Faculty of Veterinary Medicine, University of Montreal, Saint Hyacinthe, Québec, Canada.
Centre Vétérinaire Daubigny, Québec, Canada.
Vet Comp Orthop Traumatol. 2023 Nov;36(6):273-278. doi: 10.1055/s-0043-1768990. Epub 2023 Jun 19.
The aim of this study was to evaluate the biomechanical effects of transfixation pin positioning in acrylic columns of external skeletal fixators (ESF).
Twenty-four type I acrylic ESF were built simulating a fracture gap-model. Transfixation pins were placed centric ( = 12) or eccentric at ¼ of the column diameter ( = 12) in the acrylic columns. Six constructs from each group were subjected to axial compression and four-point bending tests. Stiffness, yield load and mode of failure were recorded.
Stiffness was not influenced by centring ( = 0.373), but it was higher in four-point bending than in axial compression ( < 0.001). Pin positioning had no influence on the yield ( = 0.535) and failure loads ( = 0.715) in axial compression, nor on the yield load in bending ( = 0.135). Eccentric pin positioning decreased failure loads by 28% in bending ( < 0.001).
Eccentric position of transfixation pins within the acrylic columns alters the biomechanical properties of type I ESF constructs. While acrylic offers several advantages, when forming the columns, frame strength will be optimized if pins are centrally located.
本研究旨在评估在外部骨骼固定器（ESF）的丙烯酸柱中贯穿钉定位的生物力学效应。
模拟骨折间隙模型，构建了 24 个 I 型丙烯酸 ESF。贯穿钉在丙烯酸柱中以中心（ = 12）或偏心于柱直径的四分之一（ = 12）放置。每组中的六个构建体接受轴向压缩和四点弯曲测试。记录刚度、屈服载荷和失效模式。
中心定位（ = 0.373）不会影响刚度，但四点弯曲时的刚度高于轴向压缩（ < 0.001）。在轴向压缩中，针定位对屈服（ = 0.535）和失效载荷（ = 0.715）没有影响，在弯曲时也没有影响屈服载荷（ = 0.135）。偏心贯穿钉定位使弯曲时的失效载荷降低了 28%（ < 0.001）。
贯穿钉在丙烯酸柱中的偏心位置改变了 I 型 ESF 构建体的生物力学特性。虽然丙烯酸具有多种优势，但在形成柱时，如果将针定位在中心，框架强度将得到优化。
