Navigated versus conventional total knee arthroplasty: A prospective study at three years follow-up. / Artroplastia total de rodilla navegada versus convencional; estudio prospectivo a 3 años de seguimiento.

OBJECTIVE: Computer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA. MATERIAL AND METHOD: In a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment. RESULTS: All clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group. The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (P<.01). CONCLUSIONS: The use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA.

Frontal alignment in total knee arthroplasty. Comparative study between radiographic measurement and surgical navigation. / Alineación frontal en la artroplastia total de rodilla. Estudio comparativo entre medición radiográfica y con navegación quirúrgica.

OBJECTIVE: To establish the concordance between angulation of the femoro-tibial mechanical axis measured with x-rays and surgical navigation in both the pre and postoperative period after a total knee arthroplasty (TKA) was implanted. MATERIAL AND METHOD: Pre and postoperative measurements were analyzed in 88 TKA of the same model and all performed with the same surgical navigation system. The mechanical frontal angle (MFA) and femoro-tibial anatomic angle were measured before and after the TKA. The angulation was digitally measured with a teleradiography. In the navigation, the femoro-tibial angle at rest, forced varus and valgus were registered and the average of these three measurements was calculated. RESULTS: The mean preoperative MFA measured on the radiograph was 4.55°. The mean of the same angle measured on the postoperative radiograph was 1.72°, (p=0.05). The mean of the MFA measured with navigation before TKA was 3.12° and after the implant with navigation was 0.53 (P=.013). The concordance coefficient between the MFA in teleradiography and in navigation was 0.869 (P<.001) preoperatively and 0.709 postoperatively (P=.017). CONCLUSIONS: We found a strong concordance between radiographic and surgical navigation measurements of the MFA. This may imply that teleradiography is not necessary when using surgical navigation in TKA.

Detección de iones metálicos en cabello tras artroplastia de cadera metal-metal / Detection of metal ions in hair after metal-metal hip arthroplasty

Objetivo. Tras el implante de algunos modelos de prótesis de cadera metal-metal se produce una elevación de los niveles de metales en suero y orina. Recientemente se ha demostrado que hay concordancia entre estas cifras y los niveles encontrados en el cabello. Nuestro objetivo ha sido estudiar la presencia de metales en cabello y conocer si ello se modifica con el paso del tiempo o con la extracción del implante. Material y método. En 45 pacientes con una artroplastia de superficie se ha realizado una determinación de los niveles de cromo, cobalto y molibdeno en cabello a los 3, 4, 5 y 6 años desde el implante. La edad media fue de 57,5 años, 2 eran mujeres. En 11 pacientes, en 5 de ellos por metalosis y quiste periarticular, fue necesaria una reintervención para extracción de la artroplastia e implante de un nuevo modelo con fricción metal-polietileno. Resultados. Las cifras medias de metales en cabello fueron cromo 163,27 ppm, cobalto 61,98 ppm y molibdeno 31,36 ppm, muy por encima de los niveles referidos en la población general. En los pacientes reintervenidos para extracción de la artroplastia se observó al año de la intervención una disminución del 43,8% en los niveles de cromo, del 51,1% en molibdeno y del 90,3% en cobalto. Conclusiones. En las artroplastias de cadera con fricción metal-metal se aprecia una alta concentración de metales en el cabello, que disminuye cuando dicho implante es extraído. La determinación de iones en cabello puede ser un buen marcador de la intoxicación por metales que sucede en estos modelos artroplásticos (AU)

Objective. There is an increase in the levels of metals in the serum and urine after the implantation of some models of metal-metal hip prosthesis. It has recently been demonstrated that there is an association between these levels and the levels found in hair. The aim of this study is to determine the presence of metals in hair, and to find out whether these change over time or with the removal of the implant. Material and method. The levels of chromium, cobalt and molybdenum were determined in the hair of 45 patients at 3, 4, 5, and 6 years after a hip surface replacement. The mean age was 57.5 years, and two were female. Further surgery was required to remove the replacement and implant a new model with metal-polyethylene friction in 11 patients, 5 of them due to metallosis and a periarticular cyst. Results. The mean levels of metals in hair were chromium 163.27 ppm, cobalt 61.98 ppm, and molybdenum 31.36 ppm, much higher than the levels found in the general population. A decrease in the levels of chromium (43.8%), molybdenum (51.1%), and cobalt (91.1%) was observed at one year in the patients who had further surgery to remove the prosthesis. Conclusions. High concentrations of metals in the hair are observed in hip replacements with metal-metal friction, which decrease when that implant is removed. The determination of metal ions in hair could be a good marker of the metal poisoning that occurs in these arthroplasty models (AU)

[Detection of metal ions in hair after metal-metal hip arthroplasty]. / Detección de iones metálicos en cabello tras artroplastia de cadera metal-metal.

