title: MECHANICAL STUDY ON DORSAL STABILITY OF INTRAMEDULLARY OSTEOSYNTHESIS ASSOCIATED WITH EXTERNAL FIXATION (ULSON'S METHOD).
abstract: OBJECTIVE
  To evaluate the Ulson intramedullary fixation method, with external fixation in which the level of the external locking of the Kirschner wires is varied, and without external fixation.
  
  
  METHODS
  Eighteen porcine tibias were used. Transverse osteotomy was performed in the region of the tuberosity, and two intramedullary Kirschner wires were inserted into each specimen, using three different assembly patterns: Group I: locking with external minifixator at a height of 3.0 cm; Group II: locking at a height of 4.5 cm; Group III: without external locking. Mechanical shear tests were then conducted, to determine the maximum load, proportionality limit and coefficient of rigidity.
  
  
  RESULTS
  There were no significant differences in maximum load or proportionality limit between the groups. The coefficient of rigidity was higher in Group II.
  
  
  CONCLUSIONS
  The locking height for the Kirschner wires in Ulson's method, within the limits evaluated, did not harm the stability of the fracture fixation system.
authors.affiliation: Professor, Botucatu School of Medicine - UNESP - Botucatu, SP, Brazil.
authors.forename: Trajano
authors.initials: T
authors.lastname: Sardenberg
authors.affiliation: Professor, Botucatu School of Medicine - UNESP - Botucatu, SP, Brazil.
authors.forename: Sérgio Swain
authors.initials: SS
authors.lastname: Muller
authors.affiliation: Physician; Former Resident in Orthopedics and Traumatology of the Botucatu School of Medicine - UNESP - Botucatu, SP, Brazil.
authors.forename: Daniel Ricardo
authors.initials: DR
authors.lastname: Medeiros
authors.affiliation: Physician; Former Resident in Orthopedics and Traumatology of the Botucatu School of Medicine - UNESP - Botucatu, SP, Brazil.
authors.forename: Pablo Luiz
authors.initials: PL
authors.lastname: Baptistão
keywords: Biomechanics; External Fixators; Radius Fractures