27 resultados para Hyperelasticity, Articular Cartilage, Biomechanics, Osteoarthritis, Limb, Joint, Computational Modelling


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Objective To assess several baseline risk factors that may predict patellofemoral and tibiofemoral cartilage loss during a 6-month period. Methods For 177 subjects with chronic knee pain, 3T magnetic resonance imaging (MRI) of both knees was performed at baseline and followup. Knees were semiquantitatively assessed, evaluating cartilage morphology, subchondral bone marrow lesions, meniscal morphology/extrusion, synovitis, and effusion. Age, sex, and body mass index (BMI), bone marrow lesions, meniscal damage/extrusion, synovitis, effusion, and prevalent cartilage damage in the same subregion were evaluated as possible risk factors for cartilage loss. Logistic regression models were applied to predict cartilage loss. Models were adjusted for age, sex, treatment, and BMI. Results Seventy-nine subregions (1.6%) showed incident or worsening cartilage damage at followup. None of the demographic risk factors was predictive of future cartilage loss. Predictors of patellofemoral cartilage loss were effusion, with an adjusted odds ratio (OR) of 3.5 (95% confidence interval [95% CI] 1.39.4), and prevalent cartilage damage in the same subregion with an adjusted OR of 4.3 (95% CI 1.314.1). Risk factors for tibiofemoral cartilage loss were baseline meniscal extrusion (adjusted OR 3.6 [95% CI 1.310.1]), prevalent bone marrow lesions (adjusted OR 4.7 [95% CI 1.119.5]), and prevalent cartilage damage (adjusted OR 15.3 [95% CI 4.947.4]). Conclusion Cartilage loss over 6 months is rare, but may be detected semiquantitatively by 3T MRI and is most commonly observed in knees with Kellgren/Lawrence grade 3. Predictors of patellofemoral cartilage loss were effusion and prevalent cartilage damage in the same subregion. Predictors of tibiofemoral cartilage loss were prevalent cartilage damage, bone marrow lesions, and meniscal extrusion.

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The joint torque is an important variable related to children with cerebral palsy. The present study analyzed kinetic parameters during elbow flexion and extension movements in healthy and cerebral palsy children. Ten healthy and 10 cerebral palsy children participated of the study. An isokinetic dynamometer was used to measure the elbow mean peak torque, mean angle peak torque, coefficient of variation and acceleration during flexion and extension movements at different angular speeds. The mean peak torque on extension movement in healthy children group was significant higher compared to the cerebral palsy group. The coefficient of variation on both flexion and extension movements was significantly higher in cerebral palsy group. However there were significantly difference on both groups compared the lowest and highest velocities. Although the results showed no difference in flexor peak torque, the acceleration is significantly lower in lowest and highest angular velocity.

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PURPOSE: To assess comparatively the inflammatory response that follows CO2 or Ringer's lactate joint capsular distension of horses submitted to experimental arthroscopy METHODS: Each animal was submitted to a bilateral tarsocrural arthroscopy employing gas distention in one joint and fluid distention in the contralateral joint. Synovial fluid was evaluated at 0, six, 12, 24 and 48 hours post-operative. RESULTS: The use of CO2 for arthroscopy causes an acute and mild synovitis alike to the liquid capsular distension, showing similar synovial fluid increase of leukocytes, TP, and TNF-alpha. Although synovial fluid PGE(2) content was higher in joints submitted to CO2 distension, lower levels of hemoglobin and leukocytes oxidative burst after surgery indicates that CO2 arthroscopy decreased intra-articular bleeding and activation of infiltrating leukocytes. CONCLUSIONS: The use of CO2 for arthroscopic examination causes acute and mild synovitis that is similar to the effects caused by the liquid capsular distension. CO2 also seems to decrease intra-articular bleeding and activation of leukocytes.

