Freitas Anderson, Breta Jhefferson B, Júnior Joubert, Shimano Antônio C, Daher Walter R, Bessa Munir, De Alcantara Weverton P, Ramos Lucas Sacramento, Dantas Ergon L, Aquino Ruben J
Orthopaedics, Hospital of Orthopedic and Specialized Medicine, Brasilia, BRA.
Orthopedics and Traumatology, Hospital Regional Do Gama, Brasilia, BRA.
Cureus. 2018 Dec 4;10(12):e3680. doi: 10.7759/cureus.3680.
The objective of this study was to evaluate, by means of a static flexural test, the biomechanical parameters necessary for the occurrence of a proximal femoral fracture in a synthetic bone model after the removal of a dynamic hip screw (DHS) and comparing the results obtained with a reinforcement technique using polymethylmethacrylate (PMMA). Twenty synthetic bones made of the same material and from the same manufacturer were used: ten units as the control group (CG), five units as the test group without reinforcement (TG), and five units as the test group with reinforcement (TGR). The biomechanical analysis was performed simulating a fall over the trochanter using a servo-hydraulic machine. In the control group, the assay was performed with its integrity preserved. In the TG and TGR groups, a DHS model was introduced, and the tests were performed as follows: TG after simple removal of the synthesis material, and in the TGR group, after removal of the synthesis material and filling the orifice of the femoral neck with PMMA. All groups presented with a basicervical fracture of the femoral neck. The CG group presented a mean of 935 newtons (N) of maximum load and 7.0 joules (J) of energy for fracture occurrence. TG and TGR groups presented, respectively, a maximum load of 750 N and 1,068 N, and energy of 6.0 J and 7.3 J. According to the one-way analysis of variance (ANOVA), there was no significant difference in flow load (p = 0.16), energy to flow (p = 0.16), stiffness (p = 0.28), maximum load (p = 0.10), and energy to fracture (p = 0.54) between the studied groups. The removal of the DHS implant from the synthetic bone did not present a significant increase of the maximum load and the energy necessary for the occurrence of a fracture with the use of the PMMA reinforcement technique.
本研究的目的是通过静态弯曲试验，评估在合成骨模型中取出动力髋螺钉（DHS）后发生股骨近端骨折所需的生物力学参数，并将所得结果与使用聚甲基丙烯酸甲酯（PMMA）的强化技术进行比较。使用了20个由相同材料和同一制造商生产的合成骨：10个作为对照组（CG），5个作为无强化试验组（TG），5个作为有强化试验组（TGR）。使用伺服液压机模拟转子部摔倒进行生物力学分析。在对照组中，在其完整性得以保留的情况下进行试验。在TG组和TGR组中，引入DHS模型，并按如下方式进行试验：TG组在简单移除合成材料后进行试验，而在TGR组中，在移除合成材料并用PMMA填充股骨颈孔后进行试验。所有组均出现股骨颈基底部骨折。CG组出现骨折时的最大负荷平均为935牛顿（N），能量为7.0焦耳（J）。TG组和TGR组的最大负荷分别为750 N和1,068 N，能量分别为6.0 J和7.3 J。根据单因素方差分析（ANOVA），各研究组之间在流动负荷（p = 0.16）、流动能量（p = 0.16）、刚度（p = 0.28）、最大负荷（p = 0.10）和骨折能量（p = 0.54）方面均无显著差异。从合成骨中取出DHS植入物后，使用PMMA强化技术并未使骨折发生所需的最大负荷和能量显著增加。
