Failure of reduction with an external fixator in the management of injuries of the pelvic ring - Long-term evaluation of 110 patients

We reviewed 110 patients with an unstable fracture of the pelvic ring who h ad been treated with a trapezoidal external fixator after a mean follow-up of 4.1 years. There were eight open-book (type B1, B3-1) injuries, 62 later al compression (type B2, B3-2) and 40 rotationally and vertically unstable (type C1-C3) injuries. The rate of complications was high with loss of reduction in 57%, malunion in 58%, nonunion in 5%, infection at the pin site in 24%, loosening of the pins in 2%, injury to the lateral femoral cutaneous nerve in 2%, and pressu re sores in 3%, The external fixator failed to give and maintain a proper r eduction in six of the eight open-book injuries, in 20 of the 62 lateral co mpression injuries, and in 38 of the 40 type-C: injuries. Poor functional r esults were usually associated with failure of reduction and an unsatisfact ory radiological appearance. In type-C injuries more than 10 mm of residual vertical displacement of the injury to the posterior pelvic ring was signi ficantly related to poor outcome. In 14 patients in this unsatisfactory gro up poor functional results were also affected by associated nerve injuries. In lateral compression injuries the degree of displacement of fractures of the pubic rami caused by internal rotation of the hemipelvis was an import ant prognostic factor. External fixation may be useful in the acute phase of resuscitation but it is of limited value in the definitive treatment of an unstable type-C injur y and in type-B open-book injuries. It is usually unnecessary in minimally displaced lateral compression injuries.