Surgical outcomes of transverse acetabular fractures and risk factors for poor outcomes.

<bold>Background: </bold>Transverse acetabular fractures, although classified as elementary, have worse outcomes than other types of acetabular fractures. Prognostic factors for this fracture type are not clearly established. This study aimed to assess the surgical outcomes of transverse acetabular fractures and subtypes thereof and to investigate the prognostic factors.<bold>Methods: </bold>Between 2014 and 2019, 39 patients (39 hips) had transverse fractures or subtypes thereof. We reviewed the surgical outcomes and evaluated patient factors, injury factors, and surgical factors in relation to osteoarthritis (OA) and conversion to total hip arthroplasty (THA). Additionally, we analyzed the cutoff values for postoperative residual gaps and steps.<bold>Results: </bold>Twenty-three male patients and sixteen female with a mean age of 41.7 years (range, 18-78 years) were included. There were 29 satisfactory reductions (74.4%). Eleven hips (28.2%) developed OA, and five (12.8%) of them underwent THA. Dome impaction (odds ratio [OR], 41.173; 95% confidence interval [CI], 1.804-939.814; p = 0.020) and residual gaps (OR, 4.251; 95% CI, 1.248-14.479; p = 0.021) were correlated with poor outcomes. Residual gaps (≥3 mm) and residual steps (≥1 mm) were significantly associated with OA.<bold>Conclusions: </bold>Relatively poor reduction was found for transverse acetabular fractures and subtypes thereof. However, the rates of OA and conversion to THA were not high. Dome impaction and wide residual gaps were identified as risk factors for poor outcomes. The development of OA significantly increased if residual gap and step were more than 3 mm and 1 mm, respectively. [ABSTRACT FROM AUTHOR]