Applied Mechanics and Bioengineering Group (AMB), Aragon Institute of Engineering Research (I3A), Centro de Investigación Biomédica en Red CIBER-BBN, Spain, Universidad de Zaragoza, Zaragoza, Spain.
Facultad de Enfermería, Fisioterapia y Podología, Universidad Complutense de Madrid, Madrid, Spain.
Int Wound J. 2024 Aug;21(8):e70014. doi: 10.1111/iwj.70014.
We used finite element analysis to study the mechanical stress distribution of a new intramedullary implant used for proximal interphalangeal joint (PIPJ) arthrodesis (PIPJA) to surgically correct the claw-hammer toe deformity that affects 20% of the population. After geometric reconstruction of the foot skeleton from claw toe images of a 36-year-old male patient, two implants were positioned, in the virtual model, one neutral implant (NI) and another one 10° angled (10°AI) within the PIPJ of the second through fourth HT during the toe-off phase of gait and results were compared to those derived for the non-surgical foot (NSF). A PIPJA was performed on the second toe using a NI reduced tensile stress at the proximal phalanx (PP) (45.83 MPa) compared to the NSF (59.44 MPa; p < 0.001). When using the 10°AI, the tensile stress was much higher at PP and middle phalanges (MP) of the same toe, measuring 147.58 and 160.58 MPa, respectively, versus 59.44 and 74.95 MPa at corresponding joints in the NSF (all p < 0.001). Similar results were found for compressive stresses. The NI reduced compressive stress at the second PP (-65.12 MPa) compared to the NSF (-113.23 MPa) and the 10°AI (-142 MPa) (all p < 0.001). The von Mises stresses within the implant were also significantly lower when using NI versus 10°AI (p < 0.001). Therefore, we do not recommend performing a PIPJA using the 10°AI due to the increase in stress concentration primarily at the second PP and MP, which could promote implant breakage.
我们使用有限元分析研究了一种新的用于近指间关节（PIPJ）融合术（PIPJA）的髓内植入物的力学应力分布，以手术矫正影响 20%人群的爪形锤状趾畸形。在对 36 岁男性患者的爪形趾图像进行足部骨骼的几何重建后，在虚拟模型中放置了两个植入物，一个是中性植入物（NI），另一个是在步态的离地阶段 PIPJ 内的 10°角（10°AI），比较了第二至第四 HT 的第二个脚趾的 PIPJA，结果与非手术足部（NSF）的结果进行了比较。与 NSF（59.44 MPa；p<0.001）相比，使用 NI 进行第二趾的 PIPJA 可降低近节指骨（PP）的拉伸应力（45.83 MPa）。当使用 10°AI 时，同一脚趾的 PP 和中节指骨（MP）的拉伸应力要高得多，分别为 147.58 和 160.58 MPa，而 NSF 中相应关节的拉伸应力分别为 59.44 和 74.95 MPa（所有 p<0.001）。压缩应力也有类似的结果。NI 降低了第二 PP 的压缩应力（-65.12 MPa），与 NSF（-113.23 MPa）和 10°AI（-142 MPa）相比（所有 p<0.001）。与 10°AI 相比，NI 时植入物内的 von Mises 应力也明显降低（p<0.001）。因此，我们不建议使用 10°AI 进行 PIPJA，因为主要在第二 PP 和 MP 处的应力集中会增加，这可能会导致植入物断裂。