OBJECTIVE: There is an increase in the levels of metals in the serum and urine after the implantation of some models of metal-metal hip prosthesis. It has recently been demonstrated that there is an association between these levels and the levels found in hair. The aim of this study is to determine the presence of metals in hair, and to find out whether these change over time or with the removal of the implant. MATERIAL AND METHOD: The levels of chromium, cobalt and molybdenum were determined in the hair of 45 patients at 3, 4, 5, and 6 years after a hip surface replacement. The mean age was 57.5 years, and two were female. Further surgery was required to remove the replacement and implant a new model with metal-polyethylene friction in 11 patients, 5 of them due to metallosis and a periarticular cyst. RESULTS: The mean levels of metals in hair were chromium 163.27 ppm, cobalt 61.98 ppm, and molybdenum 31.36 ppm, much higher than the levels found in the general population. A decrease in the levels of chromium (43.8%), molybdenum (51.1%), and cobalt (91.1%) was observed at one year in the patients who had further surgery to remove the prosthesis. CONCLUSIONS: High concentrations of metals in the hair are observed in hip replacements with metal-metal friction, which decrease when that implant is removed. The determination of metal ions in hair could be a good marker of the metal poisoning that occurs in these arthroplasty models.

Utilización de la estadística en cirugía ortopédica y traumatología / Statistic in orthopaedic surgery and traumatology

Los estudios de investigación epidemiológica se sustentan en los métodos de la estadística. Para poder alcanzar conocimiento sobre poblaciones frecuentemente se estudian muestras representativas de las mismas. Estos estudios se basan en la inferencia estadística. La inferencia se puede realizar mediante la estimación de parámetros por intervalos de confianza o bien mediante el cálculo de la significación estadística –valores p– mediante contrastes de hipótesis. En un intervalo de confianza se busca una solución que proporcione seguridad y precisión. Con los contrastes de hipótesis se cuantifica la probabilidad de que las observaciones muestrales puedan ser explicadas por el azar del muestreo, midiendo los errores tipo I y tipo II. En cada hipótesis de investigación existe un contraste apropiado en función de los tipos de variables estudiadas, su distribución, el número de sujetos estudiados y el número de grupos que se comparan. La utilización de valores p está sujeta a controversia, ante lo que se ofrecen alternativas como la utilización de métodos bayesianos o el enfoque a intervalos de confianza. Los estudios dirigidos a la medición de eventos a lo largo de periodos de observación se denominan estudios de supervivencia. Existen distintos métodos en función del tipo de periodos estudiados y de las variables a analizar. Los métodos estadísticos multivariantes permiten analizar dos o más variables a la vez. Existen métodos exploratorios que pueden simplificar el número de variables o de sujetos y métodos confirmatorios como la regresión logística que permite analizar el papel de variables confusoras y de interacciones (AU)

Objetive: Epidemiologic research is based on statistical methods and usually studies representative samples to attain knowledge about population. These studies are based on statistical inference. There are two ways to make inference. One is the parameter estimation with confidence intervals, another is the hypothesis test. A confidence interval allow us to control the precision (a range of the estimated variable) and the confidence (the probability of the population parameter to be included in that range) of the results. A hypothesis test quantifies the chance that a result could be explained by the random nature of the sample measuring type I and type II errors. Every research question has a matching hypothesis test according to the types of the variables, their distribution, the number of sampled units and the groups to be compared. The use of p-values is subject to controversy. Other methods like Bayesian statistics or confidence intervals offer alternatives. Survival studies measure events along time intervals. There are different methods regarding the type of intervals or the data to be analyzed. Multivariate statistics allow us to analyze two or more variables at a time. The exploratory methods can simplify the data, both the number of subjects and the variables. Confirmatory methods like logistic regression enable the analysis and importance of confounding and interacting variables (AU)

Evolución epidemiológica de las intoxicaciones agudaspor gases tóxicos atendidas durante el periodo de 2004 a 2007en urgencias de un hospital comarcal / Acute toxic gas poisoning cases treated from 2004 through 2007 at a regional hospital

