PDF(Pubmed)
Abstract：
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.
摘要：
我们使用有限元分析研究了用于近端指间关节（PIPJ）关节固定术（PIPJA）的新型髓内植入物的机械应力分布，以通过手术矫正影响20％人口的爪锤趾畸形。在根据36岁男性患者的爪趾图像对足部骨骼进行几何重建后，放置了两个植入物，在虚拟模型中，在步态的脚趾离地阶段，在第二至第四HT的PIPJ内植入了一个中性植入物（NI）和另一个10°角度（10°AI），并将结果与非手术足（NSF）的结果进行了比较。与NSF（59.44MPa；p<0.001）相比，在近端指骨（PP）（45.83MPa）上使用NI降低的拉伸应力对第二脚趾进行PIPJA。使用10°AI时，同一脚趾的PP和中指骨（MP）的拉伸应力要高得多，测量147.58和160.58MPa，分别,与NSF中相应接头的59.44和74.95MPa相比（所有p<0.001）。对于压缩应力也发现了类似的结果。与NSF(-113.23MPa)和10°Al(-142MPa)相比,NI降低了第二PP(-65.12MPa)处的压缩应力(所有p<0.001)。当使用NI相对于10°AI时,植入物内的vonMises应力也显著较低(p<0.001)。因此,我们不建议使用10°AI执行PIPJA，因为应力集中主要在第二个PP和MP处增加，这可能会促进植入物的破损。
