The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, Galveston, TX, USA.
The Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, Galveston, TX, USA.
Clin Biomech (Bristol). 2022 Jul;97:105686. doi: 10.1016/j.clinbiomech.2022.105686. Epub 2022 May 27.
The etiology of bone refractures after screw removal can be attributed to residual drill hole defects. This biomechanical study compared the torsional strength of bones containing various sized cortical drill defects in a tibia model.
Bicortical drill hole defects of 3 mm, 4 mm, and 5 mm diameters were tested in 26 composite tibias versus intact controls without a drill defect. Each tibia was secured in alignment with the rotational axis of a materials testing system and the proximal end rotated internally at a rate of 1 deg./s until mechanical failure.
All defect test groups were significantly lower (P < 0.01) in torque-to-failure than the intact group (82.80 ± 3.70 Nm). The 4 mm drill hole group was characterized by a significantly lower (P = 0.021) torque-to-failure (51.00 ± 3.27 Nm) when compared to the 3 mm drill hole (59.00 ± 5.48 Nm) group, but not different than the 5 mm hole group (55.71 ± 5.71 Nm). All bones failed through spiral fractures, bones with defects also exhibited posterior butterfly fragments.
All the tested drill hole sizes in this study significantly reduced the torque-to-failure from intact by a range of 28.4% to 38.4%, in agreement with previous similar studies. The 5 mm drill hole represented a 22.7% diameter defect, the 4 mm drill hole a 18.2% diameter defect, and the 3 mm drill hole a 13.6% diameter defect. Clinicians should be cognizant of this diminution of long bone strength after a residual bone defect in their creation and management of patient rehabilitation programs.
螺钉取出后发生骨再骨折的病因可归因于残余钻孑 L 缺陷。本生物力学研究比较了胫骨模型中存在不同大小皮质钻孑 L 缺陷时的扭转强度。
在 26 个复合胫骨中测试了 3mm、4mm 和 5mm 直径的双皮质钻孑 L 缺陷，与无钻孑 L 缺陷的完整对照相比。每个胫骨都与扭转轴对齐，并以 1 度/秒的速率使近端内部旋转，直到发生机械故障。
所有缺陷测试组的失效扭矩均显著低于完整组（P<0.01)(82.80±3.70Nm)。与 3mm 钻孑 L 组（59.00±5.48Nm)相比，4mm 钻孑 L 组的失效扭矩显著降低（P=0.021)(51.00±3.27Nm)，但与 5mm 孑 L 组无差异（55.71±5.71Nm)。所有骨骼均发生螺旋骨折，有缺陷的骨骼还出现了后蝴蝶碎片。
本研究中所有测试的钻孑 L 尺寸均显著降低了完整骨骼的失效扭矩，范围为 28.4%至 38.4%，与之前的类似研究一致。5mm 钻孑 L 代表 22.7%的直径缺陷，4mm 钻孑 L 代表 18.2%的直径缺陷，3mm 钻孑 L 代表 13.6%的直径缺陷。临床医生应该意识到在残留骨缺陷的情况下，长骨强度会减弱，在制定和管理患者康复计划时应注意这一点。
