[Translated article] Mechanical properties variations of immature bone in the earliest stages of development.

INTRODUCTION: Bone as a material varies its composition and mechanical properties throughout life. Although these variations are better understood in adulthood, there is little experimental information on the variation of these properties in early stages of development. The objective of this study is to analyze the mechanical behavior and chemical properties of cortical bone tissue from two animal species in these earliest stages. MATERIAL AND METHODOLOGY: Twenty specimens of cortical bone were manufactured from bovine and ovine species that were in different stages of development (feeding exclusively on breast milk, in the transition period to feed or pasture, and young animals but on a solid food diet). The specimens were subjected to tensile tests, recorded with a high-speed camera to obtain deformation maps. Measurements of the tensile force until the specimen broke were also carried out. A fractographic study was carried out with a scanning electron microscope to analyze the fracture surface and an analysis of the amount of calcium in each of the specimens using X-ray dispersion spectroscopy. RESULTS: A statistically significant and positive correlation was found between the elastic modulus of the specimens and their calcium content. A trend towards more rigid behavior with age was observed. CONCLUSIONS: Young bone tissue tends to stiffen with age as the calcium content increases with an increase in elastic modulus.

[Translated article] Infrapatellar fat pad resection effect on the osteoarthritis development: Experimental study in sheep.

INTRODUCTION: The fat of the synovial joints can be used to maintain the joint structure. Our objective is to analyse the evolution of joint degeneration in knees with and without adipose pack. MATERIAL AND METHODOLOGY: In six sheep, the anterior cruciate ligament was sectioned in both knees, to cause osteoarthritis. In one group the fat pack was preserved and in another group it was completely removed. We performed a histological and molecular biology study analyzing the expression, in the synovial membrane, subchondral bone, cartilage, fat, meniscus, and synovial fluid, of RUNX2, PTHrP, cathepsin-K, and MCP1. RESULTS: We did not find morphological differences. We found increased expression of RUNX2 in synovial membrane, PTHrP and Cathepsin K in synovial fluid in the group without fat, and increased expression of RUNX2 in the meniscus and MCP1 in synovial fluid in the group with fat. CONCLUSION: Infrapatellar fat participates in the inflammatory process that accompanies osteoarthritis, since Hoffa fat pad resection alters pro-inflammatory markers, while the model with intact fat increases the pro-inflammatory marker MCP1 in synovial fluid.

Infrapatellar Fat Pad resection effect on the osteoarthritis development: Experimental study in sheep. / Efecto de la resección de la grasa del paquete infrapatelar de la rodilla en el desarrollo de la artrosis. Estudio experimental en ovejas.

INTRODUCTION: The fat of the synovial joints can be used to maintain the joint structure. Our objective is to analyze the evolution of joint degeneration in knees with and without adipose pack. MATERIAL AND METHODOLOGY: In six sheep, the anterior cruciate ligament was sectioned in both knees, to cause osteoarthritis. In one group the fat pack was preserved and in another group it was completely removed. We performed a histological and molecular biology study analyzing the expression, in the synovial membrane, subchondral bone, cartilage, fat, meniscus, and synovial fluid, of RUNX2, PTHrP, cathepsin-K, and MCP1. RESULTS: We did not find morphological differences. We found increased expression of RUNX2 in synovial membrane, PTHrP and Cathepsin K in synovial fluid in the group without fat, and increased expression of RUNX2 in the meniscus and MCP1 in synovial fluid in the group with fat. CONCLUSION: Infrapatellar fat participates in the inflammatory process that accompanies osteoarthritis, since Hoffa fat pad resection alters pro-inflammatory markers, while the model with intact fat increases the pro-inflammatory marker MCP1 in synovial fluid.

Mechanical properties variations of immature bone in the earliest stages of development. / Variación de las propiedades mecánicas del hueso inmaduro en las etapas más tempranas del desarrollo.

