Freitas Anderson, Giordano Vincenzo, Nunes Welington Ferreira, da Silva Santana Kaio, Viana Fernanda Moura, Pires Robinson Esteves, Albuquerque Rodrigo Sattamini Pires E, Labronici Pedro José
Hospital Ortopédico e Medicina Especializada (HOME), SGAS Quadra 613, Conjunto C, Asa Sul, Distrito Federal, Brasília, 70200-730, Brazil.
Department of Orthopedics and Trauma, Hospital Municipal Miguel Couto, Rio de Janeiro, Brazil.
Eur J Orthop Surg Traumatol. 2024 Dec 30;35(1):50. doi: 10.1007/s00590-024-04125-z.
Although several techniques have been described for bent intramedullary nail removal, there is no universally accepted strategy. We hypothesized that a device based on the action principle of a three-point bend fixture could facilitate extraction of bent intramedullary nails; this paper describes its design and experimental testing.
Five large synthetic left femurs and five steel intramedullary nails were used. The nails were bent in a manual hydraulic press and implanted into the model femurs, which had been previously sectioned as necessary. A device to correct the angular deformity imparted to the nails was designed, and a prototype fabricated from AISI 1045 steel. Specimens were secured in a vise and the device attached; manual tension was then applied to gradually correct the nail deformity. Plain radiographs were obtained, and the nails were removed. The model femurs and intramedullary nails were visually inspected for proper contact of the device tip, coronal and sagittal alignment, and points of failure.
Before device application, the angles of the specimens averaged 40.2° (38.27°-41.32°) in the coronal plane and 7.22° (8.5°-10.2°) in the sagittal plane. After device application, these angles averaged 15.04° (2.5°-32.3°) and 4.16° (0°-9.8°), respectively. There were no implant fractures, but in two models, peri-implant fractures (one catastrophic) occurred close to the proximal and distal locking screws.
The proposed device for bent intramedullary nail extraction was effective, but homogeneous behavior in terms of angle correction was not observed in the tested specimens. Further development is needed.
尽管已经描述了几种用于取出弯曲髓内钉的技术，但尚无普遍接受的策略。我们推测，一种基于三点弯曲固定装置作用原理的器械可以促进弯曲髓内钉的取出；本文描述了其设计和实验测试。
使用五根大型合成左股骨和五根钢制髓内钉。将钉子在手动液压机中弯曲，然后植入预先根据需要进行切割的模型股骨中。设计了一种用于矫正钉子角度畸形的器械，并制作了一个由AISI 1045钢制成的原型。将标本固定在虎钳中并连接该器械；然后施加手动拉力以逐渐矫正钉子的畸形。拍摄平片，然后取出钉子。对模型股骨和髓内钉进行目视检查，以查看器械尖端的正确接触、冠状面和矢状面的对齐情况以及失效点。
在应用器械之前，标本在冠状面的角度平均为40.2°（38.27°-41.32°），在矢状面的角度平均为7.22°（8.5°-10.2°）。应用器械后，这些角度分别平均为15.04°（2.5°-32.3°）和4.16°（0°-9.8°）。没有植入物骨折，但在两个模型中，靠近近端和远端锁定螺钉处发生了植入物周围骨折（一例灾难性骨折）。
所提出的用于取出弯曲髓内钉的器械是有效的，但在测试标本中未观察到角度矫正方面的均匀表现。需要进一步改进。