Objetivo: Conocer las variaciones producidas en el agente causal en las intoxicaciones agudas por productos químicos atendidas en el servicio de urgencias (SU) del Hospital San Agustín de Avilés (HSA) durante el periodo 2004-2007.Método: Se realizó un estudio observacional descriptivo. La población objetivo fueron los pacientes intoxicados por productos químicos atendidos en los años 2004-2007 enel SU del HSA. Se recogieron las variables de la ficha de intoxicaciones de la Sección de Toxicología Clínica (STC) de la Asociación Española de Toxicología (AETOX).Resultados: Durante el periodo de 2004 a 2007 se atendieron 204 pacientes intoxicados por productos químicos: gases irritantes 32,8%, productos cáusticos 25%, gases tóxicos 21,6%, disolventes 11,3%, plaguicidas 4,4%, detergentes 2,9% y metales 2%.Las intoxicaciones por gases tóxicos (IGT) en 2004-2005 fueron el 68,2% del total y en2006-2007 el 31,8% (p < 0,001). El grupo de IGT está constituido en el 93,18% por monóxido de carbono (CO). Las intoxicaciones por CO fueron leves-moderadas (78%)con carboxihemoglobina (COHb) del 11-30%. La clínica fue fundamentalmente neurológica(95,5%). El 77,3% se resolvieron en el SU. El tratamiento mayoritario fue oxígeno a alto flujo. El elevado número de intoxicaciones en 2004-2005 fue difundido a los medios de comunicación locales, así como las medidas preventivas en relación a las fuentes de CO. Conclusiones: Se ha producido un descenso significativo de las intoxicaciones por gases tóxicos y de su mayor representante, el CO, en los últimos dos años. El esfuerzo del registro y la difusión de las medidas de mantenimiento de las instalaciones de calefacción y calentadores de los domicilios ha podido tener una influencia positiva (AU)

Objective: To determine changes in agents causing cases of chemical poisoning treated in the emergency department of Hospital San Agustín de Avilés in the period 2004 through 2007.Methods: Descriptive observational study. The target population consisted of patients suffering from chemical poisoning who required emergency care at our hospital from 2004 through 2007. Data were extracted from the records of the clinical toxicology section of the Spanish Toxicology Association (AETOX).Results: Two hundred four patients were treated for chemical poisoning during the study period. The agents involved were irritant gases (32.8%), caustic substances (25%), toxic gases (21.6%), solvents (11.3%), pesticides (4.4%),detergents (2.9%), and metals (2%). Toxic gas poisoning accounted for 68.2% of cases in the first 2 years (2004-2005)and 31.8% of cases in the second 2 years (2006-2007) (P < .001). Carbon monoxide (CO) was involved in 93.2% of the toxic gas cases. CO poisoning was mild-moderate in 78%, with carboxyhemoglobin levels between 11% and 30%. Most patients suffered from neurologic symptoms (95.%); the episode was resolved in the emergency department in 77.3% of the cases, usually by applying high-flow oxygen. The local media reported on the large number of poisonings treated in2004 and 2005, at the same time publicizing measures for preventing CO poisoning. Conclusions: The number of cases of toxic gas poisoning has decreased significantly, mainly due to a lower incidence of CO poisoning in the last 2 years. Efforts made to record cases and publicize information about how to maintain household heaters and heating systems have had a positive influence (AU)

Patrón de agregación y análisis factorial de los factoresde riesgo cardiovascular integrantes del síndrome metabólicoen población española no diabética: estudio VIVA / Aggregation pattern and factorial analysis of cardiovascular risk factors included