INTRODUCTION: Bone as a material varies its composition and mechanical properties throughout life. Although these variations are better understood in adulthood, there is little experimental information on the variation of these properties in early stages of development. The objective of this study is to analyze the mechanical behavior and chemical properties of cortical bone tissue from two animal species in these earliest stages. MATERIAL AND METHODOLOGY: Twenty specimens of cortical bone were manufactured from bovine and ovine species that were in different stages of development (feeding exclusively on breast milk, in the transition period to feed or pasture, and young animals but on a solid food diet). The specimens were subjected to tensile tests, recorded with a high-speed camera to obtain deformation maps. Measurements of the tensile force until the specimen broke were also carried out. A fractographic study was carried out with a scanning electron microscope to analyze the fracture surface and an analysis of the amount of calcium in each of the specimens using X-ray dispersion spectroscopy. RESULTS: A statistically significant and positive correlation was found between the elastic modulus of the specimens and their calcium content. A trend towards more rigid behavior with age was observed. CONCLUSIONS: Young bone tissue tends to stiffen with age as the calcium content increases with an increase in elastic modulus.

MRI study of the cruciate ligaments and menisco-femoral ligaments of the knee.

PURPOSE: It has been argued that the meniscus-femoral ligaments disappear with age. We therefore analyzed the presence of the meniscus-femoral ligaments, in MRI. MATERIALS AND METHODS: We measured the PCL, ACL and MFL, noting their presence or absence in 120 Knee MRIs, 51 in women and 69 in men. All knees underwent MRI in the coronal, sagittal and axial planes. T1 and T2 weighted sequences were obtained. A descriptive statistical study of all the variables was carried out, and a comparative study was performed between sexes, sides and age groups. RESULTS: The MFLp was more frequent, found in 67 (55.8%) cases, than the MFLa, in 36 (30%) cases, and both together were present in 27 (22.5%) knees. We found a strong correlation between ACL length and PCL length (p = 0.001), we found no correlation between the presence of the posterior MFL either with age (p = 0.307) or with sex (p = 0.779) or side (p = 0.733). We also found no relationship between the presence of the anterior MFL and age (p = 0.553), or sex (p = 0.913), or laterality (p = 0.082). CONCLUSION: We found a strong correlation between ACL length and PCL length. In our study, the presence of the posterior MFL was more frequent, being present in 55.68%, while the anterior MFL was found in 30% of the knees. We did not observe that the presence of LMF decreases with age.

Two-stage bone and meniscus allograft and autologous chondrocytes implant for unicompartmental osteoarthritis: midterm results.

BACKGROUND: We analyzed the clinical and radiographic evolution of patients with knee unicompartmental osteoarthritis and axis alteration and osteochondral lesions in the femoral condyle, treated with tibial plateau and meniscus allograft and cultured autologous chondrocyte implantation in the femur in two steps. PURPOSE: To analyze the clinical results with the first patients treated with this two-stage technique to avoid knee prosthesis in patients with unicompartmental osteoarthritis. MATERIAL AND METHODOLOGY: Sixteen patients, average age 56 years, were included in a cohort study. We performed an osteotomy with tibia plateau allograft, including the meniscus. In a second surgery, the chondrocyte fibrin scaffold was placed in the femur. Clinical symptoms and function were measured using KSSR and KOOS scores. Wilcoxon's test was performed to compare the results over the 2-year follow-up period. RESULTS: Mean KSSR before surgery was 35.69 (SD: 3.75) points, rising to 67 (SD: 15.42) at 3 months, 95.88 at 12 months (SD: 2.68) and 96.31 at 24 months (SD: 2.24). The KOOS before surgery was 65.14 (SD: 16.34), rising to 72.68 after 3 months (SD: 19.15), 76.68 at 12 months (SD: 18.92) and 64.28 at 24 months (SD: 11.79). Four of 5 patients returned to engaging in the activity that they had stopped practicing. Three patients experienced collapse of the tibia allograft, and they needed later a prosthesis. CONCLUSIONS: Simultaneous tibia plateau allograft and autologous chondrocyte implantation in the femur, after correction of the angular deformity, were performed, restoring the anatomy of the medial compartment and knee function in 82% of the patients 2 years after the operation. LEVEL OF EVIDENCE: IV.

