German Center for Orthopedics, Campus Eisenberg, Chair of Orthopedics of Jena University Hospital, Klosterlausnitzer Street 81, 07607, Eisenberg, Germany.
Sci Rep. 2024 Feb 24;14(1):4546. doi: 10.1038/s41598-024-55067-9.
Preparation of the femoral proximal medullary cavity by reaming is essential for intramedullary nail osteosynthesis and hip revision arthroplasty. The use of reamers sometimes exerts high torsional forces on the bone. Design and direction of rotation of the reamer are potential influencing factors. The aim of this biomechanical study is to evaluate the best combination of a right- or left-cutting reamer with a clockwise- or counterclockwise-rotating insert in terms of preparation and safety. Right- and left-cutting reamers with conical design were each introduced into five synthetic femurs in both clockwise and counterclockwise rotation with constant feed force. A specially constructed test system was used for this series of tests, with which the respective intramedullary channel were reamed step by step. This was then used to determine the required torque. In addition, the feed rate measurement was analyzed using a modified digital caliper. The feed rates of the reamers with rotation in the same direction as the cutting direction were significantly increased compared to rotation in the opposite cutting direction (CCRLC vs. CCRRC 76.8 ± 9.0 mm/s vs. 25.2 ± 8.3 mm/s and CRRC vs. CRLC 54.3 ± 12.3 mm/s vs. 19.3 ± 0.6 mm/s; p < 0.01). In contrast, the mean torque during the reaming process was identical in all four groups. When preparing the proximal femoral medullary cavity, especially in cases with fragile bone structure, the available reamers should be introduced in opposite rotation to the cutting direction to achieve a more controllable feed of the reamer. Left-cutting reamers represent an alternative, using them in the usual clockwise-rotating technique to reduce the risk of complications during reaming.
扩髓是髓内钉固定和髋关节翻修的重要步骤。扩髓器的使用有时会对骨骼施加很高的扭转力。扩髓器的设计和旋转方向是潜在的影响因素。本生物力学研究的目的是评估右旋或左旋扩髓器与顺时针或逆时针旋转插入物在制备和安全性方面的最佳组合。采用锥形设计的右旋和左旋扩髓器分别以恒定的进给力顺时针和逆时针旋转插入 5 个合成股骨中。采用专门设计的测试系统进行了一系列测试，通过该系统逐步扩髓各自的髓内通道，然后确定所需的扭矩。此外，使用改进的数字卡尺分析了进给率测量。与切削方向相反的旋转方向的扩髓器的进给速度明显高于切削方向相同的旋转方向（CCRLC 比 CCRRC 76.8±9.0 mm/s 比 25.2±8.3 mm/s 和 CRRC 比 CRLC 54.3±12.3 mm/s 比 19.3±0.6 mm/s；p<0.01）。相比之下，在所有四组中，扩髓过程中的平均扭矩是相同的。在准备股骨近端髓腔时，尤其是在骨结构脆弱的情况下，应将可用的扩髓器以与切削方向相反的方向插入，以实现扩髓器更可控的进给。左旋扩髓器是一种替代方案，在通常的顺时针旋转技术中使用它们可以降低扩髓过程中并发症的风险。
