Comparative Analysis of External Fixators for Managing Unstable Pelvic Ring Injuries

Introduction: More than 60% of pelvic ring fractures in the elderly are associated with osteoporosis. Early reduction and compression are vital in managing bleeding from unstable pelvic ring injuries. Pelvic ring fractures, which are particularly common in emergency settings, are often treated with the standard supra-acetabular (SA) external fixator. However, the efficacy of SA fixators in compressing the posterior pelvic ring raises clinical concerns. The purpose of this is to evaluate different fixator designs and their effectiveness in posterior pelvic ring compression.

Methods: Utilizing CT data from a patient with a Tile C pelvic fracture, a preoperative model was created, alongside a postoperative model simulating the application of an SA fixator. Finite element analysis was employed to analyze these models subjected to compression forces ranging from 100N to 600N, with a specific focus on assessing displacement within the sacral fracture gap. Additionally, the study examines the effectiveness of two alternative fixators—the X-frame and the pre-tensed curved bar—in managing this gap.

Results: Application of the SA fixator resulted in an increased sacral fracture gap under progressive compression. In contrast, the X-frame fixator consistently reduced the gap. The pre-tensed curved bar fixator showed mixed results, decreasing the ventral and superior dorsal distances but marginally increasing the mid-lower dorsal distance.

Discussion: The SA fixator, utilizing the pubic symphysis as a fulcrum, inadvertently widens the posterior pelvic ring's fracture gap due to lever mechanics. In contrast, the X-frame fixator, by altering the fulcrum and load direction, effectively compresses this gap. Although the pre-tensed curved bar fixator offers simplicity, it is less effective than the X-frame in reducing the posterior pelvic ring's fracture gap.

Keywords: pelvic fracture, posterior pelvic ring compression, external fixator

Korrespondenzadresse: Xishan Li, University Medical Center Göttingen, Department of Trauma, Orthopaedic and Plastic Surgery, Robert-Koch-Straße 40, 37099 Göttingen, Germany, E-Mail: [e-mail]

Publication History

Article published online:
13 March 2024