Diet composition influences the effect of high fat diets on bone in growing male mice.

The effect of diet-induced obesity on bone in rodents is variable, with bone mass increases, decreases, and no impact reported. The goal of this study was to evaluate whether the composition of obesogenic diet may influence bone independent of its effect on body weight. As proof-of-principle, we used a mouse model to compare the skeletal effects of a commonly used high fat 'Western' diet and a modified high fat diet. The modified high fat diet included ground English walnut and was isocaloric for macronutrients, but differed in fatty acid composition and contained nutrients (e.g. polyphenols) not present in the standard 'Western' diet. Eight-week-old mice were randomized into 1 of 3 dietary treatments (n = 8/group): (1) low fat control diet (LF; 10 % kcal fat); (2) high fat 'Western' diet (HF; 46 % kcal fat as soybean oil and lard); or (3) modified high fat diet supplemented with ground walnuts (HF + walnut; 46 % kcal fat as soybean oil, lard, and walnut) and maintained on their respective diets for 9 weeks. Bone response in femur was then evaluated using dual energy x-ray absorptiometry, microcomputed tomography, and histomorphometry. Consumption of both obesogenic diets resulted in increased weight gain but differed in impact on bone and bone marrow adiposity in distal femur metaphysis. Mice consuming the high fat 'Western' diet exhibited a tendency for lower cancellous bone volume fraction and connectivity density, and had lower osteoblast-lined bone perimeter (an index of bone formation) and higher bone marrow adiposity than low fat controls. Mice fed the modified high fat diet did not differ from mice fed control (low fat) diet in cancellous bone microarchitecture, or osteoblast-lined bone perimeter, and exhibited lower bone marrow adiposity compared to mice fed the 'Western' diet. This proof-of-principal study demonstrates that two obesogenic diets, similar in macronutrient distribution and induction of weight gain, can have different effects on cancellous bone in distal femur metaphysis. Because the composition of the diets used to induce obesity in rodents does not recapitulate a common human diet, our finding challenges the translatability of rodent studies evaluating the impact of diet-induced obesity on bone.

[Atypical femoral fractures due to the use of bisphosphonates. Experience of two institutions]. / Fracturas femorales atípicas por el uso de bifosfonatos. Experiencia de dos instituciones.

INTRODUCTION: bisphosphonates are used for the management of postmenopausal osteoporosis with high risk of fracture, glucocorticoid-induced osteoporosis, Paget's disease and hypercalcemia; as well as an adjuvant for the management of hyperparathyroidism. Bisphosphonates have been associated with previously unknown adverse effects, including atypical femur fractures. OBJECTIVE: to analyze the relationship of the history of bisphosphonate (BF) use as a risk factor for presenting atypical femur fractures (AFF). MATERIAL AND METHODS: patients aged 40 years or older from two hospital centers seen from 2009 to 2018 for femur fracture were included. The radiographic studies of 441 records were reviewed, from which the fracture site was defined. Subtrochanteric (SF) and diaphyseal (DF) femur fractures were analyzed applying the criteria of the second report of the American Society for Bone and Mineral Research for case definition of AFF. Finally, the consumption of bisphosphonates in these groups was investigated to estimate a measure of association. RESULTS: of the 441 clinical records, 98 (22.2%) were male and 343 (77.7%) were female with a mean age of 77.8 (40-103) years. Fifty-nine FS/FD were identified, of which 53% (31 records) were categorized as AFF. BF use was determined in 80.6% of patients with AFF and 3.57% in FS/FD. BF use was significantly associated with the presence of AFF (OR: 112, p 0.000, CI 95%: 12.6-1001). CONCLUSIONS: BF use significantly increases the risk of presenting AFF. AFF in patients who used BF occurred after a minimum consumption of 24 months.

