade e reduz a probabilidade de futuras lesões esportivas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: El salto de longitud es un deporte técnicamente complejo. Su técnica incluye correr, saltar y aterrizar. Tiene las características de alta velocidad, ritmo rápido y alta intensidad. Objetivo: Estudiar el efecto del entrenamiento de salto de longitud en la reparación ósea y la rehabilitación de la lesión por fatiga humana en las extremidades inferiores de jóvenes atletas. Métodos: Se utilizó la consulta de la literatura científica, la comparación experimental, la estadística matemática y otros métodos de investigación para analizar las causas y los mecanismos de las lesiones deportivas en los saltadores de distancia. Se formuló un entrenamiento de contracción excéntrica y se probó en la práctica. Resultados: Tras 12 semanas de entrenamiento de contracción excéntrica, las puntuaciones de FMS de los saltadores de longitud mejoraron, los problemas existentes se recuperaron y el entrenamiento de contracción excéntrica redujo la probabilidad de lesiones deportivas en los saltadores. Conclusión: El entrenamiento de la contracción excéntrica mejora el rendimiento de los jóvenes atletas en el salto de longitud, aumenta en gran medida la estabilidad y reduce la probabilidad de futuras lesiones deportivas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Humerus Diaphyseal Stress Fracture in a Teenage Tennis Athlete: Case Report / Fratura por estresse diafisária do úmero em atleta de tênis adolescente: Relato de caso

Abstract A teenage male tennis player had chronic pain in his dominant arm during tennis practice. Magnetic resonance imaging (MRI) suggested humerus diaphyseal stress injury. After 4 weeks, he became asymptomatic and resumed playing. However, pain recurred after 3 days. A new MRI revealed a diaphyseal undisplaced humerus fracture and significant bone marrow edema. The patient remained in rest for 4 weeks. After that, strengthening exercises were introduced and return to training was allowed after 12 weeks. Even if asymptomatic, we suggest that these patients should not return to play before 12 weeks, depending on the physical exam and imaging findings.

Resumo Um tenista adolescente tinha dor crônica no braço dominante durante os treinos de tênis. A ressonância magnética (RM) sugeriu lesão por estresse na diáfise do úmero. Depois de 4 semanas, ele se tornou assintomático e voltou a jogar. No entanto, houve recidiva da dor após 3 dias. A nova RM revelou fratura diafisária não desviada do úmero e edema significativo da medula óssea. O paciente ficou em repouso por 4 semanas. Depois disso, exercícios de fortalecimento foram introduzidos e o retorno aos treinamentos foi permitido após 12 semanas. Mesmo que assintomáticos, sugerimos que esses pacientes não voltem a jogar antes das 12 semanas, dependendo dos exames físicos e dos achados por imagem.

Correlation analysis between arch index and foot kinematic parameters and their characteristics in stress fracture of lower extremity / 中华创伤杂志

Objective:To analyze the relationship between arch index and foot kinematic parameters and their characteristics in stress fracture of lower extremity.Methods:A case-control study was performed for 108 recruits selected from a certain army unit in 2019. Before training, the recruits′ foot print images were collected by the capacitive plantar pressure measurement system to calculate their arch indices. The kinematic characteristics of the foot were analyzed by the dynamic gait posture analysis system. Spearman rank correlation analysis between arch index and foot kinematic parameters including landing elevation angle, toe-off angle, landing speed, landing varus angle, valgus amplitude and landing valgus speed were performed. Throughout the training, orthopedic physicians followed up the recruits, among whom 10 were excluded due to other types of lower extremity injuries. The arch index and foot kinematic characteristics were analyzed and compared between the remained recruits with stress fracture of lower extremity (fracture group, n=10) and those without lower extremity injury (control group, n=79). Results:(1) For the recruits, the arch index was 0.21(0.12,0.25), with landing elevation angle for (17.31±4.02)°, toe-off angle for (63.90±5.63)°, landing speed for (176.85±24.39)°/s, landing varus angle for (13.64±4.44)°, valgus amplitude for (12.16±3.42)°, and landing valgus speed for 382.50(311.05,474.80)°/s. (2) The landing varus angle ( r=0.25, P<0.01) and valgus amplitude ( r=0.14, P<0.05) were positively related to the arch index. (3) The arch index, toe-off angle and landing valgus speed were 0.20(0.07,0.24), (61.59±5.51)° and 336.00(251.02,428.67)°/s in fracture group, significantly lower than 0.23(0.17,0.26), (64.79±4.79)° and 381.20(313.63,470.92)°/s in control group ( P<0.05 or 0.01). There were no significant differences in the landing elevation angle, landing speed, landing varus angle and valgus amplitude between the two groups (all P>0.05). Conclusions:The change of the arch index can affect the landing varus angle and valgus amplitude of the foot. Recruits who suffer from stress fracture of lower extremity have the characteristics of higher arch, lower toe-off angle and lower landing valgus speed.

