Is unrestricted weight bearing immediately after fixation of rotationally unstable pelvic fractures safe?

INTRODUCTION: Rotationally unstable pelvic fractures treated with surgical fixation have traditionally been treated with restricted weight bearing on the affected side for 6–8 weeks post operatively. We have been developing pelvic fixation standards to allow for unrestricted weight bearing immediately post operatively in type B rotationally unstable pelvic fractures. AIMS: To assess for safety and efficacy of allowing unrestrictive weight bearing in this cohort of patients, we have clinically and radiologically monitored outcomes up to two years post operatively. METHODS: Through retrospective review, two cohorts of patients with Tile Type B pelvic fractures were identified that were treated at the Royal Adelaide Hospital, South Australia. Patient demographics, injury classification, surgical fixation and weight bearing status post operatively was recorded. One cohort of patients was allowed to fully weight bear post operatively, whilst the other was treated with 6 weeks of restricted post op weight bearing. At clinical follow up, post-operative x-rays were assessed for loss of reduction, screw or plate breakage and reoperation. RESULTS: Between January 2018 and January 2021, 53 patients with rotationally unstable pelvic fractures that underwent surgical fixation were included in this study. One group of patents were allowed to immediately weight bear as tolerated (WBAT) post operatively (n = 28) and the other with restricted weightbearing (RWB) (n = 25). There was 1 re operation for failure of fixation in each group. Metalwork breakage was more common in the WBAT group than in the RWB group and this was seen only in APC fractures. This increase in metalwork failure was not associated with loss of reduction. CONCLUSIONS: With surgical fixation, Tile type B rotationally unstable pelvic fractures can be allowed immediate weight bearing post operatively. We found this to be safe and effective, employing surgical strategies to address both anterior and posterior injuries to allow immediate unrestricted weight bearing. Broken metalwork was more commonly seen in the WBAT group but this was not associated with loss of reduction or reoperation.