INTRODUCCIÓN: los bifosfonatos se usan para el manejo de osteoporosis postmenopáusica con riesgo elevado de fractura, osteoporosis inducida por glucocorticoides, enfermedad de Paget e hipercalcemia; así como coadyuvante para manejo del hiperparatiroidismo. Los bifosfonatos se han asociado a efectos adversos previamente desconocidos dentro de los que se encuentran fracturas de fémur de trazo atípico. OBJETIVO: analizar la relación del antecedente de uso de bifosfonatos (BF) como factor de riesgo para presentar fracturas atípicas de fémur (FAF). MATERIAL Y MÉTODOS: se incluyeron pacientes de 40 años o más de dos centros hospitalarios atendidos desde 2009 a 2018 por fractura de fémur. Se revisaron los estudios radiográficos de 441 registros, de los cuales se definió el sitio de fractura. Se analizaron las fracturas de fémur subtrocantéricas (FS) y diafisarias (FD) aplicando los criterios del segundo reporte de la American Society for Bone and Mineral Research para la definición de caso de FAF. Finalmente, se indagó el consumo de bifosfonatos en estos grupos para para estimar una medida de asociación. RESULTADOS: de los 441 registros clínicos, 98 (22.2%) fueron del sexo masculino y 343 (77.7%) del femenino, con edad promedio de 77.8 (40-103) años. Se identificaron 59 FS/FD, de las cuales 53% (31 registros) fueron catalogadas FAF. El consumo de BF se determinó en 80.6% de pacientes con FAF y en 3.57% con FS/FD. El uso de BF se asoció significativamente con la presencia de FAF (OR: 112, p 0.000, IC 95%: 12.6-1001). CONCLUSIONES: el uso de BF aumenta significativamente el riesgo de presentar FAF. Las FAF en pacientes que usaron BF se presentó tras un consumo mínimo de 24 meses.

Rehabilitación de un paciente con fractura femoral distal izquierda con pérdida de sustancia ósea, fractura patelar y tibial izquierda: a propósito de un caso / Rehabilitation of a patient with a left distal femoral fracture with loss of bone substance, a left patellar and tibial fracture: about a case

La rehabilitación de un paciente con fractura es progresivos y secuenciales para la mejora del foco de fractura, en especial en este tipo de fracturas con pérdida de sustancia ósea ya que suelen ser agresivas y de difícil resolución, por tanto, el tratamiento ortopédico es cuidadoso y complejo como la recuperación es prolongada sujeta a varios pasos según la progresión del paciente. El objetivo de este artículo es la de describir la secuencia de pasos en la rehabilitación de este tipo de fracturas, ya que no hay un manual claro para el manejo en rehabilitación de casos similares. El seguimiento y recuperación de este caso dura 8 meses dividida en 3 etapas de rehabilitación en un total de 122 sesiones, teniendo 4 evaluaciones en base a los tres parámetros de evaluación de ingreso: dolor, movimiento, postura y fuerza muscular, mejorando progresivamente estos aspectos.

The rehabilitation of a fractured patient is progressive and sequential for the improvement of the fracture focus, especially in this type of fractures with loss of bone substance since they are usually aggressive and difficult to resolve, so orthopedic treatment is careful and complex. as the recovery is prolonged subject to several steps depending on the patient's progression. The objective of this article is to describe the sequence of steps in the rehabilitation of this type of fractures, since there is no clear manual for the management in rehabilitation of similar cases. The follow-up and recovery of this case lasts 8 months divided into 3 stages of rehabilitation in a total of 122 sessions, having 4 evaluations based on the three parameters of admission assessment: pain, movement, posture and muscular strength, progressively improving these aspects.

An examination of the cross-sectional geometrical properties of the long bone diaphyses of Holocene foragers from Roonka, South Australia.

OBJECTIVES: This study examines long bone diaphyseal rigidity and shape of hunter-gatherers at Roonka to make inferences about subsistence strategies and mobility of inhabitants of semi-arid southeastern Australia. Roonka is a cemetery site adjacent to the Lower Murray River, which contains over 200 individuals buried throughout the Holocene. Archaeological evidence indicates that populations living near this river corridor employed mobile, risk averse foraging strategies. METHODS: This prediction of lifestyle was tested by comparing the cross-sectional geometric properties of the humerus, radius, ulna, femur, tibia, and fibula of individuals from Roonka to samples of varying subsistence strategies. Bilateral asymmetry of the upper limb bones was also examined. RESULTS: Roonka males and females have moderately high lower limb diaphyseal rigidity and shape. In the upper limb, females have low rigidity and bilateral asymmetry while males have moderately high rigidity and bilateral asymmetry. This pattern is similar to other foraging groups from Australia and southern Africa that have behaviorally adapted to arid and semi-arid environments. DISCUSSION: Lower limb results suggest that populations in the Lower Murray River Valley had relatively elevated foraging mobility. Upper limb rigidity and bilateral asymmetry indicate a sexual division of labor at Roonka. Females resemble other samples that had mixed subsistence strategies that involved hunting, gathering, and processing tasks. Males display a pattern similar to groups that preferentially hunted large game, but that supplemented this source with smaller game and riverine resources.