One-stage total knee arthroplasty combined with open reduction and internal fixation for knee osteoarthritis complicated with tibial stress fracture / 中华创伤骨科杂志

Objective:To explore one-stage total knee arthroplasty (TKA) combined with open reduction and internal fixation (ORIF) for knee osteoarthritis complicated with tibial stress fracture.Methods:The 3 patients were retrospectively analyzed who had been treated for knee osteoarthritis complicated with tibial stress fracture at Department of Orthopedics, Ganzhou District People＇s Hospital from March 2018 to March 2020. They were all female, aged from 54 to 76 years (average, 66 years). There were 2 transverse fractures and one short oblique fracture; all of them had knee varus deformity. The Hospital for Special Surgery (HSS) scores averaged 37.6 (from 28 to 50) for the left knee and 28.3 (from 22 to 39) for the right knee. One-stage TKA was performed for the articular surface while ORIF for the right tibial stress fracture for all patients. Recorded were fracture union time, HSS knee score and range of articular motion.Results:The 3 patients were followed up for 25 to 44 months (average, 32 months).The fracture union time ranged from 4 to 7 months (average, 5 months). The last follow-ups revealed no such complications as prosthesis loosening, peri-prosthesis osteolysis or joint instability. Knee varus deformity was corrected in all patients. The HSS knee scores at the last follow-up averaged 89.6 (from 88 to 91) for the left knee and 88.3 (from 85 to 90) for the right knee.Conclusion:In the treatment of knee osteoarthritis complicated with tibial stress fracture, one-stage TKA combined with ORIF can restore the function of knee joint, leading to fine curative effects.

Avaliação ex vivo da durabilidade de sistemas de instrumentação de NiTi tratados termicamente / Ex-vivo evaluation of the durability of thermally treated NiTi endodontic files

Objetivo: O presente estudo teve como objetivo comparar três sistemas de instrumentação de NiTi, tratados termicamente, quanto ao número de condutos instrumentados até a fratura. Métodos: Foram utilizados 210 molares humanos inferiores e superiores com curvaturas leves a moderadas, comprimentos reais entre 19 e 21 mm e forames apicais até 200µm. Esses foram randomicamente divididos em três grupos de acordo com o sistema de instrumentação utilizado: Reciproc (REC; R25), ProDesign Duo Híbrido (PDH; #25/.01 e #25/.08) e TF Adaptive (TFA; #25/.08). Foram utilizados 5 instrumentos/kits de cada sistema. Registrou-se, então, o número de condutos instrumenta- dos até a fratura e o número de reinserções necessárias até o alcance do comprimento de trabalho. Resultados: A análise estatística apontou diferenças significativas quando comparada a durabilidade dos sistemas, tendo os instrumentos do grupo PDH oferecido os maiores valores (29,2), seguido de REC (21,6) e TFA (15,4) (p<0,05). Quanto ao número de reinserções, o sistema TFA foi o que necessitou do menor número de reinserções (p<0,05). Conclusão: Nas condições do estudo, pode-se concluir que o sistema ProDesign Duo Híbrido foi o mais durável; ainda que o sistema TF Adaptive tenha alcançado o comprimento de trabalho com maior facilidade

