Does sequential examination under anaesthesia provide a reliable method to determine a management plan for unstable lateral compression pelvic ring injuries? a prospective study

Purpose To assess the reliability of sequential examination under anaesthesia (EUA) to determine pelvic instability and to evaluate radiological and functional outcomes in unstable lateral compression (LC) injuries. Methods A prospective case series study was conducted from 2020 to 2022 at a university hospital on 43 cases with LC injuries that met the inclusion criteria. Sequential EUA was carried out in three steps. Posterior-only fixation or anterior–posterior fixation was done according to the algorithm. Each patient was followed up for at least 12 months, both radiologically and functionally. Results Forty cases proved unstable and were fixed . None showed secondary displacement in the anterior–posterior fixation group. However, five cases (19.2%) of the posterior-only fixation group showed secondary displacement with a mean of 5.9 mm. Four cases of them had tetra-ramic injuries. There is a high tendency for secondary displacement at 14.5 mm or more preoperative displacement of the rami. Patients with secondary displacement showed comparable functional outcome scores to patients without secondary displacement. Posterior-only fixation showed shorter operative time, lesser radiological exposure, blood loss and iatrogenic nerve injury than anterior–posterior fixation. Conclusion EUA is a reliable method to determine pelvic instability and management plan for LC fractures with unilateral anterior ring injury. Anterior–posterior fixation is needed if there is a tetra-ramic fracture or initial anterior ring displacement of 14.5 mm or more, irrespective of EUA.