Resultados clínicos del tratamiento de la metatarsalgia mecánica sin afectación del primer metatarsiano / Clinical results of treatment of mechanical metatarsalgia without first metatarsal involvement

Resumen: Objetivo: Analizar los resultados clínicos de las metatarsalgias tratadas con osteotomías metafisarias metatarsales distales (DMMO) por vía percutánea. Material y métodos: Estudio prospectivo y continuo de 29 pacientes afectados de metatarsalgia mecánica aislada unilateral, intervenidas con una DMMO, con un seguimiento medio de 38 meses. La edad media de los pacientes fue 58 (rango: 50-67) años y sólo dos hombres. Utilizamos la escala AOFAS, anotamos la fórmula digital y metatarsiana sobre la radiografía. Registramos la valoración subjetiva del cirujano y del paciente al final del tratamiento. Resultados: La mejoría de la puntuación final superó los 80 puntos en todos los metatarsianos (p = 0.000), con una mejoría significativa del dolor (p = 0.000) y de las callosidades (p = 0.000), mejorando la estabilidad articular metatarso-falángica e interfalángica y la alineación de los metatarsianos. El tipo del calzado no cambió después de la cirugía, no encontramos variación de la movilidad, ni en las articulaciones metatarso-falángicas (p = 0.382), ni en las interfalángicas (p = 0.672). Después de la cirugía aumentaron los pies cuadrados (p = 0.027). La fórmula metatarsiana sufrió pocas modificaciones, 96% de los pacientes y de los cirujanos se mostraron «muy satisfechos¼ o «satisfechos¼. Conclusión: La DMMO consigue un alto grado de satisfacción en pacientes y también en el cirujano, elimina el dolor y la hiperqueratosis bajo la cabeza de los metatarsianos dolorosos que mejora significativamente la capacidad funcional de los pacientes.

Abstract: Objective: To analyze the clinical results of metatarsalgia treated with percutaneous distal metatarsal metaphyseal osteotomies (DMMO). Material and methods: Prospective and continuous study of 29 patients with isolated unilateral mechanical metatarsalgia, operated on with DMMO, with a mean follow-up of 38 months. The mean age of the patients was 58 (range: 50-67) years and only two men. We use the AOFAS score, we obtained the digital and metatarsal formulas on the X-rays. We record the subjective assessment of the surgeon and the patient at the end of the treatment. Results: The improvement in the final score exceeded 80 points in all cases (p = 0.000), with a significant improvement in pain (p = 0.000) and calluses (p = 0.000), improving metatarsal-phalangeal joint stability and interphalangeal and metatarsal alignment. The type of footwear did not change after surgery, we found no variation in mobility, neither in the metatarsophalangeal joints (p = 0.382), nor in the interphalangeal joints (p = 0.672). After surgery increased the square foot morphology (p = 0.027) but the metatarsal formula underwent few modifications. Patients and surgeons were in 96% of the cases «very satisfied¼ or «satisfied¼. Conclusion: DMMO achieves a high degree of satisfaction in patients and in the surgeon, pain and hyperkeratosis under the head of the painful metatarsals disappear and that significantly improves the functional capacity of patients.

[Clinical results of treatment of mechanical metatarsalgia without first metatarsal involvement]. / Resultados clínicos del tratamiento de la metatarsalgia mecánica sin afectación del primer metatarsiano.

OBJECTIVE: To analyze the clinical results of metatarsalgia treated with percutaneous distal metatarsal metaphyseal osteotomies (DMMO). MATERIAL AND METHODS: Prospective and continuous study of 29 patients with isolated unilateral mechanical metatarsalgia, operated on with DMMO, with a mean follow-up of 38 months. The mean age of the patients was 58 (range: 50-67) years and only two men. We use the AOFAS score, we obtained the digital and metatarsal formulas on the X-rays. We record the subjective assessment of the surgeon and the patient at the end of the treatment. RESULTS: The improvement in the final score exceeded 80 points in all cases (p = 0.000), with a significant improvement in pain (p = 0.000) and calluses (p = 0.000), improving metatarsal-phalangeal joint stability and interphalangeal and metatarsal alignment. The type of footwear did not change after surgery, we found no variation in mobility, neither in the metatarsophalangeal joints (p = 0.382), nor in the interphalangeal joints (p = 0.672). After surgery increased the square foot morphology (p = 0.027) but the metatarsal formula underwent few modifications. Patients and surgeons were in 96% of the cases "very satisfied" or "satisfied". CONCLUSION: DMMO achieves a high degree of satisfaction in patients and in the surgeon, pain and hyperkeratosis under the head of the painful metatarsals disappear and that significantly improves the functional capacity of patients.

