PDF(Pubmed)
Abstract：
BACKGROUND: The purpose of this study was to perform a biomechanical analysis to compare different medial column fixation patterns for valgus pilon fractures in a case-based model.
METHODS: Based on the fracture mapping, 48 valgus pilon fracture models were produced and assigned into four groups with different medial column fixation patterns: no fixation (NF), K-wires (KW), intramedullary screws (IS), and locking compression plate (LCP). Each group contained wedge-in and wedge-out subgroups. After fixing each specimen on the machine, gradually increased axial compressive loads were applied with a load speed of one millimeter per minute. The maximum peak force was set at 1500 N. Load-displacement curves were generated and the axial stiffness was calculated. Five different loads of 200 N, 400 N, 600 N, 800 N, 1000 N were selected for analysis. The specimen failure was defined as resultant loading displacement over 3 mm.
RESULTS: For the wedge-out models, Group-IS showed less displacement (p < 0.001), higher axial stiffness (p < 0.01), and higher load to failure (p < 0.001) than Group-NF. Group-KW showed comparable displacement under loads of 200 N, 400 N and 600 N with both Group-IS and Group-LCP. For the wedge-in models, no statistical differences in displacement, axial stiffness, or load to failure were observed among the four groups. Overall, wedge-out models exhibited less axial stiffness than wedge-in models (all p < 0.01).
CONCLUSIONS: Functional reduction with stable fixation of the medial column is essential for the biomechanical stability of valgus pilon fractures and medial column fixation provides the enough biomechanical stability for this kind of fracture in the combination of anterolateral fixation. In detail, the K-wires can provide a provisional stability at an early stage. Intramedullary screws are strong enough to provide the medial column stability as a definitive fixation. In future, this technique can be recommended for medial column fixation as a complement for holistic stability in high-energy valgus pilon fractures.
METHODS: Based on the fracture mapping, 48 valgus pilon fracture models were produced and assigned into four groups with different medial column fixation patterns: no fixation (NF), K-wires (KW), intramedullary screws (IS), and locking compression plate (LCP). Each group contained wedge-in and wedge-out subgroups. After fixing each specimen on the machine, gradually increased axial compressive loads were applied with a load speed of one millimeter per minute. The maximum peak force was set at 1500 N. Load-displacement curves were generated and the axial stiffness was calculated. Five different loads of 200 N, 400 N, 600 N, 800 N, 1000 N were selected for analysis. The specimen failure was defined as resultant loading displacement over 3 mm.
RESULTS: For the wedge-out models, Group-IS showed less displacement (p < 0.001), higher axial stiffness (p < 0.01), and higher load to failure (p < 0.001) than Group-NF. Group-KW showed comparable displacement under loads of 200 N, 400 N and 600 N with both Group-IS and Group-LCP. For the wedge-in models, no statistical differences in displacement, axial stiffness, or load to failure were observed among the four groups. Overall, wedge-out models exhibited less axial stiffness than wedge-in models (all p < 0.01).
CONCLUSIONS: Functional reduction with stable fixation of the medial column is essential for the biomechanical stability of valgus pilon fractures and medial column fixation provides the enough biomechanical stability for this kind of fracture in the combination of anterolateral fixation. In detail, the K-wires can provide a provisional stability at an early stage. Intramedullary screws are strong enough to provide the medial column stability as a definitive fixation. In future, this technique can be recommended for medial column fixation as a complement for holistic stability in high-energy valgus pilon fractures.
摘要：
背景：这项研究的目的是进行生物力学分析，以在基于病例的模型中比较外翻pilon骨折的不同内侧柱固定方式。
方法：基于断裂图，制作了48个外翻pilon骨折模型，并分为四组，它们具有不同的内侧柱固定方式：无固定（NF），K线（KW），髓内螺钉(IS),和锁定压缩板（LCP）。每组包含楔入和楔出子组。将每个样本固定在机器上之后，以每分钟一毫米的载荷速度施加逐渐增加的轴向压缩载荷。最大峰值力设定在1500N。产生载荷-位移曲线并计算轴向刚度。五种不同的200N载荷，400N,600N,800N,选择1000N进行分析。试样失效定义为超过3mm的所得载荷位移。
结果：对于楔形模型，IS组显示位移较少(p<0.001)，较高的轴向刚度（p<0.01），和比NF组更高的失效载荷(p<0.001)。Group-KW在200N的载荷下显示出可比的位移，400N和600N，具有Group-IS和Group-LCP。对于楔入模型，位移没有统计学差异，轴向刚度,在四组中观察到或负荷失效。总的来说,楔入模型的轴向刚度小于楔入模型（所有p<0.01）。
结论：内侧柱稳定固定的功能复位对于外翻pilon骨折的生物力学稳定性至关重要，内侧柱固定结合前外侧固定为此类骨折提供了足够的生物力学稳定性。详细来说,K线可以在早期提供暂时的稳定性。髓内螺钉足够坚固，可以作为确定的固定提供内侧柱的稳定性。在未来,该技术可推荐用于内侧柱固定，作为高能量外翻pilon骨折整体稳定性的补充。
方法：基于断裂图，制作了48个外翻pilon骨折模型，并分为四组，它们具有不同的内侧柱固定方式：无固定（NF），K线（KW），髓内螺钉(IS),和锁定压缩板（LCP）。每组包含楔入和楔出子组。将每个样本固定在机器上之后，以每分钟一毫米的载荷速度施加逐渐增加的轴向压缩载荷。最大峰值力设定在1500N。产生载荷-位移曲线并计算轴向刚度。五种不同的200N载荷，400N,600N,800N,选择1000N进行分析。试样失效定义为超过3mm的所得载荷位移。
结果：对于楔形模型，IS组显示位移较少(p<0.001)，较高的轴向刚度（p<0.01），和比NF组更高的失效载荷(p<0.001)。Group-KW在200N的载荷下显示出可比的位移，400N和600N，具有Group-IS和Group-LCP。对于楔入模型，位移没有统计学差异，轴向刚度,在四组中观察到或负荷失效。总的来说,楔入模型的轴向刚度小于楔入模型（所有p<0.01）。
结论：内侧柱稳定固定的功能复位对于外翻pilon骨折的生物力学稳定性至关重要，内侧柱固定结合前外侧固定为此类骨折提供了足够的生物力学稳定性。详细来说,K线可以在早期提供暂时的稳定性。髓内螺钉足够坚固，可以作为确定的固定提供内侧柱的稳定性。在未来,该技术可推荐用于内侧柱固定，作为高能量外翻pilon骨折整体稳定性的补充。
