Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, United States.
Agriculture and Biological Engineering, Bagley College of Engineering, Mississippi State University, Mississippi State, Mississippi, United States.
Vet Comp Orthop Traumatol. 2021 May;34(3):171-177. doi: 10.1055/s-0040-1718404. Epub 2020 Oct 16.
Successful stabilization of comminuted supracondylar humeral fractures is challenging, and biomechanical studies are scarce. This study compares double-plate (DB-PLATE) and linear external fixator with an intramedullary pin tie-in (ESF-IMP) fixation techniques in a cadaveric gap model. The hypothesis was the DB-PLATE construct would be stiffer, stronger and more resistant to repeated loading than the ESF-IMP construct in both cyclic and load-to-failure axial compression testing.
A 2 cm ostectomy was performed on 10 pairs of canine cadaveric humeri proximal to the supratrochlear foramen. Stabilization was with DB-PLATE ( = 10) or ESF-IMP ( = 10). Cyclic testing was performed by applying a 200 N load at 2 Hz for 63,000 cycles. Axial compressive load to failure testing followed. Data analysed included dynamic stiffness, stiffness and yield load.
No constructs failed during cyclic testing or lost stiffness over time. Mean dynamic stiffness over the final 100 cycles was greater for DB-PLATE compared with ESF-IMP. Mean stiffness of DB-PLATE in load-to-failure testing was not different than ESF-IMP. Yield load of DB-PLATE was higher than ESF-IMP.
Both DB-PLATE and ESF-IMP survived cyclic testing with no change in dynamic stiffness. DB-PLATE was stronger than ESF-IMP in load-to-failure testing, which may make this construct preferable when prolonged healing or poor patient compliance is anticipated. Results suggest that either method may be appropriate for fixation of comminuted supracondylar humeral fractures.
粉碎性肱骨髁上骨折的稳定固定具有挑战性，生物力学研究也很少。本研究比较了双钢板（DB-PLATE）和带髓内钉连接的线性外固定架（ESF-IMP）固定技术在尸体间隙模型中的效果。假设 DB-PLATE 结构在循环和负荷至失效轴向压缩测试中比 ESF-IMP 结构更稳定、更强壮、更能抵抗重复加载。
在 10 对犬科肱骨标本近滑车切迹处进行 2cm 的截骨术。用 DB-PLATE（ = 10）或 ESF-IMP（ = 10）进行稳定固定。通过在 2Hz 下施加 200N 的负荷进行循环测试，持续 63000 次循环。随后进行轴向压缩负荷至失效测试。分析的数据包括动刚度、刚度和屈服载荷。
在循环测试或随时间推移而失去刚度的过程中，没有任何结构失效。DB-PLATE 在最后 100 次循环中的平均动刚度大于 ESF-IMP。DB-PLATE 在负荷至失效测试中的平均刚度与 ESF-IMP 无差异。DB-PLATE 的屈服载荷高于 ESF-IMP。
DB-PLATE 和 ESF-IMP 都能在循环测试中存活，动刚度没有变化。在负荷至失效测试中，DB-PLATE 比 ESF-IMP 更强，当预期愈合时间延长或患者依从性差时，这种结构可能更可取。结果表明，这两种方法都可以用于固定粉碎性肱骨髁上骨折。