OBJETIVO: Analizar los resultados clínicos de las metatarsalgias tratadas con osteotomías metafisarias metatarsales distales (DMMO) por vía percutánea. MATERIAL Y MÉTODOS: Estudio prospectivo y continuo de 29 pacientes afectados de metatarsalgia mecánica aislada unilateral, intervenidas con una DMMO, con un seguimiento medio de 38 meses. La edad media de los pacientes fue 58 (rango: 50-67) años y sólo dos hombres. Utilizamos la escala AOFAS, anotamos la fórmula digital y metatarsiana sobre la radiografía. Registramos la valoración subjetiva del cirujano y del paciente al final del tratamiento. RESULTADOS: La mejoría de la puntuación final superó los 80 puntos en todos los metatarsianos (p = 0.000), con una mejoría significativa del dolor (p = 0.000) y de las callosidades (p = 0.000), mejorando la estabilidad articular metatarso-falángica e interfalángica y la alineación de los metatarsianos. El tipo del calzado no cambió después de la cirugía, no encontramos variación de la movilidad, ni en las articulaciones metatarso-falángicas (p = 0.382), ni en las interfalángicas (p = 0.672). Después de la cirugía aumentaron los pies cuadrados (p = 0.027). La fórmula metatarsiana sufrió pocas modificaciones, 96% de los pacientes y de los cirujanos se mostraron "muy satisfechos" o "satisfechos". CONCLUSIÓN: La DMMO consigue un alto grado de satisfacción en pacientes y también en el cirujano, elimina el dolor y la hiperqueratosis bajo la cabeza de los metatarsianos dolorosos que mejora significativamente la capacidad funcional de los pacientes.

Graphene and graphene oxide functionalisation with silanes for advanced dispersion and reinforcement of PMMA-based bone cements.

The reinforcement of PMMA bone cements using carbon based nanomaterials has demonstrated to be a potential solution to their poor mechanical properties. The achievement of an optimal dispersion of the nanoparticles within the polymeric matrix is a crucial but not easy stage in the production of high-quality reinforced materials. In this work, a useful route for the graphene (G) functionalisation, via silanisation with (3-methacryloxypropyl) trimethoxy silane (MPS), has been developed, providing a remarkable enhancement in dispersibility and mechanical properties. With the purpose to define the critical graphene surface oxidation parameters for an optimal silanisation, different routes were thoroughly analysed using infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results showed that the silanisation significantly improved the G dispersibility: whereas the pristine G dispersion fell down within the first 24 h, the silanised G showed an adequate stability after 5 days. Additionally, this improved dispersibility produced a notable increase in the mechanical properties of the G-reinforced bone cements: in comparison with the pristine G, the compression and bending strength of silanised G increased by 12% and by 13.7% respectively and the fracture toughness by 28%. These results provide very useful information on the relevance that the characteristics of the superficial oxidation of graphene have on the effectiveness of the silanisation process, besides an interesting functionalisation procedure for advanced dispersion and reinforcement of G-PMMA bone cements.

Citoquinas proinflamatorias en la grasa articular y subcutánea del muslo en pacientes artrósicos / Pro-inflammatory cytokines in the knee fat pad and subcutaneous fat of the thigh in osteoarthritic patients

Resumen: Objetivo: Analizar el nivel de citoquinas proinflamatorias en la grasa articular del paquete adiposo en pacientes con gonartrosis, en relación con la grasa subcutánea del muslo. Material y métodos: Efectuamos un estudio de grasa del paquete adiposo articular de la rodilla afectada de artrosis y de la grasa subcutánea del muslo del mismo lado, a la mayor distancia de la articulación en seis pacientes con gonartrosis grave, con una edad media de 68 años (rango: 55-81 años). De las muestras de grasa se obtuvieron las células mesenquimales progenitoras. Los sobrenadantes de células mesenquimales obtenidas se utilizaron para analizar factores inflamatorios (IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13, IL15) y angiogénicos (VEGF, PDGF bb), así como citoquinas inmunomoduladoras (IP-10 e INF-γ) y se compararon las medias de dos muestras. Resultados: El análisis cuantitativo reveló una disminución significativa (p < 0.05) de IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 y un aumento de IL15 en la grasa de Hoffa frente al tejido adiposo subcutáneo. Del mismo modo, el análisis de factores angiógenicos como VEGF y PDGF bb, al igual que los factores IP-10 e INF-γ presentaron una disminución significativa en la grasa de Hoffa (p < 0.05) frente al tejido adiposo subcutáneo. Discusión: Las células mesenquimales del paquete adiposo articular de la rodilla artrósica grave muestran una disminución significativa de citoquinas inflamatorias, aun en el estado crónico, y una disminución significativa de factores angiogénicos y citoquinas inmunomoduladoras (IP10 e INF).

