Background

Peri-prosthetic fractures (PPFs) are steadily rising in number due to population ageing and increased performance of joint replacement procedures. Although PPFs without implant loosening are usually managed by internal fixation, no consensus exists regarding the optimal construct. The primary objective of this study was to compare five constructs, and the secondary objective was to compare sub-groups of mono-cortical screw constructs, with the goal of identifying the method most appropriate for diaphyseal fracture fixation when prosthetic material is present within the intra-medullary canal.

Hypothesis

The primary hypothesis was that fixation using bi-cortical screws, i.e., the current reference standard, was superior over other fixation methods. The secondary hypothesis was that adding double cerclage to mono-cortical screw fixation provided the greatest mechanical strength.

Materials and methods

Synthetic osteoporotic bone was used to compare five methods for locking-screw fixation of a femoral diaphyseal plate. One method involved bi-cortical screws and four methods mono-cortical screws, with no cerclage wire, a single cerclage wire on either side positioned near or at a distance from the fracture, and two cerclage wires on both sides of the fracture. A complex fracture was simulated by creating a 2-cm diaphyseal gap. Load-to-failure was determined by applying compression loading along the anatomical axis of the femur.

Results

Bi-cortical screw fixation provided greater mechanical strength than did three of the four mono-cortical screw constructs. The exception was the mono-cortical-screw and double-cerclage construct, for which no significant difference was found compared to bi-cortical screw fixation. Thus, mono-cortical screw fixation with double cerclage may be the best alternative when presence of an implant in the intra-medullary canal precludes bi-cortical screw fixation.

Conclusion

The findings from this study have clear implications for clinical practice. The study hypotheses were partly confirmed. The absence of a significant difference between the reference-standard bi-cortical screw fixation method and mono-cortical screw fixation with double cerclage, combined with the results regarding the secondary objective, suggest that mono-cortical screws plus double cerclage deserve preference in patients with an intra-medullary implant. Clinical studies are needed to assess the results of this bench study.

Level of evidence

IV, bench study.

中文翻译：

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复杂骨干骨折五种锁定钢板固定方法的比较

背景

由于人口老龄化和关节置换手术性能的提高，假体周围骨折 (PPF) 的数量正在稳步上升。尽管没有种植体松动的 PPFs 通常通过内固定进行治疗，但对于最佳结构尚无共识。本研究的主要目的是比较五种结构，次要目的是比较单皮质螺钉结构的亚组，目的是确定在内部存在假体材料时最适合骨干骨折固定的方法-髓管。

假设

主要假设是使用双皮质螺钉固定，即当前的参考标准，优于其他固定方法。第二个假设是在单皮质螺钉固定中加入双环扎提供了最大的机械强度。

材料和方法

合成骨质疏松骨用于比较五种股骨骨干钢板锁定螺钉固定方法。一种方法涉及双皮质螺钉和四种方法单皮质螺钉，没有环扎钢丝，在骨折附近或远离骨折的两侧各有一根环扎钢丝，骨折两侧有两根钢丝环扎。通过创建 2 厘米的骨干间隙来模拟复杂的骨折。通过沿股骨的解剖轴施加压缩载荷来确定载荷失效。

结果

双皮质螺钉固定提供了比四个单皮质螺钉结构中的三个更大的机械强度。例外是单皮质螺钉和双环扎结构，与双皮质螺钉固定相比没有发现显着差异。因此，当髓内管中存在植入物而无法进行双皮质螺钉固定时，采用双环扎的单皮质螺钉固定可能是最佳选择。

结论

这项研究的结果对临床实践具有明确的意义。研究假设得到了部分证实。参考标准双皮质螺钉固定方法与单皮质螺钉双环扎固定方法之间没有显着差异，结合次要目标的结果表明，单皮质螺钉加双环扎术在髓内植入物。需要进行临床研究来评估这项基准研究的结果。

证据等级

四、基准研究。