Objetivos: Describir las agregaciones más frecuentes de los factoresde riesgo cardiovascular (FRCV) que integran con el síndrome metabólico(SM) en una muestra de población española no diabética. Comprobarmediante análisis factorial si los diferentes FRCV considerados en elSM son manifestaciones de un posible único factor común. Material ymétodos: Estudio poblacional transversal, multicéntrico, realizado en2.583 sujetos de 30-65 años elegidos al azar de 9 registros poblacionales.Para el cálculo de la frecuencia de cada uno de los FRCV y de susagregaciones se utilizaron las definiciones clásicas de cada factor.Las agregaciones de factores se calcularon de forma excluyente. Lacorrelación entre los FRCV se realizó mediante análisis factorial. Resultados:De mayor a menor, la prevalencia de los distintos FRCV clásicosconsiderados en la defi nición del SM según el NCEP ATP III fue: dislipemia34% (intervalo de confi anza [IC] del 95%: 32-35,5); hipertensión32% (IC del 95%: 30,2-33,8); obesidad 27% (IC del 95%: 25,3-28,7) e hiperglucemia 23% (IC del 95%: 21,6-25). Se observan diferenciassignifi cativas entre sexos: predominaba la dislipemia en hombresy la obesidad en mujeres. El 22% de la población mostraba agregaciónde dos FRCV y el 11% de tres FRCV. Las agregaciones más frecuentesfueron: hipertensión-obesidad, 5,3% (IC del 95%: 4,4-6,2), e hipertensión-obesidad-hiperglucemia, 4,1% (IC del 95%: 3,3-5). Los FRCVconsiderados tienden en general a formar tres conglomerados: 1) índicede masa corporal, diámetro sagital abdominal y glucemia; 2) insulina,glucemia a las 2 horas y presión arterial, y 3) razón colesterol total/colesterolunido a las lipoproteínas de alta densidad y triglicéridos. En loshombres pueden identifi carse hasta cuatro conglomerados de FRCV,mientras que en las mujeres éstos pueden reducirse hasta dos (AU)

Aims: The aim of this study is to describe the most frequent cardiovascularrisk factors (CVRF) clustering related to the metabolic syndrome(MS) in a non-diabetic Spanish population sample. Test by factorial analysisif the CVRF in the MS can be considered manifestations of a uniquecommon factor. Materials and methods: Observational, multicenter,transversal epidemiologic study. 2583 subjects aged 30-65 were randomlyassigned from nine population registries. Exclusive aggregationswere considered. Correlation among the MS variables was analyzed usingfactorial analysis. Results: In order of frequency the prevalence ofconventional CVRF was: dyslipidemia: 34% (IC95%: 32-35.5); hypertension:32% (IC95%: 30.2-33.8); obesity: 27% (IC95%: 25.3-28.7);hyperglycaemia: 23% (IC95%: 21.6-25). 22% of the population showed2 CVRF and 11% 3 CVRF. The most common CVRF aggregations werehypertension-obesity (5.3%; IC95%: 4.4-6.2) and hypertension-obesity-hyper glycaemia (4.1%; IC95%: 3.3-5). MS specifi c risk variablestended to aggregate in three factors: factor 1 (BMI, waist circumferenceand basal glycaemia), factor 2 (insulin, glycaemia 2h, and arterial bloodpressure), factor 3 (total cholesterol/HDL, triglycerides). Conclusions:There is a high prevalence of CVRF and MS in the population studied.Analysis of the metabolic syndrome does not contribute with additionalinformation to predict cardiovascular risk in susceptible patients, as comparedto the clustering of CVRF. Factorial analysis do not confi rm theexistence of a unifying factor to explain MS (AU)

Aneurisma inflamatorio de aorta abdominal / Inflammatory abdominal aortic aneurysm

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Epidemiología de la demanda asistencial urgente por insuficiencia cardíaca congestiva / Epidemiology of the demand for acute health care due to congestive heart failure

Objetivo: Estudio de la demanda urgente y su proceso asistencial por insuficiencia cardiaca congestiva (ICC) en un hospital de área de salud de nivel II. Método: Diseño epidemiológico observacional de corte transversal sobre 242 pacientes mayores de 14 años con criterios de ICC, que demandaron asistencia por urgencias del 1 de junio al 20 de septiembre de 2000.Resultados: La edad media fue de 77,9 años ( =11,2). Había 113 (46,5 por ciento) hombres y 129 (53,1 por ciento) mujeres y sus edades medias (75,6 y 80 años, respectivamente) diferían significativamente (p<0,05).Demandan asistencia urgente un promedio de dos veces al año y uno de cada dos termina siendo ingresado. Los episodios se repiten en promedio cada 75 días. Sólo uno de cada tres fueron atendidos antes por su médico de atención primaria y sólo el 5 por ciento reingresan antes de las 72 horas tras el alta. Los principales factores de riesgo son la hipertensión, cardiopatía isquémica, diabetes, EPOC y obesidad (más diabetes en mujeres y más EPOC en hombres).El esquema terapéutico de la ICC sigue basándose en el diurético de asa, el inhibidor de la enzima conversiva de angiotensina y la digoxina. La práctica clínica analizada muestra poco uso de espironolactona (valvulopatía), IECAs (hipertensión y miocardiopatía) y Beta-bloqueantes (hipertensión). Conclusiones: El paciente tipo es un hombre o mujer de edad avanzada que acude a urgencias por iniciativa propia, siendo su primer ingreso. Sólo la mitad saben que tienen ICC. El varón presenta un mayor deterioro clínico en relación a su disfunción sistólica a diferencia de la mujer en la que descompensación se debe a una arritmia cardiaca por fibrilación auricular con función sistólica conservada. El esquema terapeútico sigue siendo el clásico (AU)