Abstract: Objective: To analyze the level of pro-inflammatory cytokines in osteoarthritis knee joint fat pad in relation to the subcutaneous fat of the thigh. Material and methods: We performed a study of fat of the knee joint adipose affected of osteoarthritis and subcutaneous fat of the thigh of the same side to the greater distance of the joint in six patients with severe gonarthrosis, with a mean age of 68 years (range: 55-81 years). From the fat samples the progenitor mesenchymal cells were obtained. The supernatants of mesenchymal cells obtained to analyze inflammatory factors (IL-1b, IL6, IL9, IL1ra, IL12, IL13, IL15) and angiogenic (VEGF, PDGF bb) and immunomodulatory cytokines (IP-10 and INF-γ) means of two samples. Results: Quantitative analysis revealed a significant (p < 0.05) decrease in IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 and increase of IL15 in Hoffa fat pad versus subcutaneous adipose tissue. Likewise, the analysis of angiogenic factors such as VEGF and PDGF, as well as factors IP-10 and INF-γ presented a significant decrease (p < 0.05) in Hoffa fat pad versus subcutaneous adipose tissue. Discussion: Mesenchymal cells from the adipose tissue of the severe osteoarthritic knee show a significant decrease in inflammatory cytokines even in the chronic state and a significant decrease in angiogenic factors and immunomodulatory cytokines (IP10 and INF).

[Pro-inflammatory cytokines in the knee fat pad and subcutaneous fat of the thigh in osteoarthritic patients]. / Citoquinas proinflamatorias en la grasa articular y subcutánea del muslo en pacientes artrósicos.

OBJECTIVE: To analyze the level of pro-inflammatory cytokines in osteoarthritis knee joint fat pad in relation to the subcutaneous fat of the thigh. MATERIAL AND METHODS: We performed a study of fat of the knee joint adipose affected of osteoarthritis and subcutaneous fat of the thigh of the same side to the greater distance of the joint in six patients with severe gonarthrosis, with a mean age of 68 years (range: 55-81 years). From the fat samples the progenitor mesenchymal cells were obtained. The supernatants of mesenchymal cells obtained to analyze inflammatory factors (IL-1b, IL6, IL9, IL1ra, IL12, IL13, IL15) and angiogenic (VEGF, PDGF bb) and immunomodulatory cytokines (IP-10 and INF-) means of two samples. RESULTS: Quantitative analysis revealed a significant (p 0.05) decrease in IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 and increase of IL15 in Hoffa fat pad versus subcutaneous adipose tissue. Likewise, the analysis of angiogenic factors such as VEGF and PDGF, as well as factors IP-10 and INF- presented a significant decrease (p 0.05) in Hoffa fat pad versus subcutaneous adipose tissue. DISCUSSION: Mesenchymal cells from the adipose tissue of the severe osteoarthritic knee show a significant decrease in inflammatory cytokines even in the chronic state and a significant decrease in angiogenic factors and immunomodulatory cytokines (IP10 and INF).

OBJETIVO: Analizar el nivel de citoquinas proinflamatorias en la grasa articular del paquete adiposo en pacientes con gonartrosis, en relación con la grasa subcutánea del muslo. MATERIAL Y MÉTODOS: Efectuamos un estudio de grasa del paquete adiposo articular de la rodilla afectada de artrosis y de la grasa subcutánea del muslo del mismo lado, a la mayor distancia de la articulación en seis pacientes con gonartrosis grave, con una edad media de 68 años (rango: 55-81 años). De las muestras de grasa se obtuvieron las células mesenquimales progenitoras. Los sobrenadantes de células mesenquimales obtenidas se utilizaron para analizar factores inflamatorios (IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13, IL15) y angiogénicos (VEGF, PDGF bb), así como citoquinas inmunomoduladoras (IP-10 e INF-) y se compararon las medias de dos muestras. RESULTADOS: El análisis cuantitativo reveló una disminución significativa (p 0.05) de IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 y un aumento de IL15 en la grasa de Hoffa frente al tejido adiposo subcutáneo. Del mismo modo, el análisis de factores angiógenicos como VEGF y PDGF bb, al igual que los factores IP-10 e INF- presentaron una disminución significativa en la grasa de Hoffa (p 0.05) frente al tejido adiposo subcutáneo. DISCUSIÓN: Las células mesenquimales del paquete adiposo articular de la rodilla artrósica grave muestran una disminución significativa de citoquinas inflamatorias, aun en el estado crónico, y una disminución significativa de factores angiogénicos y citoquinas inmunomoduladoras (IP10 e INF).