Objective: The present study compared three systems of thermally treated NiTi endodontic files regarding their achieved number of prepared root canals before fracture. Methods: Two hundred and ten slightly and moderately curved upper and lower molars with actual length ranging from 19 to 21 mm and apex foramens diameters up to 200 µm were used. The sample was allotted to three groups according to the instrumentation system in use: Reciproc (REC; R25), ProDesign Duo Hybrid (PDH; #25/.01 and #25/.08), and TF Adaptive (TFA; #25/.08). Five instruments/kits of each system were used. Then, it was registered the number of root canals prepared until the instrument fractured and the number of reinsertions needed until the working length was achieved. Results: The statistical analysis showed significant differences among the durability of the three systems, being the instruments of group PDH the ones that yielded higher reuses (29.2) followed by groups REC (21.6), and TFA (15.4) (P < .05). Regarding the number of insertions, the TFA system was the one that needed the lowest number of reinsertions (P < .05). Conclusion: Under this study conditions, ProDesign Duo Hybrid was the most durable system, whereas TF Adaptive system was the one that most easily achieved the working length.

Exploring of the Mechanism of Rib Fracture Caused by Landing on Different Parts of the Trunk after Falls from Height Using Finite Element Method / 法医学杂志

Objective To study the mechanism of rib fracture caused by landing on different parts of the trunk using finite element method, and to provide some new techniques and new ideas for the reconstruction of the whole process of falls from height. Methods The finite element method was used to study the rib fracture of human security model THUMS4.0 caused by landing on different parts of the trunk. Then the model was compared with actual cases and the mechanism of rib fracture caused by falls from height was analyzed from a biomechanical point of view. Results There were some differences in the stress and strain distribution as well as the rib fracture sites when different parts touched the ground. Ribs on both sides of the body were fractured when the front of the trunk touched the ground, and the fractures were mainly located in the junction of the ribs and costal cartilage and the midaxillary line area. When the right anterior part of the trunk touched the ground, rib fracture occurred first on the side that touched the ground, and rib fractures were mainly located in the area from the right midaxillary line to the posterior axillary line, and junction of ribs on both sides and costal cartilage. When the back of the trunk touched the ground, the fracture sites were mainly located on the back of the ribs on both sides. When the right posterior part of the trunk touched the ground, multiple rib fractures were likely to occur in the parts that touched the ground. The plastic strains were mainly concentrated at the fracture sites, while the von Mises stresses were not only concentrated at the fracture sites, but also at other sites. Conclusion There are some differences in rib fracture location sites and injury mechanisms when different parts of the trunk touch the ground.

Prognostic value of focal scintigraphic findings in clinically suspected cases of tibial stress fracture / Valor prognóstico dos achados focais na cintilografia óssea em pacientes suspeitos de fratura por estresse na tíbia

Abstract Objective: To investigate the correlation between tracer uptake on bone scintigraphy and recovery time in patients with tibial stress fracture. Materials and Methods: We evaluated two groups of athletes: those with clinical suspicion and a radiological diagnosis of tibial stress fracture (TSF group, n = 21); and those with no symptoms or evidence of fracture (control group, n = 10). All subjects underwent bone scintigraphy and magnetic resonance imaging with a maximum interval of 7 days between the assessments. Results: Using the region of interest technique, we obtained a quantitative evaluation index, comparing affected and unaffected legs. The mean uptake of 99mTc-MDP was significantly higher in the TSF group than in the control group (2.54 ± 0.77 vs. 1.05 ± 0.11; p < 0.001). Conclusion: In our sample of athletes, determining the bone scintigraphy uptake indices provided an objective method to estimate the appropriate recovery time after a tibial stress fracture.