Postcranial morphological variation between hunter-gatherers and horticulturalists from the lower Paraná River Delta, Argentina.

INTRODUCTION: Although pre-Hispanic hunter-gatherer and horticulturalist (known as Guaraní) societies from the lower Paraná River Delta (Argentina) presented differences in diet, pottery decoration, mortuary practices, and places of origin, differences in skeletal morphology between such groups have never been systematically explored. This work focuses on variations in humeral and femoral external linear measurements and derived structural properties of adult individuals from both societies as well as on variations in body mass and stature. MATERIALS AND METHODS: Bone length, epiphyseal size, and midshaft breadth were measured in 82 adult humeri and 100 femora from hunter-gatherer and Guaraní archeological sites. Epiphyseal and midshaft robusticity, residual strength, midshaft shape and area, stature, and body mass were then estimated. Mann-Whitney tests were run to compare the hunter-gatherer and Guaraní samples. RESULTS: Male Guaraní individuals presented stronger humeri and more robust femoral and humeral proximal epiphyses than hunter-gatherers. In addition, female Guaraní individuals showed rounder femoral diaphyses in comparison with female hunter-gatherers. Concerning stature, the Guaraní individuals were found to be shorter than hunter-gatherers, regardless of sex. No statistical differences were found in body mass. DISCUSSION: Despite the fact that skeletal variations between Guaraní and hunter-gatherers could be a consequence of differences in mechanical loadings and genetic composition, bone robusticity is also positively correlated with increased age, but as the age composition of the Guaraní sample could not be estimated, skeletal variation between the samples could be a consequence of differences in age distribution.

Treatment of aseptic tibial shaft non-union without bone defect.

Non-union is incomplete consolidation of a fracture, without effective formation of a uniting callus. Despite better understanding of the physiology of bone consolidation, management of tibial non-union remains a challenge for orthopedic surgeons. Several treatments have been developed in recent decades, and we now have a range of techniques, with indications based on type of non-union, prior treatments, available equipment, and the surgeon's experience. Firstly, there are surgical techniques such as osteo-periosteal decortication, cancellous iliac graft, or inter-tibiofibular graft. The decision to fix the non-union (or revise existing fixation) and choice of type of internal fixation depend on the stability of the fracture site. There are also non-operative biological and biochemical consolidation stimulation techniques: local injection of bone-marrow, platelet-rich plasma (PRP) or bone morphogenetic protein (BMP). Stimulation can also be physical, applying ultrasound or an electromagnetic field to the non-union site. Each technique may be used in isolation or association.

Association between leg bowing and serum alkaline phosphatase level regardless of the presence of a radiographic growth plate abnormality in pediatric patients with genu varum.

When children around 2 years of age show leg bowing and diseases are ruled out based on radiographic findings without conducting blood tests, they are classified as "physiologic" genu varum. Since whether or not physiologic genu varum is associated with bone metabolism is unclear, this study was conducted to clarify the association between genu varum and bone metabolism in children. Thirty-five pediatric patients with genu varm who visited our out-patient clinic were enrolled. While two of the 35 children had nutritional rickets, showing abnormalities on both blood test (ALP, ≥1000 IU/L; iPTH, >65 pg/mL and 25(OH)D, ≤20 ng/mL) and radiographs (such as cupping, fraying or splaying), five of 35 children showed abnormalities on blood tests but not radiographs. While metaphyseal-diaphyseal angle (MDA) correlated with serum 25-hydroxy vitamin D (r = -0.35, p = 0.04) and magnesium (r = -0.36, p = 0.04), MDA and femorotibial angle (FTA) correlated with alkaline phosphatase (r = 0.43, p = 0.01 and r = 0.51, p = 0.006, respectively). A ridge regression analysis adjusted for age and body mass index indicated that ALP was associated with MDA and FTA. A logistic regression analysis adjusted for age and BMI indicated that higher ALP influenced an MDA >11°, which indicates the risk for the progression of genu varum (odds ratio 1.002, 95% confidence interval 1.0003-1.003, p = 0.021). The higher ALP (+100 IU), the higher risk of an MDA >11° (odds ratio 1.22). In conclusion, genu varum is associated with the alkaline phosphatase level regardless of the presence of radiographic abnormalities in the growth plate in children.

