Unilateral Sacral Fragility Fractures: A Comparative Study of Unilateral vs. Bilateral Minimally Invasive Osteosynthesis

Purpose : The unilateral sacral fragility fractures are mainly treated unilaterally with percutaneous iliosacral screws. This can lead to overloading and fracture of the opposite side. The main purpose of this study was to compare the rate of complication between the unilateral and bilateral screw osteosynthesis and the risk factors for the fracture on the opposite side after the unilateral treatment. Methods: This study analyzed retrospective data from patients with unilateral fragility fractures between 2018 and 2024. The data included patient demographics, pain levels, and mobility both before and after surgery. Patients were divided into two groups: Group 1 received unilateral surgical treatment, while Group 2 underwent bilateral tratment. Clinical and radiological assessments were conducted postoperatively as well as at 3- and 12-month follow-ups. Potential risk factors were evaluated, including fracture morphology, presence of a comminuted fracture zone, and additional anterior pelvic fractures. Results: a total of 119 patients with unilateral sacral insufficiency fracture were included, 44 cases were treated unilaterally and 75 cases bilaterally. The complication rate was significantly higher in the group with unilateral fixation (26% vs. 8.9%; p = 0.03). The occurrence of a fracture on the opposite side in the group with unilateral treatment is strongly correlated with the simultaneous presence of an anterior pelvic ring fracture, although not significantly (p-value 0.2) Conclusions: The direct bilateral osteosynthesis of unilateral sacral fragility fractures shows a significantly lower complication rate compared to unilateral treatment. The presence of an additional anterior pelvic ring fracture may also increases the risk of a contralateral fracture.