Resumo Objetivo: Analisar a correlação entre a captação da cintilografia óssea e o tempo para recuperação de pacientes com fraturas de estresse na tíbia. Materiais e Métodos: Foram avaliados 21 atletas com suspeita clínica e o diagnóstico radiológico de fratura por estresse na tíbia (grupo 1) e 10 atletas assintomáticos (grupo 2). Todos os sujeitos submeteram-se a cintilografia óssea e ressonância magnética com intervalo máximo de sete dias entre as avaliações. Resultados: Índice quantitativo foi obtido usando a técnica da região de interesse, comparando pernas afetadas com não afetadas. A média de captação do 99mTc-MDP nos membros afetados foi significativamente diferente no grupo 1 (2,54 ± 0,77), comparado com o grupo 2 (1,05 ± 0,11) (p < 0,001). Conclusão: Em nossa amostra de atletas, os índices de captação obtidos pela cintilografia óssea proporcionaram um método objetivo para estimar o tempo de recuperação apropriado após uma fratura de estresse na tíbia.

Stress Fracture of the Capitate

Most capitate fractures occur in association with additional carpal injuries, particularly scaphoid fractures. Isolated fractures of the capitate account for only 0.3% of carpal injuries, and stress fractures are one form of this fracture. We report the case of a 20-year-old male who had a stress fracture of the capitate after serving as an honor guard in the military. Conventional radiographs and computed tomography of the right wrist revealed a minimally displaced fracture line located at the midcarpal aspect of the right capitate. A magnetic resonance imaging scan demonstrates a subarticular capitate fracture with diffuse bone marrow edema, small osteophytes, and irregularity of the midcarpal articular cartilage. We also review the carpal kinematics which possibly caused the stress fracture. Although stress fractures of the capitate are rare, they should also be accounted for with patients who perform repetitive motions of the wrist to a considerable extent.

Atypical Femoral Fractures: What Do We Know about Them?

Recently, atypical femoral fractures (AFFs) have been found in patients who were prescribed bisphosphonate to prevent osteoporotic fractures. Although the occurrence of AFF is rare, there are some concerns, such as a higher risk of delayed or non-union of AFF. This paper reviews the treatment of AFF and suggests some considerations during surgery.

Features of Whole-body Bone Scan and Local SPECT/CT Tomography of Insufficiency Fracture / 中国医学影像学杂志

Purpose The clinical manifestation of insufficiency fracture (IF) is in lack of specificity,thus it is prone to misdiagnosis.This paper aims explore imaging characteristics of 99Tcm-MDP whole-body bone scan and local SPECT/CT tomography for IF in the anticipation to improve its cognition and diagnosis capability to imaging manifestations.Materials and Methods Thirty patients who were diagnosed as IF by follow-up or imaging in Affiliated Hospital of Southwest Medical University from September 2015 to September 2016 were enrolled.The imaging features of their whole-body bone scan and local S PECT/CT tomography were retrospectively analyzed.Results For 30 patients,20 cases were single bone lesion,and 10 cases were multiple bone lesions.Lesions on the whole-body scan were represented as developer concentration of different level.Fracture line,sclerosis rim/line,soft tissue swelling,wedge-shaped or concave deformity of the vertebra could be observed on the images of SPECT/CT scan.Osteoporosis of different level could be seen on all the 30 patients.No bone destruction could be seen on the lesions and no obvious soft tissue mass around the lesions were formed.Conclusion Manifestation of whole-body bone scan and local SPECT/CT scan of IF is with certain specificity and is of significance in the early-stage diagnosis and differential diagnosis of IF.

A case-control study of bone mineral density and its influencing factors in 2079 recruits / 军事医学

Objective To find out about the charateristics of bone mineral density(BMD)and its influencing factors among 2079 recruits.Methods Recruits of Armed Police Force in Tianjin were selected as subjects.Their BMD was measured with dual-energy X-ray absorptiometry(DXA).A normal group and low bone mineral density group were selected according to the results of bone mineral density and the methord of 1:1 case-control analysis.Questionnaires were used to investigate their dietary nutrition and lifestyles.One-way ANOVA,chi-square test and Logistic regression analysis were used to explore the influencing factors of BMD.Results In total,2079 military recruits underwent a DXA scan.Normal bone mineral density accounted for 44.78%,and T value was -0.36 ±0.62.Medium bone mineral density made up 50.51%, and T value was -1.57 ±0.38.Low bone mineral density accounted for 4.71%,and T value was -2.82 ±0.39.Single factor analysis suggested that body weight, BMI, movement time, sports venues, spending too much time online all had influences on bone mineral density.Multiariable Logistic regression analysis showed that high animal diet(OR=3.435), spending too much time online(OR=1.246)were the risk factors for bone density.Dairy consumption(OR=0.296)and movement time(OR=0.549)were positively associated with bone mineral density.Conclusion There is a low bone mass in the recruits.We suggest that scientific and standardized management,popularization of knowledge,healthy diet and living habits are necessary to promote good bone peaks.

