The Effect of Vertical and Oblique Inclinations on Fracture Stability and Reoperation Risks in Femoral-Neck Fractures of Nongeriatric Patient

Abstract

Background: For nongeriatric patients with femoral neck fractures (FNFs), preoperative evaluation of fracture three-dimensional inclination is essential to identify fracture stability, select appropriate fixation strategies, and improved clinical prognoses. However, there is lack of evaluation system which takes into account both vertical and oblique inclinations. The purpose of this study was to comprehensively investigate the effect of vertical and oblique inclinations on fracture stability and reoperation risks.Methods: We retrospectively reviewed the medical records of 755 FNFs patients with over 2 years follow-up. The 3-D inclination angle in vertical (α) and oblique plane (β) were measured based on CT images. The optimal threshold for unstable 3-D inclination were identified by seeking the highest Youden Index in predicting reoperation and validated in the biomechanical test. According to the cut-off value proposed in the diagnostic analysis, forty-two bone models were divided into seven groups, and were all fixed with traditional three parallel screws. Interfragmentary motion (IFM) was used for comparison among seven groups. The association between reoperation outcome and 3-D inclination was analysed with a multivariate model.Results and Conclusion: The overall reoperation rate was 13.2%. Unstable 3-D inclination angles with an optimally determined Youden index (0.39) included vertical (α > 70°) and oblique (50°<α < 70° and β > 20°/β < −20°) types. Biomechanical validation showed these fractures had significantly greater (p < 0.05) interfragmentary motion (1.374–2.387 mm vs. 0.330–0.681 mm). The reoperation rate in 3-D unstable group (32.7%) is significantly (p < 0.001) higher than that in 3-D stable group (7.9%). Multivariate analysis demonstrated that 3-D inclination angle was significantly (OR = 4.699, p < 0.001) associated with reoperation. FNFs with α > 70°; 50°<α < 70° and β > 20°/β < −20° are real unstable types with significantly worse interfragmentary stability and higher reoperation risks. Fracture inclination in vertical and oblique planes is closely related to reoperation outcomes and may be a useful complement to the way FNFs are currently evaluated.

Morphological characteristics of femoral neck fractures in young and middle-aged population: a retrospective descriptive study

“…In a biomechanical study, smaller AMA indicates lower torque compared to larger AMA. Which imply that AMA may be a useful predictor of axial stability [ 17 , 25 ]. However, no significant morphological difference could be detected among the three AMA groups, which similarly means AMA classification founded by Wang [ 8 ] need to considerable again.…”

Biomechanical and clinical evaluation of interlocking hip screw in Pauwels Ⅲ femoral neck fractures: A comparison with inverted triangle cannulated screws

“…More than half of hip fractures will occur in Asia by 2040, accompanied by an enormous socioeconomic burden and medical challenge (Bhandari and Swiontkowski, 2017). Most femoral neck fractures in young adults are Pauwels Ⅲ femoral neck fractures caused by high energy trauma with a high risk of complications such as nonunion, avascular necrosis, and femoral neck shortening (Jiang et al, 2021). A series of implants have been proposed for superior prognosis of Pauwels Ⅲ femoral neck fractures (Stoffel et al, 2017;Chan, 2019;Duffin and Pilson, 2019), however, the optimal choice of internal fixation is still controversial and no consensus has been established (Florschutz et al, 2015).…”