目的 探讨四枚螺钉固定Pauwels Ⅲ型股骨颈骨折的生物力学特性与临床疗效。 方法 建立Pauwels Ⅲ型股骨颈骨折的三维有限元模型,分析3种固定方式(组1,平行三枚螺钉;组2,横向结合平行倒三角四枚螺钉;组3,动力髋螺钉结合防旋螺钉),模拟人体单腿站立时的受载,计算模型的应力和位移,比较不同固定方式的力学稳定性。结合31例四钉螺钉固定Pauwels Ⅲ型股骨颈骨折的回顾性报告,探讨其临床疗效。 结果 有限元研究提示,三组骨折端承受的应力从小到大依次为:组3<组2<组1,螺钉位移从小到大为:组3<组2<组1。31例Pauwels Ⅲ型股骨颈骨折中,24例(77.4%)随访24个月及以上(24～62个月)。未发现骨折不愈合的并发症,平均愈合时间16.3周(12～24周),3例(12.5%)发生股骨头坏死。髋关节Harris 功能评分,平均(80±8.5)分,优良率83.3%。结论 横向螺钉结合平行倒三角结构的四枚螺钉固定方式,可作为治疗Pauwels Ⅲ型股骨颈骨折的选择,但需要更大样本量和更长期的随访研究进一步评估其临床疗效。
Objective To investigate the biomechanical properties and clinical outcomes of four-screw configuration used for internal fixation of Pauwels type Ⅲ femoral neck fractures.Methods A three-dimensional finite element model (FEM) of Pauwels type Ⅲ femoral neck fracture was established and analyzed in three fixation groups (Group 1, an inverted triad of screws; Group 2, four-screw configuration with one transverse screw and three parallel inverted triangle screws; Group 3, hybrid fixation of one dynamic hip screw and one de-rotation screw).Simulated load with one leg standing was applied and then the stress and displacement of the model were calculated to compare the biomechanical stability of different fixation strategies.Retrospective clinical analysis of 31 cases with Pauwels type Ⅲ femoral neck fractures using four-screw fixation was conducted.Results Biomechanically, finite element analysis showed that the strongest construct for stabilizing a Pauwels type Ⅲ femoral neck fracture was Group 3, followed in descending order by Group 2 and Group 1, and the screw displacement in descending order was Group 3, Group 2, and Group 1.Clinically, 31 patients with Pauwels type Ⅲ femoral neck fractures were treated with four-screw configuration; 24 patients (77.4%) were followed up for 24 months and over (24-62 months).None of the cases was nonunion and the mean union time was 16.3 weeks (12-24 weeks).Three cases (12.5%) had necrosis of femoral head.The mean Harris score of hip function was 80±8.5 points, and the excellent-and-good rate was 83.3%.Conclusion The four-screw configuration with one transverse screw and three parallel inverted triangle screws can be used to fix Pauwels type Ⅲ femoral neck fracture.Further studies with larger sample size and longer follow-up are required to assess its clinical efficacy.
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