Determine the infection risk of nonoperative versus operative repair of extraperitoneal bladder ruptures in patients with pelvic ring injuries. Pelvic ring injuries with extraperitoneal bladder ruptures were identified from a prospective trauma registry at two level 1 trauma centers from 2014 to 2020. Patients, injuries, treatments, and complications were reviewed. Using Fisher's exact test with significance at P value < 0.05, associations between injury treatment and outcomes were determined. Of the 1127 patients with pelvic ring injuries, 68 (6%) had a concomitant extraperitoneal bladder rupture. All patients received IV antibiotics for an average of 2.5 days. A suprapubic catheter was placed in 4 patients. Bladder repairs were performed in 55 (81%) patients, 28 of those simultaneous with ORIF anterior pelvic ring. The other 27 bladder repair patients underwent initial ex-lap with bladder repair and on average had pelvic fixation 2.2 days later. Nonoperative management of bladder rupture with prolonged Foley catheterization was used in 13 patients. Improved fracture reduction was noted in the ORIF cohort compared to the closed reduction external fixation cohort (P = 0.04). There were 5 (7%) deep infections. Deep infection was associated with nonoperative management of bladder rupture (P = 0.003) and use of a suprapubic catheter (P = 0.02). Not repairing the bladder increased odds of infection 17-fold compared to repair (OR 16.9, 95% CI 1.75 – 164, P = 0.01). Operative repair of extraperitoneal bladder ruptures substantially decreases risk of infection in patients with pelvic ring injuries. ORIF of anterior pelvic ring does not increase risk of infection and results in better reductions compared to closed reduction. Suprapubic catheters should be avoided if possible due to increased infection risk later. Treatment algorithms for pelvic ring injuries with extraperitoneal bladder ruptures should recommend early bladder repair and emphasize anterior pelvic ORIF

Variations in pelvic anatomy are a major risk factor for misplaced percutaneous sacroiliac screws used to treat unstable posterior pelvic ring injuries. A better understanding of pelvic morphology improves preoperative planning and therefore minimises the risk of malpositioned screws, neurological or vascular injuries, failed fixation or malreduction. Hence a classification system which identifies the clinically important anatomical variations of the sacrum would improve communication among pelvic surgeons and inform treatment strategy. 300 Pelvic CT scans from skeletally mature trauma patients that did not have pre-existing posterior pelvic pathology were identified. Axial and coronal transosseous corridor widths at both S1 and S2 were recorded. Additionally, the S1 lateral mass angle were also calculated. Pelvises were classified based upon the sacroiliac joint (SIJ) height using the midpoint of the anterior cortex of L5 as a reference point. Four distinct types could be identified:. Type-A – SIJ height is above the midpoint of the anterior cortex of the L5 vertebra. Type-B – SIJ height is between the midpoint and the lowest point of the anterior cortex of the L5 vertebra. Type-C – SIJ height is below the lowest point of the anterior cortex of the L5 vertebra. Type-D – a subgroup for those with a lumbosacral transitional vertebra, in particular a sacralised L5. Differences in transosseous corridor widths and lateral mass angles between classification types were assessed using two-way ANOVAs. Type-B was the most common pelvic type followed by Type-A, Type-C, and Type-D. Significant differences in the axial and coronal corridors was observed for all pelvic types at each level. Lateral mass angles increased from Types-A to C, but were smaller in Type-D. This classification system offers a guide to surgeons navigating variable pelvic anatomy and understanding how it is associated with the differences in transosseous sacral corridors. It can assist surgeons’ preoperative planning of screw position, choice of fixation or the need for technological assistance

Summary. Application of RSA in supine and standing positions allows pelvic fracture stability to be measured more accurately than current techniques. RSA may enable a better understanding of these injuries. Introduction. The in vivo stability of the pelvic ring after fracture stabilisation remains unknown. Plain radiographs have a low accuracy in diagnosing loss of fracture reduction over time. Radiostereometric analysis (RSA) is an accurate imaging measurement method that has previously been applied to measure the healing of other fractures. This pilot study investigated the potential application of RSA in supine and standing positions to measure pelvic fracture stability over time and under weightbearing load. Methods. Five patients with a similar type C pelvic ring disruption who were all operated on using the same surgical technique and had RSA markers inserted at the time of surgery. All five patients had a unilateral comminuted sacral fracture lateral to the sacral foramina treated with posterior plating and pubic rami fractures stabilised by external fixation for six weeks. All patients were mobilised partial weight bearing after regaining leg control. RSA examinations at 2, 4, 12, 26 and 52 weeks included three radiographic pairs taken in supine, standing and supine positions at each time point. Two additional RSA examinations were performed the day prior and post pin removal at 6 weeks. Results. All patients ambulated before the 2 week follow-up and progressed uneventfully. At latest follow-up, there were no complications. Minimal displacements (translations less than 0.3mm and rotations less than 0.5°) were recorded between the supine exams pre and post standing at 2 weeks. Hence, the supine examination was found to be a reliable position to measure the migration of the ilium over time. No loss of reduction was identifiable on plain radiographs over time. At 52 weeks, in contrast to plain radiographic results, RSA measurements revealed that one patient had a fracture migration greater than 4mm. Such large displacements could result in sacral nerve root transection, leading to devastating consequences, such as incontinence, for patients whose sacral fractures are through or medial to the sacral foramina. In one patient, the migration recorded for the apparent uninjured posterior complex side exceeded the migration of the injured side suggesting an unrecognised bilateral injury. Comparative RSA examinations pre and post external fixator removal demonstrated that in three patients the injured hemipelvis migrated greater than 2mm after the removal of the external fixator, which may be indicative that the fixator was removed prematurely. Discussion and Conclusion. The application of RSA allows accurate measurement of pelvic fracture stability which is difficult, if not impossible, to identify and quantify with any other imaging techniques. Hence, RSA has the capacity to enable a better understanding of pelvic ring injuries and optimise their treatment