Clinical application value and imaging diagnosis of stress fracture / 中国骨伤

<p><b>OBJECTIVE</b>To discuss the imaging findings of stress fracture, in order to improve the ability of early diagnosis and early treatment of this disease.</p><p><b>METHODS</b>The DR, CT and MRI imaging data of 336 cases of stress fracture from January 2010 to January 2016 were analyzed retrospectively. Early diagnosis ratio in stress fractures by three methods were analyzed using²-test.</p><p><b>RESULTS</b>Early diagnosis ratio of three methods as follow: DR was 70.83%(238/332), CT was 55.93%(66/118), and MRI was 73.61%(53/72). There was statistical significance among three methods (²=10.15,=0.006), the early diagnosis ratio of DR was higher than CT (²=8.765,=0.003)and there was no statistical significance between DR and MRI (²=0.224,=0.636).</p><p><b>CONCLUSIONS</b>DR and MRI have better diagnosis of stress fractures while CT is not helpful in the early diagnosis. DR examination is preferred method due to its economical and convenient. MR is the important complement means, which can improve the early diagnosis ratio and provide imaging diagnosis basis for the clinical, so that the disease get early intervention and treatment.</p>

Bilateral stress fracture of femoral neck in non-athlete - case report / Fratura de estresse bilateral do colo do fêmur em não atleta - relato de caso

ABSTRACT Bilateral stress fracture of femoral neck in healthy young patients is an extremely rare entity, whose diagnostic and treatment represent a major challenge. Patients with history of hip pain, even non-athletes or military recruits, should be analyzed to achieve an early diagnosis and prevent possible complications from the surgical treatment. This report describes a 43-year-old male patient, non-athlete, without previous diseases, who developed bilateral stress fracture of femoral neck without displacement. He had a late diagnosis; bilateral osteosynthesis was made using cannulated screws. Although the diagnosis was delayed in this case, the study highlights the importance of the diagnosis of stress fracture, regardless of the activity level of the patients, for the success of the treatment.

RESUMO A fratura de estresse bilateral do colo do fêmur em pacientes adultos sadios é uma entidade extremamente rara, cujo diagnóstico e tratamento representam um grande desafio. Pacientes com história de dor no quadril, mesmo se não forem atletas ou militares, devem ser analisados para se obter um diagnóstico precoce e prevenir possíveis complicações provenientes do tratamento cirúrgico. Este relato descreve um paciente de 43 anos, não atleta, do gênero masculino, sem doenças prévias, que desenvolveu fratura de estresse do colo do fêmur bilateral sem desvio, diagnosticado e tratado tardiamente com osteossíntese bilateral com parafusos canulados. Apesar de o diagnóstico ter sido tardio nesse caso, enfatiza-se a importância de se obter diagnóstico de fratura de estresse, independentemente do nível de atividade dos pacientes, para o sucesso do tratamento.

Calcaneal Insufficiency Fracture after Ipsilateral Total Knee Arthroplasty

Insufficiency fracture of the calcaneus is a rare entity. In the absence of trauma, evaluating a painful ankle in an elderly patient can be difficult and also it might be overlook the insufficiency fracture. We experienced a case of insufficiency calcaneus fracture that occurred after ipsilateral total knee arthroplasty. Here, we report our case with a review of literatures.