Sensitivity and specificity of radiographic characteristics in atypical femoral fractures.

Using the American Society for Bone and Mineral Research Task Force case definition for atypical femoral fractures, sensitivity and specificity of radiographic fracture characteristics were calculated. Fracture pattern was the most sensitive and specific characteristic. This suggests that some characteristics should be weighted more heavily when identifying these fractures. INTRODUCTION: To estimate the sensitivity and specificity of each radiographic criterion in the 2013 ASBMR atypical femoral fracture (AFF) case definition for distinguishing AFF from other subtrochanteric/diaphyseal fractures (non-AFF) among women enrolled in a large integrated health care organization. METHODS: Radiographs from 55 physician-confirmed AFFs and a sample of 39 non-AFFs were reviewed by four independent expert reviewers representing four medical specialties. One image per fracture was selected for review. Using a standardized data collection tool, based on the 2013 AFF case definition, reviewers indicated the presence or absence of the following characteristics viewable on radiograph: fracture pattern, comminution, periosteal and/or endosteal thickening, and cortical thickening. Sensitivity and specificity for each characteristic was calculated for each reviewer and summarized across reviewers with the mean and range. Agreement across reviewers was quantified using Fleiss's kappa (FK) statistic. RESULTS: The most sensitive factors distinguishing AFF from non-AFF were lateral cortex transverse fracture pattern (mean 93.6 %, range 85.5-98.2 %), medial cortex transverse or oblique fracture pattern (mean 84.1 %, range 72.7-98.2 %), and minimal/non-comminution (mean 93.2 %, range 89.1-98.2 %). Specificity was the greatest for lateral cortex transverse fracture pattern (mean 95.5 %, range 92.3-97.4 %). Agreement across reviewers was the highest for lateral cortex transverse fracture pattern (FK 0.83) and incomplete fracture through the lateral cortex only (FK 0.80). CONCLUSION: Lateral cortex transverse fracture pattern was the most sensitive and specific characteristic and the most highly agreed upon across reviewers. Other characteristics were less readily agreed upon across reviewers. Measurement of discrete combinations of individual characteristics may enhance sensitivity and/or specificity.

Synergistic effects of HBO and PRP improve bone regeneration with autologous bone grafting.

Bone defects remain a challenge for patients and orthopaedic surgeons. Autologous transfer of cancellous bone grafts remains the standard of care. However, in recent years various osteoinductive substitute materials, such as platelet rich plasma (PRP) and hyperbaric oxygen therapy (HBO) have been shown to improve bone healing. This study evaluates the effects of a combined application of PRP and HBO with autologous bone grafting in an animal model. In 48 New Zealand White rabbits bone defects at the radius were filled with autologous bone harvested at the iliac crest. This was combined with application of autologous PRP and/or HBO treatment for the duration of this study. After 3 and 6 weeks histomorphometric, immunohistochemical and radiologic evaluations were performed. All animals tolerated the treatment well. Improved bone regeneration was shown in all groups at 6 weeks compared to 3 weeks. Additional application of PRP and HBO resulted in an increase in new bone formation and increased neovascularization at 3 and 6 weeks. There was no statistical significant difference between PRP and HBO application in these regards. A combinatory use of PRP and HBO resulted in an increased bone regeneration and neovascularization compared to all other groups. This study provides evidence for an improvement of bone regeneration with the combinatory application of PRP and HBO to autologous cancellous bone grafts in a model of weight bearing bone defects in rabbits. Also synergistic effects of these two measures on angiogenesis were evident.

Treatment of recalcitrant atrophic non-union of the humeral shaft with BMP-7, autologous bone graft and hydroxyapatite pellets.