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Reasons for performing study: Alternative methods to evaluate the joint condition in asymptomatic osteochondrosis dissecans (OCD) and other joint diseases may be useful. Objectives: To investigate possible changes in synovial fluid composition that may lead to joint conditions in asymptomatic OCD, in mature horses. Methods: Animals aged >2 years, of different breeds, with OCD in the intermediate ridge of distal tibia, symptomatic or not, were studied. Synovial fluid samples (10 healthy; 11 asymptomatic OCD; 25 symptomatic OCD) were collected by arthroscopy from 29 horses. Glycosaminoglycans (GAGs) were analysed by a combination of agarose gel electrophoresis and enzymatic degradation with specific GAG lyases. The viscosity, white blood cell (WBC) count, protein concentration and hyaluronic acid (HA) molecular weight were also determined. Results: The method used here to analyse synovial fluid GAGs is reliable, reproducible and specific. The main synovial fluid GAGs are HA and chondroitin sulphate (CS), 93% and 7% respectively in normal horses. In symptomatic OCD, the concentrations of both increased (expressed as GAG/urea ratios), but CS increased more. The CS increased also in asymptomatic OCD. An inflammatory reaction was suggested by the increased WBC counts in OCD. The molecular weight of the synovial fluid HA was reduced in OCD, explaining the lower viscosity observed. Conclusions: The increased CS in synovial fluid of OCD joints in mature horses suggests that the synovial fluid CS and the WBC count are good markers of the joint conditions, allowing the identification of pathological phase in joint diseases. Potential relevance: The analysis of synovial fluid GAGs shows that cartilage damage occurs even in asymptomatic OCD, implying that arthroscopic removal of osteochondral fragments should be performed even in asymptomatic OCD.

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NAKAGAWA, T. H., E. T. U. MORIYA, C. D. MACIEL, and F. V. SERRAO. Frontal Plane Biomechanics in Males and Females with and without Patellofemoral Pain. Med. Sci. Sports &ere., Vol. 44, No. 9, pp. 1747-1755, 2012. Purpose: The study's purpose was to compare trunk, pelvis, hip, and knee frontal plane biomechanics in males and females with and without patellofemoral pain syndrome (PFPS) during stepping. Methods: Eighty recreational athletes were equally divided into four groups: female PFPS, female controls, male PFPS, and male controls. Trunk, pelvis, hip, and knee frontal plane kinematics and activation of the gluteus medius were evaluated at 15 degrees, 30 degrees, 45 degrees, and 60 degrees of knee flexion during the downward and upward phases of the stepping task. Isometric hip abductor torque was also evaluated. Results: Females showed increased hip adduction and knee abduction at all knee flexion angles, greater ipsilateral trunk lean and contralateral pelvic drop from 60 degrees of knee flexion till the end of the stepping task (P = 0.027-0.001), diminished hip abductor torque (P < 0.001), and increased gluteus medius activation than males (P = 0.008-0.001). PFPS subjects presented increased knee abduction at all the angles evaluated; greater trunk, pelvis, and hip motion from 45 of knee flexion of the downward phase till the end of the maneuver; and diminished gluteus medius activation at 60 degrees of knee flexion, compared with controls (P = 0.034-0.001). Females with PFPS showed lower hip abductor torque compared with the other groups. Conclusions: Females presented with altered frontal plane biomechanics that may predispose them to knee injury. PFPS subjects showed frontal plane biomechanics that could increase the lateral patellofemoral joint stress at all the angles evaluated and could increase even more from 45 degrees of knee flexion in the downward phase untill the end of the maneuver. Hip abductor strengthening and motor control training should be considered when treating females with PFPS.

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Background: Polyneuropathy is a complication of diabetes mellitus that has been very challenging for clinicians. It results in high public health costs and has a huge impact on patients' quality of life. Preventive interventions are still the most important approach to avoid plantar ulceration and amputation, which is the most devastating endpoint of the disease. Some therapeutic interventions improve gait quality, confidence, and quality of life; however, there is no evidence yet of an effective physical therapy treatment for recovering musculoskeletal function and foot rollover during gait that could potentially redistribute plantar pressure and reduce the risk of ulcer formation. Methods/Design: A randomised, controlled trial, with blind assessment, was designed to study the effect of a physiotherapy intervention on foot rollover during gait, range of motion, muscle strength and function of the foot and ankle, and balance confidence. The main outcome is plantar pressure during foot rollover, and the secondary outcomes are kinetic and kinematic parameters of gait, neuropathy signs and symptoms, foot and ankle range of motion and function, muscle strength, and balance confidence. The intervention is carried out for 12 weeks, twice a week, for 40-60 min each session. The follow-up period is 24 weeks from the baseline condition. Discussion: Herein, we present a more comprehensive and specific physiotherapy approach for foot and ankle function, by choosing simple tasks, focusing on recovering range of motion, strength, and functionality of the joints most impaired by diabetic polyneuropathy. In addition, this intervention aims to transfer these peripheral gains to the functional and more complex task of foot rollover during gait, in order to reduce risk of ulceration. If it shows any benefit, this protocol can be used in clinical practice and can be indicated as complementary treatment for this disease.