Ondas de choque extracorpóreas en el tratamiento de la fractura por estrés de tibia. Presentación de un caso / Extracorporeal shockwave therapy in the treatment of stress fracture of tibia. Report of a case

El dolor en las extremidades inferiores inducido por el ejercicio es frecuente en cadetes militares debido a los largos períodos de trote que forman parte de su formación y también se relaciona con el sobreentrenamiento. Las fracturas por estrés de tibia son frecuentes entre las enfermedades que les afectan pero la mayoría de las veces no son diagnosticadas. El período de convalecencia es prolongado y lleva en ocasiones al abandono de sus actividades. Se presenta el caso de una cadete afectada a la que se trató mediante biocirugía por ondas de choque extracorpóreas, con lo que se consiguió reducción del dolor en reposo y aumento del tiempo de trote sin dolor. Debido a la importancia que reviste que el personal médico, principalmente cirujanos ortopédicos y médicos deportivos así como otros profesionales de la salud implicados en la atención, conozca sobre la existencia de la afección y de esta nueva alternativa terapéutica es que se presenta el caso.

Pain in the lower limbs induced by exercise is common in military cadets due to long periods of jogging as part of his training and is related to overtraining. Stress fractures of tíbia are common among the disorders affecting them but most often are not diagnosed. The period of convalescence is prolonged sometimes leading to abandon their atividades. A case of an affected cadet to which treated by extracorporeal shockwave therapy showing reduced pain at rest and increased time trotting achieved without painful. Because of the importance that medical staff primarily Orthopaedic Surgeons and Sports Physicians and other health professionals involved in the care know about the existence of pathology as this new therapeutic alternative is that the case is presented.

Cyclic fatigue resistance of two nickel-titanium instruments in different curving angles: a comparative study

The cyclic resistance of ProTaper Universal (size 25/08) and ProTaper Next (size 25/06) instruments was compared in artificial canals with different curvatures in this study. A total of 30 ProTaper Universal and 30 ProTaper Next instruments were divided into 6 groups (n = 10) and were operated into artificial canals with 3 different angles of curvature (45°, 60°, 90°). The canal length was kept consistent in this study. The number of cycles to fracture (NCF) was counted until file fracture occurred, at which point, the length of the fragment was measured. The data were analyzed statistically using ANOVA complemented by the Tukey test (p < 0.05). Cross sections of the fractured files were scanned by an electron microscope. In the fatigue test, the ProTaper Next displayed more resistance in 45° and 60° canals (p < 0.05), whereas ProTaper Universal exhibited a better operability in 90° canals (p < 0.05). The average length of the fragments from ProTaper Next was significantly shorter than that from ProTaper Universal in 90° canals (p < 0.05). The cross sections of the fractured surfaces became flatter when the curvature angles decreased from 90° to 45°. ProTaper Next was more reliable when shaping in curved canals, whereas ProTaper Universal was more sui for the preparation of root canals with severe curvatures.

Effects of Different Magnitudes of Mechanical Stretch on Human Intervertebral Disc Cells / 天津医药

Objective To investigate the effects of different magnitudes of mechanical stress on human interverte-bral disc degeneration. Methods The human intervertebral disc cells were subjected to different magnitudes of mechanical stress (0, 6%, 12%, or 18%elongation) for 24 h using a Flexercell Strain Unit. The mRNA expressions of anabolic genes (col-lagen-1A1, collagen-2A1, aggrecan and versican) and catabolic genes (MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5) were examined by real-time PCR and Western blot methods. Results The expression levels of collagen-1A1 and collagen-2A1 were increased at 12%of mechanical stress, and collagen-2A1 was decreased at 18%of mechanical stress compared with those of control. The mRNA expressions of catabolic genes, MMP-13 and ADAMTS-5, were increased at 12%and 18%of mechanical stress than those of control. The mechanical stretch induced a magnitude-dependent increase in ADAMTS-4 synthesis, which was finely tuned by stretching-triggered activation of distinct mitogen-activated protein kinase cascades. Specifically, an ERK1/2 specific inhibitor, U0126, significantly inhibited the stretching-induced ADAMTS-4 expression, whereas the inhibitors of p38 and JNK, SP6000125 and SB203580, showed only slightly effect on the stretching-induced ADAMTS-4 expression. Conclusion The different magnitudes of mechanical stretch exhibited different effects on the bio-logical behavior of intervertebral disc cells, which profoundly affects the intervertebral disc degeneration.

