Compressive Buttress Compared with Off-Axial Screw Fixation for Vertical Femoral Neck Fractures in Young Adults: A Prospective, Randomized Controlled Trial

Abstract

Abstract Background: To compare the clinical outcomes of compressive buttress screw (CBS) fixation, a novel screw fixation strategy, to off-axial screw fixation (off-axial partial-threaded cannulated screw, OPTCS) for vertical femoral neck fractures (FNFs) in young adults. Methods: 146 adults younger than 55 years old with high-energy Pauwels type III FNFs were randomized to receive CBS fixation or OPTCS fixation. Primary outcomes were complication rates, including fixation failure, fracture nonunion, and avascular necrosis of the femoral head (ANFH) at 24 months after treatment. Fixation loosening, femoral neck shortening and varus collapse, patient function and quality of life using the Harris hip score (HHS), and EuroQol-5 dimensional-5 levels (EQ-5D-5L) questionnaire (including EQ-5D-5L and EQ-VAS) were assessed as secondary outcomes at 24 months. Results: CBS and OPTCS fixation groups were similar with regard to demographics at baseline. At 24 months, patients in the CBS fixation cohort had a significantly lower rate of fixation failure (10.5% vs. 25.0%, p=0.041) and fracture nonunion (1.8% vs. 18.3%, p=0.003) compared with patients who received OPTCS fixation. There was no difference in rate of ANFH (7.0% vs. 11.7%, p=0.389) between groups. Additionally, patients managed with CBS fixation showed significantly less fixation loosening (19.3% vs. 58.3%, p<0.001), less severe femoral neck shortening and varus collapse (10.5% vs. 25.0%, p=0.007), higher HHS (93 vs 83, p=0.001) and more excellent grade (68.4% vs. 36.7%, p=0.008), higher EQ-5D-5L (0.814 vs, 0.581, p<0.001) and EQ-VAS (85 vs. 80, p=0.002). Conclusion: CBS screw fixation confers significantly lower complication rate in addition to higher functional and quality of life outcomes for young adults with high-energy FNF compared with OPTCS fixation. Trial registration: This prospective, randomized controlled trial was approved by the institutional review board of our center, Ethics Committee of Shanghai sixth people's Hospital, and registered at www.chictr.org.cn (Approval Number: ChiCTR1900026283；Registered 29 September 2019 - Retrospectively registered, https://www.chictr.org.cn/showproj.html?proj=43164).