Recalcitrant humeral non-union is a disabling condition that is extremely difficult to treat. The use of BMP-7 has been proposed to improve bone healing. This is a report of the results obtained in 12 patients with recalcitrant humeral non-union treated using stable fixation with a long locking compression plate and BMP-7, autologous bone graft and hydroxyapatite pellets applied at the non-union site. Patients had up to three surgical attempts at non-union healing prior to our treatment. The average time from the initial fracture to our surgery was 5.2 years. Average follow-up was 5.3 years. At follow-up, non-union had healed in all patients by an average of 7.3 months. All the patients were very satisfied with their final results, despite a restricted range of motion of the elbow and a moderate muscular atrophy, which was frequently observed. Our study shows that BMP-7 associated with autologous bone grafting and hydroxyapatite pellets after stable fixation is an effective adjuvant to stimulate bone healing in the treatment of recalcitrant humeral non-union.

Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial.

Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p < 0.001). Daily calcium intakes of 1000 mg or 2000 mg produced more rapid radiographic healing of rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research.

Evaluation of the effects of pulsed wave LLLT on tibial diaphysis in two rat models of experimental osteoporosis, as examined by stereological and real-time PCR gene expression analyses.

Osteoporosis (OP) and osteoporotic fracture are major public health issues for society; the burden for the affected individual is also high. Previous studies have shown that pulsed wave low-level laser therapy (PW LLLT) has osteogenic effects. This study intended to evaluate the impacts of PW LLLT on the cortical bone of osteoporotic rats' tibias in two experimental models, ovariectomized and dexamethasone-treated. We divided the rats into four ovariectomized induced OP (OVX-d) and four dexamethasone-treated (glucocorticoid-induced OP, GIOP) groups. A healthy (H) group of rats was considered for baseline evaluations. At 14 weeks following ovariectomy, we subdivided the OVX-d rats into the following groups: (i) control which had OP, (ii) OVX-d rats treated with alendronate (1 mg/kg), (iii) OVX-d rats treated with LLLT, and (iv) OVX-d rats treated with alendronate and PW LLLT. The remaining rats received dexamethasone over a 5-week period and were also subdivided into four groups: (i) control rats treated with intramuscular (i.m.) injections of distilled water (vehicle), (ii) rats treated with subcutaneous alendronate injections (1 mg/kg), (iii) laser-treated rats, and (iv) rats simultaneously treated with laser and alendronate. The rats received alendronate for 30 days and underwent PW LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) three times per week during 8 weeks. Then, the right tibias were extracted and underwent a stereological analysis of histological parameters and real-time polymerase chain reaction (RT-PCR). A significant increase in cortical bone volume (mm(3)) existed in all study groups compared to the healthy rats. There were significant decreases in trabecular bone volume (mm(3)) in all study groups compared to the group of healthy rats. The control rats with OP and rats from the vehicle group showed significantly increased osteoclast numbers compared to most other groups. Alendronate significantly decreased osteoclast numbers in osteoporotic rats. Concurrent treatments (compounded by PW LLLT and alendronate) produce the same effect on osteoporotic bone.

Insights on the paleoepidemiology of ancient tuberculosis from the structural analysis of postcranial remains from the Ligurian Neolithic (northwestern Italy).

The aim of this research is to gain insights on the progression timeline of osteoarticular tuberculosis (TB) in people from the Neolithic period by using skeletal traits that are independent of the bony lesions. The body proportions and postcranial mechanical strength of bones from two individuals from Liguria in northwestern Italy (Arene Candide 5, adolescent, and Arma dell'Aquila 1, adult), were compared with the rest of the Ligurian Neolithic skeletal series (45 individuals). If TB led to wasting of the skeleton and lack of normal function that endured for years, as often happens today, a clear signature of postcranial gracility and disruption of development should be apparent. Conversely, rapid progress of the disease would leave little systemic macroscopic change in the skeleton, except for the bony lesions directly caused by the TB pathogen, suggesting a different level of bacterial virulence in the past. The extreme biomechanical gracility observed in the lower limb of Arene Candide 5 suggests a period of compromised diaphyseal periosteal apposition during ontogeny due to metabolic disturbances likely linked to TB. Results suggest that, in Neolithic Liguria, TB in humans saw a slow, chronic progression, which is characteristic of diseases with long histories of host-pathogen co-evolution.

Lycopene treatment against loss of bone mass, microarchitecture and strength in relation to regulatory mechanisms in a postmenopausal osteoporosis model.