Graphene oxide versus graphene for optimisation of PMMA bone cement for orthopaedic applications.

Graphene (G) and graphene oxide (GO) nano-sized powders with loadings ranging from 0.1 to 1.0wt% were investigated as reinforced agents for polymethyl methacrylate (PMMA) bone cements. The mechanical properties (i.e. bend strength, bend modulus, compression strength, fracture toughness and fatigue performance) and the thermal properties (i.e. maximum temperature, setting time, curing heat and residual monomer) of the resultant nanocomposites were characterised. The mechanical performance of G-PMMA and GO-PMMA bone cements has been improved at low loadings (≤0.25wt%), especially the fracture toughness and fatigue performance. These improvements were attributed to the fact that the G and GO induced deviations in the crack fronts and hampered crack propagation. The high functionalisation of GO compared with G resulted in greater enhancements because it facilitated the creation of a stronger interfacial adhesion between the GO and PMMA. The use of loadings ≥0.25wt% showed a detriment in the mechanical performance as consequence of the formation of agglomerates as well as to an increase in the porosity. The increase in the residual monomer and the decrease in the curing heat, observed with the increase in the level of G and GO added, suggests that such materials retard and inhibit the curing reaction at high levels of loading by interfering in the radical reaction.

Mechanical and thermal behaviour of an acrylic bone cement modified with a triblock copolymer.

The basic formulation of an acrylic bone cement has been modified by the addition of a block copolymer, Nanostrength(®) (NS), in order to augment the mechanical properties and particularly the fracture toughness of the bone cement. Two grades of NS at different levels of loading, between 1 and 10 wt.%, have been used. Mechanical tests were conducted to study the behaviour of the modified cements; specific tests measured the bend, compression and fracture toughness properties. The failure mode of the fracture test specimens was analysed using scanning electron microscopy (SEM). The effect of NS addition on the thermal properties was also determined, and the polymerisation reaction using differential scanning calorimetry. It was observed that the addition of NS produced an improvement in the fracture toughness and ductility of the cement, which could have a positive contribution by reducing the premature fracture of the cement mantle. The residual monomer content was reduced when the NS was added. However this also produced an increase in the maximum temperature and the heat delivered during the polymerisation of the cement.

Epidemiology of injuries sustained by players during the 16th Under-17 South American Soccer Championship. / Epidemiología de las lesiones sufridas por los jugadores durante el XVI Campeonato Sudamericano Sub-17 de Fútbol.

OBJECTIVE: We performed an epidemiological study of the traumatic injuries during the XVI South American U-17 Football Championship, 2015. MATERIAL AND METHODS: Observational surveys submitted by the 10 teams medical services of 220 players. Thirty-five games were held and 116 goals (3.31 per game) were recorded. RESULTS: 103 lesions, ie, 2.94 per game or 32.7 injuries per 1,000 min were recorded. Fifty-six were from direct contact and 66 requiring treatment. 36% of the injuries were punished by fault and 26% of the injuries also saw card. Injuries were most common in the ankle (15 cases), Achilles tendon (14 cases) and thigh (14 cases), followed by trauma to the knee and foot (7 cases each), face and the lumbar region (6 cases each), being rare in the upper extremity. CONCLUSION: Injuries during Soccer World Cup are difficult to predict and prevent, but serious injuries are rare. Is necessary to establish protocols that get adequate health care at all levels to solve problems produce, both in training and during the competition, and be prepared to solve the serious problems that may arise.

[Experimental induction of Perthes disease in lambs]. / Inducción experimental de la enfermedad de Perthes en corderos.

