Diseño y aplicación de un sistema de distracción mecánica para artrodiastasis de rodilla

Abstract

For orthopedic treatment of severe knee flexion contractures (exceeding 90º), external systems of mechanical distraction (ESMD) which separate (arthrodiastasis) the articular surfaces (AS), translate the tibia and extend the knee, are used. The goal of this work was the design and manufacture of an ESMD for the orthopedic treatment of a first patient at the Instituto Nacional de Ortopedia, who had severe knee flexion contractures in his two knees due to poliomyelitis sequels, because the systems used in Mexico are imported so they are very expensive for patients which come to the orthopedic public institutions. Two ESMD prototypes were manufactured, the first was placed on the left knee and an arthrodiastasis of 18 millimeters was achieved along 13 weeks; the extension was 175º applying skeletal traction (ST). The second prototype was placed on the right knee, and a tensor was designed to achieve a congruent AS separation (16 millimeters); the extension obtained was only 120º with ST along 12 weeks; then the ESMD was retired. Finally, the two knees were fixed in extension.