Objective: To determine if the use of limited antibiotic prophylaxis reduces surgical site infections in pediatric orthopaedic surgery.

Introduction:The prevalence in the Mexican pediatric population of obesity and overweight was 75.7% for the year 2018. Both can modify the physiological genu valgum. Despite its high prevalence in Mexico there is no report on the frequencies of obesity and overweight in the pediatric population with idiopathic genu valgum. Objective: Determine the frequency of obesity and overweight in pediatric patients with idiopathic genu valgum at the Shriners Hospital from 2010 to 2020. Material and methods: Descriptive, observational, cross-sectional and retrolective clinical study. Universe composed of 587 patients with a representative subset of 232. Hypothesis tests to compare proportions were contrasted with χ 2 , risks were calculated with OR and 95% Confidence Intervals (CI95%); Student's t-test was used to compare two means. In all contrasts, a p < 0.05 was considered significant. Results: We found 48.7% obesity and 23.3% overweight (72%) measured from the body mass index (BMI). Of the total cases, 87.9% presented mechanical axis deviation (MAD) in both limbs. Obese or overweight patients had a 6.1 times higher risk (95% CI 2.6-14.2, p = 0.0001) of having bilateral mild to severe MAD compared to patients without obesity or overweight. In the conjoined obesity/overweight cases, the means of the lateral distal femoral angles were significantly greater (p = 0.02) than in the underweight and healthy cases. Conclusions: There is a statistically significant relationship between MAD and BMI, with MAD being more severe in cases of overweight and obesity, mainly related to deformity at the level of the distal femur. RESUMENIntroducción: La prevalencia de obesidad y sobrepeso en población pediátrica mexicana fue de 75.7% para el año 2018. Ambas pueden modificar el genu valgo fisiológico. A pesar de su alta prevalencia, a nivel nacional no hay un reporte sobre las frecuencias de obesidad y sobrepeso en la población pediátrica con genu valgo idiopático. Objetivo: Determinar la frecuencia de obesidad y sobrepeso en pacientes con genu valgo idiopático del Hospital Shriners para Niños México de 2010 a 2020. Material y métodos: Estudio clínico descriptivo, observacional, transversal y retrolectivo. Universo compuesto por 587 pacientes con un subconjunto representativo de 232. Las pruebas de hipótesis para comparar proporciones se contrastaron con χ 2 , los riesgos se calcularon con OR e intervalos de confianza de 95% (IC95%); para comparar dos promedios se utilizó t de Student. En todos los contrastes una p < 0.05 se consideró significativa. Resultados: Encontramos 48.7% de obesidad y 23.3% de sobrepeso (72%) medido a partir del índice de masa corporal (IMC). Del total de casos, 87.9% presentaba desviación del eje mecánico (MAD) en ambas extremidades. Los pacientes con obesidad o sobrepeso tuvieron un riesgo 6.1 veces mayor (IC95% 2.6-14.2, p = 0.0001) de tener MAD bilateral leve a severo respecto a los pacientes sin obesidad ni sobrepeso. En los casos obesidad/sobrepeso conjuntados, las medias de los ángulos femoral distal lateral ...