OBJECTIVE: To establish a simple, reproducible and safe experimental model, for the development of ischemic vascular necrosis of the hip in the lamb. MATERIAL AND METHODS: We used 15 lambs (10 males and 5 females) aged four weeks, divided into a control group (7 animals) and an experimental group (8 animals) producing ischemia in the proximal femur. Standard radiography and MRI were performed. The animals were euthanised at the 4th, 8th and 12th weeks after surgery. The femoral heads were extracted and measured and a histological analysis was performed with hematoxylin-eosin staining. RESULTS: Decreased height and increased width of the femoral head was observed in the X-Rays, particularly after the 4th week. We did not observe any changes in the height of the lateral pillar or trochanteric distance. The experimental group showed macroscopical hypertrophy and progressive flattening of the head. At 4 weeks necrotic areas in articular cartilage were observed, bone marrow was dense and the growth cartilage height was lower. The vessels were thickened by proliferation of the medial and adventitia layers. At 8 weeks, we found fibrosis in the subchondral bone with thinned and devitalized angiogenesis fat areas. The articular cartilage showed irregularities. At 12 weeks the closure of the physis was noted, as well as chondral areas in the trabecular bone and fat cells in the methaphysis. CONCLUSION: Although the histological changes are consistent with necrosis of the femoral head, the images obtained did not resemble Perthes disease, so we do not advise this experimental model for the study of this disease.

[Influence of the physiological medium on the mechanical properties of bone cement: can current studies be extrapolated?]. / Influencia del medio fisiológico sobre las propiedades mecánicas del cemento óseo. ¿Son los estudios actuales extrapolables?

PURPOSE: The use of bone cement is widespread in orthopaedic surgery. Most of the mechanical tests are performed in dry medium, making it difficult to extrapolate the results. The objective of this study is to assess if the mechanical properties of polymethylmethacrylate (PMMA), obtained in previous reports, are still present in a liquid medium. MATERIAL AND METHOD: An experimental study was designed with antibiotic (vancomycin) loaded PMMA. Four groups were defined according to the medium (dry or liquid) and the pre-conditioning in liquid medium (one week or one month). Wear and flexural strength tests were performed according to ASTM and ISO standards. Volumetric wear, friction coefficient, tensile strength, and Young's modulus were analyzed. All samples were examined by scanning electron microscopy. RESULTS: The samples tested in liquid medium showed lower wear and flexural strength values (P<.05). The kind of wear was modified from abrasive to adhesive in those samples studied in liquid medium. The samples with a pre-conditioning time showed lower values of wear (P<.05). CONCLUSIONS: Caution is recommended when extrapolating the results of previous PMMA results. The different mechanical strength of the cement in a liquid medium, observed in saline medium, is much closer to the clinical situation.

Trabecular metal screw implanted for avascular necrosis of the femoral head may complicate subsequent arthroplasty surgery.

A trabecular metal screw has been suggested to treat avascular osteonecrosis of the femoral head. Non-surgical management with partial weight bearing can only be selected for early stages and very small lesions. Even in such cases, it has been proven to be ineffective in 80-90 % of patients. Conversely, the results with trabecular metal implants are not always clinically satisfactory, and some patients can show emerging pain and activity limitations that could require conversion to a total hip arthroplasty. Hereby we report the results of 6 patients who underwent this implant and describe the histopathology of the bone at the femoral neck and to speculate on the causes of complications encountered during arthroplasty surgery. The necrosis was stopped in 1 case, and 5 hips showed disease progression. Two protrusions of the screw apex were observed. In one case, rupture of the greater trochanter during prosthesis implant occurred. After trabecular metal implants for avascular osteonecrosis, some patients can require conversion to a total hip arthroplasty. Two patients had an intraoperative fracture with detachment of the greater trochanter that required wiring. Complications related to implant removal can be encountered, and the orthopedic surgeon should be aware of removal techniques.

[SECOT consensus on painful knee replacement]. / Consenso SECOT sobre artroplastia de rodilla dolorosa.

The opinions of 21 experts in knee surgery were evaluated in this study, using a DELPHI questionnaire method in two successive rounds, on 64 controversial scenarios that covered both the diagnosis and possible treatment of painful knee replacements. The level of consensus was significantly unanimous in 42 items and of the design in 5, with no agreement in 17 of the questions presented. light of the published scientific evidence, the surgeons who took part showed to have a notable level of information on the most effective diagnostic tests, although, it should be pointed out that there was a lack of confidence in the possibility of ruling out an infection when the erythrocyte sedimentation rate and the C-reactive protein were within normal values, which have been demonstrated in the literature to have a high negative predictive value As regards the treatments to employ in the different situations, the responses of the expert panel were mainly in agreement with the data in the literature. The conclusions of this consensus may help other surgeons when they are faced with a painful knee prosthesis.