[Spinal cord infarction and recurrent venous thrombosis in association with estrogens and the 20210A allele of the prothrombin gene]. / Mielopatía aguda isquémica y trombosis venosa recurrente asociada a estrógenos y alelo 20210A del gen de la protrombina.

The acute spinal cord infarction is a rare cause of acute-onset paraplegia. Furthermore, it is specially uncommon that the infarction occurs in patients with apparent low predisposition to vascular disease. The 20210A allele of the prothrombin gene (causing a threefold-increased risk in venous thromboembolism) was recently associated with unexplained spinal cord infarction in young women under treatment with estrogens (contraceptive pill). We report a case of anterior spinal artery syndrome resulting from an ischaemic infarction at the anterior aspect of the spinal cord in a healthy 50-year-old woman, carrying this mutation, being the first published case under treatment with transdermal estradiol. She referred the typical sudden-onset back pain associated to clinical anterior spinal artery syndrome with sphincter dysfunction and nontraumatic paraplegia. A possible multiple sclerosis was ruled out and the steroids or immunoglobulin therapy induced no clinical improvement. Cerebrospinal fluid and other investigations were all negative. Sequential MRI scans revealed development of spinal cord infarction from T10 to T11, with increased signal in T2-weighted image (T2). Because she referred a previous thrombophlebitis and suffered a deep-vein thrombosis one month after paraplegia, a complete coagulation study was performed. Antithrombin, proteins C and S, homocysteine, factor V Leiden, lupus anticoagulant and anticardiolipin antibodies were all normal or negatives. In opposite, the 20210A variation was positive (heterozygous) and the factor VIIIc level was very high (280 U/dl eight months later). We argue the relative importance of both findings. The patient had no a substantial recovery over a period of 20 months.Certainly, the prothrombin 20210A seems to be associated with unexplained ischemic myelopathy among the young women with estrogens.

Risk of venous thromboembolism associated with the insertion/deletion polymorphism in the angiotensin-converting enzyme gene.

The circulating levels of angiotensin I-converting enzyme (ACE) are linked with a 287-base pair insertion/deletion (I/D) polymorphism at intron 16 of the ACE gene. Thus, the homozygous deletion (D/D genotype) could cause chronic vasoconstriction, arterial hypertension and, possibly, coronary artery disease. Also, the increase in plasminogen activator inhibitor-1 level and impaired fibrinolysis were related with the D/D genotype. The D allele has been recently associated with venous thrombosis among African-American men as well as among patients that underwent elective total hip replacement. We assess the risk of venous thromboembolism (VTE) linked with each genotype of the I/D ACE gene polymorphism in a Caucasian population by means of a case-control study. We genotyped the ACE gene in a series of 148 patients aged 45.0 +/- 16.0 years (range, 11-80 years), objectively diagnosed in our centre of deep-vein thrombosis or pulmonary embolism, and in 240 thrombosis-free subjects (25-75 years) from the same geographic area. The observed difference in D allele frequencies between patients (0.56) and controls (0.62) was nonsignificant overall; however, statistical significance (P = 0.05) was found by considering the recessive hypothesis (D/D versus I/ D + I/I) [odds ratio (OR) = 0.64, 95% confidence interval (CI95) = 0.42-0.99]. The OR was 0.88 (CI95 = 0.51-1.53; P = 0.65) for the dominant hypothesis (D/D + I/D versus I/I genotypes). The relative risk for the D allele was close to 1 for the dominant hypothesis, both considering gender and recurrent tendency; however, it was protective in men regarding the recessive hypothesis (OR = 0.53, CI95 = 0.29-0.97, P = 0.04). The I/D ACE allele distribution was similar among the 46 thrombophilic patients (antithrombin, protein C or protein S deficiencies, factor V R506Q, factor II G20210A or lupus anticoagulant). In conclusion, among (Spanish) Caucasians, this study does not support the hypothesis that the deletion allele (D) of the ACE gene could be a significant risk factor for VTE, being protective in men.