Lycopene supplementation decreases oxidative stress and exhibits beneficial effects on bone health, but the mechanisms through which it alters bone metabolism in vivo remain unclear. The present study aims to evaluate the effects of lycopene treatment on postmenopausal osteoporosis. Six-month-old female Wistar rats (n=264) were sham-operated (SHAM) or ovariectomized (OVX). The SHAM group received oral vehicle only and the OVX rats were randomized into five groups receiving oral daily lycopene treatment (mg/kg body weight per day): 0 OVX (control), 15 OVX, 30 OVX, and 45 OVX, and one group receiving alendronate (ALN) (2µg/kg body weight per day), for 12weeks. Bone densitometry measurements, bone turnover markers, biomechanical testing, and histomorphometric analysis were conducted. Micro computed tomography was also used to evaluate changes in microarchitecture. Lycopene treatment suppressed the OVX-induced increase in bone turnover, as indicated by changes in biomarkers of bone metabolism: serum osteocalcin (s-OC), serum N-terminal propeptide of type 1 collagen (s-PINP), serum crosslinked carboxyterminal telopeptides (s-CTX-1), and urinary deoxypyridinoline (u-DPD). Significant improvement in OVX-induced loss of bone mass, bone strength, and microarchitectural deterioration was observed in lycopene-treated OVX animals. These effects were observed mainly at sites rich in trabecular bone, with less effect in cortical bone. Lycopene treatment down-regulated osteoclast differentiation concurrent with up-regulating osteoblast together with glutathione peroxidase (GPx) catalase (CAT) and superoxide dismutase (SOD) activities. These findings demonstrate that lycopene treatment in OVX rats primarily suppressed bone turnover to restore bone strength and microarchitecture.

A low-energy femoral shaft fracture from performing a yoga posture.

The femoral shaft is rarely the site of a low-energy fracture in a healthy individual. The vast majority of these fractures are due to major trauma such as motor vehicle accidents. Although low-energy femoral shaft fractures do occur, they are typically in patients with osteoporotic bone, or prosthesis related. In this case report, we present a man in his late 30s who was practising a specific yoga stance when he experienced a femoral shaft fracture.

Estudio biomecánico de la tibia en el recambio de una artroplastia de rodilla / Biomechanical study of the tibia in knee replacement revision

No hay consenso en el tratamiento de elección de los recambios protésicos de rodilla con defectos óseos severos. Las opciones son variadas, cada una con sus ventajas e inconvenientes. Los trabajos clínicos publicados tienen sus limitaciones en cuanto al número de pacientes y el poco seguimiento clínico. Se presenta un trabajo biomecánico con elementos finitos comparativo de 5 diseños de implantes tibiales: vástago recto, con offset con/sin suplemento y vainas con/sin vástago, para poder analizar el comportamiento tanto del hueso tibial como del material a lo largo del tiempo. Dentro de las limitaciones que presenta un modelo matemático hemos podido ver que los implantes con vástago recto producen el mayor valor de reabsorción ósea alrededor del vástago, mientras que la menor reabsorción ósea tiene lugar en el hueso de la diáfisis proximal. Las vainas metafisarias tibiales sin vástago producen una menor reabsorción ósea que el resto en el canal medular (AU)

The best management of severe bone defects following total knee replacement is still controversial. Metal augments, tantalum cones and porous tibial sleeves could help the surgeon to manage any type of bone loss, providing a stable and durable knee joint reconstruction. Five different types of prostheses have been analysed: one prosthesis with straight stem; two prostheses with offset stem, with and without supplement, and two prostheses with sleeves, with and without stem. The purpose of this study is to report a finite element study of revision knee tibial implants. The main objective was to analyse the tibial bone density changes and Von Misses tension changes following different tibial implant designs. In all cases, the bone density decreases in the proximal epiphysis and medullary channels, with a bone density increase also being predicted in the diaphysis and at the bone around the stems tips. The highest value of Von Misses stress has been obtained for the straight tibial stem, and the lowest for the stemless metaphyseal sleeves prosthesis (AU)

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects.

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

Evaluation of the effects of LLLT on biomechanical properties of tibial diaphysis in two rat models of experimental osteoporosis by a three point bending test.

