AO Research Institute Davos, Davos, Switzerland; Department of Orthopaedic and Trauma Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
AO Research Institute Davos, Davos, Switzerland.
Clin Biomech (Bristol). 2023 Dec;110:106119. doi: 10.1016/j.clinbiomech.2023.106119. Epub 2023 Oct 5.
Distal femoral fractures are commonly treated with lateral straight plates. However, the lateral approach may not always be desirable, and 180°-helical plates may be an alternative.
To investigate the biomechanical competence of 180°-helical plating versus standard straight lateral plating of unstable fractures at the distal femur.
Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate-Distal Femur, using either 180°-helical plates (group 1) or conventional straight lateral plates (group 2). An unstable distal femoral fracture AO/OTA 33-A3.3 was simulated. All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading in internal rotation until failure.
Initial axial stiffness (N/mm) was significantly higher in group 1 (185.6 ± 50.1) compared to group 2 (56.0 ± 14.4), p < 0.001. Group 1 demonstrated significantly higher initial interfragmentary flexion (°) and significantly lower initial varus/valgus deformation (°) under 500 N static axial compression versus group 2 (2.76 ± 1.02 versus 0.87 ± 0.77 and 4.08 ± 1.49 versus 6.60 ± 0.47), p ≤ 0.005. Shear displacement (mm) under 6 Nm static torsion was significantly higher in group 1 versus group 2 in both internal (1.23 ± 0.28 versus 0.40 ± 0.42) and external (1.21 ± 0.40 versus 0.57 ± 0.33) rotation, p ≤ 0.013. Cycles to failure and failure load (N) (clinical/catastrophic) were significantly higher in group 1 (12,484 ± 2116/13,752 ± 1518 and 1748.4 ± 211.6/1875.2 ± 151.8) compared to group 2 (7853 ± 1262/9727 ± 836 and 1285.3 ± 126.2/1472.7 ± 83.6), p ≤ 0.001.
Although 180°-helical plating using a pre-contoured standard straight lateral plate was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, the helical plates were associated with significantly higher endurance to failure. From a biomechanical perspective, 180°-helical plating may be considered as a valuable alternative to standard straight lateral plating of unstable distal femoral fractures.
股骨远端骨折通常采用外侧直钢板治疗。然而，外侧入路并非总是理想的，180°螺旋钢板可能是一种替代方法。
研究 180°螺旋钢板与标准外侧直钢板治疗股骨远端不稳定骨折的生物力学性能。
12 个左侧人工股骨使用 15 孔锁定加压钢板-股骨远端进行器械固定，分别采用 180°螺旋钢板（第 1 组）或传统外侧直钢板（第 2 组）。模拟不稳定的股骨远端骨折 A0/OTA 33-A3.3。所有标本在内旋状态下进行准静态和逐渐增加的轴向和扭转复合循环加载直至失效的生物力学测试。
第 1 组的初始轴向刚度（N/mm）明显高于第 2 组（185.6±50.1）比组 2（56.0±14.4），p<0.001。与第 2 组相比，第 1 组在 500N 静态轴向压缩下的初始断端间弯曲（°）明显更高，初始内翻/外翻变形（°）明显更低（2.76±1.02 比 0.87±0.77 和 4.08±1.49 比 6.60±0.47），p≤0.005。第 1 组在 6Nm 静态扭转下的剪切位移（mm）在内部（1.23±0.28 比 0.40±0.42）和外部（1.21±0.40 比 0.57±0.33）旋转时均明显高于第 2 组，p≤0.013。第 1 组的失效循环和失效载荷（N）（临床/灾难性）明显高于第 2 组（12484±2116/13752±1518 和 1748.4±211.6/1875.2±151.8），p≤0.001。
尽管使用预成型标准外侧直钢板的 180°螺旋钢板与更高的剪切和弯曲运动相关，但与外侧直钢板相比，它表现出了更好的初始轴向稳定性和抗内翻/外翻变形能力。此外，螺旋钢板的失效耐力明显更高。从生物力学角度来看，180°螺旋钢板可能是治疗不稳定股骨远端骨折的标准外侧直钢板的一种有价值的替代方法。