[Lowering high levels of fasting total homocysteine with folic acid and vitamins B in patients with venous thromboembolism: relationship between response and the C677T methylenetetrahydrofolate reductase (MTHRF) genotype]. / Reducción de concentraciones elevadas de homocisteína con ácido fólico y vitaminas B en pacientes con tromboembolia venosa: relación entre respuesta y genotipo C677T de la metilén tetrahidrofólico reductasa (MTHFR).

BACKGROUND: High levels of plasma total homocysteine (tHcy) are involved in arterial or venous occlusive diseases. It essentially depends on the nutritional status of folic acid (FA) and vitamins B12 or B6, but also on the methylenetetrahydrofolate reductase (MTHFR) enzymatic activity. We aim to evaluate the response of the hyperhomocysteinemia (HHcy) to a standard schedule of vitamin supplementation, according with the MTHFR genotype. PATIENTS AND METHODS: 227 patients, diagnosed with venous thromboembolism (VTE) were analysed for tHcy (in fasting conditions), and for the MTHFR-C677T gene polymorphism. When the tHcy exceeded the cut-off point (men = 16, women = 15 mumol/l), the patients were supplemented with a dose equivalent to 1 mg FA, 0.2 mg B12 and 100 mg of B6, daily by 6 weeks. Afterwards they were reanalysed and the reduction was stratified by MTHFR genotype, looking for any difference in the response. RESULTS: The mean fasting tHcy was 12.3 mumol/l (SD = 8). The 51 hyperhomocysteinemic patients (22%) were older (65.1 y) than the normal ones (55.0 y) (p = 0.0001). The treatment was carried out properly in 46 patients (90%). The pre-treatment mean Hcy was 23.2 (SD = 10.5) mumol/l, and it was reduced to 13.0 (SD = 5.9) (p = 0.0001) (mean reduction = 42.1%). By genotype, the C/C reduced from 21.0 to 13.2 mumol/l (37%) (n = 18), the C/T from 25.0 to 12.6 mumol/l (46%) (n = 24), and the abnormal homozygotes T/T from 22.7 to 14.5 mumol/l (39%) (n = 4), although no statistical significant differences were found. In 80% of cases (37/46), tHcy values normalised. A negative correlation (r = -0.471) (p = 0.005) was observed between age and response. CONCLUSIONS: The FA/B6/B12 based therapy reduces in a simple, quick and effective way (> 40% in 6 weeks) the pathologic tHcy levels on a VTE population and this is not influenced by the MTHFR genotype. As HHcy seems related with recurrences of venous thrombosis, we could speculate if it would be useful to analyse routinely the tHcy, attempting reduction in selected cases.

Normal frequencies of the C677T genotypes on the methylenetetrahydrofolate reductase (MTHFR) gene among lymphoproliferative disorders but not in multiple myeloma.

The folate availability seems to be critical for the DNA integrity since it is required for the transfer of methyl groups in the biosynthesis of thymidilate. Although the excessive incorporation of uracils to the DNA can be efficiently removed, this mechanism of reparation produces many double-strand breaks from two opposing nicks. Several chromosomal abnormalities (mainly translocations and deletions perhaps not well understood) are involved in the origin of lymphoproliferative disorders. The TT homozygosity at nucleotide 677 in the gene of methylene tetrahydrofolatereductase (MTHFR), a key enzyme in folate metabolism, was recently linked to a significant protection against colon carcinoma and acute lymphoblastic leukaemia in adults. We analysed the genotype frequencies of C677T-MTHFR in a group of 143 patients with lymphoproliferative disorders (REAL classification) and 200 controls. Overally, the frequencies of the polymorphic allele were similar (35.3% and 32.0% respectively)(P=0.6). We did not find differences between patients and controls except for myeloma/plasmacytoma group (n=26) which showed a CC genotype less than expected (19% vs 46%) (p=0.01) with a frequency ratio of 0.28 (0.10-0.77). Even among the IgG myeloma cases only one patient showed a common genotype (CC) (1/15, 7%) (P=0.003). If these preliminary data are validated with prospective studies, the 677C allele of MTHFR gene could be confirmed as an effective multiple myeloma protective factor (specially for the IgG cases).