Jitprapaikulsarn Surasak, Chantarapanich Nattapon, Gromprasit Arthit, Mahaisavariya Chantas, Patamamongkonchai Chawanan
Department of Orthopedics, Buddhachinaraj Hospital, Phitsanulok, Thailand.
Department of Mechanical Engineering, Faculty of Engineering at Sriracha, Kasetsart University, Sriracha, Chonburi, Thailand.
Eur J Orthop Surg Traumatol. 2021 Aug;31(6):1179-1192. doi: 10.1007/s00590-020-02868-z. Epub 2021 Jan 8.
The optimal surgical management of concurrent cervicotrochanteric and shaft fractures of the femur has not been consensual. The authors investigated the reliability of combined single lag screw and reverse distal femur locking compression plate (LCP-DF) by finite element (FE) study and retrospectively described the present technique for these dual fractures.
Intact femurs were derived from CT data, and the implant models were created by using CAD software. The fractured femur and implant models were virtually aligned based on the surgical techniques before converting to the FE model. In the FE model, applied boundary conditions included body weight, muscle forces, and constraint of the joints. Regarding clinical series, three patients with these dual fractures of the femur and 2 with cervicotrochanteric fractures with subtrochanteric extension were operated on by the proposed technique. The collected data include operative time, postoperative complications, union times, and clinical outcomes.
Equivalent von Mises stress exhibited on dynamic hip screws with an anti-rotational screw was higher than the other techniques, close to the yield stress of the material. Multiple screw fixation produced better stability for transcervical fractures whereas the proposed technique of combined single lag screw and reverse LCP-DF provided better stability for intertrochanteric fractures. No significant difference in cortical bone stress was found between multiple screw construct and the proposed technique. The proposed technique presented a lower risk of secondary fractures, as the strain energy density (SED) in cancellous bone was lower than multiple screw construct. Regarding clinical series, all fractures were united with a mean union time of-16.1 weeks (range 12-20). There were no any postoperative complications. Regarding the Harris score, 1 was determined to be excellent value, and 4 to be good.
By the FE results, a combination of a single lag screw and reverse LCP-DF is an effective technique for fixation of cervicotrochanteric fractures. Empowered by the clinical results, this proposed technique could be an alternative for concurrent cervicotrochanteric and shaft fractures of the femur especially when either single-system or dual-system devices seem not to be suitable.
股骨颈转子间和骨干同时骨折的最佳手术治疗方法尚无共识。作者通过有限元（FE）研究探讨了联合使用单枚拉力螺钉和股骨远端反向锁定加压钢板（LCP-DF）的可靠性，并回顾性描述了针对这些双骨折的现有技术。
从CT数据中获取完整的股骨，并使用CAD软件创建植入物模型。在转换为FE模型之前，根据手术技术将骨折的股骨和植入物模型进行虚拟对齐。在FE模型中，应用的边界条件包括体重、肌肉力量和关节约束。关于临床系列，3例股骨双骨折患者和2例转子下延伸的股骨颈转子间骨折患者采用了所提出的技术进行手术。收集的数据包括手术时间、术后并发症、愈合时间和临床结果。
带有抗旋转螺钉的动力髋螺钉上显示的等效应力高于其他技术，接近材料的屈服应力。多枚螺钉固定对经颈骨折产生了更好的稳定性，而所提出的单枚拉力螺钉和反向LCP-DF联合技术对转子间骨折提供了更好的稳定性。在多枚螺钉结构和所提出的技术之间，皮质骨应力没有显著差异。所提出的技术显示出二次骨折的风险较低，因为松质骨中的应变能密度（SED）低于多枚螺钉结构。关于临床系列，所有骨折均愈合，平均愈合时间为16.1周（范围12 - 20周）。没有任何术后并发症。关于Harris评分，1分为优秀，4分为良好。
根据有限元结果，单枚拉力螺钉和反向LCP-DF联合是固定股骨颈转子间骨折的有效技术。基于临床结果，这项所提出的技术可能是股骨颈转子间和骨干同时骨折的一种替代方法，特别是当单系统或双系统装置似乎都不合适时。