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Objective: The purpose of this study was to determine the impact of pharmacologic treatment with cilostazol and pentoxifylline on gait biomechanics of ischemic rat hindlimbs compared with nonischemic controls. Methods: An experimental study was designed using 30 Wistar rats divided into five groups (n = 6): control (C); ischemia (I) - animals submitted to left common iliac artery interruption without pharmacologic treatment; pentoxifylline (Pen) - rats submitted to procedure and treated with pentoxifylline 3 mg/kg twice a day for 6 weeks; cilostazol (Cil) - animals submitted to procedure and treated with cilostazol 30 mg/kg twice a day for 6 weeks; and sham (S) - animals submitted to procedure without artery interruption. Gait analysis was performed using a computed treadmill. Time, number, and duration of each hindlimb contact were obtained. The total number of contacts (TNC) and the total duration of contacts (TDC) were compared between left and right hindlimb and among groups. Left hindlimb ischemic incapacitation index (LHII) was defined by the formula: LHII = (1 - TNCleft x TDCleft/TNCright x TDCright) x 100 Results: Left hindlimb TNC values were twofold lower in I, Pen, and Cil groups than in C and S groups (P < .01). In I, Pen, and Cil groups, TNC values for the left hindlimb were half of the right hindlimb ones (P < .01). Left hindlimb TDC values were lower in I and Pen groups than the other groups (P < .01). Cil group presented twofold increased values, not different from C and S groups (P = 0.16). Right hindlimb TNC values were greater for I group (P < .01). LHII was around zero in C and S groups and 82 in both I and Pen groups (P < .01). Cil group presented a LHII of 42; higher than C and S groups, but lower than I and Pen groups (P < .01). Conclusions: Cilostazol at a dose of 30 mg/kg twice a day promoted improvement in gait performance in rats submitted to chronic hindlimb ischemia. Pentoxifylline at a dose of 3 mg/kg twice a day did not show this effect. (J Vasc Surg 2012;56:476-81.)

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Intracellular pattern recognition receptors such as the nucleotide-binding oligomerization domain (NOD)-like receptors family members are key for innate immune recognition of microbial infection and may play important roles in the development of inflammatory diseases, including rheumatic diseases. In this study, we evaluated the role of NOD1 and NOD2 on development of experimental arthritis. Ag-induced arthritis was generated in wild-type, NOD1(-/-)!, NOD2(-/-), or receptor-interacting serine-threonine kinase 2(-/-) (RIPK2(-/-)) immunized mice challenged intra-articularly with methylated BSA. Nociception was determined by electronic Von Frey test. Neutrophil recruitment and histopathological analysis of proteoglycan lost was evaluated in inflamed joints. Joint levels of inflammatory cytokine/chemokine were measured by ELISA. Cytokine (IL-6 and IL-23) and NOD2 expressions were determined in mice synovial tissue by RT-PCR. The NOD2(-/-) and RIPK2(-/-), but not NOD1(-/-), mice are protected from Ag-induced arthritis, which was characterized by a reduction in neutrophil recruitment, nociception, and cartilage degradation. NOD2/RIPK2 signaling impairment was associated with a reduction in proinflammatory cytokines and chemokines (TNF, IL-1 beta, and CXCL1/KC). IL-17 and IL-17 triggering cytokines (IL-6 and IL-23) were also reduced in the joint, but there is no difference in the percentage of CD4(+) IL-17(+) cells in the lymph node between arthritic wild-type and NOD2(-/-) mice. Altogether, these findings point to a pivotal role of the NOD2/RIPK2 signaling in the onset of experimental arthritis by triggering an IL-17-dependent joint immune response. Therefore, we could propose that NOD2 signaling is a target for the development of new therapies for the control of rheumatoid arthritis. The Journal of Immunology, 2012, 188: 5116-5122.