Osteoporosis (OP) is a disease which causes bone loss and fractures, leading to severe pain and deformity. This study has aimed to assess the effects of pulsed wave low-level laser therapy (PW LLLT) on cortical bone in two experimental models of OP in rats. There were four ovariectomized (OVX-d) groups and four dexamethasone-treated groups. The healthy group were considered for baseline evaluations. At 14 weeks following ovariectomy, the OVX-d rats were further subdivided into the following: control rats with OP, OVX-d rats that received alendronate (1 mg/kg), OVX-d rats treated with LLLT, and OVX-d rats treated with alendronate and LLLT. The remaining rats received dexamethasone for 5 weeks and were divided into four groups: control, alendronate-treated rats (1 mg/kg), laser-treated rats, and laser-treated rats with concomitant administration of alendronate. The rats received alendronate for 30 days. LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) was performed on the tibias three times per week for 8 weeks. After 8 weeks, tibias were extracted and submitted to a three-point bending test. PW LLLT did not increase the biomechanical parameters of osteoporotic bones compared to controls and healthy rats. PW LLLT associated with alendronate treatment significantly increased stress high load in OVX-d rats compared to the healthy group. PW LLLT at the current study parameters failed to cause beneficial biomechanical effects in the examined osteoporotic cortical bones. PW LLLT associated with alendronate treatment produced a more remarkable effect on bone strength in the ovariectomized induced OP rat model.

Femoral subtrochanteric shape variation in Albania: implications for use in forensic applications.

This paper investigates temporal trends in femoral subtrochanteric shape in Albanian skeletal material to evaluate levels of platymeria in a set of populations with European ancestry. Although flattening of the diaphysis in the subtrochanteric region has been associated with individuals of Native American and Asian ancestry, high levels of platymeria may not be unique to those groups. The forensic utility of Gilbert and Gill's (Skeletal Attribution of Race: Methods for Forensic Anthropology, University of New Mexico, Albuquerque, 1990) method for identifying ancestry from femoral subtrochanteric shape is examined using non-American skeletons of European ancestry. Femoral subtrochanteric anteroposterior and mediolateral diameters for Albanian skeletons from Apollonia (n=117) and Lofkënd (n=50) are assessed for temporal trends and then compared with published data using one-way ANOVA and post-hoc Tukey tests. High degrees of subtrochanteric flattening are identified in the Albanian samples and statistically significant temporal trends of decreasing platymeria are documented. Although recent publications suggest that subtrochanteric shape is less effective in identifying ancestry then was initially proposed, forensic anthropologists still commonly use femoral subtrochanteric shape to determine ancestry among skeletonized remains. This paper's findings support the assertion that proximal femoral morphology is functionally related, and more likely to be influenced by biomechanical adaptation and body proportions than genetic constraints.

Effect of intermittent administration of hPTH(1-34) on cortical bone geometry in rats treated with high-dose glucocorticoids.

High-dose glucocorticoids reduce cortical bone gain in rats. The aim of the present study was to examine the effect of the intermittent administration of human parathyroid hormone (1-34) (hPTH[1-34]) on cortical bone in rats treated with high-dose prednisolone (PSL). Twenty-five female Sprague-Dawley rats (6 weeks old) were randomized into the following three groups: a vehicle administration (control) group, a PSL (10 mg/kg s.c., 5 times a week) administration group, and a PSL + hPTH(1-34) (30 µg/kg s.c., 3 times a week) administration group. After 8 weeks of treatment, the bone mineral density (BMD) of the femoral diaphysis was determined using peripheral quantitative computed tomography, and a static bone histomorphometric analysis was performed on the tibial diaphysis. PSL administration induced a decrease in the BMD of the femoral diaphysis, compared with the control group, as well as decreases in the total tissue area, cortical area, percent cortical area, and periosteal perimeter and increases in the marrow area, percent marrow area, and endocortical perimeter of the tibial diaphysis, compared with the control group. The intermittent administration of hPTH(1-34) to PSL-treated rats attenuated PSL-related changes in the BMD of the femoral diaphysis and the percent cortical area, marrow area, percent marrow area, and endocortical perimeter of the tibial diaphysis. The findings of the present study suggest that the intermittent administration of hPTH(1-34) improves cortical BMD, acts on the endocortical bone surface, and improves cortical bone geometry, in rats treated with highdose PSL.