Three-dimensional finite element analysis on intramedullary controlled dynamic nailing for femoral shaft fracture / 中国组织工程研究

BACKGROUND:Interlocking intramedul ary nail complications contain nail bent or broken, exit, re-fracture at spiketail or nail hole. Thus, our team designs a novel intramedul ary control ed dynamic nail. OBJECTIVE:To evaluate the rationality and safety of intramedul ary control ed dynamic nail design and strength, and to give rational proposal for its clinical application. METHODThe three-dimensional finite element models of composite femur, transverse fractures of the femoral shaft were constructed with intramedul ary control ed dynamic nailing. The stress and strain were detected under vertical loads and gait cycle. RESULTS AND CONCLUSION:The maximum stress of the intact femur under the compression load was at femoral neck and the medial and lateral aspects of the femoral shaft;while the stresses of fractured femur were at the interface between screw and screw hole. In gait cycle, in case of intact bone, large stresses were found in the distal 1/2 of anteriomedialis of femoral shaft;while the stress distribution in fractured femur was similar with the  former. Intramedul ary control ed dynamic nailing has the ability of generating compression between fragments. These suggest that intramedul ary control ed dynamic nailing is rational and good at design and biomechanical properties.

Value of ultrasonography in early diagnosis of metatarsal fatigue fractures / 中华超声影像学杂志

Objective To observe the ultrasonic manifestation of metatarsal fatigue fractures and probe into the clinical values of ultrasonic diagnosis and follow-up to the disease.Methods The clinical data and sonographic features of 30 cases with metatarsal fatigue fracture confirmed by X-ray and CT were analyzed retrospectively.Results All the subjects in this study were metatarsals insufficiency fractures located in the second or third diaphysis.2D-ultrasound found microfracture in the cortex and the periosteal elevation by increased vascularity in the early stage.During the 3-month follow-up,thickened cortex and callus shown as the shape of mushroom or cauliflower and a great amount of neovascularisation were visualised with color Doppler flow imaging.Then,the cortex surface became gradually changing from rough to smooth and obvious posterior shadows were observed with the illness progression.Conclusions Ultrasonography could be used to detect the cortical continuity,callus characteristics and blood flow perfusion of fatigue fracture in the different damage stages.

Low-density extracorporeal shock wave and low-dose intermittent recombinant human parathyroid hormone 1-34 influence proliferation and differentiation of osteoblasts / 中国组织工程研究

BACKGROUND:Suitable stress signals such as extracorporeal shock wave (ESW) and parathyroid hormone can be involved in regulation of bone formation and metabolism. OBJECTIVE:To investigate the effects of low-density ESW and low-dose intermittent recombinant human parathyroid hormone 1-34 (rhPTH1-34) on the proliferation and differentiation of osteoblasts from rats cultured in vitro. METHODS:Osteoblasts from the skul of neonatal rats were cultured using col agenase digestion method. After 60-150 times of stimulations of 0.18 mJ/mm2 ESW, different patterns of rhPTH1-34 at 10-12-10-10 mol/L and ESW+intermittent rhPTH1-34 (10-11 mol/L), osteoblasts were col ected to observe cel proliferation by cel counting, MTT and flow cytometry analysis and to observe cel differentiation by measuring alkaline phosphatase and type I col agen expression. RESULTS AND CONCLUSION:0.18 mJ/mm 2 ESW (60-150 times), intermittent rhPTH1-34 (10-11 and 10-10 mol/L) and ESW+intermittent rhPTH1-34 (10-11 mol/L) stimulations could al improve proliferation and differentiation of rat osteoblasts cultured in vitro (P<0.05). ESW (60-150 times)+intermittent rhPTH1-34 stimulation showed better effects than ESW and intermittent rhPTH1-34 alone (P<0.05). These findings indicate that the combination of suitable ESW stimulation and low-dose intermittent rhPTH1-34 stimulation can improve the proliferation and differentiation of rat osteoblasts significantly.