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The aim of this study was to analyze the rat temporomandibular joint (TMJ) synovial membrane at different ages using light, scanning, and transmission electron microscopy. Under light microscopic analysis, the TMJ structures were observed such as condyle, capsule, disk, the synovial membrane collagen type, and cells distribution. In the scanning electron microscopy, the synovial membrane surface exhibited a smooth aspect in young animals and there was an increase with ageing in the number of folds. The transmission electron microscopic analysis showed more synoviocytes in the synovial layer in the young group and still a great number of vesicles and cisterns dilation of rough endoplasmic reticulum in the aged group. In the three groups, a dense layer of collagen fibers in the synovial layer and cytoplasmic extensions were clearly seen. It was possible to conclude that synovial membrane structures in aged group showed alterations contributing to the decrease in joint lubrication and in the sliding between disk and joint surfaces. These characteristic will reflect in biomechanics of chewing, and may cause the TMJ disorders, currently observed in clinical processes. Microsc. Res. Tech. (c) 2012 Wiley Periodicals, Inc.

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OBJETIVOS: Avaliar os resultados funcionais iniciais e o índice de complicações precoces das artroplastias totais do quadril cerâmica-cerâmica em pacientes que convivem com o HIV e apresentam osteonecrose da cabeça femoral. MÉTODO: Doze pacientes HIV+ com diagnóstico de osteonecrose da cabeça do fêmur incongruente foram avaliados através de critérios clínicos, laboratoriais, pela escala funcional WOMAC antes e após o tratamento com substituição articular. RESULTADOS: Observamos que 83,3% dos indivíduos faziam uso de inibidores de protease, 75% apresentavam dislipidemia e 66,6% síndrome lipodistrófica, a melhora na evolução no escore WOMAC foi estatisticamente significativa para seis e 12 meses de pós-operatório em comparação com o escore pré-operatório e não observamos complicações secundárias a esse procedimento. CONCLUSÃO: A artroplastia total do quadril com implante de cerâmica-cerâmica para o tratamento da necrose avascular do quadril nessa parcela da população é opção cirúrgica adequada, apresenta melhora funcional inicial significativa e baixo índice de complicação precoce.

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The American Academy of Orofacial Pain (AAOP) defines ankylosis of the temporomandibular joint (TMJ) as a restriction of movements due to intracapsular fibrous adhesions, fibrous changes in capsular ligaments (fibrous-ankylosis) and osseous mass formation resulting in the fusion of the articular components (osseous-ankylosis). The clinical features of the fibrous-ankylosis are severely limited mouth-opening capacity (limited range of motion during the opening), usually no pain and no joint sounds, marked deflection to the affected side and marked limitation of movement to the contralateral side. A variety of factors may cause TMJ ankylosis, such as trauma, local and systemic inflammatory conditions, neoplasms and TMJ infection. Rheumatoid arthritis (RA) is one of the systemic inflammatory conditions that affect the TMJ and can cause ankylosis. The aim of this study is to present a case of a female patient diagnosed with bilateral asymptomatic fibrous-ankylosis of the TMJ associated with asymptomatic rheumatoid arthritis. This case illustrates the importance of a comprehensive clinical examination and correct diagnosis of an unusual condition causing severe mouth opening limitation.

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BACKGROUND: Anxiety disorders are often associated with several non-psychiatric medical conditions. Among the clinical conditions found in association with anxiety stands out the joint hypermobility (JH). OBJECTIVES: To carry out a systematic review of the clinical association between anxiety disorders and JH. METHOD: A survey was conducted in MEDLINE, PsychINFO, LILACS e SciELO databases up to December 2011. We searched for articles using the keywords 'anxiety', 'joint' and 'hypermobility' and Boolean operators. The review included articles describing empirical studies on the association between JH and anxiety. The reference lists of selected articles were systematically hand-searched for other publications relevant to the review. RESULTS: Seventeen articles were included in the analysis and classified to better extract data. We found heterogeneity between the studies relate to the methodology used. Most of the studies found an association between anxiety features and JH. Panic disorder/agoraphobia was the anxiety disorder associated with JH in several studies. Etiological explanation of the relationship between anxiety and JH is still controversial. CONCLUSION: Future research in large samples from the community and clinical setting and longitudinal studies of the association between anxiety and HA and the underlying biological mechanisms involved in this association are welcome.