Browsing by Author "Orrego, Mario"

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    An assessment of the Chilean National Examination of Orthopaedic Surgery
    (2016) Urrutia Escobar, Julio Octavio; Orrego, Mario; Wright Navarrete, Ana Cecilia; Amenábar Velasco, Diego José.
    Abstract Background The Chilean National Examination of Orthopaedic Surgery (EMNOT) has been administered since 2009. It was developed to determine whether individual residents are meeting minimal knowledge standards at the end of their training programs. Methods We performed a retrospective evaluation of the EMNOT for all years it has been administered (2009–2015). The test was analyzed for content, taxonomy of questions asked (1: direct recall; 2: diagnosis; 3: evaluation/decision-making), residents’ performance, difficulty index and discrimination index. Results During the years of EMNOT administration, the most frequently tested areas have been pediatric orthopaedics (22.9 %), spine (13.8 %), general orthopaedics (13.8 %) and musculoskeletal trauma (9.9 %). A significant increase in questions with images was observed, as well as a significant decrease in the percentage of Type 1 and an increase in Type 3 questions. The Difficulty Index showed a medium level of difficulty for all years the examination has been administered. The Discrimination Index showed good discrimination in 2009, fair discrimination from 2010 through 2012, and excellent discrimination from 2013 through 2015. Conclusion The EMNOT has evolved over several years to include better quality questions, better discrimination, and a more representative distribution of questions covering the different orthopaedic sub-specialties. This examination represents an effective instrument for quality assurance of orthopaedic residency programs in Chile.
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    Anterior and distal tunnel orientation for anatomic reconstruction of the medial patellofemoral ligament is safer in patients with open growth plates
    (SPRINGER, 2020) Irarrazaval, Sebastian; Besa, Pablo; Fernandez, Francisco; Fernandez, Tomas; Tuca, Maria; Lira, Maria J.; Orrego, Mario
    Purpose In patients with open growth plates, the direction of tunneling that avoids distal femoral physis (DFP) damage in anatomic reconstructions of the medial patellofemoral ligament (MPFL) has been a topic of discussion. The objective of this study was to determine the ideal orientation for anatomic reconstructions of MPFL tunneling that minimized DFP damage while avoiding breaching the intercondylar notch. Methods Eighty magnetic resonance images of patients aged 10 through 17 were obtained, randomly sampled from the institutional database. A de novo software was developed to obtain 3D models of the distal femur and DFP. In each model, the anatomical insertion point of the MPFL was determined as defined by Stephen. A 20-mm-depth drilling was simulated, starting from the insertion point at every possible angle within a 90 degrees cone using 5-, 6- and 7-mm drills. Physeal damage for each pair of angles and each drill size was determined. Damage was expressed as a percentage of total physis volume. Statistical analysis was conducted using Student'sttest and one-way ANOVA. Results Maximum physeal damage (5.35% [4.47-6.24]) was obtained with the 7-mm drill when drilling 3 degrees cephalic and 15 degrees posterior from insertion without differences between sexes (n.s.). Minimal physeal damage (0.22% [0.07-0.37]) was obtained using the 5-mm drill aimed 45 degrees distal and 0 degrees anteroposterior, not affected by sex (n.s.). Considering intra-articular drilling avoidance, the safest zone was obtained when aiming 30 degrees-40 degrees distal and 5 degrees-35 degrees anterior, regardless of sex. Conclusion Ideal femoral tunnel orientation, avoiding physeal damage and breaching of the intercondylar notch, was obtained when aiming 30 degrees-40 degrees distal and 5 degrees-35 degrees anterior, regardless of sex. This area is a safe zone that allows anatomic MPFL reconstruction of patients with an open physis.
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    Artroplastia total de rodilla en luxación inveterada de patela: Reporte de un caso
    (2024) Vicuña, Bernardita; Mendez, Magdalena; Orrego, Mario; Arteaga, Matías
    Introducción La luxación patelar inveterada (LPI) asociada a artrosis es un problema infrecuente y de difícil manejo, especialmente en pacientes con síndrome de Down (SD). La alteración crónica del funcionamiento patelofemoral (PF) debido a un severo mal alineamiento conduce a una progresiva destrucción articular que puede culminar en artrosis tricompartimental. Se han descrito distintas técnicas para su resolución, desde procedimientos en partes blandas hasta el uso de prótesis total de rodilla (PTR).Presentación del caso Hombre de 29 años con SD consultó por un año de gonalgia derecha atraumática, asociado a episodios de derrame articular. Inicialmente, se diagnosticó como artritis séptica. El examen físico mostró hiperlaxitud (Beighton 8), marcha claudicante, LPI, genu valgo irreductible y artrosis tricompartimental con genu valgo de 13,3° a derecha. Se trató con una PTR y realineamiento del aparato extensor mediante alargamiento del retináculo lateral y avance del vasto medial oblicuo (VMO) con técnica de Insall. A los 8 meses postoperatorios, el paciente está sin dolor, sin nuevos episodios de luxación patelar y es independiente para las actividades básicas de la vida diaria.Discusión Se trata de un caso complejo de gonartrosis e inestabilidad patelar asociado a genu valgo, en un paciente con SD e hiperlaxitud. Junto con la LPI, enfrentamos un valgo de 13,3° y artrosis tricompartimental. Se planificó una PTR primaria estabilizada posterior (PS) con posibilidad de mayor constricción intraoperatoria, junto con realineamiento de partes blandas. La literatura demuestra que este paso es esencial para restaurar la biomecánica PF y lograr buena funcionalidad.
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    Tibial Cut Accuracy in Mechanically Aligned Total Knee Arthroplasty Using Extensor Hallucis Longus Tendon to Determine Extramedullary Tibial Guide Position
    (2022) Besa, Pablo; Vega, Rafael; Ledermann, Gerardo; Calvo, Claudio; Angulo, Manuela; Lira, Maria Jesus; Vidal, Catalina; Orrego, Mario; Irribarra, Luis; Espinosa, Julio; Vial, Raimundo; Irarrazaval, Sebastian
    This study aimed to determine the tibial cut (TC) accuracy using extensor hallucis longus (EHL) tendon as an anatomical landmark to position the total knee arthroplasty (TKA) extramedullary tibial guide (EMTG), and its impact on the TKA mechanical alignment (MA). We retrospectively studied 96 TKA, performed by a single surgeon, using a femoral tailored intramedullary guide technique. Seventeen were prior to the use of the EHL and 79 used the EHL tendon to position the EMTG. We analyzed preoperative and postoperative standing total lower extremity radiographs to determine the tibial component angle (TCA) and the correction in MA, comparing pre-EHL use and post-EHL technique incorporation. Mean TCA was 88.89 degrees and postoperative MA was neutral in 81% of patients. Pre- and postoperative MAs were not correlated. As a conclusion of this study, using the EHL provides a safe and easy way to determine the position of EMTG.