Ultrasound evaluation of a new surface reference line to describe sural nerve location and safe zones to consider in posterior leg approaches.

PURPOSE: Several authors have described methods to predict the sural nerve pathway with non-proportional numerical distances, but none have proposed a person-proportional, reproducible method with anatomical references. The aim of this research is to describe ultrasonographically the distance and crossing zone between a surface reference line and the position of the sural nerve. METHODS: Descriptive cross-sectional study, performed between January and April 2022 in patients requiring foot surgery who met inclusion criteria. The sural nerve course in the posterior leg was located and marked using ultrasound. Landmarks were drawn with a straight line from the medial femoral condyle to the tip of the fibula. Four equal zones were established in the leg by subdividing the distal half of the line. This way, areas based on simple anatomical proportions for each patient were studied. The distance between the marking and the ultrasound nerve position was measured in these 4 zones, creating intersection points and safety areas. Location and distances from the sural nerve to the proposed landmarks were assessed. RESULTS: One-hundred and four lower limbs, 52 left and 52 right, assessed in 52 patients were included. The shortest median distance of the nerve passage was 2.9 mm from Point 2. The sural nerve intersection was 60/104 (57.7%) in Zone B, 21/104 (20.1%) in Zone C and 19/104 (18.3%) in Zone A. Safety zones were established. Average 80.5% of coincidence in sural nerve localization was found in the distal half of the leg, in relation to the surface reference line when comparing both legs of each patient. CONCLUSIONS: This study proposes a simple, reproducible, non-invasive and, for the first time, person-proportional method, that describes the distance and location of the main areas of intersection of the sural nerve with points and zones (risk and safe zones) determined by a line guided by superficial anatomical landmarks. Its application when surgeons plan and perform posterior leg approaches will help to avoid iatrogenic nerve injuries. LEVEL OF EVIDENCE: IV.

Ácido tranexámico tópico e infiltración periarticular vs administración tópica para la disminución de pérdida sanguínea en artroplastia de rodilla. Estudio de cohorte retrospectiva / Topical tranexamic acid and periarticular infiltration vs topical administration for the reduction of blood loss in knee arthroplasty. a cohort study

Introducción El ácido tranexámico (TXA) es uno de los métodos farmacológicos más efectivos para disminución de pérdida de sangre en reemplazos articulares. El objetivo fue evaluar los efectos de la administración de TXA en infiltración periarticular combinado con vía intraarticular comparado con TXA tópico en la pérdida sanguínea en remplazo total de rodilla (RTC). Materiales & Métodos Estudio observacional retrospectivo. Se incluyeron pacientes sometidos a RTC. Se recolectó valores de hematocrito y hemoglobina pre y posquirúrgica en pacientes operados entre marzo de 2016 y marzo de 2018. Al primer grupo se les realizó infiltración periarticular con mezcla de bupivacaina con epinefrina 150mg, ketorolaco 30mg, morfina 0.1mg/kg y 2g. de TXA intraarticular; al segundo grupo administró el mismo protocolo anterior más 1g. de TXA en la mezcla infiltrada. Resultados 174 pacientes [Grupo 1: 174 (65.9%) y Grupo 2: 90 (34.1%)]. Del grupo 1, el porcentaje de transfusión fue del 0,57% (1 paciente). La disminución promedio del hematocrito fue del 7,03% (-1.4 a 18.3) y la disminución de la hemoglobina de 2,51 (-0.5 a -5.7) g/dl. En el grupo 2 sin transfusiones. Disminución media del hematocrito fue del 7,05 (-0.3 a 15.1) y la disminución de la hemoglobina de 2,56 (0.0-5.2) g/dl. Discusión Los resultados de nuestro estudio son similares a reportes de estudios previos. La utilización de TXA en la mezcla de infiltración periarticular adicional a su uso tópico no genera beneficio en el control de pérdida sanguínea en el remplazo total de rodilla.

Introduction The tranexamic acid is currently one of the most effective pharmacological methods for blood lose in articular replacements. The study aimed to evaluate the effects of TXA administration in periarticular infiltration combined with intraarticular administration compared to topical TXA in blood lose in total knee arthoplasty. Methods Retrospective observational study. Patients undergoing total primary knee arthoplasty were included. Hematocrit and pre-surgical and post-surgical hemoglobin values ??were collected in patients operated between March 2016 and March 2018. The first group underwent peripheral joint infiltration with bupivacaine mixture with epinephrine 150mg, ketorolac 30mg, morphine 0.1mg / kg and 2g. of intraarticular TXA; the second group administered the same previous protocol plus 1g. of TXA in the infiltrated mixture. Outcomes 174 patients [Group 1: 174 (65.9%) and Group 2: 90 (34.1%)]. From group 1, the percentage of transfusion was 0.57% (1 patient). The average decrease in hematocrit was 7.03% (-1.4 to 18.3) and the decrease in hemoglobin from 2.51 (-0.5 to -5.7) g / dl. In group 2 there were no transfusions. The average decrease in hematocrit was 7.05 (-0.3 to 15.1) and the decrease in hemoglobin of 2.56 (0.0-5.2) g / dl. Discussion The results of our study are similar to reports from previous studies. The use of TXA in the mixture of periarticular infiltration in addition to its topical use does not generate benefit in the control of blood loss in the total knee arthroplasty.