Pelvic fractures are often occult. Patients with run-over or crush injuries should be screened with an anteroposterior x-ray of the pelvis. The initial assessment of patients with pelvic fractures includes checking the patient's vital signs, a neurovascular examination of the lower limb (the lumbosacral plexus and peripheral nerves may be damaged), and examination for associated injuries to the head, chest, abdomen, and perineum.
Is the Fracture Stable or Unstable?
It is useful for the non-orthopaedic specialist to have some understanding of the nomenclature used to describe pelvic fractures
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and the associated injuries that one can anticipate. Most pelvic fractures can withstand normal physiological forces and are therefore stable. Fractures that cannot withstand normal physiological forces are unstable. Early identification of an unstable pelvic fracture is important. First, its presence suggests a greater degree of trauma to the pelvis and increases the likelihood of serious associated injuries, which should be looked for and treated if found. Second, fixation of an unstable fracture reduces blood loss, mortality, hospital stay, leg length discrepancy, and long-term disability (Latenser et al. 1991, Leung et al. 1992) and makes nursing care easier (turning, sitting, early mobilisation) and lowers the need for analgesic consumption.
Pelvic stability is maintained by a series of ligaments. Anterior and much stronger posterior sacroiliac ligaments stabilise the sacroiliac joints. The sacrum and the ischium are stabilised by sacrotuberous ligaments and in front of this the sacrospinous ligaments. The sacrospinous ligaments resist external rotation of the hemipelvis and the sacrotuberous ligaments resist rotational and shearing forces in the vertical plane. The two pubic bones are joined by a cartilaginous symphysis (Fig. 5.15).
Types of Pelvic Fracture
The Tile classification system of pelvic ring disruptions includes stable fractures (type A), horizontally unstable fractures (B), and vertically unstable fractures (C) (Table 5.2) (Tile 1984).